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Nagoya K, Tsujimura T, Yoshihara M, Watanabe M, Magara J, Kawasaki K, Inoue M. Physiological analyses of swallowing changes due to chronic obstructive pulmonary disease in anesthetized male rats. Front Physiol 2024; 15:1445336. [PMID: 39170764 PMCID: PMC11337103 DOI: 10.3389/fphys.2024.1445336] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2024] [Accepted: 07/18/2024] [Indexed: 08/23/2024] Open
Abstract
Chronic obstructive pulmonary disease (COPD) was previously known as chronic bronchitis and emphysema. It has various main symptoms, such as dyspnea, chronic cough, and sputum, and is often accompanied by dysphagia. Although many published clinical reports have described COPD-related dysphagia, the physiological mechanisms underlying swallowing changes due to COPD remain unclear. Therefore, we analyzed how COPD affects the swallowing reflex using COPD model rats. We performed an electrophysiological study of respiration and swallowing using COPD model induced by intratracheal administration of porcine pancreatic elastase and lipopolysaccharide in Sprague-Dawley male rats. To identify the respiration and swallowing responses, electromyographic activity was recorded from the diaphragm, digastric (Dig), and thyrohyoid (TH) muscles. We confirmed COPD using micro-computed tomography analysis and hematoxylin and eosin staining of the lungs. The duty cycle was defined as the ratio of the inspiration duration to the total respiratory duration. In COPD model rats, the duty cycle was significantly higher than that in control rats. The frequency of the swallowing reflex evoked by electrical stimulation of the superior laryngeal nerve during the inspiration phase was higher in COPD model rats than in control rats. Furthermore, long-term COPD altered Dig and TH muscle activity without pathological muscle change. Our results suggest that COPD increases the frequency of swallowing initiation during the inspiration phase. Furthermore, long-term COPD affects swallowing-related muscle activity without pathological muscle changes. These physiological changes may increase the risk of developing dysphagia. Further studies are necessary to clarify the mechanisms contributing to the functional changes in respiration and swallowing in COPD.
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Affiliation(s)
- Kouta Nagoya
- Division of Oral Functional Rehabilitation Medicine, Department of Oral Health Management, Showa University School of Dentistry, Tokyo, Japan
- Division of Dysphagia Rehabilitation, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Takanori Tsujimura
- Division of Dysphagia Rehabilitation, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Midori Yoshihara
- Division of Dysphagia Rehabilitation, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Masahiro Watanabe
- Department of Hygiene and Oral Health, Showa University School of Dentistry, Tokyo, Japan
| | - Jin Magara
- Division of Dysphagia Rehabilitation, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Katsushige Kawasaki
- Division of Oral Anatomy, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Makoto Inoue
- Division of Dysphagia Rehabilitation, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
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Yoshida T, Yagi N, Ogawa T, Nakanome A, Ohkoshi A, Katori Y, Oku Y. Breathing-Swallowing discoordination after definitive chemoradiotherapy for head and neck cancers is associated with aspiration pneumonia. PLoS One 2024; 19:e0305560. [PMID: 38990865 PMCID: PMC11238977 DOI: 10.1371/journal.pone.0305560] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Accepted: 05/31/2024] [Indexed: 07/13/2024] Open
Abstract
PURPOSE Swallowing dysfunction and the risk of aspiration pneumonia are frequent clinical problems in the treatment of head and neck squamous cell carcinomas (HNSCCs). Breathing-swallowing coordination is an important factor in evaluating the risk of aspiration pneumonia. To investigate breathing-swallowing discoordination after chemoradiotherapy (CRT), we monitored respiration and swallowing activity before and after CRT in patients with HNSCCs. METHODS Non-invasive swallowing monitoring was prospectively performed in 25 patients with HNSCCs treated with CRT and grade 1 or lower radiation-induced dermatitis. Videoendoscopy, videofluoroscopy, Food Intake LEVEL Scale, and patient-reported swallowing difficulties were assessed. RESULTS Of the 25 patients selected for this study, four dropped out due to radiation-induced dermatitis. The remaining 21 patients were analyzed using a monitoring system before and after CRT. For each of the 21 patients, 405 swallows were analyzed. Swallowing latency and pause duration after the CRT were significantly extended compared to those before the CRT. In the analysis of each swallowing pattern, swallowing immediately followed by inspiration (SW-I pattern), reflecting breathing-swallowing discoordination, was observed more frequently after CRT (p = 0.0001). In 11 patients, the SW-I pattern was observed more frequently compared to that before the CRT (p = 0.00139). One patient developed aspiration pneumonia at 12 and 23 months after the CRT. CONCLUSION The results of this preliminary study indicate that breathing-swallowing discoordination tends to increase after CRT and could be involved in aspiration pneumonia. This non-invasive method may be useful for screening swallowing dysfunction and its potential risks.
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Affiliation(s)
- Takuya Yoshida
- Department of Otolaryngology, Iwate Prefectural Iwai Hospital, Ichinoseki, Iwate, Japan
- Department of Otolaryngology-Head and Neck Surgery, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan
| | - Naomi Yagi
- Advanced Medical Engineering Research Institute, University of Hyogo, Himeji, Hyogo, Japan
| | - Takenori Ogawa
- Department of Otolaryngology, Gifu University Graduate School of Medicine, Gifu, Japan
| | - Ayako Nakanome
- Department of Otolaryngology-Head and Neck Surgery, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan
| | - Akira Ohkoshi
- Department of Otolaryngology-Head and Neck Surgery, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan
| | - Yukio Katori
- Department of Otolaryngology-Head and Neck Surgery, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan
| | - Yoshitaka Oku
- Department of Physiology, Hyogo College of Medicine, Nishinomiya, Hyogo, Japan
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Fogarty MJ. Dendritic morphology of motor neurons and interneurons within the compact, semicompact, and loose formations of the rat nucleus ambiguus. Front Cell Neurosci 2024; 18:1409974. [PMID: 38933178 PMCID: PMC11199410 DOI: 10.3389/fncel.2024.1409974] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2024] [Accepted: 05/27/2024] [Indexed: 06/28/2024] Open
Abstract
Introduction Motor neurons (MNs) within the nucleus ambiguus innervate the skeletal muscles of the larynx, pharynx, and oesophagus. These muscles are activated during vocalisation and swallowing and must be coordinated with several respiratory and other behaviours. Despite many studies evaluating the projections and orientation of MNs within the nucleus ambiguus, there is no quantitative information regarding the dendritic arbours of MNs residing in the compact, and semicompact/loose formations of the nucleus ambiguus.. Methods In female and male Fischer 344 rats, we evaluated MN number using Nissl staining, and MN and non-MN dendritic morphology using Golgi-Cox impregnation Brightfield imaging of transverse Nissl sections (15 μm) were taken to stereologically assess the number of nucleus ambiguus MNs within the compact and semicompact/loose formations. Pseudo-confocal imaging of Golgi-impregnated neurons within the nucleus ambiguus (sectioned transversely at 180 μm) was traced in 3D to determine dendritic arbourisation. Results We found a greater abundance of MNs within the compact than the semicompact/loose formations. Dendritic lengths, complexity, and convex hull surface areas were greatest in MNs of the semicompact/loose formation, with compact formation MNs being smaller. MNs from both regions were larger than non-MNs reconstructed within the nucleus ambiguus. Conclusion Adding HBLS to the diet could be a potentially effective strategy to improve horses' health.
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Affiliation(s)
- Matthew J. Fogarty
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN, United States
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Frazure M, Morimoto I, Fielder N, Mellen N, Iceman K, Pitts T. Serotonin therapies for opioid-induced disordered swallow and respiratory depression. J Appl Physiol (1985) 2024; 136:821-843. [PMID: 38385184 DOI: 10.1152/japplphysiol.00509.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Revised: 02/13/2024] [Accepted: 02/19/2024] [Indexed: 02/23/2024] Open
Abstract
Opioids are well-known to cause respiratory depression, but despite clinical evidence of dysphagia, the effects of opioids on swallow excitability and motor pattern are unknown. We tested the effects of the clinically relevant opioid buprenorphine on pharyngeal swallow and respiratory drive in male and female rats. We also evaluated the utility of 5-HT1A agonists (8-OH-DPAT and buspirone) to improve swallowing and breathing following buprenorphine administration. Experiments were performed on 44 freely breathing Sprague-Dawley rats anesthetized with sodium pentobarbital. Bipolar fine wire electrodes were inserted into the mylohyoid, thyroarytenoid, posterior cricoarytenoid, thyropharyngeus, and diaphragm muscles to measure electromyographic (EMG) activity of swallowing and breathing. We evaluated the hypotheses that swallowing varies by stimulus, opioids depress swallowing and breathing, and that 5-HT1A agonists improve these depressions. Our results largely confirmed the following hypotheses: 1) swallow-related EMG activity was larger during swallows elicited by esophageal distension plus oral water infusion than by either stimulus alone. 2) Buprenorphine depressed swallow in both sexes, but females were more susceptible to total swallow suppression. 3) Female animals were also more vulnerable to opioid-induced respiratory depression. 4) 8-OH-DPAT rescued breathing following buprenorphine-induced respiratory arrest, and pretreatment with the partial 5-HT1A agonist buspirone prevented buprenorphine-induced respiratory arrest in female animals. 5) 8-OH-DPAT enhanced mylohyoid and thyropharyngeus EMG amplitude during swallow but did not restore excitability of the swallow pattern generator following total suppression by buprenorphine. Our results highlight sex-specific and behavior-specific effects of buprenorphine and provide preclinical evidence of a 5HT1A agonist for the treatment of respiratory depression and dysphagia.NEW & NOTEWORTHY This is the first study, to our knowledge, to evaluate sex-specific effects of opioid administration on pharyngeal swallow. We expand on a small but growing number of studies that report a lower threshold for opioid-induced respiratory depression in females compared with males, and we are the first to produce this effect with the partial μ-opioid-receptor agonist buprenorphine. This is the first demonstration, to our knowledge, that activation of 5-HT1A receptors can improve swallow and breathing outcomes following systemic buprenorphine administration.
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Affiliation(s)
- Michael Frazure
- Department of Physiology, School of Medicine, University of Louisville, Louisville, Kentucky, United States
| | - In Morimoto
- Department of Mechanical and Intelligent Systems Engineering, The University of Electro-Communications, Tokyo, Japan
| | - Nathan Fielder
- School of Medicine, University of Louisville, Louisville, Kentucky, United States
| | - Nicholas Mellen
- Department of Neurology, School of Medicine, University of Louisville, Louisville, Kentucky, United States
| | - Kimberly Iceman
- Department of Speech, Language, and Hearing Sciences and Dalton Cardiovascular Center, University of Missouri, Columbia, Missouri, United States
| | - Teresa Pitts
- Department of Speech, Language, and Hearing Sciences and Dalton Cardiovascular Center, University of Missouri, Columbia, Missouri, United States
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Poliacek I, Martvon L, Simera M, Veternik M, Misek J, Cibulkova L, Iceman KE, Bolser DC, Pitts T. Cough and swallow after laparotomy in anesthetized cats. Respir Physiol Neurobiol 2024; 319:104179. [PMID: 37858661 DOI: 10.1016/j.resp.2023.104179] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Revised: 10/02/2023] [Accepted: 10/14/2023] [Indexed: 10/21/2023]
Abstract
An anesthetized cat animal model was used to evaluate changes in cough and swallow after a small midline upper abdominal incision (laparotomy). Two additional conditions were tested: sealing the laparotomy with gentle suctioning via a small cannula, and subsequent closure of the abdominal wall with suture. These abdominal wall manipulations resulted in no changes in the cough reflex, but produced higher motor drive to pharyngeal musculature (thyropharyngeus and geniohyoid muscles) during swallow. Swallow-breathing coordination phase preference shifted towards swallow occurring more during the inspiratory phase. There were no significant changes in cough motor pattern, or cough and swallow number and temporal features. The respiratory changes were limited to reduced inspiratory motor drive to the diaphragm. The results are consistent with an important role of sensory feedback from the abdominal wall in regulation of swallow motor pattern. The level of reflex modulation may depend on the extent of injury and likely on its position in the abdomen.
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Affiliation(s)
- Ivan Poliacek
- Comenius University in Bratislava, Jessenius Faculty of Medicine in Martin, Institute of Medical Biophysics, Mala Hora 4, 03601 Martin, Slovak Republic
| | - Lukas Martvon
- Comenius University in Bratislava, Jessenius Faculty of Medicine in Martin, Institute of Medical Biophysics, Mala Hora 4, 03601 Martin, Slovak Republic; Comenius University in Bratislava, Jessenius Faculty of Medicine in Martin, Medical Education Support Center, Martin, Slovak Republic.
| | - Michal Simera
- Comenius University in Bratislava, Jessenius Faculty of Medicine in Martin, Institute of Medical Biophysics, Mala Hora 4, 03601 Martin, Slovak Republic
| | - Marcel Veternik
- Comenius University in Bratislava, Jessenius Faculty of Medicine in Martin, Institute of Medical Biophysics, Mala Hora 4, 03601 Martin, Slovak Republic
| | - Jakub Misek
- Comenius University in Bratislava, Jessenius Faculty of Medicine in Martin, Institute of Medical Biophysics, Mala Hora 4, 03601 Martin, Slovak Republic
| | - Lucia Cibulkova
- Comenius University in Bratislava, Jessenius Faculty of Medicine in Martin, Institute of Medical Biophysics, Mala Hora 4, 03601 Martin, Slovak Republic
| | - Kimberly E Iceman
- Department of Speech Language Hearing Sciences, Dalton Cardiovascular Center, University of Missouri, Columbia, MO, USA
| | - Donald C Bolser
- Dept. of Physiological Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL, USA
| | - Teresa Pitts
- Department of Speech Language Hearing Sciences, Dalton Cardiovascular Center, University of Missouri, Columbia, MO, USA
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6
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Gould FDH, Mayerl CJ, Adjerid K, Edmonds C, Charles N, Johnson M, German RZ. Impact of volume and rate of milk delivery on coordination of respiration and swallowing in infant pigs. JOURNAL OF EXPERIMENTAL ZOOLOGY. PART A, ECOLOGICAL AND INTEGRATIVE PHYSIOLOGY 2023; 339:1052-1058. [PMID: 37653670 PMCID: PMC11321598 DOI: 10.1002/jez.2754] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Revised: 08/17/2023] [Accepted: 08/21/2023] [Indexed: 09/02/2023]
Abstract
The coordination of respiration and swallowing is a life-critical function in infants. Varying volume and rate of milk delivery changes swallowing frequency and bolus volume but any impact on swallow-respiration coordination is unknown. Five infant pigs were filmed with simultaneous high speed videofluoroscopy and plethysmography while feeding from an automatic system delivering milk across a range of volumes and frequencies. Swallow inspiration delay, respiratory cycle duration, and distribution of inspiratory and expiratory swallows were calculated. At constant volume, there were more inspiratory phase swallows when frequency increased. At high constant frequency, increasing volume changed swallow-respiration coordination patterns, with increased occurrence of inspiratory phase swallows. Respiratory cycle duration did not change in response to changes in oral milk delivery. These results suggest that the observed pattern of expiratory swallowing in infants is achieved primarily by regulation of milk intake, not modulation of respiratory patterns by oral sensation.
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Affiliation(s)
- Francois D. H. Gould
- Cell Biology and Neuroscience, Rowan School of Osteopathic Medicine, Stratford, New Jersey, USA
| | | | - Khaled Adjerid
- Biomedical Engineering, Tulane University, New Orleans, Los Angeles, USA
| | - Chloe Edmonds
- Anatomy and Neuroscience, Northeast Ohio Medical University, Rootstown, Ohio, USA
| | - Nicole Charles
- Cell Biology and Neuroscience, Rowan School of Osteopathic Medicine, Stratford, New Jersey, USA
| | - Maxwell Johnson
- Anatomy and Neuroscience, Northeast Ohio Medical University, Rootstown, Ohio, USA
| | - Rebecca Z. German
- Anatomy and Neuroscience, Northeast Ohio Medical University, Rootstown, Ohio, USA
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7
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Huff A, Karlen-Amarante M, Oliveira LM, Ramirez JM. Role of the postinspiratory complex in regulating swallow-breathing coordination and other laryngeal behaviors. eLife 2023; 12:e86103. [PMID: 37272425 PMCID: PMC10264072 DOI: 10.7554/elife.86103] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Accepted: 06/01/2023] [Indexed: 06/06/2023] Open
Abstract
Breathing needs to be tightly coordinated with upper airway behaviors, such as swallowing. Discoordination leads to aspiration pneumonia, the leading cause of death in neurodegenerative disease. Here, we study the role of the postinspiratory complex (PiCo) in coordinating breathing and swallowing. Using optogenetic approaches in freely breathing anesthetized ChATcre:Ai32, Vglut2cre:Ai32 and intersectional recombination of ChATcre:Vglut2FlpO:ChR2 mice reveals PiCo mediates airway protective behaviors. Activation of PiCo during inspiration or the beginning of postinspiration triggers swallow behavior in an all-or-nothing manner, while there is a higher probability for stimulating only laryngeal activation when activated further into expiration. Laryngeal activation is dependent on stimulation duration. Sufficient bilateral PiCo activation is necessary for preserving the physiological swallow motor sequence since activation of only a few PiCo neurons or unilateral activation leads to blurred upper airway behavioral responses. We believe PiCo acts as an interface between the swallow pattern generator and the preBötzinger complex to coordinate swallow and breathing. Investigating PiCo's role in swallow and laryngeal coordination will aid in understanding discoordination with breathing in neurological diseases.
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Affiliation(s)
- Alyssa Huff
- Center for Integrative Brain Research, Seattle Children’s Research InstituteSeattleUnited States
| | - Marlusa Karlen-Amarante
- Center for Integrative Brain Research, Seattle Children’s Research InstituteSeattleUnited States
| | - Luiz M Oliveira
- Center for Integrative Brain Research, Seattle Children’s Research InstituteSeattleUnited States
| | - Jan-Marino Ramirez
- Center for Integrative Brain Research, Seattle Children’s Research InstituteSeattleUnited States
- Department of Neurological Surgery, University of Washington School of MedicineSeattleUnited States
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Oku Y. Swallowing disorder - a possible therapeutic target for preventing COPD exacerbations. Respir Physiol Neurobiol 2023; 313:104061. [PMID: 37059160 DOI: 10.1016/j.resp.2023.104061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Revised: 04/04/2023] [Accepted: 04/10/2023] [Indexed: 04/16/2023]
Abstract
Dysphagia is a common comorbidity of chronic obstructive pulmonary disease (COPD). In this review article, we show that swallowing disorder can be detected at its early stage as a manifestation of breathing-swallowing discoordination. Furthermore, we provide evidence that low-pressure continuous airway pressure (CPAP) and transcutaneous electrical sensory stimulation using interferential current (IFC-TESS) counteract swallowing disorders and may reduce exacerbations in patients with COPD. Our first prospective study showed that inspiration immediately before or after swallowing is associated with COPD exacerbation. However, the inspiration before swallowing (I-SW) pattern could be interpreted as an airway-protecting behavior. Indeed, the second prospective study showed that the I-SW pattern is more frequently observed in patients who did not experience exacerbations. As potential therapeutic candidates, CPAP normalizes the timing of swallowing, and IFC-TESS applied to the neck acutely facilitates swallowing and chronically improves nutrition and airway protection. Further studies are necessary to elucidate whether such interventions reduce exacerbations in patients with COPD.
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Affiliation(s)
- Yoshitaka Oku
- Division of Physiome, Department of Physiology, Hyogo Medical University, Nishinomiya, Hyogo 663-8501, Japan.
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9
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Huff A, Karlen-Amarante M, Oliveira LM, Ramirez JM. Postinspiratory complex acts as a gating mechanism regulating swallow-breathing coordination and other laryngeal behaviors. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.18.524513. [PMID: 36712111 PMCID: PMC9882227 DOI: 10.1101/2023.01.18.524513] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Breathing needs to be tightly coordinated with upper airway behaviors, such as swallowing. Discoordination leads to aspiration pneumonia, the leading cause of death in neurodegenerative diseases. Here we study the role of the postinspiratory complex, (PiCo) in coordinating breathing and swallowing. Using optogenetic approaches in freely breathing-anesthetized ChATcre, Vglut2cre and co-transmission of ChATcre/Vglut2FlpO mice reveals this small brainstem microcircuit acts as a central gating mechanism for airway protective behaviors. Activation of PiCo during inspiration or the beginning of postinspiration triggers swallow behavior, while there is a higher probability for stimulating laryngeal activation when activated further into expiration, suggesting PiCo's role in swallow-breathing coordination. PiCo triggers consistent swallow behavior and preserves physiologic swallow motor sequence, while stimulates laryngeal activation variable to stimulation duration. Sufficient bilateral PiCo activation is necessary for gating function since activation of only a few PiCo neurons or unilateral activation leads to blurred behavioral response. Viral tracing experiments reveal projections from the caudal nucleus of the solitary tract (cNTS), the presumed swallow pattern generator (SPG), to PiCo and vice versa. However, PiCo does not directly connect to laryngeal muscles. Investigating PiCo's role in swallow and laryngeal coordination will aid in understanding discoordination in breathing and neurological diseases.
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Affiliation(s)
- Alyssa Huff
- Center for Integrative Brain Research, Seattle Children’s Research Institute, Seattle, WA, 98101
| | - Marlusa Karlen-Amarante
- Center for Integrative Brain Research, Seattle Children’s Research Institute, Seattle, WA, 98101
| | - Luiz Marcelo Oliveira
- Center for Integrative Brain Research, Seattle Children’s Research Institute, Seattle, WA, 98101
| | - Jan Marino Ramirez
- Center for Integrative Brain Research, Seattle Children’s Research Institute, Seattle, WA, 98101,Department of Neurological Surgery, University of Washington School of Medicine, Seattle, WA, USA, 98108
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Pitts T, Iceman KE. Deglutition and the Regulation of the Swallow Motor Pattern. Physiology (Bethesda) 2023; 38:0. [PMID: 35998250 PMCID: PMC9707372 DOI: 10.1152/physiol.00005.2021] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Revised: 08/19/2022] [Accepted: 08/19/2022] [Indexed: 11/22/2022] Open
Abstract
Despite centuries of investigation, questions and controversies remain regarding the fundamental genesis and motor pattern of swallow. Two significant topics include inspiratory muscle activity during swallow (Schluckatmung, i.e., "swallow-breath") and anatomical boundaries of the swallow pattern generator. We discuss the long history of reports regarding the presence or absence of Schluckatmung and the possible advantages of and neural basis for such activity, leading to current theories and novel experimental directions.
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Affiliation(s)
- Teresa Pitts
- Department of Neurological Surgery, Kentucky Spinal Cord Injury Research Center, University of Louisville, Louisville, Kentucky
| | - Kimberly E Iceman
- Department of Neurological Surgery, Kentucky Spinal Cord Injury Research Center, University of Louisville, Louisville, Kentucky
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11
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Kelley DB. Convergent and divergent neural circuit architectures that support acoustic communication. Front Neural Circuits 2022; 16:976789. [PMID: 36466364 PMCID: PMC9712726 DOI: 10.3389/fncir.2022.976789] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Accepted: 10/19/2022] [Indexed: 11/18/2022] Open
Abstract
Vocal communication is used across extant vertebrates, is evolutionarily ancient, and been maintained, in many lineages. Here I review the neural circuit architectures that support intraspecific acoustic signaling in representative anuran, mammalian and avian species as well as two invertebrates, fruit flies and Hawaiian crickets. I focus on hindbrain motor control motifs and their ties to respiratory circuits, expression of receptors for gonadal steroids in motor, sensory, and limbic neurons as well as divergent modalities that evoke vocal responses. Hindbrain and limbic participants in acoustic communication are highly conserved, while forebrain participants have diverged between anurans and mammals, as well as songbirds and rodents. I discuss the roles of natural and sexual selection in driving speciation, as well as exaptation of circuit elements with ancestral roles in respiration, for producing sounds and driving rhythmic vocal features. Recent technical advances in whole brain fMRI across species will enable real time imaging of acoustic signaling partners, tying auditory perception to vocal production.
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12
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Huff A, Karlen-Amarante M, Pitts T, Ramirez JM. Optogenetic stimulation of pre-Bötzinger complex reveals novel circuit interactions in swallowing-breathing coordination. Proc Natl Acad Sci U S A 2022; 119:e2121095119. [PMID: 35858334 PMCID: PMC9304034 DOI: 10.1073/pnas.2121095119] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Accepted: 05/31/2022] [Indexed: 02/02/2023] Open
Abstract
The coordination of swallowing with breathing, in particular inspiration, is essential for homeostasis in most organisms. While much has been learned about the neuronal network critical for inspiration in mammals, the pre-Bötzinger complex (preBötC), little is known about how this network interacts with swallowing. Here we activate within the preBötC excitatory neurons (defined as Vglut2 and Sst neurons) and inhibitory neurons (defined as Vgat neurons) and inhibit and activate neurons defined by the transcription factor Dbx1 to gain an understanding of the coordination between the preBötC and swallow behavior. We found that stimulating inhibitory preBötC neurons did not mimic the premature shutdown of inspiratory activity caused by water swallows, suggesting that swallow-induced suppression of inspiratory activity is not directly mediated by the inhibitory neurons in the preBötC. By contrast, stimulation of preBötC Dbx1 neurons delayed laryngeal closure of the swallow sequence. Inhibition of Dbx1 neurons increased laryngeal closure duration and stimulation of Sst neurons pushed swallow occurrence to later in the respiratory cycle, suggesting that excitatory neurons from the preBötC connect to the laryngeal motoneurons and contribute to the timing of swallowing. Interestingly, the delayed swallow sequence was also caused by chronic intermittent hypoxia (CIH), a model for sleep apnea, which is 1) known to destabilize inspiratory activity and 2) associated with dysphagia. This delay was not present when inhibiting Dbx1 neurons. We propose that a stable preBötC is essential for normal swallow pattern generation and disruption may contribute to the dysphagia seen in obstructive sleep apnea.
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Affiliation(s)
- Alyssa Huff
- Center for Integrative Brain Research, Seattle Children’s Research Institute, Seattle, WA 98101
| | - Marlusa Karlen-Amarante
- Center for Integrative Brain Research, Seattle Children’s Research Institute, Seattle, WA 98101
| | - Teresa Pitts
- Department of Neurological Surgery, School of Medicine, University of Louisville, Louisville, KY 40202
| | - Jan Marino Ramirez
- Center for Integrative Brain Research, Seattle Children’s Research Institute, Seattle, WA 98101
- Department of Neurological Surgery, School of Medicine, University of Washington, Seattle, WA 98108
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Hao N, Sasa A, Kulvanich S, Nakajima Y, Nagoya K, Magara J, Tsujimura T, Inoue M. Coordination of Respiration, Swallowing, and Chewing in Healthy Young Adults. Front Physiol 2021; 12:696071. [PMID: 34326780 PMCID: PMC8313873 DOI: 10.3389/fphys.2021.696071] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Accepted: 06/15/2021] [Indexed: 11/18/2022] Open
Abstract
Examining the coordination of respiration and swallowing is important for elucidating the mechanisms underlying these functions and assessing how respiration is linked to swallowing impairment in dysphagic patients. In this study, we assessed the coordination of respiration and swallowing to clarify how voluntary swallowing is coordinated with respiration and how mastication modulates the coordination of respiration and swallowing in healthy humans. Twenty-one healthy volunteers participated in three experiments. The participants were asked to swallow 3 ml of water with or without a cue, to drink 100 ml of water using a cup without breathing between swallows, and to eat a 4-g portion of corned beef. The major coordination pattern of respiration and swallowing was expiration–swallow–expiration (EE type) while swallowing 3 ml of water either with or without a cue, swallowing 100 ml of water, and chewing. Although cueing did not affect swallowing movements, the expiratory time was lengthened with the cue. During 100-ml water swallowing, the respiratory cycle time and expiratory time immediately before swallowing were significantly shorter compared with during and after swallowing, whereas the inspiratory time did not differ throughout the recording period. During chewing, the respiratory cycle time was decreased in a time-dependent manner, probably because of metabolic demand. The coordination of the two functions is maintained not only in voluntary swallowing but also in involuntary swallowing during chewing. Understanding the mechanisms underlying respiration and swallowing is important for evaluating how coordination affects physiological swallowing in dysphagic patients.
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Affiliation(s)
- Naohito Hao
- Division of Dysphagia Rehabilitation, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Anna Sasa
- Division of Dysphagia Rehabilitation, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Sirima Kulvanich
- Division of Dysphagia Rehabilitation, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Yuta Nakajima
- Division of Dysphagia Rehabilitation, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Kouta Nagoya
- Division of Dysphagia Rehabilitation, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Jin Magara
- Division of Dysphagia Rehabilitation, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Takanori Tsujimura
- Division of Dysphagia Rehabilitation, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Makoto Inoue
- Division of Dysphagia Rehabilitation, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
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14
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Simera M, Veternik M, Martvon L, Kotmanova Z, Mostafavi S, Bosko O, Kralikova O, Poliacek I. Distinct modulation of tracheal and laryngopharyngeal cough via superior laryngeal nerve in cat. Respir Physiol Neurobiol 2021; 293:103716. [PMID: 34119702 DOI: 10.1016/j.resp.2021.103716] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Revised: 06/08/2021] [Accepted: 06/08/2021] [Indexed: 11/26/2022]
Abstract
Unilateral and bilateral cooling and bilateral transsection of the superior laryngeal nerve (SLN) were employed to modulate mechanically induced tracheobronchial (TB) and laryngopharyngeal (LPh) cough in 12 anesthetized cats. There was little effect of SLN block or cut on TB. Bilateral SLN cooling reduced the number of LPh (<50 %, p < 0.05), amplitudes of diaphragm EMG activity (<55 %, p < 0.05), and cough expiratory efforts (<40 %, p < 0.01) during LPh. Effects after unilateral SLN cooling were less pronounced. Temporal analysis of LPh showed only shortening of diaphragm and abdominal muscles burst overlap in the inspiratory-expiratory transition after unilateral SLN cooling. Bilateral cooling reduced both expiratory phase and total cough cycle duration. There was no significant difference in the average effects of cooling left or right SLN on LPh or TB as well as no differences in contralateral and ipsilateral diaphragm and abdominal EMG amplitudes. Our results show that reduced afferent drive in the SLN markedly attenuates LPh with virtually no effect on TB.
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Affiliation(s)
- Michal Simera
- Institute of Medical Biophysics, Jessenius Faculty of Medicine in Martin, Comenius University in Bratislava, Malá Hora 4, 036 01 Martin, Slovak Republic.
| | - Marcel Veternik
- Institute of Medical Biophysics, Jessenius Faculty of Medicine in Martin, Comenius University in Bratislava, Malá Hora 4, 036 01 Martin, Slovak Republic
| | - Lukas Martvon
- Institute of Medical Biophysics, Jessenius Faculty of Medicine in Martin, Comenius University in Bratislava, Malá Hora 4, 036 01 Martin, Slovak Republic
| | - Zuzana Kotmanova
- Institute of Medical Biophysics, Jessenius Faculty of Medicine in Martin, Comenius University in Bratislava, Malá Hora 4, 036 01 Martin, Slovak Republic
| | - Soheil Mostafavi
- Institute of Medical Biophysics, Jessenius Faculty of Medicine in Martin, Comenius University in Bratislava, Malá Hora 4, 036 01 Martin, Slovak Republic
| | - Ondrej Bosko
- Institute of Medical Biophysics, Jessenius Faculty of Medicine in Martin, Comenius University in Bratislava, Malá Hora 4, 036 01 Martin, Slovak Republic
| | - Olga Kralikova
- Institute of Medical Biophysics, Jessenius Faculty of Medicine in Martin, Comenius University in Bratislava, Malá Hora 4, 036 01 Martin, Slovak Republic
| | - Ivan Poliacek
- Institute of Medical Biophysics, Jessenius Faculty of Medicine in Martin, Comenius University in Bratislava, Malá Hora 4, 036 01 Martin, Slovak Republic
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15
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Frazure ML, Brown AD, Greene CL, Iceman KE, Pitts T. Rapid activation of esophageal mechanoreceptors alters the pharyngeal phase of swallow: Evidence for inspiratory activity during swallow. PLoS One 2021; 16:e0248994. [PMID: 33798212 PMCID: PMC8018667 DOI: 10.1371/journal.pone.0248994] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Accepted: 03/09/2021] [Indexed: 11/17/2022] Open
Abstract
Swallow is a complex behavior that consists of three coordinated phases: oral, pharyngeal, and esophageal. Esophageal distension (EDist) has been shown to elicit pharyngeal swallow, but the physiologic characteristics of EDist-induced pharyngeal swallow have not been specifically described. We examined the effect of rapid EDist on oropharyngeal swallow, with and without an oral water stimulus, in spontaneously breathing, sodium pentobarbital anesthetized cats (n = 5). Electromyograms (EMGs) of activity of 8 muscles were used to evaluate swallow: mylohyoid (MyHy), geniohyoid (GeHy), thyrohyoid (ThHy), thyropharyngeus (ThPh), thyroarytenoid (ThAr), cricopharyngeus (upper esophageal sphincter: UES), parasternal (PS), and costal diaphragm (Dia). Swallow was defined as quiescence of the UES with overlapping upper airway activity, and it was analyzed across three stimulus conditions: 1) oropharyngeal water infusion only, 2) rapid esophageal distension (EDist) only, and 3) combined stimuli. Results show a significant effect of stimulus condition on swallow EMG amplitude of the mylohyoid, geniohyoid, thyroarytenoid, diaphragm, and UES muscles. Collectively, we found that, compared to rapid cervical esophageal distension alone, the stimulus condition of rapid distension combined with water infusion is correlated with increased laryngeal adductor and diaphragm swallow-related EMG activity (schluckatmung), and post-swallow UES recruitment. We hypothesize that these effects of upper esophageal distension activate the brainstem swallow network, and function to protect the airway through initiation and/or modulation of a pharyngeal swallow response.
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Affiliation(s)
- Michael L Frazure
- Department of Neurological Surgery and Kentucky Spinal Cord Injury Research Center, College of Medicine, University of Louisville, Louisville, Kentucky, United States of America.,Department of Physiology, University of Louisville, Louisville, Kentucky, United States of America
| | - Alyssa D Brown
- School of Medicine, University of Louisville, Louisville, Kentucky, United States of America.,Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine, Rochester, Minnesota, United States of America
| | - Clinton L Greene
- Department of Neurological Surgery and Kentucky Spinal Cord Injury Research Center, College of Medicine, University of Louisville, Louisville, Kentucky, United States of America
| | - Kimberly E Iceman
- Department of Neurological Surgery and Kentucky Spinal Cord Injury Research Center, College of Medicine, University of Louisville, Louisville, Kentucky, United States of America
| | - Teresa Pitts
- Department of Neurological Surgery and Kentucky Spinal Cord Injury Research Center, College of Medicine, University of Louisville, Louisville, Kentucky, United States of America
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16
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Trevizan-Baú P, Dhingra RR, Furuya WI, Stanić D, Mazzone SB, Dutschmann M. Forebrain projection neurons target functionally diverse respiratory control areas in the midbrain, pons, and medulla oblongata. J Comp Neurol 2020; 529:2243-2264. [PMID: 33340092 DOI: 10.1002/cne.25091] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Revised: 11/25/2020] [Accepted: 11/29/2020] [Indexed: 12/12/2022]
Abstract
Eupnea is generated by neural circuits located in the ponto-medullary brainstem, but can be modulated by higher brain inputs which contribute to volitional control of breathing and the expression of orofacial behaviors, such as vocalization, sniffing, coughing, and swallowing. Surprisingly, the anatomical organization of descending inputs that connect the forebrain with the brainstem respiratory network remains poorly defined. We hypothesized that descending forebrain projections target multiple distributed respiratory control nuclei across the neuroaxis. To test our hypothesis, we made discrete unilateral microinjections of the retrograde tracer cholera toxin subunit B in the midbrain periaqueductal gray (PAG), the pontine Kölliker-Fuse nucleus (KFn), the medullary Bötzinger complex (BötC), pre-BötC, or caudal midline raphé nuclei. We quantified the regional distribution of retrogradely labeled neurons in the forebrain 12-14 days postinjection. Overall, our data reveal that descending inputs from cortical areas predominantly target the PAG and KFn. Differential forebrain regions innervating the PAG (prefrontal, cingulate cortices, and lateral septum) and KFn (rhinal, piriform, and somatosensory cortices) imply that volitional motor commands for vocalization are specifically relayed via the PAG, while the KFn may receive commands to coordinate breathing with other orofacial behaviors (e.g., sniffing, swallowing). Additionally, we observed that the limbic or autonomic (interoceptive) systems are connected to broadly distributed downstream bulbar respiratory networks. Collectively, these data provide a neural substrate to explain how volitional, state-dependent, and emotional modulation of breathing is regulated by the forebrain.
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Affiliation(s)
- Pedro Trevizan-Baú
- The Florey Institute of Neuroscience and Mental Health, Discovery Neuroscience Theme, The University of Melbourne, Parkville, Victoria, Australia
| | - Rishi R Dhingra
- The Florey Institute of Neuroscience and Mental Health, Discovery Neuroscience Theme, The University of Melbourne, Parkville, Victoria, Australia
| | - Werner I Furuya
- The Florey Institute of Neuroscience and Mental Health, Discovery Neuroscience Theme, The University of Melbourne, Parkville, Victoria, Australia
| | - Davor Stanić
- The Florey Institute of Neuroscience and Mental Health, Discovery Neuroscience Theme, The University of Melbourne, Parkville, Victoria, Australia
| | - Stuart B Mazzone
- Department of Anatomy and Neuroscience, The University of Melbourne, Parkville, Victoria, Australia
| | - Mathias Dutschmann
- The Florey Institute of Neuroscience and Mental Health, Discovery Neuroscience Theme, The University of Melbourne, Parkville, Victoria, Australia
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17
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Dhingra RR, Furuya WI, Dick TE, Dutschmann M. Response to: The post-inspiratory complex (PiCo), what is the evidence? J Physiol 2020; 599:361-362. [PMID: 33197048 DOI: 10.1113/jp280958] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2020] [Accepted: 11/09/2020] [Indexed: 12/14/2022] Open
Affiliation(s)
- Rishi R Dhingra
- The Florey Institute of Neuroscience & Mental Health, University of Melbourne, 30 Royal Parade, Parkville, Victoria, Australia
| | - Werner I Furuya
- The Florey Institute of Neuroscience & Mental Health, University of Melbourne, 30 Royal Parade, Parkville, Victoria, Australia
| | - Thomas E Dick
- Division of Pulmonary, Critical Care and Sleep, Department of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio, USA
| | - Mathias Dutschmann
- The Florey Institute of Neuroscience & Mental Health, University of Melbourne, 30 Royal Parade, Parkville, Victoria, Australia
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18
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Gould FDH, Lammers AR, Mayerl C, Ohlemacher J, German RZ. Muscle activity and kinematics show different responses to recurrent laryngeal nerve lesion in mammal swallowing. J Neurophysiol 2020; 124:1743-1753. [PMID: 32966748 DOI: 10.1152/jn.00409.2020] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Understanding the interactions between neural and musculoskeletal systems is key to identifying mechanisms of functional failure. Mammalian swallowing is a complex, poorly understood motor process. Lesion of the recurrent laryngeal nerve, a sensory and motor nerve of the upper airway, results in airway protection failure (liquid entry into the airway) during swallowing through an unknown mechanism. We examined how muscle and kinematic changes after recurrent laryngeal nerve lesion relate to airway protection in eight infant pigs. We tested two hypotheses: 1) kinematics and muscle function will both change in response to lesion in swallows with and without airway protection failure, and 2) differences in both kinematics and muscle function will predict whether airway protection failure occurs in lesion and intact pigs. We recorded swallowing with high-speed videofluoroscopy and simultaneous electromyography of oropharyngeal muscles pre- and postrecurrent laryngeal nerve lesion. Lesion changed the relationship between airway protection and timing of tongue and hyoid movements. Changes in onset and duration of hyolaryngeal muscles postlesion were less associated with airway protection outcomes. The tongue and hyoid kinematics all predicted airway protection outcomes differently pre- and postlesion. Onset and duration of activity in only one infrahyoid and one suprahyoid muscle showed a change in predictive relationship pre- and postlesion. Kinematics of the tongue and hyoid more directly reflect changes in airway protections pre- and postlesion than muscle activation patterns. Identifying mechanisms of airway protection failure requires specific functional hypotheses that link neural motor outputs to muscle activation to specific movements.NEW & NOTEWORTHY Kinematic and muscle activity patterns of oropharyngeal structures used in swallowing show different patterns of response to lesion of the recurrent laryngeal nerve. Understanding how muscles act on structures to produce behavior is necessary to understand neural control.
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Affiliation(s)
- François D H Gould
- Department of Cell Biology and Neuroscience, Rowan School of Osteopathic Medicine, Stratford, New Jersey
| | | | - Christopher Mayerl
- Department of Anatomy and Neuroscience, Northeast Ohio Medical University, Rootstown, Ohio
| | - Jocelyn Ohlemacher
- Department of Anatomy and Neuroscience, Northeast Ohio Medical University, Rootstown, Ohio
| | - Rebecca Z German
- Department of Anatomy and Neuroscience, Northeast Ohio Medical University, Rootstown, Ohio
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19
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Quipazine Elicits Swallowing in the Arterially Perfused Rat Preparation: A Role for Medullary Raphe Nuclei? Int J Mol Sci 2020; 21:ijms21145120. [PMID: 32698469 PMCID: PMC7404031 DOI: 10.3390/ijms21145120] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Revised: 07/06/2020] [Accepted: 07/16/2020] [Indexed: 12/17/2022] Open
Abstract
Pharmacological neuromodulation of swallowing may represent a promising therapeutic option to treat dysphagia. Previous studies suggested a serotonergic control of swallowing, but mechanisms remain poorly understood. Here, we investigated the effects of the serotonergic agonist quipazine on swallowing, using the arterially perfused working heart-brainstem (in situ) preparation in rats. Systemic injection of quipazine produced single swallows with motor patterns and swallow-breathing coordination similar to spontaneous swallows, and increased swallow rate with moderate changes in cardiorespiratory functions. Methysergide, a 5-HT2 receptor antagonist, blocked the excitatory effect of quipazine on swallowing, but had no effect on spontaneous swallow rate. Microinjections of quipazine in the nucleus of the solitary tract were without effect. In contrast, similar injections in caudal medullary raphe nuclei increased swallow rate without changes in cardiorespiratory parameters. Thus, quipazine may exert an excitatory effect on raphe neurons via stimulation of 5-HT2A receptors, leading to increased excitability of the swallowing network. In conclusion, we suggest that pharmacological stimulation of swallowing by quipazine in situ represents a valuable model for experimental studies. This work paves the way for future investigations on brainstem serotonergic modulation, and further identification of neural populations and mechanisms involved in swallowing and/or swallow-breathing interaction.
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20
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Huff A, Reed MD, Iceman KE, Howland DR, Pitts T. Sex-specific vagal and spinal modulation of swallow and its coordination with breathing. PLoS One 2020; 15:e0234194. [PMID: 32525920 PMCID: PMC7289368 DOI: 10.1371/journal.pone.0234194] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Accepted: 05/20/2020] [Indexed: 12/18/2022] Open
Abstract
Swallow-breathing coordination is influenced by changes in lung volume, which is modulated by feedback from both vagal and spinal sensory afferents. The purpose of this study was to manipulate feedback from these afferents, with and without a simultaneous mechanical challenge (chest compression), in order to assess the influence of each sensory pathway on swallow in rats. We hypothesized that manipulation of afferent feedback would shift the occurrence of swallow toward the inspiratory phase of breathing. Afferent feedback was perturbed by lidocaine nebulization, extra-thoracic vagotomy, or lidocaine administration to the pleural space in sodium pentobarbital anesthetized rats (N = 43). These different afferent perturbations were performed both in control conditions (no chest compression), and with chest compression. Manipulating pulmonary stretch receptor-mediated volume feedback in male animals decreased swallow occurrence. Female rats appear to rely more on spinal afferent feedback, as swallow occurrence shifted to late expiration with chest compression and vagotomy or lidocaine injections. Results suggest that sex-specific mechanisms modulate swallow-breathing coordination, and that vagal feedback is inhibitory to swallow-related muscles, while spinal feedback from pleural afferents has excitatory effects. This study supports the theory that a balance of vagal and spinal afferent feedback is necessary to maintain an optimal swallow pattern and swallow-breathing coordination.
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Affiliation(s)
- Alyssa Huff
- Department of Physiology, University of Louisville, Louisville, Kentucky, United States of America
- Department of Neurological Surgery, Kentucky Spinal Cord Injury Research Center, University of Louisville, Louisville, Kentucky, United States of America
| | - Mitchell D. Reed
- Department of Neurological Surgery, Kentucky Spinal Cord Injury Research Center, University of Louisville, Louisville, Kentucky, United States of America
| | - Kimberly E. Iceman
- Department of Neurological Surgery, Kentucky Spinal Cord Injury Research Center, University of Louisville, Louisville, Kentucky, United States of America
| | - Dena R. Howland
- Department of Neurological Surgery, Kentucky Spinal Cord Injury Research Center, University of Louisville, Louisville, Kentucky, United States of America
- Research Service, Robley Rex Veterans Affairs Medical Center, Louisville, Kentucky, United States of America
| | - Teresa Pitts
- Department of Neurological Surgery, Kentucky Spinal Cord Injury Research Center, University of Louisville, Louisville, Kentucky, United States of America
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21
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Fogarty MJ, Sieck GC. Spinal cord injury and diaphragm neuromotor control. Expert Rev Respir Med 2020; 14:453-464. [PMID: 32077350 PMCID: PMC7176525 DOI: 10.1080/17476348.2020.1732822] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Accepted: 02/18/2020] [Indexed: 12/22/2022]
Abstract
Introduction: Neuromotor control of diaphragm muscle and the recovery of diaphragm activity following spinal cord injury have been narrowly focused on ventilation. By contrast, the understanding of neuromotor control for non-ventilatory expulsive/straining maneuvers (including coughing, defecation, and parturition) is relatively impoverished. This variety of behaviors are achieved via the recruitment of the diverse array of motor units that comprise the diaphragm muscle.Areas covered: The neuromotor control of ventilatory and non-ventilatory behaviors in health and in the context of spinal cord injury is explored. Particular attention is played to the neuroplasticity of phrenic motor neurons in various models of cervical spinal cord injury.Expert opinion: There is a remarkable paucity in our understanding of neuromotor control of maneuvers in spinal cord injury patients. Dysfunction of these expulsive/straining maneuvers reduces patient quality of life and contributes to severe morbidity and mortality. As spinal cord injury patient life expectancies continue to climb steadily, a nexus of spinal cord injury and age-associated comorbidities are likely to occur. While current research remains concerned only with the minutiae of ventilation, the major functional deficits of this clinical cohort will persist intractably. We posit some future research directions to avoid this scenario.
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Affiliation(s)
- Matthew J Fogarty
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN, 55905, USA
| | - Gary C Sieck
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN, 55905, USA
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22
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King SN, Shen TY, Musselwhite MN, Huff A, Reed MD, Poliacek I, Howland DR, Dixon W, Morris KF, Bolser DC, Iceman KE, Pitts T. Swallow Motor Pattern Is Modulated by Fixed or Stochastic Alterations in Afferent Feedback. Front Hum Neurosci 2020; 14:112. [PMID: 32327986 PMCID: PMC7160698 DOI: 10.3389/fnhum.2020.00112] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Accepted: 03/12/2020] [Indexed: 11/30/2022] Open
Abstract
Afferent feedback can appreciably alter the pharyngeal phase of swallow. In order to measure the stability of the swallow motor pattern during several types of alterations in afferent feedback, we assessed swallow during a conventional water challenge in four anesthetized cats, and compared that to swallows induced by fixed (20 Hz) and stochastic (1-20Hz) electrical stimulation applied to the superior laryngeal nerve. The swallow motor patterns were evaluated by electromyographic activity (EMG) of eight muscles, based on their functional significance: laryngeal elevators (mylohyoid, geniohyoid, and thyrohyoid); laryngeal adductor (thyroarytenoid); inferior pharyngeal constrictor (thyropharyngeus); upper esophageal sphincter (cricopharyngeus); and inspiratory activity (parasternal and costal diaphragm). Both the fixed and stochastic electrical stimulation paradigms increased activity of the laryngeal elevators, produced short-term facilitation evidenced by increasing swallow durations over the stimulus period, and conversely inhibited swallow-related diaphragm activity. Both the fixed and stochastic stimulus conditions also increased specific EMG amplitudes, which never occurred with the water challenges. Stochastic stimulation increased swallow excitability, as measured by an increase in the number of swallows produced. Consistent with our previous results, changes in the swallow motor pattern for pairs of muscles were only sometimes correlated with each other. We conclude that alterations in afferent feedback produced particular variations of the swallow motor pattern. We hypothesize that specific SLN feedback might modulate the swallow central pattern generator during aberrant feeding conditions (food/liquid entering the airway), which may protect the airway and serve as potentially important clinical diagnostic indicators.
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Affiliation(s)
- Suzanne N King
- Department of Otolaryngology-Head and Neck Surgery, University of Louisville, Louisville, KY, United States.,Kentucky Spinal Cord Injury Research Center, University of Louisville, Louisville, KY, United States
| | - Tabitha Y Shen
- Department of Physiological Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL, United States
| | - M Nicholas Musselwhite
- Department of Physiological Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL, United States
| | - Alyssa Huff
- Kentucky Spinal Cord Injury Research Center, University of Louisville, Louisville, KY, United States.,Department of Neurological Surgery, School of Medicine, University of Louisville, Louisville, KY, United States
| | - Mitchell D Reed
- Kentucky Spinal Cord Injury Research Center, University of Louisville, Louisville, KY, United States.,Department of Neurological Surgery, School of Medicine, University of Louisville, Louisville, KY, United States
| | - Ivan Poliacek
- Department of Physiological Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL, United States.,Department of Medical Biophysics, Jessenius Faculty of Medicine, Comenius University, Bratislava, Slovakia
| | - Dena R Howland
- Kentucky Spinal Cord Injury Research Center, University of Louisville, Louisville, KY, United States.,Department of Neurological Surgery, School of Medicine, University of Louisville, Louisville, KY, United States.,Robley Rex VA Medical Center, Louisville, KY, United States
| | - Warren Dixon
- Department of Mechanical and Aerospace Engineering, Herbert Wertheim College of Engineering, University of Florida, Gainesville, FL, United States
| | - Kendall F Morris
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, FL, United States
| | - Donald C Bolser
- Department of Physiological Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL, United States
| | - Kimberly E Iceman
- Kentucky Spinal Cord Injury Research Center, University of Louisville, Louisville, KY, United States.,Department of Neurological Surgery, School of Medicine, University of Louisville, Louisville, KY, United States
| | - Teresa Pitts
- Kentucky Spinal Cord Injury Research Center, University of Louisville, Louisville, KY, United States.,Department of Neurological Surgery, School of Medicine, University of Louisville, Louisville, KY, United States
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23
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Bond LE, Mayerl CJ, Stricklen BM, German RZ, Gould FDH. Changes in the coordination between respiration and swallowing from suckling through weaning. Biol Lett 2020; 16:20190942. [PMID: 32264794 DOI: 10.1098/rsbl.2019.0942] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
All mammals undergo weaning from milk to solid food. This process requires substantial changes to mammalian oropharyngeal function. The coordination of swallowing and respiration is a crucial component of maintaining airway function throughout feeding and matures over infant development. However, how this coordination is affected by weaning is unknown. In this study, we ask how changes in posture, neural maturation and food properties associated with the weaning affect coordination of respiration and swallowing in a validated infant pig model. We recorded seven piglets feeding before and during the weaning age with liquid milk in a bottle and in a bowl, and solid feed in a bowl. Using videofluoroscopy synchronized with respiration, we found (i) the delay in the onset of inspiration after swallowing does not change with head position, (ii) the delay is different between solid food and bowl drinking at the same age and (iii) the delay increases over time when bottle feeding, suggesting a maturational effect. Significant changes in aerodigestive coordination occur prior to and post-weaning, resulting in distinctive patterns for liquid and solid food. The interplay of maturational timelines of oropharyngeal function at weaning may serve as a locus for behavioural and life-history plasticity.
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Affiliation(s)
- Laura E Bond
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University (NEOMED), Rootstown, OH, USA
| | - Christopher J Mayerl
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University (NEOMED), Rootstown, OH, USA
| | - Bethany M Stricklen
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University (NEOMED), Rootstown, OH, USA
| | - Rebecca Z German
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University (NEOMED), Rootstown, OH, USA
| | - Francois D H Gould
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University (NEOMED), Rootstown, OH, USA.,Department of Cell Biology and Neuroscience, Rowan School of Osteopathic Medicine, Stratford, NJ, USA
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24
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Oku Y. Coordination of Swallowing and Breathing: How Is the Respiratory Control System Connected to the Swallowing System? STRUCTURE-FUNCTION RELATIONSHIPS IN VARIOUS RESPIRATORY SYSTEMS 2020. [DOI: 10.1007/978-981-15-5596-1_3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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25
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Schöneich S, Hedwig B. Feedforward discharges couple the singing central pattern generator and ventilation central pattern generator in the cricket abdominal central nervous system. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2019; 205:881-895. [PMID: 31691096 PMCID: PMC6863954 DOI: 10.1007/s00359-019-01377-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Revised: 10/19/2019] [Accepted: 10/24/2019] [Indexed: 12/28/2022]
Abstract
We investigated the central nervous coordination between singing motor activity and abdominal ventilatory pumping in crickets. Fictive singing, with sensory feedback removed, was elicited by eserine-microinjection into the brain, and the motor activity underlying singing and abdominal ventilation was recorded with extracellular electrodes. During singing, expiratory abdominal muscle activity is tightly phase coupled to the chirping pattern. Occasional temporary desynchronization of the two motor patterns indicate discrete central pattern generator (CPG) networks that can operate independently. Intracellular recordings revealed a sub-threshold depolarization in phase with the ventilatory cycle in a singing-CPG interneuron, and in a ventilation-CPG interneuron an excitatory input in phase with each syllable of the chirps. Inhibitory synaptic inputs coupled to the syllables of the singing motor pattern were present in another ventilatory interneuron, which is not part of the ventilation-CPG. Our recordings suggest that the two centrally generated motor patterns are coordinated by reciprocal feedforward discharges from the singing-CPG to the ventilation-CPG and vice versa. Consequently, expiratory contraction of the abdomen usually occurs in phase with the chirps and ventilation accelerates during singing due to entrainment by the faster chirp cycle.
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Affiliation(s)
- Stefan Schöneich
- Department of Zoology, University of Cambridge, Cambridge, UK
- Institute of Zoology and Evolutionary Research, Friedrich-Schiller-University Jena, Jena, Germany
| | - Berthold Hedwig
- Department of Zoology, University of Cambridge, Cambridge, UK.
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26
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Fuse S, Sugiyama Y, Dhingra RR, Hirano S, Dutschmann M, Oku Y. Effects of pharmacological lesion of the nucleus retroambiguus region on the pharyngeal phase of swallowing. Respir Physiol Neurobiol 2019; 268:103244. [PMID: 31226424 DOI: 10.1016/j.resp.2019.06.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Revised: 06/07/2019] [Accepted: 06/08/2019] [Indexed: 11/16/2022]
Abstract
Pharyngeal swallowing is controlled by synaptic interactions within a swallowing central pattern generator (sw-CPG) that is composed of a dorsal and a ventral swallowing group (VSG). Here, we used electrical stimulation (10 s) of the superior laryngeal nerve (SLN; 20 Hz; pulse width: 100 μs) to explore the role of the VSG in an arterially-perfused brainstem preparation of rats. To investigate the effects of pharmacological lesion (local microinjection of an GABA(A)-R agonist) of the nucleus retroambiguus (NRA), a designated component of the VSG, we recorded phrenic (PNA) and vagal nerve (VNA) activities. Control SLN stimulation with stepwise increasing stimulus intensities (from 20 μA to 160 μA) elicited robust suppression of PNA and evoked sequential swallowing activity in the VNA. Lesioning of the NRA had no effect on the pattern of pharyngeal swallowing, but significantly increased the sensory gating of SLN inputs. We conclude that the NRA is not part of the VSG, but appears to have important roles for the central gating of swallowing.
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Affiliation(s)
- S Fuse
- Department of Otolaryngology-Head and Neck Surgery, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Y Sugiyama
- Department of Otolaryngology-Head and Neck Surgery, Kyoto Prefectural University of Medicine, Kyoto, Japan.
| | - R R Dhingra
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, Victoria, Australia
| | - S Hirano
- Department of Otolaryngology-Head and Neck Surgery, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - M Dutschmann
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, Victoria, Australia.
| | - Y Oku
- Department of Physiology, Hyogo College of Medicine, Hyogo, Japan
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27
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Revill AL, Chu NY, Ma L, LeBlancq MJ, Dickson CT, Funk GD. Postnatal development of persistent inward currents in rat XII motoneurons and their modulation by serotonin, muscarine and noradrenaline. J Physiol 2019; 597:3183-3201. [PMID: 31038198 DOI: 10.1113/jp277572] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Accepted: 04/23/2019] [Indexed: 01/04/2023] Open
Abstract
KEY POINTS Persistent inward currents (PICs) in spinal motoneurons are long-lasting, voltage-dependent currents that increase excitability; they are dramatically potentiated by serotonin, muscarine, and noradrenaline (norepinephrine). Loss of these modulators (and the PIC) during sleep is hypothesized as a major contributor to REM sleep atonia. Reduced excitability of XII motoneurons that drive airway muscles and maintain airway patency is causally implicated in obstructive sleep apnoea (OSA), but whether XII motoneurons possess a modulator-sensitive PIC that could be a factor in the reduced airway tone of sleep is unknown. Whole-cell recordings from rat XII motoneurons in brain slices indicate that PIC amplitude increases ∼50% between 1 and 23 days of age, when potentiation of the PIC by 5HT2 , muscarinic, or α1 noradrenergic agonists peaks at <50%, manyfold lower than the potentiation observed in spinal motoneurons. α1 noradrenergic receptor activation produced changes in XII motoneuron firing behaviour consistent with PIC involvement, but indicators of strong PIC activation were never observed; in vivo experiments are needed to determine the role of the modulator-sensitive PIC in sleep-dependent reductions in airway tone. ABSTRACT Hypoglossal (XII) motoneurons play a key role in maintaining airway patency; reductions in their excitability during sleep through inhibition and disfacilitation, i.e. loss of excitatory modulation, is implicated in obstructive sleep apnoea. In spinal motoneurons, 5HT2 , muscarinic and α1 noradrenergic modulatory systems potentiate persistent inward currents (PICs) severalfold, dramatically increasing excitability. If the PICs in XII and spinal motoneurons are equally sensitive to modulation, loss of the PIC secondary to reduced modulatory tone during sleep could contribute to airway atonia. Modulatory systems also change developmentally. We therefore characterized developmental changes in magnitude of the XII motoneuron PIC and its sensitivity to modulation by comparing, in neonatal (P1-4) and juvenile (P14-23) rat brainstem slices, the PIC elicited by slow voltage ramps in the absence and presence of agonists for 5HT2 , muscarinic, and α1 noradrenergic receptors. XII motoneuron PIC amplitude increased developmentally (from -195 ± 12 to -304 ± 19 pA). In neonatal XII motoneurons, the PIC was only potentiated by α1 receptor activation (5 ± 4%). In contrast, all modulators potentiated the juvenile XII motoneurons PIC (5HT2 , 5 ± 5%; muscarine, 22 ± 11%; α1 , 18 ± 5%). These data suggest that the influence of the PIC and its modulation on XII motoneuron excitability will increase with postnatal development. Notably, the modulator-induced potentiation of the PIC in XII motoneurons was dramatically smaller than the 2- to 6-fold potentiation reported for spinal motoneurons. In vivo measurements are required to determine if the modulator-sensitive, XII motoneuron PIC is an important factor in sleep-state dependent reductions in airway tone.
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Affiliation(s)
- Ann L Revill
- Department of Physiology, University of Alberta, Edmonton, AB, Canada.,Neuroscience and Mental Health Institute, University of Alberta, Edmonton, AB, Canada.,Women and Children's Health Research Institute, University of Alberta, Edmonton, AB, Canada
| | - Nathan Y Chu
- Department of Physiology, University of Alberta, Edmonton, AB, Canada.,Neuroscience and Mental Health Institute, University of Alberta, Edmonton, AB, Canada.,Women and Children's Health Research Institute, University of Alberta, Edmonton, AB, Canada
| | - Li Ma
- Department of Physiology, University of Alberta, Edmonton, AB, Canada.,Neuroscience and Mental Health Institute, University of Alberta, Edmonton, AB, Canada
| | | | - Clayton T Dickson
- Department of Physiology, University of Alberta, Edmonton, AB, Canada.,Neuroscience and Mental Health Institute, University of Alberta, Edmonton, AB, Canada.,Women and Children's Health Research Institute, University of Alberta, Edmonton, AB, Canada.,Department of Psychology, University of Alberta, Edmonton, AB, Canada
| | - Gregory D Funk
- Department of Physiology, University of Alberta, Edmonton, AB, Canada.,Neuroscience and Mental Health Institute, University of Alberta, Edmonton, AB, Canada.,Women and Children's Health Research Institute, University of Alberta, Edmonton, AB, Canada
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28
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Fogarty MJ, Sieck GC. Evolution and Functional Differentiation of the Diaphragm Muscle of Mammals. Compr Physiol 2019; 9:715-766. [PMID: 30873594 PMCID: PMC7082849 DOI: 10.1002/cphy.c180012] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Symmorphosis is a concept of economy of biological design, whereby structural properties are matched to functional demands. According to symmorphosis, biological structures are never over designed to exceed functional demands. Based on this concept, the evolution of the diaphragm muscle (DIAm) in mammals is a tale of two structures, a membrane that separates and partitions the primitive coelomic cavity into separate abdominal and thoracic cavities and a muscle that serves as a pump to generate intra-abdominal (Pab ) and intrathoracic (Pth ) pressures. The DIAm partition evolved in reptiles from folds of the pleural and peritoneal membranes that was driven by the biological advantage of separating organs in the larger coelomic cavity into separate thoracic and abdominal cavities, especially with the evolution of aspiration breathing. The DIAm pump evolved from the advantage afforded by more effective generation of both a negative Pth for ventilation of the lungs and a positive Pab for venous return of blood to the heart and expulsive behaviors such as airway clearance, defecation, micturition, and child birth. © 2019 American Physiological Society. Compr Physiol 9:715-766, 2019.
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Affiliation(s)
- Matthew J Fogarty
- Mayo Clinic, Department of Physiology & Biomedical Engineering, Rochester, Minnesota, USA
| | - Gary C Sieck
- Mayo Clinic, Department of Physiology & Biomedical Engineering, Rochester, Minnesota, USA
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29
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Ouahchi Y, Ben Salah N, Mjid M, Hedhli A, Abdelhedi N, Beji M, Toujani S, Verin E. Breathing pattern during sequential swallowing in healthy adult humans. J Appl Physiol (1985) 2018; 126:487-493. [PMID: 30412029 DOI: 10.1152/japplphysiol.00150.2018] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Sequential liquid swallowing is a common daily occurrence during which coordination of deglutition and breathing are highly regulated to avoid pulmonary aspiration and to maintain hematosis. We studied the effects of sequential water swallowing (SWS) at fixed swallowing rates and with regular succession of swallows on respiration in healthy subjects. Thirty-one normal adults (19 men, 12 women) with a mean age of 27.96 ± 3.68 yr were explored at rest and during SWS (at 12 and 24 swallows/min). Respiration was recorded by intranasal air pressure changes and timing of deglutition by an acoustic method. Oxygen saturation [arterial O2 saturation from pulse oximetry ( SpO2 )] was monitored with a finger probe. During SWS, we determined the respiratory phase (inspiration or expiration) before and after each ingestion cycle (IC; period of sustained apnea including 1 or more swallows). We also measured inspiratory time (TI), expiratory time (TE), respiratory cycle duration (TT), respiratory rate (RR) and SpO2 at rest and during SWS. We showed that respiration was interrupted by sequential swallows determining a succession of ICs that were often preceded and followed by expiration. During SWS, TI decreased and TE increased compared with rest ( P < 0.01). However, TT, RR, and SpO2 did not change. It seems that the preferential coupling of swallowing with expiration during SWS is favored by an increase in TE to ensure airway protection, although the repetitive swallows, RR, and SpO2 were not altered during SWS. These data may be useful to study the effects of aging and pathological conditions on swallowing and breathing coordination during SWS. NEW & NOTEWORTHY Sequential water swallowing induces ingestion cycles that are often preceded and followed by expiration. Moreover, inspiratory time decreases and expiratory time increases during sequential swallowing compared with rest without changes in ventilatory cycle duration, respiratory rate, and oxygen saturation.
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Affiliation(s)
- Yacine Ouahchi
- Pneumology Department (RU 12SP06), La Rabta Hospital, Faculty of Medicine of Tunis, University of Tunis El Manar , Tunis , Tunisia.,EA 3830, Research Group on Ventilatory Handicap, Rouen University , Rouen , France
| | - Nozha Ben Salah
- Pneumology Department (RU 12SP06), Mongi-Slim Hospital-La Marsa, Faculty of Medicine of Tunis, University of Tunis El Manar , Tunis , Tunisia
| | - Meriem Mjid
- Pneumology Department (RU 12SP06), La Rabta Hospital, Faculty of Medicine of Tunis, University of Tunis El Manar , Tunis , Tunisia
| | - Abir Hedhli
- Pneumology Department (RU 12SP06), La Rabta Hospital, Faculty of Medicine of Tunis, University of Tunis El Manar , Tunis , Tunisia
| | - Nour Abdelhedi
- Pneumology Department (RU 12SP06), La Rabta Hospital, Faculty of Medicine of Tunis, University of Tunis El Manar , Tunis , Tunisia
| | - Majed Beji
- Pneumology Department (RU 12SP06), La Rabta Hospital, Faculty of Medicine of Tunis, University of Tunis El Manar , Tunis , Tunisia
| | - Sonia Toujani
- Pneumology Department (RU 12SP06), La Rabta Hospital, Faculty of Medicine of Tunis, University of Tunis El Manar , Tunis , Tunisia
| | - Eric Verin
- EA 3830, Research Group on Ventilatory Handicap, Rouen University , Rouen , France.,Rouen University Hospital and EA 3830, Normandy University , Rouen , France
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30
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Horton KK, Segers LS, Nuding SC, O'Connor R, Alencar PA, Davenport PW, Bolser DC, Pitts T, Lindsey BG, Morris KF, Gestreau C. Central Respiration and Mechanical Ventilation in the Gating of Swallow With Breathing. Front Physiol 2018; 9:785. [PMID: 30013484 PMCID: PMC6036260 DOI: 10.3389/fphys.2018.00785] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Accepted: 06/05/2018] [Indexed: 11/13/2022] Open
Abstract
Swallow-breathing coordination safeguards the lower airways from tracheal aspiration of bolus material as it moves through the pharynx into the esophagus. Impaired movements of the shared muscles or structures of the aerodigestive tract, or disruptions in the interaction of brainstem swallow and respiratory central pattern generators (CPGs) result in dysphagia. To maximize lower airway protection these CPGs integrate respiratory rhythm generation signals and vagal afferent feedback to synchronize swallow with breathing. Despite extensive study, the roles of central respiratory activity and vagal feedback from the lungs as key elements for effective swallow-breathing coordination remain unclear. The effect of altered timing of bronchopulmonary vagal afferent input on swallows triggered during electrical stimulation of the superior laryngeal nerves or by injection of water into the pharyngeal cavity was studied in decerebrate, paralyzed, and artificially ventilated cats. We observed two types of single swallows that produced distinct effects on central respiratory-rhythm across all conditions: post-inspiratory type swallows disrupted central-inspiratory activity without affecting expiration, whereas expiratory type swallows prolonged expiration without affecting central-inspiratory activity. Repetitive swallows observed during apnea reset the E2 phase of central respiration and produced facilitation of swallow motor output nerve burst durations. Moreover, swallow initiation was negatively modulated by vagal feedback and was reset by lung inflation. Collectively, these findings support a novel model of reciprocal inhibition between the swallow CPG and inspiratory or expiratory cells of the respiratory CPG where lung distension and phases of central respiratory activity represent a dual peripheral and central gating mechanism of swallow-breathing coordination.
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Affiliation(s)
- Kofi-Kermit Horton
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, FL, United States
| | - Lauren S Segers
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, FL, United States
| | - Sarah C Nuding
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, FL, United States
| | - Russell O'Connor
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, FL, United States
| | - Pierina A Alencar
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, FL, United States
| | - Paul W Davenport
- Department of Physiological Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL, United States
| | - Donald C Bolser
- Department of Physiological Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL, United States
| | - Teresa Pitts
- Department of Neurological Surgery, Kentucky Spinal Cord Injury Research Center, University of Louisville, Louisville, KY, United States
| | - Bruce G Lindsey
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, FL, United States
| | - Kendall F Morris
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, FL, United States
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31
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Swallow-breathing coordination during incremental ascent to altitude. Respir Physiol Neurobiol 2018; 265:121-126. [PMID: 29920337 DOI: 10.1016/j.resp.2018.06.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2018] [Revised: 06/11/2018] [Accepted: 06/12/2018] [Indexed: 12/26/2022]
Abstract
Swallow and breathing are highly coordinated behaviors reliant on shared anatomical space and neural pathways. Incremental ascent to high altitudes results in hypoxia/hypocapnic conditions altering respiratory drive, however it is not known whether these changes also alter swallow. We examined the effect of incremental ascent (1045 m, 3440 m and 4371 m) on swallow motor pattern and swallow-breathing coordination in seven healthy adults. Submental surface electromyograms (sEMG) and spirometry were used to evaluate swallow triggered by saliva and water infusion. Swallow-breathing phase preference was different between swallows initiated by saliva versus water. With ascent, saliva swallows changed to a dominate pattern of occurrence during the transition from inspiration to expiration. Additionally, water swallows demonstrated a significant decrease in submental sEMG duration and a shift in submental activity to earlier in the apnea period, especially at 4371 m. Our results suggest that there are changes in swallow-breathing coordination and swallow production that likely increase airway protection with incremental ascent to high altitude. The adaptive changes in swallow were likely due to the exposure to hypoxia and hypocapnia, along with airway irritation.
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32
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Fogarty MJ, Mantilla CB, Sieck GC. Breathing: Motor Control of Diaphragm Muscle. Physiology (Bethesda) 2018; 33:113-126. [PMID: 29412056 PMCID: PMC5899234 DOI: 10.1152/physiol.00002.2018] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2018] [Accepted: 01/05/2018] [Indexed: 12/12/2022] Open
Abstract
Breathing occurs without thought but is controlled by a complex neural network with a final output of phrenic motor neurons activating diaphragm muscle fibers (i.e., motor units). This review considers diaphragm motor unit organization and how they are controlled during breathing as well as during expulsive behaviors.
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Affiliation(s)
- Matthew J Fogarty
- Department of Physiology and Biomedical Engineering, Mayo Clinic , Rochester, Minnesota
- School of Biomedical Sciences, The University of Queensland , Brisbane , Australia
| | - Carlos B Mantilla
- Department of Physiology and Biomedical Engineering, Mayo Clinic , Rochester, Minnesota
- Department of Anesthesiology and Perioperative Medicine, Mayo Clinic , Rochester, Minnesota
| | - Gary C Sieck
- Department of Physiology and Biomedical Engineering, Mayo Clinic , Rochester, Minnesota
- Department of Anesthesiology and Perioperative Medicine, Mayo Clinic , Rochester, Minnesota
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33
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Ouahchi Y, Duclos C, Marie JP, Verin E. Implication of the vagus nerve in breathing pattern during sequential swallowing in rats. Physiol Behav 2017; 179:434-441. [DOI: 10.1016/j.physbeh.2017.07.014] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Revised: 07/03/2017] [Accepted: 07/07/2017] [Indexed: 10/19/2022]
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34
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Feeding and Respiration. Dysphagia 2017. [DOI: 10.1007/174_2017_59] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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35
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Koizumi H, Nomura K, Ishihama K, Yamanishi T, Enomoto A, Kogo M. Inhibition of Trigeminal Respiratory Activity by Suckling. J Dent Res 2016; 86:1073-7. [DOI: 10.1177/154405910708601110] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The trigeminal motor system is involved in many rhythmic oral-motor behaviors, such as suckling, mastication, swallowing, and breathing. Despite the obvious importance of functional coordination among these rhythmic activities, the system is not well-understood. In the present study, we examined the hypothesis that an interaction between suckling and breathing exists in the brainstem, by studying the respiratory activity in trigeminal motoneurons (TMNs) during fictive suckling using a neonatal rat in vitro brainstem preparation. The results showed that fictive suckling, which was neurochemically induced by bath application of N-methyl-D,L-aspartate and bicuculline-methiodide, or by local micro-injection of the same drugs to the trigeminal motor nucleus, inhibited the inspiratory activities in both respiration TMNs and respiratory rhythm-generating neurons. Under patch-clamp recording, fictive suckling caused membrane potential hyperpolarization of respiration TMNs. We conclude that the brainstem preparation contains an inhibitory circuit for respiratory activity in the trigeminal motor system via the rhythm-generating network for suckling. Abbreviations: BIC, bicuculline methiodide; GABA, gamma aminobutyric acid; NMA, N-methyl-D,L-aspartate; NMDA, N-methyl-D-aspartate; and TMN, trigeminal motoneuron.
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Affiliation(s)
- H. Koizumi
- The First Department of Oral and Maxillofacial Surgery, Osaka University Graduate School of Dentistry, 1-8 Yamadaoka, Suita, Osaka 565-0871 Japan
| | - K. Nomura
- The First Department of Oral and Maxillofacial Surgery, Osaka University Graduate School of Dentistry, 1-8 Yamadaoka, Suita, Osaka 565-0871 Japan
| | - K. Ishihama
- The First Department of Oral and Maxillofacial Surgery, Osaka University Graduate School of Dentistry, 1-8 Yamadaoka, Suita, Osaka 565-0871 Japan
| | - T. Yamanishi
- The First Department of Oral and Maxillofacial Surgery, Osaka University Graduate School of Dentistry, 1-8 Yamadaoka, Suita, Osaka 565-0871 Japan
| | - A. Enomoto
- The First Department of Oral and Maxillofacial Surgery, Osaka University Graduate School of Dentistry, 1-8 Yamadaoka, Suita, Osaka 565-0871 Japan
| | - M. Kogo
- The First Department of Oral and Maxillofacial Surgery, Osaka University Graduate School of Dentistry, 1-8 Yamadaoka, Suita, Osaka 565-0871 Japan
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36
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Yagi N, Nagami S, Lin MK, Yabe T, Itoda M, Imai T, Oku Y. A noninvasive swallowing measurement system using a combination of respiratory flow, swallowing sound, and laryngeal motion. Med Biol Eng Comput 2016; 55:1001-1017. [PMID: 27665103 PMCID: PMC5440489 DOI: 10.1007/s11517-016-1561-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Accepted: 09/02/2016] [Indexed: 11/16/2022]
Abstract
The assessment of swallowing function is important for the prevention of aspiration pneumonia. We developed a new swallowing monitoring system that uses respiratory flow, swallowing sound, and laryngeal motion. We applied this device to 11 healthy volunteers and 10 patients with dysphagia. Videofluoroscopy (VF) was conducted simultaneously with swallowing monitoring using our device. We measured laryngeal rising time (LRT), the time required for the larynx to elevate to the highest position, and laryngeal activation duration (LAD), the duration between the onset of rapid laryngeal elevation and the time when the larynx returned to the lowest position. In addition, we evaluated the coordination between swallowing and breathing. We found that LAD was correlated with a VF-derived parameter, pharyngeal response duration (PRD) in healthy subjects (LAD: 959 ± 259 ms vs. PRD: 1062 ± 149 ms, r = 0.60); however, this correlation was not found in the dysphagia patients. LRT was significantly prolonged in patients (healthy subjects: 320 ± 175 ms vs. patients: 465 ± 295 ms, P < 0.001, t test). Furthermore, frequency of swallowing immediately after inspiration was significantly increased in patients. Therefore, the new device may facilitate the assessment of some aspects of swallowing dysfunction.
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Affiliation(s)
- Naomi Yagi
- Department of Neurology, Graduate School of Medicine, Kyoto University, 54 Shogoin-Kawaharacho, Sakyo-ku, Kyoto, 606-8507, Japan
- Clinical Research Center for Medical Equipment Development (CRCMeD), Kyoto University Hospital, 54 Shogoin-Kawaharacho, Sakyo-ku, Kyoto, 606-8507, Japan
| | - Shinsuke Nagami
- Department of Neurology, Graduate School of Medicine, Kyoto University, 54 Shogoin-Kawaharacho, Sakyo-ku, Kyoto, 606-8507, Japan
- Clinical Research Center for Medical Equipment Development (CRCMeD), Kyoto University Hospital, 54 Shogoin-Kawaharacho, Sakyo-ku, Kyoto, 606-8507, Japan
- Department of Physiology, Division of Physiome, Hyogo College of Medicine, 1-1 Mukogawa-cho, Hyogo, Nishinomiya, 663-8501, Japan
| | - Meng-Kuan Lin
- Department of Physiology, Division of Physiome, Hyogo College of Medicine, 1-1 Mukogawa-cho, Hyogo, Nishinomiya, 663-8501, Japan
| | - Toru Yabe
- Murata Manufacturing Co., Ltd., 1-10-1, Higashikotari, Nagaokakyo, Kyoto, 617-8555, Japan
| | - Masataka Itoda
- Wakakusa Tatsuma Rehabilitation Hospital, 1580 Oaza-tatsuma, Daito, Osaka, 574-0012, Japan
| | - Takahisa Imai
- Ashiya Municipal Hospital, 39-1 Asahigaoka-cho, Ashiya, Hyogo, 659-0012, Japan
| | - Yoshitaka Oku
- Department of Physiology, Division of Physiome, Hyogo College of Medicine, 1-1 Mukogawa-cho, Hyogo, Nishinomiya, 663-8501, Japan.
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37
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Bolser DC, Pitts TE, Davenport PW, Morris KF. Role of the dorsal medulla in the neurogenesis of airway protection. Pulm Pharmacol Ther 2015; 35:105-10. [PMID: 26549786 DOI: 10.1016/j.pupt.2015.10.012] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Revised: 10/29/2015] [Accepted: 10/30/2015] [Indexed: 12/23/2022]
Abstract
The dorsal medulla encompassing the nucleus of the tractus solitarius (NTS) and surrounding reticular formation (RF) has an important role in processing sensory information from the upper and lower airways for the generation and control of airway protective behaviors. These behaviors, such as cough and swallow, historically have been studied in isolation. However, recent information indicates that these and other airway protective behaviors are coordinated to minimize risk of aspiration. The dorsal medullary neural circuits that include the NTS are responsible for rhythmogenesis for repetitive swallowing, but previous models have assigned a role for this portion of the network for coughing that is restricted to monosynaptic sensory processing. We propose a more complex NTS/RF circuit that controls expression of swallowing and coughing and the coordination of these behaviors. The proposed circuit is supported by recordings of activity patterns of selected neural elements in vivo and simulations of a computational model of the brainstem circuit for breathing, coughing, and swallowing. This circuit includes separate rhythmic sub-circuits for all three behaviors. The revised NTS/RF circuit can account for the mode of action of antitussive drugs on the cough motor pattern, as well as the unique coordination of cough and swallow by a meta-behavioral control system for airway protection.
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Affiliation(s)
- Donald C Bolser
- Department of Physiological Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL 32610-0144, USA.
| | - Teresa E Pitts
- Department of Neurological Surgery, Kentucky Spinal Cord Injury Research Center, University of Louisville, Louisville, KY 40202, USA
| | - Paul W Davenport
- Department of Physiological Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL 32610-0144, USA
| | - Kendall F Morris
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, 12901 Bruce B. Downs Blvd., Tampa, FL 33612-4799, USA
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Lamvik K, Jones R, Sauer S, Erfmann K, Huckabee ML. The capacity for volitional control of pharyngeal swallowing in healthy adults. Physiol Behav 2015; 152:257-63. [PMID: 26432453 DOI: 10.1016/j.physbeh.2015.09.026] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2015] [Revised: 08/16/2015] [Accepted: 09/28/2015] [Indexed: 01/30/2023]
Abstract
INTRODUCTION Previous research has documented that pressure and duration of brainstem-generated pharyngeal swallowing can be cortically modulated. But there is a commonly held belief that the sequence of pharyngeal pressure remains constant. However, Huckabee et al. [19] reported a patient cohort who demonstrated reduced latency of peak pressure in the proximal and distal pharynx, disproportionate and sometimes inversely correlated with overall swallowing duration, suggesting independent timing of underlying muscle contraction within the overall pharyngeal response. This study examined if healthy adults can volitionally produce altered latency of pharyngeal closure in isolation following intensive training, thereby evaluating the capacity for pharyngeal adaptation in a healthy system. METHOD Six healthy participants were seen for intensive training, consisting of daily one-hour sessions over two weeks (10 days) using pharyngeal manometry as a visual biofeedback modality. The participants were instructed to produce simultaneous pressure in the pharyngeal sensors when swallowing. The temporal separation of peak proximal and distal pharyngeal pressure was measured with discrete-sensor pharyngeal manometry at baseline, during training with biofeedback, and following training without biofeedback. RESULTS Following intensive training, participants were able to reduce temporal separation of peak pressure between the proximal and distal pharyngeal sensors from a baseline median of 188 ms (IQR=231 ms) to 68 ms (IQR=92 ms; p=0.002). In contrast, there was no significant change in overall swallowing duration during training (p=0.41). However, change in pharyngeal pressure latency was moderately correlated with both change in swallowing duration (r=0.444) and amplitude (r=0.571) during training, and there was a reduction in swallowing duration post-training (p=0.03). CONCLUSION Given intensive manometric biofeedback training, participants substantially reduced temporal separation of peak proximal and distal pharyngeal pressure when volitionally swallowing. However, correlation with overall pressure and duration measures suggest the adaptation was one of modulating the cumulative pharyngeal response rather than altering discrete components of timing of pharyngeal pressure in isolation. This is inconsistent with the pattern of behaviour documented by Huckabee et al. [19] in the patient population. Further research on modulatory control over targeted aspects of the pharyngeal swallow is needed, and may provide avenues for rehabilitative treatment of patients with dysphagia.
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Affiliation(s)
- Kristin Lamvik
- The University of Canterbury Rose Centre for Stroke Recovery and Research, Christchurch, New Zealand; Department of Communication Disorders, University of Canterbury, Christchurch, New Zealand; New Zealand Brain Research Institute, Christchurch, New Zealand.
| | - Richard Jones
- The University of Canterbury Rose Centre for Stroke Recovery and Research, Christchurch, New Zealand; Department of Communication Disorders, University of Canterbury, Christchurch, New Zealand; New Zealand Brain Research Institute, Christchurch, New Zealand; Department of Medical Physics & Bioengineering, Christchurch Hospital, Christchurch, New Zealand
| | - Sonja Sauer
- Department of Communication Disorders, University of Canterbury, Christchurch, New Zealand; New Zealand Brain Research Institute, Christchurch, New Zealand
| | - Kerstin Erfmann
- The University of Canterbury Rose Centre for Stroke Recovery and Research, Christchurch, New Zealand; Department of Communication Disorders, University of Canterbury, Christchurch, New Zealand; New Zealand Brain Research Institute, Christchurch, New Zealand
| | - Maggie-Lee Huckabee
- The University of Canterbury Rose Centre for Stroke Recovery and Research, Christchurch, New Zealand; Department of Communication Disorders, University of Canterbury, Christchurch, New Zealand; New Zealand Brain Research Institute, Christchurch, New Zealand
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Sugiyama Y, Shiba K, Mukudai S, Umezaki T, Sakaguchi H, Hisa Y. Role of the retrotrapezoid nucleus/parafacial respiratory group in coughing and swallowing in guinea pigs. J Neurophysiol 2015. [PMID: 26203106 DOI: 10.1152/jn.00332.2015] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The retrotrapezoid/parafacial respiratory group (RTN/pFRG) located ventral to the facial nucleus plays a key role in regulating breathing, especially enhanced expiratory activity during hypercapnic conditions. To clarify the roles of the RTN/pFRG region in evoking coughing, during which reflexive enhanced expiration is produced, and in swallowing, during which the expiratory activity is consistently halted, we recorded extracellular activity from RTN/pFRG neurons during these fictive behaviors in decerebrate, paralyzed, and artificially ventilated guinea pigs. The activity of the majority of recorded respiratory neurons was changed in synchrony with coughing and swallowing. To further evaluate the contribution of RTN/pFRG neurons to these nonrespiratory behaviors, the motor output patterns during breathing, coughing, and swallowing were compared before and after brain stem transection at the caudal margin of RTN/pFRG region. In addition, the effects of transection at its rostral margin were also investigated to evaluate pontine contribution to these behaviors. During respiration, transection at the rostral margin attenuated the postinspiratory activity of the recurrent laryngeal nerve. Meanwhile, the late expiratory activity of the abdominal nerve was abolished after caudal transection. The caudal transection also decreased the amplitude of the coughing-related abdominal nerve discharge but did not abolish the activity. Swallowing could be elicited even after the caudal end transection. These findings raise the prospect that the RTN/pFRG contributes to expiratory regulation during normal respiration, although this region is not an essential element of the neuronal networks involved in coughing and swallowing.
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Affiliation(s)
- Yoichiro Sugiyama
- Department of Otolaryngology-Head and Neck Surgery, Kyoto Prefectural University of Medicine, Kyoto, Japan;
| | - Keisuke Shiba
- Hikifune Otolaryngology Clinic, Sumida, Tokyo, Japan
| | - Shigeyuki Mukudai
- Department of Otolaryngology, Japanese Red Cross Kyoto Daini Hospital, Kyoto, Japan; and
| | - Toshiro Umezaki
- Department of Otolaryngology, Graduate School of Medicine, Kyushu University, Fukuoka, Japan
| | - Hirofumi Sakaguchi
- Department of Otolaryngology-Head and Neck Surgery, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Yasuo Hisa
- Department of Otolaryngology-Head and Neck Surgery, Kyoto Prefectural University of Medicine, Kyoto, Japan
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Alsahafi Z, Dickson CT, Pagliardini S. Optogenetic excitation of preBötzinger complex neurons potently drives inspiratory activity in vivo. J Physiol 2015; 593:3673-92. [PMID: 26010654 DOI: 10.1113/jp270471] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2015] [Accepted: 05/15/2015] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS This study investigates the effects on ventilation of an excitatory stimulus delivered in a spatially and temporally precise manner to the inspiratory oscillator, the preBötzinger complex (preBötC). We used an adeno-associated virus expressing channelrhodopsin driven by the synapsin promoter to target the region of the preBötC. Unilateral optogenetic stimulation of preBötC increased respiratory rate, minute ventilation and increased inspiratory modulated genioglossus muscle activity. Unilateral optogenetic stimulation of preBötC consistently entrained respiratory rate up to 180 breaths min(-1) both in presence of ongoing respiratory activity and in absence of inspiratory activity. Unilateral optogenetic stimulation of preBötC induced a strong phase-independent Type 0 respiratory reset, with a short delay in the response of 100 ms. We identified a refractory period of ∼200 ms where unilateral preBötC optogenetic stimulation is not able to initiate the next respiratory event. ABSTRACT Understanding the sites and mechanisms underlying respiratory rhythmogenesis is of fundamental interest in the field of respiratory neurophysiology. Previous studies demonstrated the necessary and sufficient role of preBötzinger complex (preBötC) in generating inspiratory rhythms in vitro and in vivo. However, the influence of timed activation of the preBötC network in vivo is as yet unknown given the experimental approaches previously used. By unilaterally infecting preBötC neurons using an adeno-associated virus expressing channelrhodopsin we photo-activated the network in order to assess how excitation delivered in a spatially and temporally precise manner to the inspiratory oscillator influences ongoing breathing rhythms and related muscular activity in urethane-anaesthetized rats. We hypothesized that if an excitatory drive is necessary for rhythmogenesis and burst initiation, photo-activation of preBötC not only will increase respiratory rate, but also entrain it over a wide range of frequencies with fast onset, and have little effect on ongoing respiratory rhythm if a stimulus is delivered during inspiration. Stimulation of preBötC neurons consistently increased respiratory rate and entrained respiration up to fourfold baseline conditions. Furthermore, brief pulses of photostimulation delivered at random phases between inspiratory events robustly and consistently induced phase-independent (Type 0) respiratory reset and recruited inspiratory muscle activity at very short delays (∼100 ms). A 200 ms refractory period following inspiration was also identified. These data provide strong evidence for a fine control of inspiratory activity in the preBötC and provide further evidence that the preBötC network constitutes the fundamental oscillator of inspiratory rhythms.
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Affiliation(s)
- Zaki Alsahafi
- Department of Physiology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Canada.,Women and Children's Health Research Institute, University of Alberta, Edmonton, Canada
| | - Clayton T Dickson
- Department of Physiology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Canada.,Department of Psychology, Faculty of Science, University of Alberta, Edmonton, Alberta, Canada.,Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Canada
| | - Silvia Pagliardini
- Department of Physiology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Canada.,Women and Children's Health Research Institute, University of Alberta, Edmonton, Canada.,Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Canada
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41
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Pitts T, Gayagoy AG, Rose MJ, Poliacek I, Condrey JA, Musslewhite MN, Shen TY, Davenport PW, Bolser DC. Suppression of Abdominal Motor Activity during Swallowing in Cats and Humans. PLoS One 2015; 10:e0128245. [PMID: 26020240 PMCID: PMC4447283 DOI: 10.1371/journal.pone.0128245] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Accepted: 04/23/2015] [Indexed: 11/18/2022] Open
Abstract
Diseases affecting pulmonary mechanics often result in changes to the coordination of swallow and breathing. We hypothesize that during times of increased intrathoracic pressure, swallow suppresses ongoing expiratory drive to ensure bolus transport through the esophagus. To this end, we sought to determine the effects of swallow on abdominal electromyographic (EMG) activity during expiratory threshold loading in anesthetized cats and in awake-healthy adult humans. Expiratory threshold loads were applied to recruit abdominal motor activity during breathing, and swallow was triggered by infusion of water into the mouth. In both anesthetized cats and humans, expiratory cycles which contained swallows had a significant reduction in abdominal EMG activity, and a greater percentage of swallows were produced during inspiration and/or respiratory phase transitions. These results suggest that: a) spinal expiratory motor pathways play an important role in the execution of swallow, and b) a more complex mechanical relationship exists between breathing and swallow than has previously been envisioned.
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Affiliation(s)
- Teresa Pitts
- Department of Neurological Surgery, Kentucky Spinal Cord Injury Research Center, University of Louisville, Louisville, KY, United States of America
- * E-mail:
| | - Albright G. Gayagoy
- Department of Physiological Sciences, University of Florida, Gainesville, FL, United States of America
| | - Melanie J. Rose
- Department of Physiological Sciences, University of Florida, Gainesville, FL, United States of America
| | - Ivan Poliacek
- Department of Physiological Sciences, University of Florida, Gainesville, FL, United States of America
| | - Jillian A. Condrey
- Department of Physiological Sciences, University of Florida, Gainesville, FL, United States of America
| | - M. Nicholas Musslewhite
- Department of Physiological Sciences, University of Florida, Gainesville, FL, United States of America
| | - Tabitha Y. Shen
- Department of Physiological Sciences, University of Florida, Gainesville, FL, United States of America
| | - Paul W. Davenport
- Department of Physiological Sciences, University of Florida, Gainesville, FL, United States of America
| | - Donald C Bolser
- Department of Physiological Sciences, University of Florida, Gainesville, FL, United States of America
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Pitts T, Rose MJ, Poliacek I, Condrey J, Davenport PW, Bolser DC. Effect of laparotomy on the swallow-breathing relationship in the cat. Lung 2015; 193:129-33. [PMID: 25331536 PMCID: PMC4320662 DOI: 10.1007/s00408-014-9662-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2014] [Accepted: 10/12/2014] [Indexed: 10/24/2022]
Abstract
Swallow occurs predominantly in the expiratory phase (E) of breathing. This phase preference is thought to contribute to airway protection by limiting the passage of material through the pharyngeal airway with little or no inspiratory (I) airflow. This phase preference is attributed to central interactions between the swallow and breathing pattern generators. We speculated that changes in peripheral mechanical factors would influence the respiratory phase preference for swallow initiation. We induced swallowing in anesthetized spontaneously breathing cats by injection of water into the oropharynx. In animals with intact abdomens, 83 % of swallows were initiated during E, 7 % during I, 7 % during E-I phase transition, and 3 % during I-E transition. In animals with open anterior midline laparotomy, only 38 % of swallows were initiated during E, 33 % during I, 17 % during the E-I transition, and 12 % during I-E. The results support an important role for feedback from somatic and/or visceral thoraco-abdominal mechanoreceptors for swallow-breathing coordination after laparotomy.
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Affiliation(s)
- Teresa Pitts
- Department of Physiological Sciences, College of Veterinary Medicine, University of Florida, PO Box 100144, Gainesville, FL, 32610-0144, USA,
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Moraes DJA, Machado BH. Electrophysiological properties of laryngeal motoneurones in rats submitted to chronic intermittent hypoxia. J Physiol 2015; 593:619-34. [PMID: 25433075 DOI: 10.1113/jphysiol.2014.283085] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2014] [Accepted: 11/17/2014] [Indexed: 12/12/2022] Open
Abstract
KEY POINTS The respiratory control of the glottis by laryngeal motoneurones is characterized by inspiratory abduction and post-inspiratory adduction causing decreases and increases in upper airway resistance, respectively. Chronic intermittent hypoxia (CIH), an important component of obstructive sleep apnoea, exaggerated glottal abduction (before inspiration), associated with active expiration and decreased glottal adduction during post-inspiration. CIH increased the inspiratory and decreased the post-inspiratory laryngeal motoneurone activities, which is not associated to changes in their intrinsic electrophysiological properties. We conclude that the changes in the respiratory network after CIH seem to be an adaptive process required for an appropriated pulmonary ventilation and control of upper airway resistance under intermittent episodes of hypoxia. ABSTRACT To keep an appropriate airflow to and from the lungs under physiological conditions a precise neural co-ordination of the upper airway resistance by laryngeal motoneurones in the nucleus ambiguus is essential. Chronic intermittent hypoxia (CIH), an important component of obstructive sleep apnoea, may alter these fine mechanisms. Here, using nerve and whole cell patch clamp recordings in in situ preparations of rats we investigated the effects of CIH on the respiratory control of the upper airway resistance, on the electrophysiological properties of laryngeal motoneurones in the nucleus ambiguus, and the role of carotid body (CB) afferents to the brainstem on the underlying mechanisms of these effects. CIH rats exhibited longer pre-inspiratory and lower post-inspiratory superior laryngeal nerve activities than control rats. These changes produced exaggerated glottal abduction (before inspiration) and decreased glottal adduction during post-inspiration, indicating a reduction of upper airway resistance during these respiratory phases after CIH. CB denervation abolished these changes produced by CIH. Regarding choline acetyltransferase positive-laryngeal motoneurones, CIH increased the firing frequency of inspiratory and decreased the firing frequency of post-inspiratory laryngeal motoneurones, without changes in their intrinsic electrophysiological properties. These data show that the effects of CIH on the upper airway resistance and laryngeal motoneurones activities are driven by the integrity of CB, which afferents induce changes in the central respiratory generators in the brainstem. These neural changes in the respiratory network seem to be an adaptive process required for an appropriated pulmonary ventilation and control of upper airway resistance under intermittent episodes of hypoxia.
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Affiliation(s)
- Davi J A Moraes
- Department of Physiology, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil
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44
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Troche MS, Brandimore AE, Godoy J, Hegland KW. A framework for understanding shared substrates of airway protection. J Appl Oral Sci 2014; 22:251-60. [PMID: 25141195 PMCID: PMC4126819 DOI: 10.1590/1678-775720140132] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2014] [Accepted: 05/06/2014] [Indexed: 02/01/2023] Open
Abstract
Deficits of airway protection can have deleterious effects to health and quality of
life. Effective airway protection requires a continuum of behaviors including
swallowing and cough. Swallowing prevents material from entering the airway and
coughing ejects endogenous material from the airway. There is significant overlap
between the control mechanisms for swallowing and cough. In this review we will
present the existing literature to support a novel framework for understanding shared
substrates of airway protection. This framework was originally adapted from Eccles'
model of cough28 (2009) by Hegland,
et al.42 (2012). It will serve to
provide a basis from which to develop future studies and test specific hypotheses
that advance our field and ultimately improve outcomes for people with airway
protective deficits.
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Affiliation(s)
- Michelle Shevon Troche
- Department of Speech, Language, and Hearing Sciences, University of Florida, Gainesville, FL, USA
| | | | - Juliana Godoy
- Bauru School of Dentistry, University of São Paulo, Bauru, SP, Brazil
| | - Karen Wheeler Hegland
- Department of Speech, Language, and Hearing Sciences, University of Florida, Gainesville, FL, USA
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Spearman DG, Poliacek I, Rose MJ, Bolser DC, Pitts T. Variability of the pharyngeal phase of swallow in the cat. PLoS One 2014; 9:e106121. [PMID: 25171095 PMCID: PMC4149527 DOI: 10.1371/journal.pone.0106121] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2014] [Accepted: 07/28/2014] [Indexed: 11/18/2022] Open
Abstract
Objective The pharyngeal phase of swallow has been thought to be a stereotypical motor behavior. Study Design This is a prospective, preclinical, hypothesis driven, one group by three-task design. Methods We sought to compare the effects of pharyngeal swabbing, water only, and water plus punctate mechanical stimulation on the spatiotemporal features of the pharyngeal phase of swallow in the cat. Swallow was elicited under these three conditions in six anaesthetized cats. Electromyographic activity was recorded from seven muscles used to evaluate swallow: mylohyoid, geniohyoid, thyrohyoid, thyroarytenoid, thyropharyngeus, cricopharyngeus, and parasternal. Results Pharyngeal swabbing in comparison to the other stimulus conditions, results in decreases in post-swallow cricopharyngeus activity (upper esophageal sphincter); a significant increase in parasternal (schluckatmung; swallow breath) activity; and increases in thyrohyoid (laryngeal elevator), thyroarytenoid (laryngeal adductor) and parasternal muscles burst duration. Pearson correlations were found of moderate strength between 19% of burst duration comparisons and weak to moderate relationships between 29% of burst amplitude comparisons. However, there were no positive significant relationships between phase durations and electromyogram amplitudes between any of the muscles studied during swallow. Conclusions The results support the concept that a stereotypical behavior, such as pharyngeal swallowing in animal models, can be modified by sensory feedback from pharyngeal mucosal mechanoreceptors. Furthermore, differences in swallow phase durations and amplitudes provide evidence that separate regulatory mechanisms exist which regulate spatial and temporal aspects of the behavior.
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Affiliation(s)
- Daniel G. Spearman
- Department of Physiological Sciences, University of Florida, Gainesville, Florida, United States of America
| | - Ivan Poliacek
- Department of Physiological Sciences, University of Florida, Gainesville, Florida, United States of America
- Institute of Medical Biophysics, Jessenius Faculty of Medicine, Comenius University, Martin, Slovak Republic
| | - Melanie J. Rose
- Department of Physiological Sciences, University of Florida, Gainesville, Florida, United States of America
| | - Donald C. Bolser
- Department of Physiological Sciences, University of Florida, Gainesville, Florida, United States of America
| | - Teresa Pitts
- Department of Physiological Sciences, University of Florida, Gainesville, Florida, United States of America
- * E-mail:
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Bautista TG, Sun QJ, Pilowsky PM. The generation of pharyngeal phase of swallow and its coordination with breathing: interaction between the swallow and respiratory central pattern generators. PROGRESS IN BRAIN RESEARCH 2014; 212:253-75. [PMID: 25194202 DOI: 10.1016/b978-0-444-63488-7.00013-6] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Swallowing and breathing utilize common muscles and an anatomical passage: the pharynx. The risk of aspiration of ingested material is minimized not only by the laryngeal adduction of the vocal folds and laryngeal elevation but also by the precise coordination of swallows with breathing. Namely, swallows: (1) are preferentially initiated in the postinspiratory/expiratory phase, (2) are accompanied by a brief apnea, and (3) are often followed by an expiration and delay of the next breath. This review summarizes the expiratory evidence on the brainstem regions comprising the central pattern generator (CPG) that produces the pharyngeal stage of swallow, how the motor acts of swallowing and breathing are coordinated, and lastly, brainstem regions where the swallowing and respiratory CPGs may interact in order to ensure "safe" swallows.
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Affiliation(s)
- Tara G Bautista
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria, Australia; Australian School of Advanced Medicine, Macquarie University, North Ryde, New South Wales, Australia.
| | - Qi-Jian Sun
- Australian School of Advanced Medicine, Macquarie University, North Ryde, New South Wales, Australia
| | - Paul M Pilowsky
- Heart Research Institute, Newtown, New South Wales, Australia
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Sugiyama Y, Shiba K, Mukudai S, Umezaki T, Hisa Y. Activity of respiratory neurons in the rostral medulla during vocalization, swallowing, and coughing in guinea pigs. Neurosci Res 2013; 80:17-31. [PMID: 24380791 DOI: 10.1016/j.neures.2013.12.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2013] [Revised: 12/04/2013] [Accepted: 12/18/2013] [Indexed: 10/25/2022]
Abstract
To examine the relationship between the neuronal networks underlying respiration and non-respiratory behaviors such as vocalization and airway defensive reflexes, we compared the activity of respiratory neurons in the ventrolateral medulla during breathing with that during non-respiratory behaviors including vocalization, swallowing, and coughing in guinea pigs. During fictive vocalization the activity of augmenting expiratory neurons ceased, whereas the other types of expiratory neurons did not show a consistent tendency of increasing or decreasing activity. All inspiratory neurons discharged in synchrony with the phrenic nerve activity. Most of the phase-spanning neurons were activated throughout the vocal phase. During fictive swallowing, many expiratory and inspiratory neurons were silent, whereas many phase-spanning neurons were activated. During fictive coughing, many expiratory neurons were activated during the expiratory phase of coughing. Most inspiratory neurons discharged in parallel with the phrenic nerve activity during coughing. Many phase-spanning neurons were activated during the expiratory phase of coughing. These findings indicate that the medullary respiratory neurons help shape respiratory muscle nerve activity not only during breathing but also during these non-respiratory behaviors, and thus suggest that at least some of the respiratory neurons are shared among the neuronal circuits underlying the generation of breathing and non-respiratory behaviors.
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Affiliation(s)
- Yoichiro Sugiyama
- Department of Otolaryngology-Head and Neck Surgery, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan.
| | - Keisuke Shiba
- Hikifune Otolaryngology Clinic, Sumida, Tokyo 131-0046, Japan
| | - Shigeyuki Mukudai
- Department of Otolaryngology-Head and Neck Surgery, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan
| | - Toshiro Umezaki
- Department of Otolaryngology, Graduate School of Medicine, Kyushu University, Fukuoka 812-8582, Japan
| | - Yasuo Hisa
- Department of Otolaryngology-Head and Neck Surgery, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan
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Abstract
Airway protections is the prevention and/or removal of material by behaviors such as cough and swallow. We hypothesized these behaviors are coordinated to respond to aspiration. Anesthetized animals were challenged with simulated aspiration that induced both coughing and swallowing. Electromyograms of upper airway and respiratory muscles together with esophageal pressure were recorded to identify and evaluate cough and swallow. During simulated aspiration, both cough and swallow intensity increased and swallow duration decreased consistent with rapid pharyngeal clearance. Phase restriction between cough and swallow was observed; swallow was restricted to the E2 phase of cough. These results support three main conclusions: 1) the cough and swallow pattern generators are tightly coordinated so as to generate a protective meta-behavior; 2) the trachea provides feedback on swallow quality, informing the brainstem about aspiration incidences; and 3) the larynx and upper esophageal sphincter act as two separate valves controlling the direction of positive and negative pressures from the upper airway into the thorax.
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49
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Contribution of the lateral lemniscus to the control of swallowing in decerebrate cats. Neuroscience 2013; 254:260-74. [DOI: 10.1016/j.neuroscience.2013.09.036] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2013] [Revised: 09/16/2013] [Accepted: 09/19/2013] [Indexed: 11/20/2022]
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50
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Pitts T, Rose MJ, Mortensen AN, Poliacek I, Sapienza CM, Lindsey BG, Morris KF, Davenport PW, Bolser DC. Coordination of cough and swallow: a meta-behavioral response to aspiration. Respir Physiol Neurobiol 2013; 189:543-51. [PMID: 23998999 PMCID: PMC3882902 DOI: 10.1016/j.resp.2013.08.009] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2013] [Revised: 08/15/2013] [Accepted: 08/16/2013] [Indexed: 11/18/2022]
Abstract
Airway protections is the prevention and/or removal of material by behaviors such as cough and swallow. We hypothesized these behaviors are coordinated to respond to aspiration. Anesthetized animals were challenged with simulated aspiration that induced both coughing and swallowing. Electromyograms of upper airway and respiratory muscles together with esophageal pressure were recorded to identify and evaluate cough and swallow. During simulated aspiration, both cough and swallow intensity increased and swallow duration decreased consistent with rapid pharyngeal clearance. Phase restriction between cough and swallow was observed; swallow was restricted to the E2 phase of cough. These results support three main conclusions: 1) the cough and swallow pattern generators are tightly coordinated so as to generate a protective meta-behavior; 2) the trachea provides feedback on swallow quality, informing the brainstem about aspiration incidences; and 3) the larynx and upper esophageal sphincter act as two separate valves controlling the direction of positive and negative pressures from the upper airway into the thorax.
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Affiliation(s)
- Teresa Pitts
- Department of Physiological Sciences, University of Florida, Gainesville, FL, United States.
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