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Kondo T, Yamanishi T, Nishio T, Yokota Y, Seikai T, Enomoto A, Harada T, Tsuji T, Tanaka S. Swallowing-like activity elicited in neonatal rat medullary slice preparation. Brain Res 2024; 1837:148955. [PMID: 38679314 DOI: 10.1016/j.brainres.2024.148955] [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: 01/13/2024] [Revised: 03/30/2024] [Accepted: 04/20/2024] [Indexed: 05/01/2024]
Abstract
Swallowing is induced by a central pattern generator in the nucleus tractus solitarius (NTS). We aimed to create a medullary slice preparation to elucidate the neural architecture of the central pattern generator of swallowing (Sw-CPG) and record its neural activities. Experiments were conducted on 2-day-old Sprague-Dawley rats (n = 46). The brainstem-spinal cord was transected at the pontomedullary and cervicothoracic junctions; the medulla was sliced transversely at thicknesses of 600, 700, or 800 μm. The rostral end of the slice was 100 μm rostral to the vagus nerve. We recorded hypoglossal nerve activity and electrically stimulated the vagus nerve or microinjected bicuculline methiodide (BIC) into the NTS. The 800-μm slices generated both rhythmic respiratory activity and electrically elicited neural activity. The 700-μm slices generated only respiratory activity, while the 600-μm slices did not generate any neural activity. BIC microinjection into the NTS in 800-μm slices resulted in the typical activity that closely resembled the swallowing activity reported in other experiments. This swallowing-like activity consistently lengthened the respiratory interval. Despite complete inhibition of respiratory activity, weak swallowing-like activity was observed under bath application of a non-NMDA receptor antagonist. Contrastingly, bath application of NMDA receptor antagonists resulted in a complete loss of swallowing-like activity and no change in respiratory activity. These results suggest that the 800-μm medullary slice preparation contains both afferent and efferent neural circuits and pattern generators of swallowing activity. Additionally, NMDA receptors may be necessary for generating swallowing activity. This medullary slice preparation can therefore elucidate Sw-CPG neural networks.
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Affiliation(s)
- Takahide Kondo
- First Department of Oral and Maxillofacial Surgery, Graduate School of Dentistry, Osaka University, 1-8 Yamadaoka, Suita, Osaka, Japan.
| | - Tadashi Yamanishi
- First Department of Oral and Maxillofacial Surgery, Graduate School of Dentistry, Osaka University, 1-8 Yamadaoka, Suita, Osaka, Japan; Department of Oral and Maxillofacial Surgery, Osaka Women's and Children's Hospital, Osaka, Japan
| | - Takahiro Nishio
- First Department of Oral and Maxillofacial Surgery, Graduate School of Dentistry, Osaka University, 1-8 Yamadaoka, Suita, Osaka, Japan; Department of Oral and Maxillofacial Surgery, Osaka Women's and Children's Hospital, Osaka, Japan
| | - Yusuke Yokota
- First Department of Oral and Maxillofacial Surgery, Graduate School of Dentistry, Osaka University, 1-8 Yamadaoka, Suita, Osaka, Japan
| | - Tetsuya Seikai
- Department of Oral and Maxillofacial Surgery, Division of Oral Pathobiological Science, Graduate School of Dental Medicine, Faculty of Dental Medicine, Hokkaido University, Hokkaido, Japan
| | - Akifumi Enomoto
- Department of Oral and Maxillofacial Surgery, Faculty of Medicine, Kindai University, Osaka, Japan
| | - Takeshi Harada
- Department of Oral and Maxillofacial Surgery, Kansai Rosai Hospital, Osaka, Japan
| | - Tadataka Tsuji
- First Department of Oral and Maxillofacial Surgery, Graduate School of Dentistry, Osaka University, 1-8 Yamadaoka, Suita, Osaka, Japan
| | - Susumu Tanaka
- First Department of Oral and Maxillofacial Surgery, Graduate School of Dentistry, Osaka University, 1-8 Yamadaoka, Suita, Osaka, Japan
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Optical imaging of neurons related to fictive swallowing using GCaMP6f in an arterially perfused rat preparation. J Oral Biosci 2023; 65:126-131. [PMID: 36738967 DOI: 10.1016/j.job.2023.01.009] [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: 01/16/2023] [Revised: 01/19/2023] [Accepted: 01/20/2023] [Indexed: 02/05/2023]
Abstract
OBJECTIVE It is difficult to comprehensively study the activity patterns and distribution of neurons in the brainstem that control the act of swallowing, as they are located deep in the brain. In this study, we aimed to evaluate the usefulness of calcium imaging using GCaMP6f in arterially perfused preparations to study the activity of swallowing-related neurons in the brainstem. METHODS Arterially perfused rat preparations were prepared 3-4 weeks after the injection of a neuron-specific virus expressing GCaMP6f. Fictive swallowing was induced by repetitive electrical stimulation of the superior laryngeal nerve (SLN). Simultaneously, the activity of GCaMP6f-expressing neurons in the dorsal brainstem, between 0.1 and 4.8 mm rostral to the obex, was assessed by changes in the intracellular calcium concentration using confocal laser microscopy. RESULTS Neurons responding to stimulation of the SLN included swallowing-related neurons (48%), which showed an increase in fluorescence intensity at the time of swallowing bursts in the cervical vagus nerve, and stimulation-related neurons (52%), which showed an increase in fluorescence intensity through stimulation, regardless of the swallowing bursts. Despite a broad search area, swallowing-related neurons were localized exclusively in and around the solitary nucleus. In contrast, most stimulation-related neurons were located in the brainstem reticular formation, which is more rostral than the solitary nucleus. CONCLUSIONS Calcium imaging using GCaMP in arterially perfused rat preparations is useful for an efficient search of the activity pattern and distribution of neurons located in a wide area of the brainstem.
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Tsujimura T, Nakajima Y, Chotirungsan T, Kawada S, Tsutsui Y, Yoshihara M, Suzuki T, Nagoya K, Magara J, Inoue M. Inhibition of Water-Evoked Swallowing During Noxious Mechanical Stimulation of Tongue in Anesthetized Rats. Dysphagia 2022; 38:965-972. [PMID: 36127446 DOI: 10.1007/s00455-022-10522-5] [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: 01/11/2022] [Accepted: 09/11/2022] [Indexed: 11/30/2022]
Abstract
Dysphagia is sometimes accompanied by pain. Because orofacial structures subserve mastication and swallowing, orofacial pain might impair both functions. Tongue biting can occur not only accidentally while eating but also in some pathological conditions. However, it remains unclear whether noxious mechanical stimulation of the tongue affects swallowing. To explore this question, we evaluated the effects of lingual pinch stimulation on the initiation of swallowing evoked by distilled water (DW) infusion with a flow rate of 5.0 µL/s for 20 s into the pharyngolaryngeal region in anesthetized rats. The swallowing reflex was identified by electromyographic (EMG) bursts in the suprahyoid muscles which include the anterior belly of the digastric muscle, mylohyoid and geniohyoid muscles, and laryngeal elevation by visual inspection. The number of DW-evoked swallows during pinch stimulation was significantly smaller than that in a control condition or during pressure stimulation. The onset latency of the first swallow during pinch stimulation was significantly longer than that in the control condition. DW-evoked swallowing was almost abolished following bilateral transection of the superior laryngeal nerve (SLN) compared with the control condition, suggesting that the SLN plays a crucial role in the initiation of DW-evoked swallowing. Finally, electrophysiological data indicated that some SLN-responsive neurons in the nucleus tractus solitarii (nTS) exhibited delayed latency from a single SLN stimulation during lingual pinch stimulation. These results suggest that noxious mechanical stimulation of the tongue inhibits the initiation of swallowing and modulates neuronal activity in the nTS.
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Affiliation(s)
- Takanori Tsujimura
- Division of Dysphagia Rehabilitation, Niigata University Graduate School of Medical and Dental Sciences, Chuo-ku, Niigata, 951-8514, Japan.
| | - Yuta Nakajima
- Division of Dysphagia Rehabilitation, Niigata University Graduate School of Medical and Dental Sciences, Chuo-ku, Niigata, 951-8514, Japan
| | - Titi Chotirungsan
- Division of Dysphagia Rehabilitation, Niigata University Graduate School of Medical and Dental Sciences, Chuo-ku, Niigata, 951-8514, Japan
| | - Satomi Kawada
- Division of Dysphagia Rehabilitation, Niigata University Graduate School of Medical and Dental Sciences, Chuo-ku, Niigata, 951-8514, Japan
| | - Yuhei Tsutsui
- Division of Dysphagia Rehabilitation, Niigata University Graduate School of Medical and Dental Sciences, Chuo-ku, Niigata, 951-8514, Japan
| | - Midori Yoshihara
- Division of Dysphagia Rehabilitation, Niigata University Graduate School of Medical and Dental Sciences, Chuo-ku, Niigata, 951-8514, Japan
| | - Taku Suzuki
- Division of Dysphagia Rehabilitation, Niigata University Graduate School of Medical and Dental Sciences, Chuo-ku, Niigata, 951-8514, Japan
| | - Kouta Nagoya
- Division of Dysphagia Rehabilitation, Niigata University Graduate School of Medical and Dental Sciences, Chuo-ku, Niigata, 951-8514, Japan
| | - Jin Magara
- Division of Dysphagia Rehabilitation, Niigata University Graduate School of Medical and Dental Sciences, Chuo-ku, Niigata, 951-8514, Japan
| | - Makoto Inoue
- Division of Dysphagia Rehabilitation, Niigata University Graduate School of Medical and Dental Sciences, Chuo-ku, Niigata, 951-8514, Japan
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Yamamoto R, Sugiyama Y, Hashimoto K, Kinoshita S, Takemura A, Fuse S, Kaneko M, Mukudai S, Umezaki T, Dutschmann M, Nakagawa T, Hirano S. Firing characteristics of swallowing interneurons in the dorsal medulla during physiologically induced swallowing in perfused brainstem preparation in rats. Neurosci Res 2021; 177:64-77. [PMID: 34808248 DOI: 10.1016/j.neures.2021.11.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Revised: 11/09/2021] [Accepted: 11/17/2021] [Indexed: 12/23/2022]
Abstract
Oropharyngeal swallowing is centrally mediated by a swallowing central pattern generator (Sw-CPG) in the medulla oblongata. The activity of the Sw-CPG depends on the sensory inputs determined by physical and chemical bolus properties. Here we investigate the sensory-motor integration during swallowing arising from different sensory sources. To do so we electrically stimulated the superior laryngeal nerve and we triggered swallowing with oral injections of distilled water or capsaicin solution and extracellularly recorded from swallowing interneurons in arterially perfused brainstem preparations of rats. We recorded the activities of 40 neurons, while monitoring the motor activities of the phrenic, vagal and hypoglossal nerves. Eighteen neurons responded to electrical stimulation of the ipsilateral superior laryngeal nerve, and 6 neurons were excited by oral fluid injection, while 16 non-respiratory neurons did not receive afferent inputs to either electrical or physiological stimuli. The cellular activities displayed by swallowing interneurons during electrical and physiological stimulation of pharyngeal and laryngeal afferent input reveal complex adaptations of the timing of firing patterns and frequencies. The modulation of neuronal activity is likely to contribute to the coordination of efficient bolus transfer during the pharyngeal stage of swallowing.
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Affiliation(s)
- Ryota Yamamoto
- Department of Otolaryngology-Head and Neck Surgery, Kyoto Prefectural University of Medicine, Kyoto, 602-8566, Japan; Department of Otolaryngology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, 812-5852, Japan
| | - Yoichiro Sugiyama
- Department of Otolaryngology-Head and Neck Surgery, Kyoto Prefectural University of Medicine, Kyoto, 602-8566, Japan.
| | - Keiko Hashimoto
- Department of Otolaryngology-Head and Neck Surgery, Kyoto Prefectural University of Medicine, Kyoto, 602-8566, Japan
| | - Shota Kinoshita
- Department of Otolaryngology-Head and Neck Surgery, Kyoto Prefectural University of Medicine, Kyoto, 602-8566, Japan
| | - Akiyo Takemura
- Department of Otolaryngology-Head and Neck Surgery, Kyoto Prefectural University of Medicine, Kyoto, 602-8566, Japan
| | - Shinya Fuse
- Department of Otolaryngology-Head and Neck Surgery, Kyoto Prefectural University of Medicine, Kyoto, 602-8566, Japan
| | - Mami Kaneko
- Department of Otolaryngology-Head and Neck Surgery, Kyoto Prefectural University of Medicine, Kyoto, 602-8566, Japan
| | - Shigeyuki Mukudai
- Department of Otolaryngology-Head and Neck Surgery, Kyoto Prefectural University of Medicine, Kyoto, 602-8566, Japan
| | - Toshiro Umezaki
- Department of Speech and Hearing Sciences, International University of Health and Welfare, and the Voice and Swallowing Center, Fukuoka Sanno Hospital, Fukuoka, 814-0001, Japan
| | - Mathias Dutschmann
- Florey Institute of Neuroscience and Mental Health, Gate 11, Royal Parade, University of Melbourne, VIC 3052, Australia
| | - Takashi Nakagawa
- Department of Otolaryngology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, 812-5852, Japan
| | - Shigeru Hirano
- Department of Otolaryngology-Head and Neck Surgery, Kyoto Prefectural University of Medicine, Kyoto, 602-8566, Japan
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Fuse S, Sugiyama Y, Hashimoto K, Umezaki T, Oku Y, Dutschmann M, Hirano S. Laryngeal afferent modulation of swallowing interneurons in the dorsal medulla in perfused rats. Laryngoscope 2019; 130:1885-1893. [PMID: 31498463 DOI: 10.1002/lary.28284] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Revised: 08/02/2019] [Accepted: 08/19/2019] [Indexed: 12/14/2022]
Abstract
OBJECTIVES The purpose of this study was to investigate the influence of laryngeal afferent inputs on brainstem circuits that mediate and transmit swallowing activity to the orofacial musculature. METHODS Experiments were performed on 19 arterially perfused juvenile rats. The activities of swallowing interneurons in relation to their respective motor outputs in the hypoglossal and vagus nerves were assessed during fictive swallowing with or without concurrent laryngeal sensory stimulation at intensities of 20, 40, and 60 μA. RESULTS The hypoglossal nerve activity was gradually enhanced with increasing intensity of the sensory stimulation, while the vagus nerve activity was not altered. The activities of various interneurons were modulated by the laryngeal stimulation, but more than 50% of the recorded neurons were inhibited by the stimulation. Some interneurons demonstrated no obvious change in their discharge rates with laryngeal sensory stimulation during fictive swallowing. CONCLUSION Laryngeal afferent inputs partially modulated the swallowing motor activity via enhanced or suppressed activities of the swallowing interneurons, while the essential motor pattern underlying the pharyngeal stage of swallowing remained basically unchanged. Thus, the output patterns of the complex sequential movements of swallowing could be basically predetermined and further adjusted according to sensory information related to the properties of the ingested food by a swallowing central pattern generator. LEVEL OF EVIDENCE NA Laryngoscope, 130: 1885-1893, 2020.
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Affiliation(s)
- Shinya Fuse
- Department of Otolaryngology-Head and Neck Surgery, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Yoichiro Sugiyama
- Department of Otolaryngology-Head and Neck Surgery, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Keiko Hashimoto
- Department of Otolaryngology-Head and Neck Surgery, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Toshiro Umezaki
- Department of Speech and Hearing Sciences, International University of Health and Welfare, Voice and Swallowing Center, Fukuoka Sanno Hospital, Fukuoka, Japan
| | - Yoshitaka Oku
- Department of Physiology, Hyogo College of Medicine, Hyogo, Japan
| | - Mathias Dutschmann
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Victoria, Australia
| | - Shigeru Hirano
- Department of Otolaryngology-Head and Neck Surgery, Kyoto Prefectural University of Medicine, Kyoto, Japan
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Hashimoto K, Sugiyama Y, Fuse S, Umezaki T, Oku Y, Dutschmann M, Hirano S. Activity of swallowing-related neurons in the medulla in the perfused brainstem preparation in rats. Laryngoscope 2018; 129:E72-E79. [PMID: 30408193 DOI: 10.1002/lary.27401] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/29/2018] [Indexed: 11/09/2022]
Abstract
OBJECTIVES/HYPOTHESIS We aimed to investigate and validate the cellular activity patterns and the potential topographical organization of neurons of the medullary swallowing pattern generator (Sw-CPG). We used the perfused brainstem preparation as an innovative experimental model that allows for stable neuronal recording in the brainstem. STUDY DESIGN Animal model. METHODS Experiments were conducted in 14 juvenile Wistar rats. The activities of the phrenic, vagus, and hypoglossal nerves were recorded at baseline, and fictive swallowing was elicited by stimulation of the superior laryngeal nerve. Extracellular action potentials of 72 swallowing-related neurons were recorded in the Sw-CPG of the dorsal medulla oblongata. RESULTS Neurons could be classified into three types: sensory relay, and neurons that were excited or inhibited during fictive swallowing. Approximately one-third of the neurons likely received monosynaptic input from the laryngeal afferents. One-third of neurons recorded showed respiratory-related activity, most of which exhibited inspiratory modulation. The neurons were widely distributed in the nucleus tractus solitarius and reticular formation. CONCLUSIONS The perfused brainstem preparation of rat fully preserves the Sw-CPG. The recorded cellular activities and general topographical organization of swallowing neurons are in accordance with previous in vivo studies. Thus, the perfused brainstem preparation is an ideal experimental model to advance the understanding of neuronal mechanisms underlying swallowing. LEVEL OF EVIDENCE NA Laryngoscope, 129:E72-E79, 2019.
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Affiliation(s)
- Keiko Hashimoto
- Department of Otolaryngology-Head and Neck Surgery, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Yoichiro Sugiyama
- Department of Otolaryngology-Head and Neck Surgery, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Shinya Fuse
- Department of Otolaryngology-Head and Neck Surgery, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Toshiro Umezaki
- Department of Speech and Hearing Sciences, International University of Health and Welfare, and the Voice and Swallowing Center, Fukuoka Sanno Hospital, Fukuoka, Japan
| | - Yoshitaka Oku
- Department of Physiology, Hyogo College of Medicine, Hyogo, Japan
| | - Mathias Dutschmann
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, Victoria, Australia
| | - Shigeru Hirano
- Department of Otolaryngology-Head and Neck Surgery, Kyoto Prefectural University of Medicine, Kyoto, Japan
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Audrit KJ, Delventhal L, Aydin Ö, Nassenstein C. The nervous system of airways and its remodeling in inflammatory lung diseases. Cell Tissue Res 2017; 367:571-590. [PMID: 28091773 DOI: 10.1007/s00441-016-2559-7] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Accepted: 12/13/2016] [Indexed: 12/20/2022]
Abstract
Inflammatory lung diseases are associated with bronchospasm, cough, dyspnea and airway hyperreactivity. The majority of these symptoms cannot be primarily explained by immune cell infiltration. Evidence has been provided that vagal efferent and afferent neurons play a pivotal role in this regard. Their functions can be altered by inflammatory mediators that induce long-lasting changes in vagal nerve activity and gene expression in both peripheral and central neurons, providing new targets for treatment of pulmonary inflammatory diseases.
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Affiliation(s)
- Katrin Julia Audrit
- Institute of Anatomy and Cell Biology, Aulweg 123, 35385, Giessen, Germany.,German Center for Lung Research (DZL), Giessen, Germany
| | - Lucas Delventhal
- Institute of Anatomy and Cell Biology, Aulweg 123, 35385, Giessen, Germany.,German Center for Lung Research (DZL), Giessen, Germany
| | - Öznur Aydin
- Institute of Anatomy and Cell Biology, Aulweg 123, 35385, Giessen, Germany.,German Center for Lung Research (DZL), Giessen, Germany
| | - Christina Nassenstein
- Institute of Anatomy and Cell Biology, Aulweg 123, 35385, Giessen, Germany. .,German Center for Lung Research (DZL), Giessen, Germany.
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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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Haji A, Kimura S, Ohi Y. A Model of the Central Regulatory System for Cough Reflex. Biol Pharm Bull 2013; 36:501-8. [DOI: 10.1248/bpb.b13-00052] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- Akira Haji
- Laboratory of Neuropharmacology, School of Pharmacy, Aichi Gakuin University
| | - Satoko Kimura
- Laboratory of Neuropharmacology, School of Pharmacy, Aichi Gakuin University
| | - Yoshiaki Ohi
- Laboratory of Neuropharmacology, School of Pharmacy, Aichi Gakuin University
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Cough-related neurons in the nucleus tractus solitarius of decerebrate cats. Neuroscience 2012; 218:100-9. [DOI: 10.1016/j.neuroscience.2012.05.053] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2012] [Revised: 05/21/2012] [Accepted: 05/21/2012] [Indexed: 01/09/2023]
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Expiratory-modulated laryngeal motoneurons exhibit a hyperpolarization preceding depolarization during superior laryngeal nerve stimulation in the in vivo adult rat. Brain Res 2012; 1445:52-61. [DOI: 10.1016/j.brainres.2012.01.037] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2011] [Revised: 01/10/2012] [Accepted: 01/15/2012] [Indexed: 11/19/2022]
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Sugiyama Y, Shiba K, Nakazawa K, Suzuki T, Umezaki T, Ezure K, Abo N, Yoshihara T, Hisa Y. Axonal projections of medullary swallowing neurons in guinea pigs. J Comp Neurol 2011; 519:2193-211. [DOI: 10.1002/cne.22624] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Sun QJ, Bautista TG, Berkowitz RG, Zhao WJ, Pilowsky PM. The temporal relationship between non-respiratory burst activity of expiratory laryngeal motoneurons and phrenic apnoea during stimulation of the superior laryngeal nerve in rat. J Physiol 2011; 589:1819-30. [PMID: 21320890 DOI: 10.1113/jphysiol.2010.203794] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
A striking effect of stimulating the superior laryngeal nerve (SLN) is its ability to inhibit central inspiratory activity (cause ‘phrenic apnoea'), but the mechanism underlying this inhibition remains unclear. Here we demonstrate, by stimulating the SLN at varying frequencies, that the evoked non-respiratory burst activity recorded from expiratory laryngeal motoneurons (ELMs) has an intimate temporal relationship with phrenic apnoea. During 1–5 Hz SLN stimulation, occasional absences of phrenic nerve discharge (PND) occurred such that every absent PND was preceded by an ELM burst activity. During 10–20 Hz SLN stimulation, more bursts were evoked together with more absent PNDs, leading eventually to phrenic apnoea. Interestingly, subsequent microinjections of isoguvacine (10 mm, 20–40 nl) into ipsilateral Bötzinger complex (BötC) and contralateral nucleus tractus solitarii (NTS) significantly attenuated the apnoeic response but not the ELM burst activity. Our results suggest a bifurcating projection from NTS to both the caudal nucleus ambiguus and BötC, which mediates the closely related ELM burst and apnoeic response, respectively. We believe that such an intimate timing between laryngeal behaviour and breathing is crucial for the effective elaboration of the different airway protective behaviours elicited following SLN stimulation, including the laryngeal adductor reflex, swallowing and cough.
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Affiliation(s)
- Qi-Jian Sun
- Australian School of Advanced Medicine, Macquarie University, NSW 2109, Australia
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Multiple forebrain systems converge on motor neurons innervating the thyroarytenoid muscle. Neuroscience 2009; 162:501-24. [PMID: 19426785 DOI: 10.1016/j.neuroscience.2009.05.005] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2008] [Revised: 04/13/2009] [Accepted: 05/02/2009] [Indexed: 11/20/2022]
Abstract
The present study investigated the central connections of motor neurons innervating the thyroarytenoid laryngeal muscle that is active in swallowing, respiration and vocalization. In both intact and sympathectomized rats, the pseudorabies virus (PRV) was inoculated into the muscle. After initial infection of laryngomotor neurons in the ipsilateral loose division of the nucleus ambiguus (NA) by 3 days post-inoculation, PRV spread to the ipsilateral compact portion of the NA, the central and intermediate divisions of the nucleus tractus solitarii, the Botzinger complex, and the parvicellular reticular formation by 4 days. Infection was subsequently expanded to include the ipsilateral granular and dysgranular parietal insular cortex, the ipsilateral medial division of the central nucleus of the amygdala, the lateral, paraventricular, ventrolateral and medial preoptic nuclei of the hypothalamus (generally bilaterally), the lateral periaqueductal gray, the A7 and oral and caudal pontine nuclei. At the latest time points sampled post-inoculation (5 days), infected neurons were identified in the ipsilateral agranular insular cortex, the caudal parietal insular cortex, the anterior cingulate cortex, and the contralateral motor cortex. In the amygdala, infection had spread to the lateral central nucleus and the parvicellular portion of the basolateral nucleus. Hypothalamic infection was largely characterized by an increase in the number of infected cells in earlier infected regions though the posterior, dorsomedial, tuberomammillary and mammillary nuclei contained infected cells. Comparison with previous connectional data suggests PRV followed three interconnected systems originating in the forebrain; a bilateral system including the ventral anterior cingulate cortex, periaqueductal gray and ventral respiratory group; an ipsilateral system involving the parietal insular cortex, central nucleus of the amygdala and parvicellular reticular formation, and a minor contralateral system originating in motor cortex. Hypothalamic innervation involved several functionally specific nuclei. Overall, the data imply complex CNS control over the multi-functional thyroarytenoid muscle.
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Kubin L, Alheid GF, Zuperku EJ, McCrimmon DR. Central pathways of pulmonary and lower airway vagal afferents. J Appl Physiol (1985) 2006; 101:618-27. [PMID: 16645192 PMCID: PMC4503231 DOI: 10.1152/japplphysiol.00252.2006] [Citation(s) in RCA: 312] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Lung sensory receptors with afferent fibers coursing in the vagus nerves are broadly divided into three groups: slowly (SAR) and rapidly (RAR) adapting stretch receptors and bronchopulmonary C fibers. Central terminations of each group are found in largely nonoverlapping regions of the caudal half of the nucleus of the solitary tract (NTS). Second order neurons in the pathways from these receptors innervate neurons located in respiratory-related regions of the medulla, pons, and spinal cord. The relative ease of selective activation of SARs, and to a lesser extent RARs, has allowed for more complete physiological and morphological characterization of the second and higher order neurons in these pathways than for C fibers. A subset of NTS neurons receiving afferent input from SARs (termed pump or P-cells) mediates the Breuer-Hering reflex and inhibits neurons receiving afferent input from RARs. P-cells and second order neurons in the RAR pathway also provide inputs to regions of the ventrolateral medulla involved in control of respiratory motor pattern, i.e., regions containing a predominance of bulbospinal premotor neurons, as well as regions containing respiratory rhythm-generating neurons. Axon collaterals from both P-cells and RAR interneurons, and likely from NTS interneurons in the C-fiber pathway, project to the parabrachial pontine region where they may contribute to plasticity in respiratory control and integration of respiratory control with other systems, including those that provide for voluntary control of breathing, sleep-wake behavior, and emotions.
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Affiliation(s)
- Leszek Kubin
- Dept. of Physiology-M211, Feinberg School of Medicine, Northwestern Univ., 303 E. Chicago Ave., Chicago, IL 60611-3008, USA
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Ambalavanar R, Tanaka Y, Selbie WS, Ludlow CL. Neuronal activation in the medulla oblongata during selective elicitation of the laryngeal adductor response. J Neurophysiol 2004; 92:2920-32. [PMID: 15212423 PMCID: PMC2376830 DOI: 10.1152/jn.00064.2004] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Swallow and cough are complex motor patterns elicited by rapid and intense electrical stimulation of the internal branch of the superior laryngeal nerve (ISLN). The laryngeal adductor response (LAR) includes only a laryngeal response, is elicited by single stimuli to the ISLN, and is thought to represent the brain stem pathway involved in laryngospasm. To identify which regions in the medulla are activated during elicitation of the LAR alone, single electrical stimuli were presented once every 2 s to the ISLN. Two groups of five cats each were studied; an experimental group with unilateral ISLN stimulation at 0.5 Hz and a surgical control group. Three additional cats were studied to evaluate whether other oral, pharyngeal, or respiratory muscles were activated during ISLN stimulation eliciting LAR. We quantified < or = 22 sections for each of 14 structures in the medulla to determine if regions had increased Fos-like immunoreactive neurons in the experimental group. Significant increases (P < 0.0033) occurred with unilateral ISLN stimulation in the interstitial subnucleus, the ventrolateral subnucleus, the commissural subnucleus of the nucleus tractus solitarius, the lateral tegmental field of the reticular formation, the area postrema, and the nucleus ambiguus. Neither the dorsal motor nucleus of the vagus, usually active for swallow, nor the nucleus retroambiguus, retrofacial nucleus, and the lateral reticular nucleus, usually active for cough, were active with elicitation of the laryngeal adductor response alone. The results demonstrate that the laryngeal adductor pathway is contained within the broader pathways for cough and swallow in the medulla.
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Affiliation(s)
- Ranjinidevi Ambalavanar
- Laryngeal and Speech Section, National Institute of Neurological Disorders and Strokes, Bethesda, MD 20892-1416, USA
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Saito Y, Ezure K, Tanaka I, Osawa M. Activity of neurons in ventrolateral respiratory groups during swallowing in decerebrate rats. Brain Dev 2003; 25:338-45. [PMID: 12850513 DOI: 10.1016/s0387-7604(03)00008-1] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
To elucidate the neuronal basis of the coordination between swallowing and respiration, we examined the swallowing-related activity of respiratory neurons in the ventrolateral respiratory groups of the medulla oblongata of decerebrate, paralyzed and artificially ventilated rats (n = 14). Extracellular recording was made during fictive swallowing evoked by the electrical stimulation of the superior laryngeal nerve from a total of 141 neurons with respiratory rhythm (99 expiratory and 42 inspiratory neurons). The burst of discharge by the hypoglossal nerve was used to monitor the pharyngeal phase of swallowing. The decrementing-expiratory (E-DEC) neurons (n = 62) were activated during (n = 46) or after (n = 10) the hypoglossal bursts, or showed no swallowing-related activity (n = 6). All of the augmenting-expiratory (E-AUG) neurons (n = 37) were silent during the hypoglossal bursts but were activated after each swallow. Inspiratory neurons showed either no swallowing-related bursts (n = 27), or were activated after the hypoglossal bursts (n = 15). Activation of the majority of E-DEC neurons may be related to the arrest of respiration during swallowing, and the post-swallow activation of E-AUG neurons may correspond to the expiratory phase that follows swallowing. We suggest that these behaviors of expiratory neurons are essential in the phase resetting of the respiratory cycle in association with the swallowing.
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Affiliation(s)
- Yoshiaki Saito
- Department of Neurobiology, Tokyo Metropolitan Institute for Neuroscience, Tokyo, Japan.
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18
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Potas JR, Keay KA, Henderson LA, Bandler R. Somatic and visceral afferents to the 'vasodepressor region' of the caudal midline medulla in the rat. Eur J Neurosci 2003; 17:1135-49. [PMID: 12670302 DOI: 10.1046/j.1460-9568.2003.02535.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Previous research has found that the integrity of a restricted region of the caudal midline medulla (including caudal portions of nucleus raphé obscurus and nucleus raphé pallidus) was critical for vasodepression (hypotension, bradycardia, decreased cardiac contractility) evoked either by haemorrhage or deep pain. In this anatomical tracing study we found that the vasodepressor part of the caudal midline medulla (CMM) receives inputs arising from spinal cord, spinal trigeminal nucleus (SpV) and nucleus of the solitary tract (NTS). Specifically: (i) a spinal-CMM projection arises from neurons of the deep dorsal horn, medial ventral horn and lamina X at all spinal segmental levels, with approximately 60% of the projection originating from the upper cervical spinal cord (C1-C4); (ii) a SpV-CMM projection arises primarily from neurons at the transition between subnucleus caudalis and subnucleus interpolaris; (iii) a NTS-CMM projection arises primarily from neurons in ventrolateral and medial subnuclei. In combination, the specific spinal, SpV and NTS regions which project to the CMM receive the complete range of somatic and visceral afferents known to trigger vasodepression. The role(s) of each specific projection is discussed.
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Affiliation(s)
- Jason R Potas
- Department of Anatomy and Histology, The University of Sydney, NSW, Australia 2006
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19
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Saito Y, Ezure K, Tanaka I. Swallowing-related activities of respiratory and non-respiratory neurons in the nucleus of solitary tract in the rat. J Physiol 2002; 540:1047-60. [PMID: 11986389 PMCID: PMC2290262 DOI: 10.1113/jphysiol.2001.014985] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Swallowing-related activity was examined in respiratory (n = 60) and non-respiratory (n = 82) neurons that were located in and around the nucleus of the solitary tract (NTS) in decerebrated, neuromuscularly blocked and artificially ventilated rats. Neurons that were orthodromically activated by electrical stimulation of the superior laryngeal nerve (SLN) were identified, and fictive swallowing was evoked by SLN stimulation. The pharyngeal phase of swallowing was monitored by hypoglossal nerve activity. Two types of non-respiratory neurons with swallowing-related bursts were identified: 'early' swallowing neurons (n = 24) fired during periods of hypoglossal bursts, and 'late' swallowing neurons (n = 8) fired after the end of hypoglossal bursts. The remaining non-respiratory neurons were either suppressed (n = 21) or showed no change in activity (n = 29) during swallowing. On the other hand, respiratory neurons with SLN inputs included 56 inspiratory and four expiratory neurons. Inspiratory neurons were classified into two major types: a group of neurons discharged simultaneously with hypoglossal bursts (type 1 neurons, n = 19), while others were silent during bursts but were active during inter-hypoglossal bursts when swallowing was provoked repetitively (type 2 neurons, n = 34). Three of the expiratory neurons fired during hypoglossal bursts. Many of the swallowing-related non-respiratory neurons and the majority of the inspiratory neurons received presumed monosynaptic inputs from the SLN. Details of the distribution and firing patterns of these NTS neurons, which have been revealed for the first time in a fictive swallowing preparation in the rat, suggest their participation in the initiation, pattern formation and mutual inhibition between swallowing and respiration.
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Affiliation(s)
- Yoshiaki Saito
- Department of Neurobiology, Tokyo Metropolitan Institute for Neuroscience, Tokyo Women's Medical University, Japan
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Goyal RK, Padmanabhan R, Sang Q. Neural circuits in swallowing and abdominal vagal afferent-mediated lower esophageal sphincter relaxation. Am J Med 2001; 111 Suppl 8A:95S-105S. [PMID: 11749933 DOI: 10.1016/s0002-9343(01)00863-4] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The purpose of this review is to identify the medullary subnuclei that house neural circuits for lower esophageal sphincter (LES) relaxation. LES relaxation may occur as a component of primary peristalsis elicited by superior laryngeal nerve (SLN) afferent stimulation, secondary peristalsis elicited by esophageal distention or as a component of belch reflex, and transient LES relaxation elicited by gastric vagal afferent stimulation. In mice, SLN stimulation at 10 Hz elicited complete swallowing reflex, including pharyngeal and esophageal peristalsis, and LES relaxation. SLN stimulation at 5 Hz elicited pharyngeal contractions and isolated LES relaxation, which is not accompanied by esophageal peristalsis. Electric stimulation of afferents in the ventral branch of the subdiaphragmatic vagus (vSDV) at 10 Hz also elicited isolated LES relaxation. Using these defined stimuli, c-fos expression was examined in the entire craniocaudal extent of the medullary nuclei. SLN stimulation at 10 Hz induced c-fos expression in neurons in: (1) interstitial (SolI), intermediate (SolIM), central (SolCe), occasional medial (SolM), and dorsomedial (SolDM) solitary subnuclei; (2) motor neurons in the nucleus ambiguus, including its semicompact (NAsc), loose (NAl), and compact (NAc) formations; and (3) dorsal motor nucleus of vagus, including its rostral (DMVr) and caudal (DMVc) parts. The activated neurons represent neurons involved with afferent SLN-mediated reflexes, including swallowing. SLN stimulation at 5 Hz evoked c-fos expression in neurons in SolI, SolIM, SolM, and SolDM but not in SolCe; and motor neurons in NAsc, NAl, and DMVc but not in NAc or DMVr. Stimulation of vSDV induced c-fos expression in neurons in SolM and SolDM and in motoneurons in DMVc. When considered with published reports in other animal species, these data support the speculation that (1) swallow-evoked primary peristalsis involves the following neural circuits: SolI/SolIM --> NAsc/NAl for pharyngeal and SolCe --> NAc for esophageal (striated muscle) peristalsis, SolM/SolDM --> preganglionic neurons in DMVc and DMVr and nitrergic and cholinergic neurons in myenteric plexus for esophageal (smooth muscle) peristalsis, and SolM/SolDM --> preganglionic neurons in DMVc --> postganglionic nitrergic neurons in the myenteric plexus for LES relaxation; and (2) abdominal vagus-stimulated isolated LES relaxation may involve neurons in SolM and SolDM --> preganglionic motor neurons in DMVc --> postganglionic nitrergic neurons in the myenteric plexus.
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Affiliation(s)
- R K Goyal
- Center for Swallowing and Motility Disorders, Department of Veterans Affairs Medical Center, Harvard Medical School, Boston, Massachusetts, USA
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21
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Abstract
Neural control of airway muscles and secretions is predominantly by excitatory parasympathetic and non-adrenergic, non-cholinergic innervations (excitatory and/or inhibitory depending on the species). Functionally distinct afferents effecting airway reflexes terminate in different but overlapping parts of the nucleus tractus solitarius, where integration of simultaneously evoked reflex responses occurs. Parasympathetic preganglionic neurones are located in the dorsal vagal nucleus and nucleus ambiguus, which also contains upper airway motoneurones. These output neurones receive inputs from the central respiratory network which modify the effectiveness of reflex activity. This is particularly important since many afferents evoking airway reflexes concurrently modify respiratory drive. Thus, their effect on the outflow is twofold, a direct reflex effect and an indirect respiratory action and these may facilitate or antagonise one another. Although there is reflex control of individual motor outflows, in some defined situations, e.g. swallowing and coughing a stereotypical pattern of motor outflow is evoked. The neural mechanisms underlying these aspects of airway control are discussed.
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Affiliation(s)
- D Jordan
- Department of Physiology, Royal Free and University College Medical School, Royal Free Campus, Rowland Hill Street, NW3 2PF, London, UK.
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Sang Q, Goyal RK. Swallowing reflex and brain stem neurons activated by superior laryngeal nerve stimulation in the mouse. Am J Physiol Gastrointest Liver Physiol 2001; 280:G191-200. [PMID: 11208540 DOI: 10.1152/ajpgi.2001.280.2.g191] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The purpose of the present study was to identify vagal subnuclei that participate in reflex swallowing in response to electrical stimulation of the left superior laryngeal nerve (SLN). SLN stimulation at 10 Hz evoked primary peristalsis, including oropharyngeal and esophageal peristalsis, and LES relaxation. It also induced c-fos expression in interneurons in the interstitial (SolI), intermediate (SolIM), central (SolCe), dorsomedial (SolDM) and commissural (SolC) solitary subnuclei. Neurons in parvicellular reticular nucleus (PCRt) and area postrema (AP) and motoneurons in the semicompact (NAsc), loose (NAl), and compact (NAc) formations of the nucleus ambiguus and both rostral (DMVr) and caudal (DMVc) parts of the dorsal motor nucleus of vagus were also activated. The activated neurons represent all neurons concerned with afferent SLN-mediated reflexes, including the swallowing-related neurons. SLN stimulation at 5 Hz elicited oropharyngeal and LES but not esophageal responses and evoked c-fos expression in neurons in SolI, SolIM, SolDM, PCRt, AP, NAsc, NAl, and DMVc but not in SolCe, NAc, or DMVr. These data are consistent with the role of SolI, SolIM, SolDM, NAsc, NAl, and DMVc circuit in oropharyngeal peristalsis and LES relaxation and SolCe, NAc, DMVc, and DMVr in esophageal peristalsis and LES responses.
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Affiliation(s)
- Q Sang
- Center for Swallowing and Motility Disorders, West Roxbury Division of Veterans Affairs Boston Healthcare System, West Roxbury, Massachusetts 02132, USA
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23
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Yin S, Qiu WW, Stucker FJ. Laryngeal reflexomyographic responses in rabbits: a neurolaryngological study of glottal movement. Ann Otol Rhinol Laryngol 2000; 109:576-80. [PMID: 10855569 DOI: 10.1177/000348940010900608] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The role of the laryngeal reflex in glottal movement has been reported, but its mechanism remains unclear. To further investigate the neurophysiological characteristics of glottal movement, we recorded the laryngeal reflexomyographic responses (LRMRs) to electrical stimulation of the superior laryngeal nerve (SLN) in rabbits. The procedure involved simultaneous recording of the LRMRs from the thyroarytenoid muscles by means of bipolar hooked wire electrodes after electrical stimulation to the SLN. The results demonstrated characteristic patterns of the responses, consisting of R1 and R2, similar to those found in humans. The R1 response was obtained with a latency of 10.7 +/- 0.78 ms. The ipsilateral R2 response was obtained with a latency of 43.76 +/- 4.67 ms in all rabbits, and the contralateral R2 response with a latency from 42.6 to 50.2 ms in 4 rabbits. It was concluded that LRMRs may serve as a potential central laryngeal function test in the investigation of glottal movement control.
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Affiliation(s)
- S Yin
- Department of Otolaryngology-Head and Neck Surgery, Louisiana State University Medical Center, Shreveport 71130-3359, USA
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24
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Taylor EW, Jordan D, Coote JH. Central control of the cardiovascular and respiratory systems and their interactions in vertebrates. Physiol Rev 1999; 79:855-916. [PMID: 10390519 DOI: 10.1152/physrev.1999.79.3.855] [Citation(s) in RCA: 234] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
This review explores the fundamental neuranatomical and functional bases for integration of the respiratory and cardiovascular systems in vertebrates and traces their evolution through the vertebrate groups, from primarily water-breathing fish and larval amphibians to facultative air-breathers such as lungfish and some adult amphibians and finally obligate air-breathers among the reptiles, birds, and mammals. A comparative account of respiratory rhythm generation leads to consideration of the changing roles in cardiorespiratory integration for central and peripheral chemoreceptors and mechanoreceptors and their central projections. We review evidence of a developing role in the control of cardiorespiratory interactions for the partial relocation from the dorsal motor nucleus of the vagus into the nucleus ambiguus of vagal preganglionic neurons, and in particular those innervating the heart, and for the existence of a functional topography of specific groups of sympathetic preganglionic neurons in the spinal cord. Finally, we consider the mechanisms generating temporal modulation of heart rate, vasomotor tone, and control of the airways in mammals; cardiorespiratory synchrony in fish; and integration of the cardiorespiratory system during intermittent breathing in amphibians, reptiles, and diving birds. Concluding comments suggest areas for further productive research.
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Affiliation(s)
- E W Taylor
- School of Biological Sciences and Department of Physiology, The University of Birmingham, Edgbaston, Birmingham, United Kingdom
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25
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Peden EM, Sweazey RD. Chemical stimulation of the laryngopharynx increases Fos-like immunoreactivity in the rat hypothalamus and amygdala. Brain Res Bull 1999; 48:629-39. [PMID: 10386844 DOI: 10.1016/s0361-9230(99)00050-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Using immunohistochemical detection of the Fos protein as a cellular marker of neuronal activation, we examined forebrain areas that may be activated upon chemical stimulation of the laryngeal opening. Anesthetized rats were subject to multiple infusions of a chemical solution into the laryngopharynx. These animals were compared to two control groups: a surgical control group in which the animals were subject to the surgical procedure but received no stimulus infusions and a flow control group in which physiological saline replaced the chemical stimulus. Comparing the numbers of Fos-like-immunoreactive neurons in regions of the forebrain across groups revealed that infusing the chemical stimulus solution into the laryngopharyngeal opening selectively increased the number of Fos-like-immunoreactive nuclei in the paraventricular nucleus of the hypothalamus and the central nucleus of the amygdala, two autonomic-visceral related forebrain regions. Within the paraventricular nucleus of the hypothalamus, Fos-like-immunoreactive nuclei were significantly increased in the parvocellular subdivision while in the central nucleus of the amygdala, significant increases in Fos-like-immunoreactive nuclei were limited to the lateral capsular subdivision. These data suggest that in the rat laryngopharyngeal chemosensory stimulation activates forebrain regions that receive oral sensory information and are involved in visceral and autonomic functions.
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Affiliation(s)
- E M Peden
- Department of Anatomy, Indiana University School of Medicine, Fort Wayne 46805-1499, USA
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Pierrefiche O, Haji A, Foutz AS, Takeda R, Champagnat J, Denavit-Saubie M. Synaptic potentials in respiratory neurones during evoked phase switching after NMDA receptor blockade in the cat. J Physiol 1998; 508 ( Pt 2):549-59. [PMID: 9508816 PMCID: PMC2230878 DOI: 10.1111/j.1469-7793.1998.549bq.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
1. Blockade of NMDA receptors by dizocilpine impairs the inspiratory off-switch (IOS) of central origin but not the IOS evoked by stimulation of sensory afferents. To investigate whether this difference was due to the effects of different patterns of synaptic interactions on respiratory neurones, we stimulated electrically the superior laryngeal nerve (SLN) or vagus nerve in decerebrate cats before and after i.v. administration of dizocilpine, whilst recording intracellularly. 2. Phrenic nerve responses to ipsilateral SLN or vagal stimulation were: at mid-inspiration, a transient inhibition often followed by a brief burst of activity; at late inspiration, an IOS; and at mid-expiration, a late burst of activity. 3. In all neurones (n = 16), SLN stimulation at mid-inspiration evoked an early EPSP during phase 1 (latency to the arrest of phrenic nerve activity), followed by an IPSP in inspiratory (I) neurones (n = 8) and by a wave of EPSPs in post-inspiratory (PI) neurones (n = 8) during phase 2 (inhibition of phrenic activity). An EPSP in I neurones and an IPSP in PI neurones occurred during phase 3 (brief phrenic burst) following phase 2. 4. Evoked IOS was associated with a fast (phase 1) activation of PI neurones, whereas during spontaneous IOS, a progressive (30-50 ms) depolarization of PI neurones preceded the arrest of phrenic activity. 5. Phase 3 PSPs were similar to those occurring during the burst of activity seen at the start of spontaneous inspiration. 6. Dizocilpine did not suppress the evoked phrenic inhibition and the late burst of activity. The shapes and timing of the evoked PSPs and the changes in membrane potential in I and PI neurones during the phase transition were not altered. 7. We hypothesize that afferent sensory pathways not requiring NMDA receptors (1) terminate inspiration through a premature activation of PI neurones, and (2) evoke a late burst of phrenic activity which might be the first stage of the inspiratory on-switch.
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Affiliation(s)
- O Pierrefiche
- Physiologie Animale, Faculte des Sciences, Universite de Picardie Jules Verne, 80039 Amiens, France
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Differential brainstem Fos-like immunoreactivity after laryngeal-induced coughing and its reduction by codeine. J Neurosci 1997. [PMID: 9364079 DOI: 10.1523/jneurosci.17-23-09340.1997] [Citation(s) in RCA: 69] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
We used the expression of the immediate-early gene c-fos, a marker of neuronal activation, to localize brainstem neuronal populations functionally related to fictive cough (FC). In decerebrate, paralyzed, and ventilated cats, the level of Fos-like immunoreactivity (FLI) was examined in five groups of animals: (1) controls, sham-operated unstimulated animals; (2) coughing cats, including both animals in which FC was elicited by unilateral electrical stimulation of the superior laryngeal nerve (SLN) and (3) those in which FC was elicited by bilateral SLN stimulation; (4) stimulated-treated cats, in which bilateral SLN stimulation was applied after selective blockade of FC by codeine; and (5) codeine controls, sham-operated unstimulated cats subjected to administration of codeine. Fifteen brainstem structures were compared for numbers of labeled cells. Because codeine selectively blocks FC, brainstem nuclei activated specifically during FC were identified as regions showing increased FLI after FC and significant reductions in FLI after FC suppression by codeine in stimulated-treated cats. In coughing animals, we observed a selective immunoreactivity in the interstitial and ventrolateral subdivisions of the nucleus of the tractus solitarius, the medial part of the lateral tegmental field, the internal division of the lateral reticular nucleus, the nucleus retroambiguus, the para-ambigual region, the retrofacial nucleus, and the medial parabrachial nucleus. FLI in all these nuclei was significantly reduced in stimulated-treated cats. Our results are consistent with the involvement of neurons overlapping the main brainstem respiratory-related regions as well as the lateral tegmental field and the lateral reticular nucleus in the neural processing of laryngeal-induced FC.
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Umezaki T, Zheng Y, Shiba K, Miller AD. Role of nucleus retroambigualis in respiratory reflexes evoked by superior laryngeal and vestibular nerve afferents and in emesis. Brain Res 1997; 769:347-56. [PMID: 9374205 DOI: 10.1016/s0006-8993(97)00756-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
An ascending projection from the medullary nucleus retroambigualis (NRA) has recently been described as important for the control of the upper airway during vocalization. We evaluated the importance of this projection in other behaviors by making localized injections of the neurotoxin kainic acid in the NRA in decerebrate cats, most of which were paralyzed and artificially ventilated. In contrast to its importance for vocalization, the NRA is not essential for activation of upper airway musculature during respiration, swallowing, vomiting, or reflexes elicited by superior laryngeal or vestibular nerve afferents. However, kainic acid injections in the NRA and adjacent reticular formation prolonged the inhibitory phrenic motoneuronal response to superior laryngeal nerve stimulation and abolished or reduced abdominal motoneuronal responses during respiration, vomiting, and superior laryngeal nerve stimulation. Thus, of the behaviors we investigated, the importance of the ascending projection from the NRA appears to be limited to vocalization, while descending projections from the NRA region are important in a number of behaviors.
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Affiliation(s)
- T Umezaki
- The Rockefeller University, New York, NY 10021-6399, USA
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29
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30
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Haji A, Pierrefiche O, Foutz AS, Champagnat J, Denavit-Saubié M, Takeda R. Pharmacological properties of peripherally induced postsynaptic potentials in bulbar respiratory neurons of decerebrate cats. Neurosci Lett 1996; 211:17-20. [PMID: 8809837 DOI: 10.1016/0304-3940(96)12708-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Intracellular recordings of bulbar inspiratory and post-inspiratory neurons, combined with extracellular iontophoresis of antagonists of putative neurotransmitters, were performed in decerebrate cats. Inhibitory postsynaptic potentials (IPSPs) evoked by stimulation of the superior laryngeal nerve or vagus nerve were depressed by bicuculline in all 22 neurons tested, but not modified by strychnine. The non-N-methyl-D-aspartate (NMDA) glutamate antagonist 6,7-dinitroquinoxaline-2,3-dione (DNQX) decreased the neurally evoked excitatory postsynaptic potentials (EPSPs) in 23 out of 26 neurons tested, while the NMDA antagonist dizocilpine had no notable effect. The present results suggest that the peripherally induced IPSPs are mediated through gamma-aminobutyric acid (GABA)A receptors and the EPSPs through non-NMDA glutamate receptors in bulbar respiratory neurons.
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Affiliation(s)
- A Haji
- Department of Pharmacology, Faculty of Medicine, Toyama Medical and Pharmaceutical University, Japan
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31
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Haxhiu MA, Loewy AD. Central connections of the motor and sensory vagal systems innervating the trachea. JOURNAL OF THE AUTONOMIC NERVOUS SYSTEM 1996; 57:49-56. [PMID: 8867085 DOI: 10.1016/0165-1838(95)00092-5] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Cholera toxin beta-subunit was used as both a transganglionic and retrograde cell body tracer to determine respectively the central sensory and motor systems innervating the trachea in three mammalian species, dog, ferret and rat. A basic pattern was found in all three animals. Sensory fibers terminated in three subnuclei of the nucleus tractus solitarius (NTS) with the densest concentration localized in a restricted part of the medial part of the rostral NTS. Weaker projections were identified in the ventrolateral NTS subnucleus and sparse labeling was seen in the commissural NTS subnucleus. No labeling was identified in the area postrema. The pattern of retrograde cell-body labeling was also similar in all three species. Two main sites were labeled: the rostralmost part of the dorsal vagal nucleus and the rostral nucleus ambiguus (NA). In the NA, cell labeling was found in mainly in the ventral (or external) portion of the nucleus, but some labeled neurons were consistently found in the compact NA as well. In addition, labeled neurons were also seen in the dorsomedial part of the C1-C2 ventral horn. In summary, the central sites of termination of the sensory fibers and cells of origin innervating the trachea were similar in all three species.
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Affiliation(s)
- M A Haxhiu
- Department of Medicine, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
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Dawid-Milner MS, Silva-Carvalho L, Goldsmith GE, Spyer KM. Hypothalamic modulation of laryngeal reflexes in the anaesthetized cat: role of the nucleus tractus solitarii. J Physiol 1995; 487 ( Pt 3):739-49. [PMID: 8544135 PMCID: PMC1156659 DOI: 10.1113/jphysiol.1995.sp020914] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
1. This investigation was initiated because activation of laryngeal afferents, either by electrical stimulation of the superior laryngeal nerve (SLN) or by natural stimulation of receptors in the laryngeal mucosa, results in a cardiorespiratory response comprising bradycardia, hypotension and apnoea (phrenic nerve activity was suppressed). This pattern of response is qualitatively equivalent to the response that is evoked on activation of the arterial baroreceptors. 2. Preliminary studies indicated that the effects of activating the SLN were suppressed during stimulation in the hypothalamic defence area (HDA) at points that also blocked the effects of baroreceptor stimulation. 3. Recordings were taken from seventy-two neurones localized within the ipsilateral nucleus tractus solitarii (NTS) whose activity was modified by SLN stimulation. Sixty neurones responded with an EPSP on SLN stimulation; nine of these had an inspiratory firing pattern. Five neurones were seen to receive an IPSP on SLN stimulation. 4. Five respiratory SLN-activated neurones were unresponsive to stimulation of the other nerve inputs, whilst four received convergent EPSP inputs on sinus nerve (SN) stimulation. One cell of these four also received inputs from the aortic and the vagus nerves. Sixty-one non-respiratory SLN-activated neurones also received convergent inputs from the sinus nerve. Of these, fifty displayed an EPSP, four an IPSP and seven an EPSP-IPSP. Fifteen neurones also received inputs from the aortic nerve and seventeen from the vagus. 5. From the population of neurones affected by SLN stimulation, twenty-four of seventy were also influenced by HDA stimulation (3 were respiratory cells). Sixteen of these responses consisted of an EPSP (2 respiratory cells), five of an IPSP (1 respiratory cell) and three of an EPSP-IPSP. 6. In neurones receiving an IPSP on HDA stimulation, the SLN-evoked excitatory response was reduced throughout the period of HDA-evoked inhibition. These neurones were all shown to receive excitatory inputs from the arterial baroreceptors and laryngeal mechanoreceptors. 7. Additionally, in the thirty-seven neurones that were excited by SLN stimulation but received no direct synaptic input on HDA stimulation, a conditioning stimulus to the HDA evoked a block of SLN-evoked responses without an accompanying change in membrane potential. Several of these neurones were also affected by both baroreceptor and laryngeal mechanoreceptor stimulation. 8. These observations are discussed in the context of the role of the NTS in cardiorespiratory control. The potential importance of these interactions in respiratory distress are highlighted and the implications for the organization of central pathways for the control of autonomic and respiratory function are discussed.
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Affiliation(s)
- M S Dawid-Milner
- Department of Physiology, Royal Free Hospital School of Medicine, London, UK
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Duffin J. Neural drives to breathing during exercise. CANADIAN JOURNAL OF APPLIED PHYSIOLOGY = REVUE CANADIENNE DE PHYSIOLOGIE APPLIQUEE 1994; 19:289-304. [PMID: 8000355 DOI: 10.1139/h94-025] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
This article presents the author's views about the neural drives to breathing during exercise. Two hypotheses are developed, the first being that the rapid changes in ventilation at the start and end of exercise are due to a fast neural drive whose magnitude is related to the frequency of limb movement. Experimental data are presented that this drive persists throughout exercise but declines as exercise continues. Second, the excessive increase in ventilation that occurs above the first ventilatory threshold during an incremental exercise test is due to a heavy exercise neural drive whose magnitude is related to the motor commands to the exercising muscles. Using the electromyographical activity of the working muscles as an index of the strength of the motor commands, experimental evidence is presented showing the coincidence of the first ventilatory threshold and that for the electromyographic activity of the working muscles during incremental exercise tests.
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Affiliation(s)
- J Duffin
- Department of Physiology, University of Toronto, Ontario
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Jordan D. Central integration of chemoreceptor afferent activity. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 1994; 360:87-98. [PMID: 7872132 DOI: 10.1007/978-1-4615-2572-1_8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- D Jordan
- Department of Physiology, Royal Free Hospital School of Medicine, London
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Ezure K, Oku Y, Tanaka I. Location and axonal projection of one type of swallowing interneurons in cat medulla. Brain Res 1993; 632:216-24. [PMID: 8149230 DOI: 10.1016/0006-8993(93)91156-m] [Citation(s) in RCA: 51] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Extracellular recordings were made from a type of relay neurons of the superior laryngeal nerve (SLN) afferents in the vicinity of the retrofacial nucleus (RFN) in either pentobarbitone-anesthetized or unanesthetized and decerebrate cats, which were paralyzed and artificially ventilated. A total of 26 neurons that could be activated both orthodromically by electrical stimulation of the SLN and antidromically by stimulation of the brainstem were analyzed. All 26 neurons were activated from the ipsilateral SLN and 13 were activated from the contralateral SLN with mean latencies of 7.7 ms and 11.4 ms, respectively. The majority of these neurons were located in the parvocellular reticular formation dorsomedial to the RFN and to the rostral part of the nucleus ambiguus (AMB). Antidromic stimulation of the medulla showed that 22 of the 26 neurons projected to the hypoglossal nucleus (HYP) and 19 neurons tested projected to the AMB. Of these, 15 neurons projected to both the HYP and AMB and two projected to the lateral reticular nucleus as well. Seventeen neurons were tested for their behavior during fictive swallowing which was elicited by continual electrical stimulation of the SLN and monitored by the activity of the hypoglossal nerve. Twelve neurons showed brief (100-200 ms) burst firing at the onset of swallowing; the firing of the other 5 neurons were suppressed during swallowing. Both the swallowing-active and swallowing-inactive neurons projected to the HYP and AMB. Thus, the SLN relay neurons in the vicinity of the RFN might participate in the early stage of SLN-induced swallowing by integrating inputs from SLN afferents.
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Affiliation(s)
- K Ezure
- Department of Neurobiology, Tokyo Metropolitan Institute for Neuroscience, Japan
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Jiang C, Lipski J. Synaptic inputs to medullary respiratory neurons from superior laryngeal afferents in the cat. Brain Res 1992; 584:197-206. [PMID: 1515939 DOI: 10.1016/0006-8993(92)90895-g] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Synaptic inputs from afferents in the superior laryngeal nerve (SLN) to medullary respiratory neurons (n = 154) in the dorsal respiratory group (DRG), ventral respiratory group (VRG) and the region of the Bötzinger complex (BOT) were studied in anesthetized cats. Single pulse stimulation of the SLN-evoked monosynaptic EPSPs in most inspiratory bulbospinal (I-BS) neurons in the DRG, and disynaptic or oligosynaptic chloride-dependent IPSPs in other I-BS neurons in the DRG and VRG. Stimulation of laryngeal afferents also inhibited oligosynaptically expiratory bulbospinal neurons in the VRG, and all types of respiratory neurons recorded in the BOT region. Oligosynaptic potentials (usually EPSPs) were recorded in inspiratory and expiratory laryngeal motoneurons. These results provide evidence of a processing of SLN-evoked synaptic responses by all tested groups of medullary respiratory neurons. The pathways mediating these synaptic responses are discussed.
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Affiliation(s)
- C Jiang
- Department of Physiology, School of Medicine, University of Auckland, New Zealand
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