1
|
Pho H, Amorim MR, Qiu Q, Shin M, Kim LJ, Anokye‐Danso F, Jun JJ, Ahima RS, Branco LGS, Kuhn DM, Mateika JH, Polotsky VY. The effect of brain serotonin deficiency on breathing is magnified by age. Physiol Rep 2022; 10:e15245. [PMID: 35581741 PMCID: PMC9114658 DOI: 10.14814/phy2.15245] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Revised: 02/25/2022] [Accepted: 03/13/2022] [Indexed: 11/24/2022] Open
Abstract
Serotonin is an important mediator modulating behavior, metabolism, sleep, control of breathing, and upper airway function, but the role of aging in serotonin-mediated effects has not been previously defined. Our study aimed to examine the effect of brain serotonin deficiency on breathing during sleep and metabolism in younger and older mice. We measured breathing during sleep, hypercapnic ventilatory response (HCVR), CO2 production (VCO2 ), and O2 consumption (VO2 ) in 16-18-week old and 40-44-week old mice with deficiency of tryptophan hydroxylase 2 (Tph2), which regulates serotonin synthesis specifically in neurons, compared to Tph2+/+ mice. As expected, aging decreased VCO2 and VO2 . Tph2 knockout resulted in an increase in both metabolic indexes and no interaction between age and the genotype was observed. During wakefulness, neither age nor genotype had an effect on minute ventilation. The genotype did not affect hypercapnic sensitivity in younger mice. During sleep, Tph2-/- mice showed significant decreases in maximal inspiratory flow in NREM sleep, respiratory rate, and oxyhemoglobin saturation in REM sleep, compared to wildtype, regardless of age. Neither serotonin deficiency nor aging affected the frequency of flow limited breaths (a marker of upper airway closure) or apneas. Serotonin deficiency increased the amount and efficiency of sleep only in older animals. In conclusion, younger Tph2-/- mice were able to defend their ventilation and phenotypically did not differ from wildtype during wakefulness. In contrast, both young and old Tph2-/- mice showed sleep-related hypoventilation, which was manifested by hypoxemia during REM sleep.
Collapse
Affiliation(s)
- Huy Pho
- Division of Pulmonary and Critical Care MedicineDepartment of MedicineJohns Hopkins University School of MedicineBaltimoreMarylandUSA
| | - Mateus R. Amorim
- Division of Pulmonary and Critical Care MedicineDepartment of MedicineJohns Hopkins University School of MedicineBaltimoreMarylandUSA
| | - Qingchao Qiu
- Department of PhysiologyWayne State UniversityDetroitMichiganUSA
| | - Mi‐Kyung Shin
- Division of Pulmonary and Critical Care MedicineDepartment of MedicineJohns Hopkins University School of MedicineBaltimoreMarylandUSA
| | - Lenise J. Kim
- Division of Pulmonary and Critical Care MedicineDepartment of MedicineJohns Hopkins University School of MedicineBaltimoreMarylandUSA
| | - Frederick Anokye‐Danso
- Division of Endocrinology, Diabetes, and MetabolismDepartment of MedicineJohns Hopkins University School of MedicineBaltimoreMarylandUSA
| | - Jonathan J. Jun
- Division of Pulmonary and Critical Care MedicineDepartment of MedicineJohns Hopkins University School of MedicineBaltimoreMarylandUSA
| | - Rexford S. Ahima
- Division of Endocrinology, Diabetes, and MetabolismDepartment of MedicineJohns Hopkins University School of MedicineBaltimoreMarylandUSA
| | - Luiz G. S. Branco
- Dental School of Ribeirão PretoUniversity of São PauloSão PauloBrazil
| | - Donald M. Kuhn
- Department of Psychiatry and Behavioral NeurosciencesWayne State University School of MedicineDetroitMichiganUSA
- John D. Dingell Veterans Affairs Medical CenterDetroitMichiganUSA
| | - Jason H. Mateika
- Department of PhysiologyWayne State UniversityDetroitMichiganUSA
- John D. Dingell Veterans Affairs Medical CenterDetroitMichiganUSA
- Department of Internal MedicineWayne State University School of MedicineDetroitMichiganUSA
| | - Vsevolod Y. Polotsky
- Division of Pulmonary and Critical Care MedicineDepartment of MedicineJohns Hopkins University School of MedicineBaltimoreMarylandUSA
| |
Collapse
|
2
|
Effect of dexmedetomidine on cardiorespiratory regulation in spontaneously breathing adult rats. PLoS One 2022; 17:e0262263. [PMID: 35030204 PMCID: PMC8759648 DOI: 10.1371/journal.pone.0262263] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Accepted: 12/21/2021] [Indexed: 11/19/2022] Open
Abstract
Purpose
We examined the cardiorespiratory effect of dexmedetomidine, an α2- adrenoceptor/imidazoline 1 (I1) receptor agonist, in spontaneously breathing adult rats.
Methods
Male rats (226−301 g, n = 49) under isoflurane anesthesia had their tail vein cannulated for drug administration and their tail artery cannulated for analysis of mean arterial pressure (MAP), pulse rate (PR), and arterial blood gases (PaO2, PaCO2, pH). After recovery, one set of rats received normal saline for control recording and was then divided into three experimental groups, two receiving dexmedetomidine (5 or 50 μg·kg−1) and one receiving normal saline (n = 7 per group). Another set of rats was divided into four groups receiving dexmedetomidine (50 μg·kg−1) followed 5 min later by 0.5 or 1 mg∙kg−1 atipamezole (selective α2-adrenoceptor antagonist) or efaroxan (α2-adrenoceptor/I1 receptor antagonist) (n = 6 or 8 per group). Recordings were performed 15 min after normal saline or dexmedetomidine administration.
Results
Compared with normal saline, dexmedetomidine (5 and 50 μg·kg−1) decreased respiratory frequency (fR, p = 0.04 and < 0.01, respectively), PR (both p < 0.01), and PaO2 (p = 0.04 and < 0.01), and increased tidal volume (both p = 0.049). Dexmedetomidine at 5 μg·kg−1 did not significantly change minute ventilation (V′E) (p = 0.87) or MAP (p = 0.24), whereas dexmedetomidine at 50 μg·kg−1 significantly decreased V′E (p = 0.03) and increased MAP (p < 0.01). Only dexmedetomidine at 50 μg·kg−1 increased PaCO2 (p < 0.01). Dexmedetomidine (5 and 50 μg·kg−1) significantly increased blood glucose (p < 0.01), and dexmedetomidine at 50 μg·kg−1 increased hemoglobin (p = 0.04). Supplemental atipamezole or efaroxan administration similarly prevented the 50 μg·kg−1 dexmedetomidine-related cardiorespiratory changes.
Principal conclusion
These results suggest that dexmedetomidine-related hypoventilation and hypertension are observed simultaneously and occur predominantly through activation of α2-adrenoceptors, but not I1 receptors, in spontaneously breathing adult rats.
Collapse
|
3
|
Gennaro M, Mattiello A, Mazziotti R, Antonelli C, Gherardini L, Guzzetta A, Berardi N, Cioni G, Pizzorusso T. Focal Stroke in the Developing Rat Motor Cortex Induces Age- and Experience-Dependent Maladaptive Plasticity of Corticospinal System. Front Neural Circuits 2017; 11:47. [PMID: 28706475 PMCID: PMC5489564 DOI: 10.3389/fncir.2017.00047] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2017] [Accepted: 06/13/2017] [Indexed: 12/16/2022] Open
Abstract
Motor system development is characterized by an activity-dependent competition between ipsilateral and contralateral corticospinal tracts (CST). Clinical evidence suggests that age is crucial for developmental stroke outcome, with early lesions inducing a “maladaptive” strengthening of ipsilateral projections from the healthy hemisphere and worse motor impairment. Here, we investigated in developing rats the relation between lesion timing, motor outcome and CST remodeling pattern. We induced a focal ischemia into forelimb motor cortex (fM1) at two distinct pre-weaning ages: P14 and P21. We compared long-term motor outcome with changes in axonal sprouting of contralesional CST at red nucleus and spinal cord level using anterograde tracing. We found that P14 stroke caused a more severe long-term motor impairment than at P21, and induced a strong and aberrant contralesional CST sprouting onto denervated spinal cord and red nucleus. The mistargeted sprouting of CST, and the worse motor outcome of the P14 stroke rats were reversed by an early skilled motor training, underscoring the potential of early activity-dependent plasticity in modulating lesion outcome. Thus, changes in the mechanisms controlling CST plasticity occurring during the third postnatal week are associated with age-dependent regulation of the motor outcome after stroke.
Collapse
Affiliation(s)
- Mariangela Gennaro
- Department of Neuroscience, Psychology, Drug Research and Child Health NEUROFARBA, University of FlorenceFlorence, Italy.,Institute of Neuroscience, National Research Council (CNR)Pisa, Italy
| | - Alessandro Mattiello
- Department of Neuroscience, Psychology, Drug Research and Child Health NEUROFARBA, University of FlorenceFlorence, Italy.,Institute of Neuroscience, National Research Council (CNR)Pisa, Italy
| | - Raffaele Mazziotti
- Department of Neuroscience, Psychology, Drug Research and Child Health NEUROFARBA, University of FlorenceFlorence, Italy.,Institute of Neuroscience, National Research Council (CNR)Pisa, Italy
| | - Camilla Antonelli
- Department of Clinical and Experimental Medicine, University of PisaPisa, Italy.,Department of Developmental Neuroscience, IRCCS Stella Maris Scientific InstitutePisa, Italy
| | - Lisa Gherardini
- Institute of Neuroscience, National Research Council (CNR)Pisa, Italy.,Institute of Clinical Physiology, National Research Council (CNR)Siena, Italy
| | - Andrea Guzzetta
- Department of Clinical and Experimental Medicine, University of PisaPisa, Italy.,Department of Developmental Neuroscience, IRCCS Stella Maris Scientific InstitutePisa, Italy
| | - Nicoletta Berardi
- Department of Neuroscience, Psychology, Drug Research and Child Health NEUROFARBA, University of FlorenceFlorence, Italy.,Institute of Neuroscience, National Research Council (CNR)Pisa, Italy
| | - Giovanni Cioni
- Department of Clinical and Experimental Medicine, University of PisaPisa, Italy.,Department of Developmental Neuroscience, IRCCS Stella Maris Scientific InstitutePisa, Italy
| | - Tommaso Pizzorusso
- Department of Neuroscience, Psychology, Drug Research and Child Health NEUROFARBA, University of FlorenceFlorence, Italy.,Institute of Neuroscience, National Research Council (CNR)Pisa, Italy
| |
Collapse
|
4
|
Kanjhan R, Fogarty MJ, Noakes PG, Bellingham MC. Developmental changes in the morphology of mouse hypoglossal motor neurons. Brain Struct Funct 2016; 221:3755-86. [PMID: 26476929 PMCID: PMC5009180 DOI: 10.1007/s00429-015-1130-8] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2015] [Accepted: 10/03/2015] [Indexed: 12/19/2022]
Abstract
Hypoglossal motor neurons (XII MNs) innervate tongue muscles important in breathing, suckling and vocalization. Morphological properties of 103 XII MNs were studied using Neurobiotin™ filling in transverse brainstem slices from C57/Bl6 mice (n = 34) from embryonic day (E) 17 to postnatal day (P) 28. XII MNs from areas thought to innervate different tongue muscles showed similar morphology in most, but not all, features. Morphological properties of XII MNs were established prior to birth, not differing between E17-18 and P0. MN somatic volume gradually increased for the first 2 weeks post-birth. The complexity of dendritic branching and dendrite length of XII MNs increased throughout development (E17-P28). MNs in the ventromedial XII motor nucleus, likely to innervate the genioglossus, frequently (42 %) had dendrites crossing to the contralateral side at all ages, but their number declined with postnatal development. Unexpectedly, putative dendritic spines were found in all XII MNs at all ages, and were primarily localized to XII MN somata and primary dendrites at E18-P4, increased in distal dendrites by P5-P8, and were later predominantly found in distal dendrites. Dye-coupling between XII MNs was common from E18 to P7, but declined strongly with maturation after P7. Axon collaterals were found in 20 % (6 of 28) of XII MNs with filled axons; collaterals terminated widely outside and, in one case, within the XII motor nucleus. These results reveal new morphological features of mouse XII MNs, and suggest that dendritic projection patterns, spine density and distribution, and dye-coupling patterns show specific developmental changes in mice.
Collapse
Affiliation(s)
- Refik Kanjhan
- School of Biomedical Sciences, University of Queensland, Brisbane, QLD, 4072, Australia
| | - Matthew J Fogarty
- School of Biomedical Sciences, University of Queensland, Brisbane, QLD, 4072, Australia
| | - Peter G Noakes
- School of Biomedical Sciences, University of Queensland, Brisbane, QLD, 4072, Australia
- Queensland Brain Institute, University of Queensland, Brisbane, QLD, 4072, Australia
| | - Mark C Bellingham
- School of Biomedical Sciences, University of Queensland, Brisbane, QLD, 4072, Australia.
| |
Collapse
|
5
|
Revill AL, Vann NC, Akins VT, Kottick A, Gray PA, Del Negro CA, Funk GD. Dbx1 precursor cells are a source of inspiratory XII premotoneurons. eLife 2015; 4. [PMID: 26687006 PMCID: PMC4764567 DOI: 10.7554/elife.12301] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2015] [Accepted: 12/18/2015] [Indexed: 11/28/2022] Open
Abstract
All behaviors require coordinated activation of motoneurons from central command and premotor networks. The genetic identities of premotoneurons providing behaviorally relevant excitation to any pool of respiratory motoneurons remain unknown. Recently, we established in vitro that Dbx1-derived pre-Bötzinger complex neurons are critical for rhythm generation and that a subpopulation serves a premotor function (Wang et al., 2014). Here, we further show that a subpopulation of Dbx1-derived intermediate reticular (IRt) neurons are rhythmically active during inspiration and project to the hypoglossal (XII) nucleus that contains motoneurons important for maintaining airway patency. Laser ablation of Dbx1 IRt neurons, 57% of which are glutamatergic, decreased ipsilateral inspiratory motor output without affecting frequency. We conclude that a subset of Dbx1 IRt neurons is a source of premotor excitatory drive, contributing to the inspiratory behavior of XII motoneurons, as well as a key component of the airway control network whose dysfunction contributes to sleep apnea. DOI:http://dx.doi.org/10.7554/eLife.12301.001
Collapse
Affiliation(s)
- Ann L Revill
- Department of Physiology, Neuroscience and Mental Health Institute, Women and Children's Health Research Institute, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Canada
| | - Nikolas C Vann
- Department of Applied Science, The College of William and Mary, Williamsburg, United States
| | - Victoria T Akins
- Department of Applied Science, The College of William and Mary, Williamsburg, United States
| | - Andrew Kottick
- Department of Applied Science, The College of William and Mary, Williamsburg, United States
| | - Paul A Gray
- Department of Anatomy and Neurobiology, Washington University School of Medicine, St. Louis, United States
| | | | - Gregory D Funk
- Department of Physiology, Neuroscience and Mental Health Institute, Women and Children's Health Research Institute, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Canada
| |
Collapse
|
6
|
Abrupt changes in pentobarbital sensitivity in preBötzinger complex region, hypoglossal motor nucleus, nucleus tractus solitarius, and cortex during rat transitional period (P10-P15). Respir Physiol Neurobiol 2014; 207:61-71. [PMID: 25550216 DOI: 10.1016/j.resp.2014.12.016] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2014] [Revised: 12/19/2014] [Accepted: 12/22/2014] [Indexed: 01/01/2023]
Abstract
On postnatal days P10-P15 in rat medulla, neurotransmitter receptor subunit composition shifts toward a more mature phenotype. Since medullary GABAARs regulate cardiorespiratory function, abrupt alterations in GABAergic synaptic inhibition could disrupt homeostasis. We hypothesized that GABAARs on medullary neurons become more resistant to positive allosteric modulation during P10-P15. Medullary and cortical slices from P10 to P20 rats were used to record spontaneous action potentials in pre-Botzinger Complex (preBötC-region), hypoglossal (XII) motor nucleus, nucleus tractus solitarius (NTS), and cortex during exposure to pentobarbital (positive allosteric modulator of GABAARs). On P14, pentobarbital resistance abruptly increased in preBötC-region and decreased in NTS, but these changes in pentobarbital resistance were not present on P15. Pentobarbital resistance decreased in XII motor nucleus during P11-P15 with a nadir at P14. Abrupt changes in pentobarbital resistance indicate changes in GABAergic receptor composition and function that may compensate for potential increased GABAergic inhibition and respiratory depression that occurs during this key developmental transitional period.
Collapse
|
7
|
Jin X, Zhong W, Jiang C. Time-dependent modulation of GABA(A)-ergic synaptic transmission by allopregnanolone in locus coeruleus neurons of Mecp2-null mice. Am J Physiol Cell Physiol 2013; 305:C1151-60. [PMID: 24067915 DOI: 10.1152/ajpcell.00195.2013] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Rett syndrome (RTT) is a neurodevelopmental disorder with symptoms starting 6-18 mo after birth, while what underlies the delayed onset is unclear. Allopregnanolone (Allop) is a metabolite of progesterone and a potent modulator of GABAA-ergic currents whose defects are seen in RTT. Allop changes its concentration during the perinatal period, which may affect central neurons via the GABAA-ergic synaptic transmission, contributing to the onset of the disease. To determine whether Mecp2 disruption affects Allop modulation, we performed studies in brain slices obtained from wild-type (WT) and Mecp2(-/Y) mice. Allop dose dependently suppressed locus coeruleus (LC) neuronal excitability in WT mice, while Mecp2-null neurons showed significant defects. Using optogenetic approaches, channelrhodopsin was specifically expressed in GABA-ergic neurons in which optical stimulation evoked action potentials. In LC neurons of WT mice, Allop exposure increased the amplitude of GABAA-ergic inhibitory postsynaptic currents (IPSCs) evoked by optical stimulation and prolonged the IPSC decay time. Consistently, Allop augmented both frequency and amplitude of GABAA-ergic spontaneous IPSCs (sIPSCs) and extended the decay time of sIPSCs. The Allop-induced potentiation of sIPSCs was deficient in Mecp2(-/Y) mice. Surprisingly, the impairment occurred at 3 wk postnatal age, while no significant difference in Allop modulation was observed in 1-2 wk between WT and Mecp2(-/Y) mice. These results indicate that the modulation of GABAA-ergic synaptic transmission by Allop is impaired in LC neurons of Mecp2-null mice at a time when RTT-like symptoms manifest, suggesting a potential mechanism for the delayed onset of the disease.
Collapse
Affiliation(s)
- Xin Jin
- Department of Biology, Georgia State University, Atlanta, Georgia
| | | | | |
Collapse
|
8
|
Kato T, Nakamura N, Masuda Y, Yoshida A, Morimoto T, Yamamura K, Yamashita S, Sato F. Phasic bursts of the antagonistic jaw muscles during REM sleep mimic a coordinated motor pattern during mastication. J Appl Physiol (1985) 2012. [PMID: 23195628 DOI: 10.1152/japplphysiol.00895.2012] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Sleep-related movement disorders are characterized by the specific phenotypes of muscle activities and movements during sleep. However, the state-specific characteristics of muscle bursts and movement during sleep are poorly understood. In this study, jaw-closing and -opening muscle electromyographic (EMG) activities and jaw movements were quantified to characterize phenotypes of motor patterns during sleep in freely moving and head-restrained guinea pigs. During non-rapid eye movement (NREM) sleep, both muscles were irregularly activated in terms of duration, activity, and intervals. During rapid eye movement (REM) sleep, clusters of phasic bursts occurred in the two muscles. Compared with NREM sleep, burst duration, activity, and intervals were less variable during REM sleep for both muscles. Although burst activity was lower during the two sleep states than during chewing, burst duration and intervals during REM sleep were distributed within a similar range to those during chewing. A trigger-averaged analysis of muscle bursts revealed that the temporal association between the bursts of the jaw-closing and -opening muscles during REM sleep was analogous to the temporal association during natural chewing. The burst characteristics of the two muscles reflected irregular patterns of jaw movements during NREM sleep and repetitive alternating bilateral movements during REM sleep. The distinct patterns of jaw muscle bursts and movements reflect state-specific regulations of the jaw motor system during sleep states. Phasic activations in the antagonistic jaw muscles during REM sleep are regulated, at least in part, by the neural networks involving masticatory pattern generation, demonstrating that waking jaw motor patterns are replayed during sleep periods.
Collapse
Affiliation(s)
- T Kato
- Osaka University Graduate School of Dentistry, Department of Oral Anatomy and Neurobiology, Osaka, Japan.
| | | | | | | | | | | | | | | |
Collapse
|
9
|
Niebert M, Vogelgesang S, Koch UR, Bischoff AM, Kron M, Bock N, Manzke T. Expression and function of serotonin 2A and 2B receptors in the mammalian respiratory network. PLoS One 2011; 6:e21395. [PMID: 21789169 PMCID: PMC3138749 DOI: 10.1371/journal.pone.0021395] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2011] [Accepted: 05/27/2011] [Indexed: 12/20/2022] Open
Abstract
Neurons of the respiratory network in the lower brainstem express a variety of serotonin receptors (5-HTRs) that act primarily through adenylyl cyclase. However, there is one receptor family including 5-HT2A, 5-HT2B, and 5-HT2C receptors that are directed towards protein kinase C (PKC). In contrast to 5-HT2ARs, expression and function of 5-HT2BRs within the respiratory network are still unclear. 5-HT2BR utilizes a Gq-mediated signaling cascade involving calcium and leading to activation of phospholipase C and IP3/DAG pathways. Based on previous studies, this signal pathway appears to mediate excitatory actions on respiration. In the present study, we analyzed receptor expression in pontine and medullary regions of the respiratory network both at the transcriptional and translational level using quantitative RT-PCR and self-made as well as commercially available antibodies, respectively. In addition we measured effects of selective agonists and antagonists for 5-HT2ARs and 5-HT2BRs given intra-arterially on phrenic nerve discharges in juvenile rats using the perfused brainstem preparation. The drugs caused significant changes in discharge activity. Co-administration of both agonists revealed a dominance of the 5-HT2BR. Given the nature of the signaling pathways, we investigated whether intracellular calcium may explain effects observed in the respiratory network. Taken together, the results of this study suggest a significant role of both receptors in respiratory network modulation.
Collapse
MESH Headings
- Animals
- Antibodies/immunology
- Antibody Specificity/immunology
- Calcium/metabolism
- Fluorescence
- Gene Expression Regulation/drug effects
- In Vitro Techniques
- Male
- Mammals/metabolism
- Medulla Oblongata/cytology
- Medulla Oblongata/drug effects
- Medulla Oblongata/metabolism
- Mice
- Pons/cytology
- Pons/drug effects
- Pons/metabolism
- Rats
- Receptor, Serotonin, 5-HT2A/genetics
- Receptor, Serotonin, 5-HT2A/metabolism
- Receptor, Serotonin, 5-HT2B/chemistry
- Receptor, Serotonin, 5-HT2B/genetics
- Receptor, Serotonin, 5-HT2B/metabolism
- Recombinant Proteins/metabolism
- Reproducibility of Results
- Respiration/drug effects
- Respiratory System/drug effects
- Respiratory System/metabolism
- Serotonin 5-HT2 Receptor Antagonists/pharmacology
- Signal Transduction/drug effects
Collapse
Affiliation(s)
- Marcus Niebert
- Department of Neuro- and Sensory Physiology, Georg-August-University of Göttingen, Göttingen, Germany
- German Research Council Research Center for Molecular Physiology of the Brain, Göttingen, Germany
| | - Steffen Vogelgesang
- Department of Neuro- and Sensory Physiology, Georg-August-University of Göttingen, Göttingen, Germany
- German Research Council Research Center for Molecular Physiology of the Brain, Göttingen, Germany
| | - Uwe R. Koch
- Department of Neuro- and Sensory Physiology, Georg-August-University of Göttingen, Göttingen, Germany
| | - Anna-Maria Bischoff
- Department of Neuro- and Sensory Physiology, Georg-August-University of Göttingen, Göttingen, Germany
| | - Miriam Kron
- German Research Council Research Center for Molecular Physiology of the Brain, Göttingen, Germany
| | - Nathalie Bock
- Department of Child and Adolescent Psychiatry, Georg-August-University of Göttingen, Göttingen, Germany
| | - Till Manzke
- Department of Neuro- and Sensory Physiology, Georg-August-University of Göttingen, Göttingen, Germany
- German Research Council Research Center for Molecular Physiology of the Brain, Göttingen, Germany
- * E-mail:
| |
Collapse
|
10
|
MacFarlane PM, Vinit S, Mitchell GS. Serotonin 2A and 2B receptor-induced phrenic motor facilitation: differential requirement for spinal NADPH oxidase activity. Neuroscience 2011; 178:45-55. [PMID: 21223996 DOI: 10.1016/j.neuroscience.2011.01.011] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2010] [Revised: 12/08/2010] [Accepted: 01/05/2011] [Indexed: 10/18/2022]
Abstract
Acute intermittent hypoxia (AIH) facilitates phrenic motor output by a mechanism that requires spinal serotonin (type 2) receptor activation, NADPH oxidase activity and formation of reactive oxygen species (ROS). Episodic spinal serotonin (5-HT) receptor activation alone, without changes in oxygenation, is sufficient to elicit NADPH oxidase-dependent phrenic motor facilitation (pMF). Here we investigated: (1) whether serotonin 2A and/or 2B (5-HT2A/B) receptors are expressed in identified phrenic motor neurons, and (2) which receptor subtype is capable of eliciting NADPH-oxidase-dependent pMF. In anesthetized, artificially ventilated adult rats, episodic C4 intrathecal injections (3×6 μl injections, 5 min intervals) of a 5-HT2A (DOI) or 5-HT2B (BW723C86) receptor agonist elicited progressive and sustained increases in integrated phrenic nerve burst amplitude (i.e. pMF), an effect lasting at least 90 min post-injection for both receptor subtypes. 5-HT2A and 5-HT2B receptor agonist-induced pMF were both blocked by selective antagonists (ketanserin and SB206553, respectively), but not by antagonists to the other receptor subtype. Single injections of either agonist failed to elicit pMF, demonstrating a need for episodic receptor activation. Phrenic motor neurons retrogradely labeled with cholera toxin B fragment expressed both 5-HT2A and 5-HT2B receptors. Pre-treatment with NADPH oxidase inhibitors (apocynin and diphenylenodium (DPI)) blocked 5-HT2B, but not 5-HT2A-induced pMF. Thus, multiple spinal type 2 serotonin receptors elicit pMF, but they act via distinct mechanisms that differ in their requirement for NADPH oxidase activity.
Collapse
Affiliation(s)
- P M MacFarlane
- Department of Comparative Biosciences, University of Wisconsin, Madison; School of Veterinary Medicine, 2015 Linden Drive, Madison, WI 53706, USA.
| | | | | |
Collapse
|
11
|
Penatti EM, Barina AE, Raju S, Li A, Kinney HC, Commons KG, Nattie EE. Maternal dietary tryptophan deficiency alters cardiorespiratory control in rat pups. J Appl Physiol (1985) 2010; 110:318-28. [PMID: 20966190 DOI: 10.1152/japplphysiol.00788.2010] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Malnutrition during pregnancy adversely affects postnatal forebrain development; its effect upon brain stem development is less certain. To evaluate the role of tryptophan [critical for serotonin (5-HT) synthesis] on brain stem 5-HT and the development of cardiorespiratory function, we fed dams a diet ∼45% deficient in tryptophan during gestation and early postnatal life and studied cardiorespiratory variables in the developing pups. Deficient pups were of normal weight at postnatal day (P)5 but weighed less than control pups at P15 and P25 (P < 0.001) and had lower body temperatures at P15 (P < 0.001) and P25 (P < 0.05; females only). Oxygen consumption (Vo(2)) was unaffected. At P15, deficient pups had an altered breathing pattern and slower heart rates. At P25, they had significantly lower ventilation (Ve) and Ve-to-Vo(2) ratios in both air and 7% CO(2). The ventilatory response to CO(2) (% increase in Ve/Vo(2)) was significantly increased at P5 (males) and reduced at P15 and P25 (males and females). Deficient pups had 41-56% less medullary 5-HT (P < 0.01) compared with control pups, without a difference in 5-HT neuronal number. These data indicate important interactions between nutrition, brain stem physiology, and age that are potentially relevant to understanding 5-HT deficiency in the sudden infant death syndrome.
Collapse
Affiliation(s)
- Eliana M Penatti
- Dartmouth Medical School, Dept. of Physiology, Borwell Bldg., 1 Medical Center Dr. HB7700, Lebanon, NH 03756, USA
| | | | | | | | | | | | | |
Collapse
|
12
|
MacFarlane PM, Mitchell GS. Episodic spinal serotonin receptor activation elicits long-lasting phrenic motor facilitation by an NADPH oxidase-dependent mechanism. J Physiol 2009; 587:5469-81. [PMID: 19805745 DOI: 10.1113/jphysiol.2009.176982] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Phrenic long-term facilitation (pLTF) is a serotonin (5-HT)-dependent augmentation of phrenic motor output induced by acute intermittent hypoxia (AIH). AIH-induced pLTF requires spinal NADPH oxidase activity and reactive oxygen species (ROS) formation. Since 5-HT receptor activation stimulates NADPH oxidase activity in some cell types, we tested the hypothesis that episodic spinal 5-HT receptor activation (without AIH) is sufficient to elicit an NADPH oxidase-dependent facilitation of phrenic motor output (pMF). In anaesthetised, artificially ventilated adult male rats, episodic intrathecal 5-HT injections (3 x 6 microl injections at 5 min intervals) into the cerebrospinal fluid (CSF) near cervical spinal segments containing the phrenic motor nucleus elicited a progressive increase in integrated phrenic nerve burst amplitude (i.e. pMF) lasting at least 60 min post-5-HT administration. Hypoglossal (XII) nerve activity was unaffected, suggesting that effective doses of 5-HT did not reach the brainstem. A single 5-HT injection was without effect. 5-HT-induced pMF was dose dependent, but exhibited a bell-shaped dose-response curve. Activation of different 5-HT receptor subtypes, specifically 5-HT(2) versus 5-HT(7) receptors, may underlie the bell-shaped dose-response curve via a mechanism of 'cross-talk' inhibition. Pre-treatment with NADPH oxidase inhibitors, apocynin or diphenylenodium (DPI), blocked 5-HT induced pMF. Thus, episodic spinal 5-HT receptor activation is sufficient to elicit pMF by an NADPH oxidase-dependent mechanism, suggesting common mechanisms of ROS formation with AIH-induced pLTF. An understanding of the mechanisms giving rise to AIH-induced pLTF and 5-HT induced pMF may inspire novel therapeutic strategies for respiratory insufficiency in diverse conditions, such as sleep apnoea, cervical spinal injury or amyotrophic lateral sclerosis.
Collapse
Affiliation(s)
- P M MacFarlane
- Department of Comparative Biosciences, University of Wisconsin, Madison, WI 53706, USA
| | | |
Collapse
|
13
|
Fenik VB, Rukhadze I, Kubin L. Antagonism of alpha1-adrenergic and serotonergic receptors in the hypoglossal motor nucleus does not prevent motoneuronal activation elicited from the posterior hypothalamus. Neurosci Lett 2009; 462:80-4. [PMID: 19573578 PMCID: PMC2734450 DOI: 10.1016/j.neulet.2009.06.083] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2009] [Revised: 06/23/2009] [Accepted: 06/25/2009] [Indexed: 11/27/2022]
Abstract
The perifornical (PF) region of the posterior hypothalamus plays an important role in the regulation of sleep-wake states and motor activity. Disinhibition of PF neurons by the GABA(A) receptor antagonist, bicuculline, has been used to study the mechanisms of wake- and motor activity-promoting effects that emanate from the PF region. Bicuculline activates PF neurons, including the orexin-containing cells that have major excitatory projections to brainstem noradrenergic and serotonergic neurons. Since premotor aminergic neurons are an important source of motoneuronal activation, we hypothesized that they mediate the excitation of motoneurons that results from disinhibition of PF neurons with bicuculline. In urethane-anesthetized, paralyzed and artificially ventilated rats, we found that PF bicuculline injections (1mM, 20 nl) made after combined microinjections into the hypoglossal (XII) nucleus of alpha(1)-adrenergic and serotonergic receptor antagonists (prazosin and methysergide) increased XII nerve activity by 80+/-16% (SE) of the control activity level. Thus, activation of XII motoneurons originating in the hypothalamic PF region was not abolished despite effective elimination by the aminergic antagonists of the endogenous noradrenergic and serotonergic excitatory drives to XII motoneurons and abolition of XII motoneuronal activation by exogenous serotonin or phenylephrine. These results show that a major component of XII motoneuronal activation originating in the posterior hypothalamus is mediated by pathways other than the noradrenergic and serotonergic projections to motoneurons.
Collapse
Affiliation(s)
- Victor B Fenik
- Department of Animal Biology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104-6046, USA.
| | | | | |
Collapse
|
14
|
Liu Q, Wong-Riley MTT. Postnatal changes in the expressions of serotonin 1A, 1B, and 2A receptors in ten brain stem nuclei of the rat: implication for a sensitive period. Neuroscience 2009; 165:61-78. [PMID: 19800944 DOI: 10.1016/j.neuroscience.2009.09.078] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2009] [Revised: 09/25/2009] [Accepted: 09/28/2009] [Indexed: 01/08/2023]
Abstract
A critical period in respiratory network development occurs in the rat around postnatal days (P) 12-13, when abrupt neurochemical, metabolic, and physiological changes were evident. As serotonin and its receptors are involved in respiratory modulation, and serotonergic abnormality is implicated in sudden infant death syndrome, we hypothesized that 5-HT receptors are significantly downregulated during the critical period. This was documented recently for 5-HT(2A)R in several respiratory nuclei. The present study represents a comprehensive analysis of postnatal development of 5-HT(1A)R and 5-HT(1B)R in 10 brain stem nuclei and 5-HT(2A)R in six nuclei not previously examined. Optical densitometric analysis of immunohistochemically-reacted neurons from P2 to P21 indicated four developmental patterns of expression: (1) Pattern I: a high level of expression at P2-P11, an abrupt and significant reduction at P12, followed by a plateau until P21 (5-HT(1A)R and 5-HT(1B)R in raphé magnus [RM], raphé obscurus [ROb], raphé pallidus [RP], pre-Bötzinger complex [PBC], nucleus ambiguus [Amb], and hypoglossal nucleus [XII; 5-HT(1A)R only]). (2) Pattern II: a high level at P2-P9, a gradual decline from P9 to P12, followed by a plateau until P21 (5-HT(1A)R and 5-HT(1B)R in the retrotrapezoid nucleus (RTN)/parafacial respiratory group (pFRG)). (3) Pattern III: a high level at P2-P11, followed by a gradual decline until P21 (5-HT(1A)R in the ventrolateral subnucleus of solitary tract nucleus [NTS(VL)] and the non-respiratory cuneate nucleus [CN]). (4) Pattern IV: a relatively constant level maintained from P2 to P21 (5-HT(1A)R in the commissural subnucleus of solitary tract nucleus (NTS(COM)); 5-HT(1B)R in XII, NTS(VL), NTS(COM), and CN; and 5-HT(2A)R in RM, ROb, RP, RTN/pFRG, NTS(VL), and NTS(COM)). Thus, a significant reduction in the expression of 5-HT(1A)R, 5-HT(1B)R, and 5-HT(2A)R in multiple respiratory-related nuclei at P12 is consistent with reduced serotonergic transmission during the critical period, thereby rendering the animals less able to respond adequately to ventilatory distress.
Collapse
Affiliation(s)
- Q Liu
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, 53226, USA
| | | |
Collapse
|
15
|
Lu JW, Kubin L. Electromyographic activity at the base and tip of the tongue across sleep-wake states in rats. Respir Physiol Neurobiol 2009; 167:307-15. [PMID: 19539786 DOI: 10.1016/j.resp.2009.06.004] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2009] [Revised: 05/19/2009] [Accepted: 06/09/2009] [Indexed: 11/19/2022]
Abstract
Obstructive sleep apnea (OSA) patients have elevated tonic and phasic inspiratory activity in the genioglossus and other upper airway muscles during wakefulness; this protects their upper airway from collapse. In this group, sleep-related decrements of upper airway motor tone result in sleep-related upper airway obstructions. We previously reported that in the rat, a species widely used to study the neural mechanisms of both sleep and breathing, lingual electromyographic activity (EMG) is minimal or absent during slow-wave sleep (SWS) and then gradually increases after the onset of rapid eye movement sleep (REMS) due to the appearance of large phasic bursts. Here, we investigated whether sleep-wake patterns and respiratory modulation of lingual EMG depend on the site of EMG recording within the tongue. In nine chronically instrumented rats, we recorded from 17 sites within the tongue and from the diaphragm across sleep-wake states. We quantified lingual EMG in successive 10s intervals of continuous 2h recordings (1-3 p.m.). We found that sleep-wake patterns of lingual EMG did not differ between the base and tip of the tongue, and that respiratory modulation was extremely rare regardless of the recording site. We also determined that the often rhythmic lingual bursts during REMS do not occur with respiratory rhythmicity. This pattern differs from that in OSA subjects who, unlike rats, have collapsible upper airway, exhibit prominent respiratory modulation of upper airway motor tone during quiet wakefulness, retain considerable tonic and inspiratory phasic activity during SWS, and show nadirs of activity during REMS.
Collapse
Affiliation(s)
- Jackie W Lu
- Department of Animal Biology 209E/VET, School of Veterinary Medicine and Center for Sleep and Respiratory Neurobiology, University of Pennsylvania, 3800 Spruce Street, Philadelphia, PA 19104-6046, USA
| | | |
Collapse
|
16
|
Pilowsky PM. Neurochemical phenotypes of cardiorespiratory neurons. Respir Physiol Neurobiol 2009; 164:12-7. [PMID: 18707031 DOI: 10.1016/j.resp.2008.07.016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2008] [Revised: 07/20/2008] [Accepted: 07/21/2008] [Indexed: 02/07/2023]
Abstract
Interactions between the cardiovascular and respiratory systems have been known for many years but the functional significance of the interactions is still widely debated. Here I discuss the possible role of metabotropic receptors in regulating cardiorespiratory neurons in the brainstem and spinal cord. It is clear that, although much has been discovered, cardiorespiratory regulation is certainly one area that still has a long way to go before its secrets are fully divulged and their function in controlling circulatory and respiratory function is revealed.
Collapse
Affiliation(s)
- Paul M Pilowsky
- Australian School ofAdvanced Medicine, Dow-Corning Building, Level 1, 3 Innovation Road, Macquarie University, Sydney 2109, NSW, Australia.
| |
Collapse
|
17
|
McCrimmon DR, Mitchell GS, Alheid GF. Overview: the neurochemistry of respiratory control. Respir Physiol Neurobiol 2008; 164:1-2. [PMID: 18721910 PMCID: PMC2642897 DOI: 10.1016/j.resp.2008.07.021] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2008] [Accepted: 07/23/2008] [Indexed: 01/25/2023]
Abstract
This special issue of Respiratory Physiology and Neurobiology surveys a broad range of topics focused on the neurochemical control of breathing. A variety of approaches have integrated the neurochemistry of breathing with the physiology of individual neurons, with the neuroanatomy of brainstem and forebrain respiratory circuits, and with the clinical pathology of respiratory disorders all of which has been fueled by the ongoing explosion of information in the molecular biology of the nervous system. Accordingly, substantial progress has identified neurotransmitters, neuromodulators, receptors, signaling cascades, trophic factors, hormones, and genes mediating normal and pathological breathing. Dynamic changes in the neurochemistry of breathing are addressed with respect to brainstem development, environmental challenges such as intermittent or chronic hypoxia, and as a function of the sleep-wake cycle. Respiratory disruption has also been identified in an increasing variety of genetic-based disorders and remarkable progress has been made in determining the affected genes and their mutations that negatively impact respiration.
Collapse
Affiliation(s)
- Donald R. McCrimmon
- Department of Physiology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA 60611−3088
| | - Gordon S. Mitchell
- Department of Comparative Biosciences, School of Veterinary Medicine, University of Wisconsin, Madison, WI, USA, 53706
| | - George F. Alheid
- Department of Physiology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA 60611−3088
| |
Collapse
|
18
|
Volgin DV, Rukhadze I, Kubin L. Hypoglossal premotor neurons of the intermediate medullary reticular region express cholinergic markers. J Appl Physiol (1985) 2008; 105:1576-84. [PMID: 18772326 DOI: 10.1152/japplphysiol.90670.2008] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The inspiratory drive to hypoglossal (XII) motoneurons originates in the caudal medullary intermediate reticular (IRt) region. This drive is mainly glutamatergic, but little is known about the neurochemical features of IRt XII premotor neurons. Prompted by the evidence that XII motoneuronal activity is controlled by both muscarinic (M) and nicotinic cholinergic inputs and that the IRt region contains cells that express choline acetyltransferase (ChAT), a marker of cholinergic neurons, we investigated whether some IRt XII premotor neurons are cholinergic. In seven rats, we applied single-cell reverse transcription-polymerase chain reaction to acutely dissociated IRt neurons retrogradely labeled from the XII nucleus. We found that over half (21/37) of such neurons expressed mRNA for ChAT and one-third (13/37) also had M2 receptor mRNA. In contrast, among the IRt neurons not retrogradely labeled, only 4 of 29 expressed ChAT mRNA (P < 0.0008) and only 3 of 29 expressed M2 receptor mRNA (P < 0.04). The distributions of other cholinergic receptor mRNAs (M1, M3, M4, M5, and nicotinic alpha4-subunit) did not differ between IRt XII premotor neurons and unlabeled IRt neurons. In an additional three rats with retrograde tracers injected into the XII nucleus and ChAT immunohistochemistry, 5-11% of IRt XII premotor neurons located at, and caudal to, the area postrema were ChAT positive, and 27-48% of ChAT-positive caudal IRt neurons were retrogradely labeled from the XII nucleus. Thus the pre- and postsynaptic cholinergic effects previously described in XII motoneurons may originate, at least in part, in medullary IRt neurons.
Collapse
Affiliation(s)
- Denys V Volgin
- Department of Animal Biology, School of Veterinary Medicine, University of Pennsylvania, 3800 Spruce St., Philadelphia, PA 19104-6046, USA
| | | | | |
Collapse
|