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Yegen CH, Marchant D, Bernaudin JF, Planes C, Boncoeur E, Voituron N. Chronic pulmonary fibrosis alters the functioning of the respiratory neural network. Front Physiol 2023; 14:1205924. [PMID: 37383147 PMCID: PMC10293840 DOI: 10.3389/fphys.2023.1205924] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Accepted: 06/02/2023] [Indexed: 06/30/2023] Open
Abstract
Some patients with idiopathic pulmonary fibrosis present impaired ventilatory variables characterised by low forced vital capacity values associated with an increase in respiratory rate and a decrease in tidal volume which could be related to the increased pulmonary stiffness. The lung stiffness observed in pulmonary fibrosis may also have an effect on the functioning of the brainstem respiratory neural network, which could ultimately reinforce or accentuate ventilatory alterations. To this end, we sought to uncover the consequences of pulmonary fibrosis on ventilatory variables and how the modification of pulmonary rigidity could influence the functioning of the respiratory neuronal network. In a mouse model of pulmonary fibrosis obtained by 6 repeated intratracheal instillations of bleomycin (BLM), we first observed an increase in minute ventilation characterised by an increase in respiratory rate and tidal volume, a desaturation and a decrease in lung compliance. The changes in these ventilatory variables were correlated with the severity of the lung injury. The impact of lung fibrosis was also evaluated on the functioning of the medullary areas involved in the elaboration of the central respiratory drive. Thus, BLM-induced pulmonary fibrosis led to a change in the long-term activity of the medullary neuronal respiratory network, especially at the level of the nucleus of the solitary tract, the first central relay of the peripheral afferents, and the Pre-Bötzinger complex, the inspiratory rhythm generator. Our results showed that pulmonary fibrosis induced modifications not only of pulmonary architecture but also of central control of the respiratory neural network.
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Affiliation(s)
- Céline-Hivda Yegen
- Laboratoire Hypoxie & Poumon, UMR INSERM U1272, Université Sorbonne Paris Nord, Bobigny, France
| | - Dominique Marchant
- Laboratoire Hypoxie & Poumon, UMR INSERM U1272, Université Sorbonne Paris Nord, Bobigny, France
| | - Jean-François Bernaudin
- Laboratoire Hypoxie & Poumon, UMR INSERM U1272, Université Sorbonne Paris Nord, Bobigny, France
- Faculté de Médecine, Sorbonne Université, Paris, France
| | - Carole Planes
- Laboratoire Hypoxie & Poumon, UMR INSERM U1272, Université Sorbonne Paris Nord, Bobigny, France
- Service de Physiologie et d’Explorations Fonctionnelles, Hôpital Avicenne, APHP, Bobigny, France
| | - Emilie Boncoeur
- Laboratoire Hypoxie & Poumon, UMR INSERM U1272, Université Sorbonne Paris Nord, Bobigny, France
| | - Nicolas Voituron
- Laboratoire Hypoxie & Poumon, UMR INSERM U1272, Université Sorbonne Paris Nord, Bobigny, France
- Département STAPS, Université Sorbonne Paris Nord, Bobigny, France
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Getsy PM, Coffee GA, Lewis SJ. Loss of ganglioglomerular nerve input to the carotid body impacts the hypoxic ventilatory response in freely-moving rats. Front Physiol 2023; 14:1007043. [PMID: 37008015 PMCID: PMC10060956 DOI: 10.3389/fphys.2023.1007043] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Accepted: 02/17/2023] [Indexed: 03/18/2023] Open
Abstract
The carotid bodies are the primary sensors of blood pH, pO2 and pCO2. The ganglioglomerular nerve (GGN) provides post-ganglionic sympathetic nerve input to the carotid bodies, however the physiological relevance of this innervation is still unclear. The main objective of this study was to determine how the absence of the GGN influences the hypoxic ventilatory response in juvenile rats. As such, we determined the ventilatory responses that occur during and following five successive episodes of hypoxic gas challenge (HXC, 10% O2, 90% N2), each separated by 15 min of room-air, in juvenile (P25) sham-operated (SHAM) male Sprague Dawley rats and in those with bilateral transection of the ganglioglomerular nerves (GGNX). The key findings were that 1) resting ventilatory parameters were similar in SHAM and GGNX rats, 2) the initial changes in frequency of breathing, tidal volume, minute ventilation, inspiratory time, peak inspiratory and expiratory flows, and inspiratory and expiratory drives were markedly different in GGNX rats, 3) the initial changes in expiratory time, relaxation time, end inspiratory or expiratory pauses, apneic pause and non-eupneic breathing index (NEBI) were similar in SHAM and GGNX rats, 4) the plateau phases obtained during each HXC were similar in SHAM and GGNX rats, and 5) the ventilatory responses that occurred upon return to room-air were similar in SHAM and GGNX rats. Overall, these changes in ventilation during and following HXC in GGNX rats raises the possibility the loss of GGN input to the carotid bodies effects how primary glomus cells respond to hypoxia and the return to room-air.
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Affiliation(s)
- Paulina M. Getsy
- Department of Pediatrics, Division of Pulmonology, Allergy and Immunology, Case Western Reserve University, Cleveland, OH, United States
- *Correspondence: Paulina M. Getsy,
| | - Gregory A. Coffee
- Department of Pediatrics, Division of Pulmonology, Allergy and Immunology, Case Western Reserve University, Cleveland, OH, United States
| | - Stephen J. Lewis
- Department of Pediatrics, Division of Pulmonology, Allergy and Immunology, Case Western Reserve University, Cleveland, OH, United States
- Department of Pharmacology, Case Western Reserve University, Cleveland, OH, United States
- Functional Electrical Stimulation Center, Case Western Reserve University, Cleveland, OH, United States
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3
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Jeton F, Perrin-Terrin AS, Yegen CH, Marchant D, Richalet JP, Pichon A, Boncoeur E, Bodineau L, Voituron N. In Transgenic Erythropoietin Deficient Mice, an Increase in Respiratory Response to Hypercapnia Parallels Abnormal Distribution of CO 2/H +-Activated Cells in the Medulla Oblongata. Front Physiol 2022; 13:850418. [PMID: 35514353 PMCID: PMC9061944 DOI: 10.3389/fphys.2022.850418] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Accepted: 03/21/2022] [Indexed: 12/03/2022] Open
Abstract
Erythropoietin (Epo) and its receptor are expressed in central respiratory areas. We hypothesized that chronic Epo deficiency alters functioning of central respiratory areas and thus the respiratory adaptation to hypercapnia. The hypercapnic ventilatory response (HcVR) was evaluated by whole body plethysmography in wild type (WT) and Epo deficient (Epo-TAgh) adult male mice under 4%CO2. Epo-TAgh mice showed a larger HcVR than WT mice because of an increase in both respiratory frequency and tidal volume, whereas WT mice only increased their tidal volume. A functional histological approach revealed changes in CO2/H+-activated cells between Epo-TAgh and WT mice. First, Epo-TAgh mice showed a smaller increase under hypercapnia in c-FOS-positive number of cells in the retrotrapezoid nucleus/parafacial respiratory group than WT, and this, independently of changes in the number of PHOX2B-expressing cells. Second, we did not observe in Epo-TAgh mice the hypercapnic increase in c-FOS-positive number of cells in the nucleus of the solitary tract present in WT mice. Finally, whereas hypercapnia did not induce an increase in the c-FOS-positive number of cells in medullary raphe nuclei in WT mice, chronic Epo deficiency leads to raphe pallidus and magnus nuclei activation by hyperacpnia, with a significant part of c-FOS positive cells displaying an immunoreactivity for serotonin in the raphe pallidus nucleus. All of these results suggest that chronic Epo-deficiency affects both the pattern of ventilatory response to hypercapnia and associated medullary respiratory network at adult stage with an increase in the sensitivity of 5-HT and non-5-HT neurons of the raphe medullary nuclei leading to stimulation of fR for moderate level of CO2.
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Affiliation(s)
- Florine Jeton
- Laboratoire "Hypoxie et Poumons", UMR INSERM U1272, Université Paris 13, UFR SMBH, Bobigny, France.,Laboratory of Excellence (Labex) GR-Ex, PRES Sorbonne Paris Cité, Paris, France
| | - Anne-Sophie Perrin-Terrin
- Laboratoire "Hypoxie et Poumons", UMR INSERM U1272, Université Paris 13, UFR SMBH, Bobigny, France.,Inserm, UMR_S1158 Neurophysiologie Respiratoire Expérimentale et Clinique, Sorbonne Université, Paris, France
| | - Celine-Hivda Yegen
- Laboratoire "Hypoxie et Poumons", UMR INSERM U1272, Université Paris 13, UFR SMBH, Bobigny, France
| | - Dominique Marchant
- Laboratoire "Hypoxie et Poumons", UMR INSERM U1272, Université Paris 13, UFR SMBH, Bobigny, France
| | - Jean-Paul Richalet
- Laboratoire "Hypoxie et Poumons", UMR INSERM U1272, Université Paris 13, UFR SMBH, Bobigny, France.,Laboratory of Excellence (Labex) GR-Ex, PRES Sorbonne Paris Cité, Paris, France
| | - Aurélien Pichon
- Laboratoire "Hypoxie et Poumons", UMR INSERM U1272, Université Paris 13, UFR SMBH, Bobigny, France.,Laboratory of Excellence (Labex) GR-Ex, PRES Sorbonne Paris Cité, Paris, France
| | - Emilie Boncoeur
- Laboratoire "Hypoxie et Poumons", UMR INSERM U1272, Université Paris 13, UFR SMBH, Bobigny, France
| | - Laurence Bodineau
- Inserm, UMR_S1158 Neurophysiologie Respiratoire Expérimentale et Clinique, Sorbonne Université, Paris, France
| | - Nicolas Voituron
- Laboratoire "Hypoxie et Poumons", UMR INSERM U1272, Université Paris 13, UFR SMBH, Bobigny, France.,Laboratory of Excellence (Labex) GR-Ex, PRES Sorbonne Paris Cité, Paris, France
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4
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Getsy PM, Coffee GA, Hsieh YH, Lewis SJ. The superior cervical ganglia modulate ventilatory responses to hypoxia independently of preganglionic drive from the cervical sympathetic chain. J Appl Physiol (1985) 2021; 131:836-857. [PMID: 34197230 DOI: 10.1152/japplphysiol.00216.2021] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Superior cervical ganglia (SCG) postganglionic neurons receive preganglionic drive via the cervical sympathetic chains (CSC). The SCG projects to structures like the carotid bodies (e.g., vasculature, chemosensitive glomus cells), upper airway (e.g., tongue, nasopharynx), and to the parenchyma and cerebral arteries throughout the brain. We previously reported that a hypoxic gas challenge elicited an array of ventilatory responses in sham-operated (SHAM) freely moving adult male C57BL6 mice and that responses were altered in mice with bilateral transection of the cervical sympathetic chain (CSCX). Since the CSC provides preganglionic innervation to the SCG, we presumed that mice with superior cervical ganglionectomy (SCGX) would respond similarly to hypoxic gas challenge as CSCX mice. However, while SCGX mice had altered responses during hypoxic gas challenge that occurred in CSCX mice (e.g., more rapid occurrence of changes in frequency of breathing and minute ventilation), SCGX mice displayed numerous responses to hypoxic gas challenge that CSCX mice did not, including reduced total increases in frequency of breathing, minute ventilation, inspiratory and expiratory drives, peak inspiratory and expiratory flows, and appearance of noneupneic breaths. In conclusion, hypoxic gas challenge may directly activate subpopulations of SCG cells, including subpopulations of postganglionic neurons and small intensely fluorescent (SIF) cells, independently of CSC drive, and that SCG drive to these structures dampens the initial occurrence of the hypoxic ventilatory response, while promoting the overall magnitude of the response. The multiple effects of SCGX may be due to loss of innervation to peripheral and central structures with differential roles in breathing control.NEW & NOTEWORTHY We present data showing that the ventilatory responses elicited by a hypoxic gas challenge in male C57BL6 mice with bilateral superior cervical ganglionectomy are not equivalent to those reported for mice with bilateral transection of the cervical sympathetic chain. These data suggest that hypoxic gas challenge may directly activate subpopulations of superior cervical ganglia (SCG) cells, including small intensely fluorescent (SIF) cells and/or principal SCG neurons, independently of preganglionic cervical sympathetic chain drive.
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Affiliation(s)
- Paulina M Getsy
- Division of Pulmonology, Allergy and Immunology, Department of Pediatrics, Case Western Reserve University, Cleveland, Ohio.,Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, Ohio
| | - Gregory A Coffee
- Division of Pulmonology, Allergy and Immunology, Department of Pediatrics, Case Western Reserve University, Cleveland, Ohio
| | - Yee-Hsee Hsieh
- Division of Pulmonary, Critical Care and Sleep Medicine, University Hospital Case Medical Center, Case Western Reserve University, Cleveland, Ohio
| | - Stephen J Lewis
- Division of Pulmonology, Allergy and Immunology, Department of Pediatrics, Case Western Reserve University, Cleveland, Ohio.,Department of Pharmacology, Case Western Reserve University, Cleveland, Ohio
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5
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Getsy PM, Coffee GA, Hsieh YH, Lewis SJ. Loss of Cervical Sympathetic Chain Input to the Superior Cervical Ganglia Affects the Ventilatory Responses to Hypoxic Challenge in Freely-Moving C57BL6 Mice. Front Physiol 2021; 12:619688. [PMID: 33967819 PMCID: PMC8100345 DOI: 10.3389/fphys.2021.619688] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Accepted: 03/30/2021] [Indexed: 11/13/2022] Open
Abstract
The cervical sympathetic chain (CSC) innervates post-ganglionic sympathetic neurons within the ipsilateral superior cervical ganglion (SCG) of all mammalian species studied to date. The post-ganglionic neurons within the SCG project to a wide variety of structures, including the brain (parenchyma and cerebral arteries), upper airway (e.g., nasopharynx and tongue) and submandibular glands. The SCG also sends post-ganglionic fibers to the carotid body (e.g., chemosensitive glomus cells and microcirculation), however, the function of these connections are not established in the mouse. In addition, nothing is known about the functional importance of the CSC-SCG complex (including input to the carotid body) in the mouse. The objective of this study was to determine the effects of bilateral transection of the CSC on the ventilatory responses [e.g., increases in frequency of breathing (Freq), tidal volume (TV) and minute ventilation (MV)] that occur during and following exposure to a hypoxic gas challenge (10% O2 and 90% N2) in freely-moving sham-operated (SHAM) adult male C57BL6 mice, and in mice in which both CSC were transected (CSCX). Resting ventilatory parameters (19 directly recorded or calculated parameters) were similar in the SHAM and CSCX mice. There were numerous important differences in the responses of CSCX and SHAM mice to the hypoxic challenge. For example, the increases in Freq (and associated decreases in inspiratory and expiratory times, end expiratory pause, and relaxation time), and the increases in MV, expiratory drive, and expiratory flow at 50% exhaled TV (EF50) occurred more quickly in the CSCX mice than in the SHAM mice, although the overall responses were similar in both groups. Moreover, the initial and total increases in peak inspiratory flow were higher in the CSCX mice. Additionally, the overall increases in TV during the latter half of the hypoxic challenge were greater in the CSCX mice. The ventilatory responses that occurred upon return to room-air were essentially similar in the SHAM and CSCX mice. Overall, this novel data suggest that the CSC may normally provide inhibitory input to peripheral (e.g., carotid bodies) and central (e.g., brainstem) structures that are involved in the ventilatory responses to hypoxic gas challenge in C57BL6 mice.
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Affiliation(s)
- Paulina M Getsy
- Department of Pediatrics, Division of Pulmonology, Allergy and Immunology, Case Western Reserve University, Cleveland, OH, United States.,The Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, OH, United States
| | - Gregory A Coffee
- Department of Pediatrics, Division of Pulmonology, Allergy and Immunology, Case Western Reserve University, Cleveland, OH, United States
| | - Yee-Hsee Hsieh
- Division of Pulmonary, Critical Care and Sleep Medicine, University Hospitals Case Medical Center, Case Western Reserve University, Cleveland, OH, United States
| | - Stephen J Lewis
- Department of Pediatrics, Division of Pulmonology, Allergy and Immunology, Case Western Reserve University, Cleveland, OH, United States.,Department of Pharmacology, Case Western Reserve University, Cleveland, OH, United States
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6
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Eugenín J, Larraín C, Zapata P. Plasticity of cardiovascular chemoreflexes after prolonged unilateral carotid body denervation: implications for its therapeutic use. Am J Physiol Heart Circ Physiol 2020; 318:H1325-H1336. [PMID: 32330089 DOI: 10.1152/ajpheart.00451.2019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Unilateral carotid body denervation has been proposed as treatment for sympathetic-related human diseases such as systolic heart failure, hypertension, obstructive sleep apnea, and cardiometabolic diseases. The long-term therapeutic effects of carotid body removal will be maintained if the remnant "buffer nerves," that is, the contralateral carotid nerve and the aortic nerves that innervate second-order neurons at the solitary tract nuclei (NTS), do not modify their contributions to the cardiovascular chemoreflexes. Here, we studied the cardiovascular chemoreflexes 1 mo after unilateral carotid body denervation either by excision of the petrosal ganglion (petrosal ganglionectomy, which eliminates central carotid afferents) or exeresis of a segment of one carotid nerve (carotid neurectomy, which preserves central afferents). Cardiovascular chemoreflexes were induced by intravenous (iv) injections of sodium cyanide in pentobarbitone-anesthetized adult cats. After 1 mo of unilateral petrosal ganglionectomy, without significant changes in basal arterial pressure, the contribution of the contralateral carotid nerve to the chemoreflex increases in arterial pressure was enhanced without changes in the contribution provided by the aortic nerves. By contrast, after 1 mo of unilateral carotid neurectomy, the contribution of remnant buffer nerves to cardiovascular chemoreflexes remained unmodified. These results indicate that a carotid nerve interruption involving denervation of second-order chemosensory neurons at the NTS will trigger cardiovascular chemoreflex plasticity on the contralateral carotid pathway. Then, unilateral carotid body denervation as therapeutic tool should consider the maintenance of the integrity of carotid central chemoafferents to prevent plasticity on remnant buffer nerves.NEW & NOTEWORTHY Unilateral carotid body denervation has been proposed as treatment for sympathetic hyperactivity-related human disorders. Its therapeutic effectiveness for maintaining a persistent decrease in the sympathetic outflow activity will depend on the absence of compensatory chemoreflex plasticity in the remnant carotid and aortic afferents. Here, we suggest that the integrity of central afferents after carotid body denervation is essential to prevent the emergence of plastic functional changes on the contralateral "intact" carotid nerve.
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Affiliation(s)
- Jaime Eugenín
- Laboratorio de Sistemas Neurales, Departamento de Biología, Facultad de Química y Biología, Universidad de Santiago de Chile, Santiago, Chile.,Laboratorio de Neurobiología, Departamento de Fisiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Carolina Larraín
- Centro de Fisiología Celular e Integrativa, Facultad de Medicina, Clínica Alemana, Universidad del Desarrollo, Santiago, Chile.,Laboratorio de Neurobiología, Departamento de Fisiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Patricio Zapata
- Centro de Fisiología Celular e Integrativa, Facultad de Medicina, Clínica Alemana, Universidad del Desarrollo, Santiago, Chile.,Laboratorio de Neurobiología, Departamento de Fisiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
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Wang FB, Liao YH, Kao CK, Fang CL. Vagal baro- and chemoreceptors in middle internal carotid artery and carotid body in rat. J Anat 2019; 235:953-961. [PMID: 31347697 DOI: 10.1111/joa.13054] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/07/2019] [Indexed: 11/28/2022] Open
Abstract
The glossopharyngeal nerve, via the carotid sinus nerve (CSN), presents baroreceptors from the internal carotid artery (ICA) and chemoreceptors from the carotid body. Although neurons in the nodose ganglion were labelled after injecting tracer into the carotid body, the vagal pathway to these baro- and chemoreceptors has not been identified. Neither has the glossopharyngeal intracranial afferent/sensory pathway that connects to the brainstem been defined. We investigated both of these issues in male Sprague-Dawley rats (n = 40) by injecting neural tracer wheat germ agglutinin-horseradish peroxidase into: (i) the peripheral glossopharyngeal or vagal nerve trunk with or without the intracranial glossopharyngeal rootlet being rhizotomized; or (ii) the nucleus of the solitary tract right after dorsal and ventral intracranial glossopharyngeal rootlets were dissected. By examining whole-mount tissues and brainstem sections, we verified that only the most rostral rootlet connects to the glossopharyngeal nerve and usually four caudal rootlets connect to the vagus nerve. Furthermore, vagal branches may: (i) join the CSN originating from the pharyngeal nerve base, caudal nodose ganglion, and rostral or caudal superior laryngeal nerve; or (ii) connect directly to nerve endings in the middle segment of the ICA or to chemoreceptors in the carotid body. The aortic depressor nerve always presents and bifurcates from either the rostral or the caudal part of the superior laryngeal nerve. The vagus nerve seemingly provides redundant carotid baro- and chemoreceptors to work with the glossopharyngeal nerve. These innervations confer more extensive roles on the vagus nerve in regulating body energy that is supplied by the cardiovascular, pulmonary and digestive systems.
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Affiliation(s)
- Feng-Bin Wang
- Department of Psychology, National Chung Cheng University, Chiayi, Taiwan.,Mental Health Promotion Center, National Chung Cheng University, Chiayi, Taiwan.,Doctoral Program in Cognitive Sciences, National Chung Cheng University, Chiayi, Taiwan.,Center for Innovative Research on Aging Society, National Chung Cheng University, Chiayi, Taiwan.,Advanced Institute of Manufacturing with High-Tech Innovations, National Chung Cheng University, Chiayi, Taiwan
| | - Yi-Han Liao
- Department of Psychology, National Chung Cheng University, Chiayi, Taiwan
| | - Chih-Kuan Kao
- Department of Psychology, National Chung Cheng University, Chiayi, Taiwan
| | - Chien-Liang Fang
- Department of Psychology, National Chung Cheng University, Chiayi, Taiwan.,Department of Traditional Chinese Medicine, Ditmanson Medical Foundation Chiayi Christian Hospital, Chiayi, Taiwan
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Porzionato A, Macchi V, Stecco C, De Caro R. The Carotid Sinus Nerve-Structure, Function, and Clinical Implications. Anat Rec (Hoboken) 2018; 302:575-587. [PMID: 29663677 DOI: 10.1002/ar.23829] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2017] [Revised: 06/24/2017] [Accepted: 08/01/2017] [Indexed: 12/12/2022]
Abstract
Interest has been renewed in the anatomy and physiology of the carotid sinus nerve (CSN) and its targets (carotid sinus and carotid body, CB), due to recent proposals of surgical procedures for a series of common pathologies, such as carotid sinus syndrome, hypertension, heart failure, and insulin resistance. The CSN originates from the glossopharyngeal nerve soon after its appearance from the jugular foramen. It shows frequent communications with the sympathetic trunk (usually at the level of the superior cervical ganglion) and the vagal nerve (main trunk, pharyngeal branches, or superior laryngeal nerve). It courses on the anterior aspect of the internal carotid artery to reach the carotid sinus, CB, and/or intercarotid plexus. In the carotid sinus, type I (dynamic) carotid baroreceptors have larger myelinated A-fibers; type II (tonic) baroreceptors show smaller A- and unmyelinated C-fibers. In the CB, afferent fibers are mainly stimulated by acetylcholine and ATP, released by type I cells. The neurons are located in the petrosal ganglion, and centripetal fibers project on to the solitary tract nucleus: chemosensory inputs to the commissural subnucleus, and baroreceptor inputs to the commissural, medial, dorsomedial, and dorsolateral subnuclei. The baroreceptor component of the CSN elicits sympatho-inhibition and the chemoreceptor component stimulates sympatho-activation. Thus, in refractory hypertension and heart failure (characterized by increased sympathetic activity), baroreceptor electrical stimulation, and CB removal have been proposed. Instead, denervation of the carotid sinus has been proposed for the "carotid sinus syndrome." Anat Rec, 302:575-587, 2019. © 2018 Wiley Periodicals, Inc.
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Affiliation(s)
- Andrea Porzionato
- Department of Neuroscience, Institute of Human Anatomy, University of Padova, Padova, Italy
| | - Veronica Macchi
- Department of Neuroscience, Institute of Human Anatomy, University of Padova, Padova, Italy
| | - Carla Stecco
- Department of Neuroscience, Institute of Human Anatomy, University of Padova, Padova, Italy
| | - Raffaele De Caro
- Department of Neuroscience, Institute of Human Anatomy, University of Padova, Padova, Italy
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9
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Plasticity in the Interoceptive System. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 1015:59-74. [DOI: 10.1007/978-3-319-62817-2_4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/08/2023]
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10
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Tanphaichitr A, Tanphaichitr P, Apiwattanasawee P, Brockbank J, Rutter MJ, Simakajornboon N. Prevalence and risk factors for central sleep apnea in infants with laryngomalacia. Otolaryngol Head Neck Surg 2014; 150:677-83. [PMID: 24493785 DOI: 10.1177/0194599814521379] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE To identify the prevalence of and risk factors for central sleep apnea (CSA) in infants who are diagnosed with laryngomalacia. STUDY DESIGN Case series with chart review. SETTING Quaternary care pediatric hospital. SUBJECTS AND METHODS We performed a chart review in infants with laryngomalacia. All infants had diagnostic polysomnography (PSG) performed from 2003 to 2012. Infants who underwent supraglottoplasty or other upper airway surgery prior to PSG were excluded. CSA was defined as central apnea index ≥ 5. Demographic data, underlying diseases, and PSG data were reviewed and analyzed. RESULTS Fifty-four patients met the inclusion criteria. The mean age at the date PSG was performed was 3.4 ± 2.7 months. The prevalence of CSA in infants with laryngomalacia was 46.3%. Odds ratio (OR) of CSA was above 2.0 in patients with the following risk factors: underlying neurologic disease, hypotonia, or syndrome (OR = 2.5, P = .13), history of apparent life-threatening events (OR = 2.7, P = .19), premature infants (OR = 2.2, P = .33), and age less than 3 months (OR = 2.3, P = .15). However, none of the risk factors were statistically significant. Analysis of sleep architecture revealed a decrease in total sleep time (345.4 ± 70.6 minutes vs 393.5 ± 68.3 minutes, P = .02) and sleep efficiency (67.7 ± 8.9% vs 75.2 ± 9.3%, P = .004) in the CSA group. CONCLUSION CSA is relatively common in infants with laryngomalacia. There seems to be a higher prevalence of CSA in infants with certain risk factors, but none of the risk factors are statistically significant. The presence of CSA can lead to alteration in sleep architecture. In addition to clinical evaluation, polysomnography may be warranted for the evaluation of infants with laryngomalacia and associated complex medical conditions.
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Affiliation(s)
- Archwin Tanphaichitr
- Sleep Disorders Center, Cincinnati Children's Hospital Medical Center, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
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11
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Talman WT, Lin LH. Sudden death following selective neuronal lesions in the rat nucleus tractus solitarii. Auton Neurosci 2012; 175:9-16. [PMID: 23245583 DOI: 10.1016/j.autneu.2012.11.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2012] [Revised: 11/14/2012] [Accepted: 11/15/2012] [Indexed: 01/29/2023]
Abstract
In efforts to assess baroreflex and cardiovascular responses in rats in which substance P (SP) or catecholamine transmission had been eliminated we studied animals after bilateral injections into the nucleus tractus solitarii (NTS) of SP or stabilized SP (SSP) conjugated to saporin (SP-SAP or SSP-SAP respectively) or SAP conjugated to an antibody to dopamine-β-hydroxylase (anti-DBH-SAP). We found that SP- and SSP-SAP eliminated NTS neurons that expressed the SP neurokinin-1 receptor (NK1R) while anti-DBH-SAP eliminated NTS neurons expressing tyrosine hydroxylase (TH) and DBH. The toxins were selective. Thus SP- or SSP-SAP did not eliminate TH/DBH neurons and anti-DBH-SAP did not eliminate NK1R neurons in the NTS. Each toxin, however, led to chronic lability of arterial blood pressure, diminished baroreflex function, cardiac ventricular irritability, coagulation necrosis of cardiac myocytes and, in some animals, sudden death associated with asystole. However, when TH/DBH neurons were targeted and eliminated by injection of 6-hydroxydopamine (6-OHDA), none of the cardiovascular or cardiac changes occurred. The studies reviewed here reveal that selective lesions of the NTS lead to altered baroreflex control and to cardiac changes that may lead to sudden death. Though the findings could support a role for SP or catecholamines in baroreflex transmission neither is proven in that NK1R colocalizes with glutamate receptors. Thus neurons with both are lost when treated with SP- or SSP-SAP. In addition, loss of catecholamine neurons after treatment with 6-OHDA does not affect cardiovascular control. Thus, the effect of the toxins may depend on an action of SAP independent of the effects of the SAP conjugates on targeted neuronal types.
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Affiliation(s)
- William T Talman
- Department of Neurology, Carver College of Medicine University of Iowa and Veterans Affairs Healthcare System, Iowa City, IA 52242, USA.
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12
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Calcitonin gene-related peptide immunoreactive neurons innervating the soft palate, the root of tongue, and the pharynx in the superior glossopharyngeal ganglion of the rat. J Chem Neuroanat 2009; 39:221-7. [PMID: 20034556 DOI: 10.1016/j.jchemneu.2009.12.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2009] [Revised: 11/26/2009] [Accepted: 12/13/2009] [Indexed: 10/20/2022]
Abstract
We have examined whether calcitonin gene-related peptide immunoreactive (CGRP-ir) neurons in the glossopharyngeal ganglia innervate the soft palate, the root of tongue, and the pharynx of the rat. Immunohistochemical observations revealed that numerous CGRP-ir neurons are located in the superior glossopharyngeal ganglion located ventrolateral to the medulla oblongata in the cranial cavity, and that CGRP-ir neurons are also located in the inferior glossopharyngeal ganglion at the jugular foramen. When Fluorogold was injected into the soft palate, the root of tongue, or the pharyngeal constrictor muscles, many retrogradely Fluorogold-labeled neurons were found in the superior glossopharyngeal ganglion and the nodose ganglion, and several Fluorogold-labeled neurons were found in the inferior glossopharyngeal ganglion. Double labeling with immunohistochemistry for CGRP and Fluorogold showed that in every case of injections of Fluorogold into the soft palate, the root of tongue, or the pharynx, about 30% of the Fluorogold-labeled neurons in the superior glossopharyngeal ganglion expressed CGRP-like immunoreactivity, while no double-labeled neurons were found in the inferior glossopharyngeal ganglion or the nodose ganglion. These results indicate that nociceptive sensory information from the soft palate, the root of tongue, and the pharynx might be conveyed by the neurons in the superior glossopharyngeal ganglion to the nucleus tractus solitarii.
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13
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Talman WT, Nitschke Dragon D. Neuronal nitric oxide mediates cerebral vasodilatation during acute hypertension. Brain Res 2007; 1139:126-32. [PMID: 17291465 PMCID: PMC1885240 DOI: 10.1016/j.brainres.2007.01.008] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2006] [Revised: 10/09/2006] [Accepted: 10/16/2006] [Indexed: 12/21/2022]
Abstract
Parasympathetic nerves from the pterygopalatine ganglia provide nitroxidergic innervation to forebrain cerebral blood vessels. Disruption of that innervation attenuates cerebral vasodilatation seen during acute hypertension as does systemic administration of a non-selective nitric oxide synthase (NOS) inhibitor. Although such studies suggest that nitric oxide (NO) released from parasympathetic nerves participates in vasodilatation of cerebral vessels during hypertension, that hypothesis has not been tested with selective local inhibition of neuronal NOS (nNOS). We tested that hypothesis through these studies performed in anesthetized rats instrumented for continuous measurement of blood pressure, heart rate and pial arterial diameter through a cranial window. We sought to determine if the nNOS inhibitor propyl-L-arginine delivered directly to the outer surface of a pial artery would (1) attenuate changes in pial arterial diameter during acute hypertension and (2) block nNOS-mediated dilator effects of N-methyl-D-aspartate (NMDA) delivered into the window but (3) not block vasodilatation elicited by acetylcholine (ACh) and mediated by endothelial NOS dilator. Without the nNOS inhibitor arterial diameter abruptly increased 70+/-15% when mean arterial pressure (MAP) reached 183+/-3 mm Hg while with nNOS inhibition diameter increased only 13+/-10% (p<0.05) even when MAP reached 191+/-4 mm Hg (p>0.05). The nNOS inhibitor significantly attenuated vasodilatation induced by NMDA but not ACh delivered into the window. Thus, local nNOS inhibition attenuates breakthrough from autoregulation during hypertension as does complete interruption of the parasympathetic innervation of cerebral vessels. These findings further support the hypothesis that NO released from parasympathetic fibers contributes to cerebral vasodilatation during acute hypertension.
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Affiliation(s)
- William T Talman
- Laboratory of Neurobiology, Department of Neurology, VAHCS, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA.
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Gauda EB, McLemore GL, Tolosa J, Marston-Nelson J, Kwak D. Maturation of peripheral arterial chemoreceptors in relation to neonatal apnoea. ACTA ACUST UNITED AC 2004; 9:181-94. [PMID: 15050211 DOI: 10.1016/j.siny.2003.11.002] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Apnoea and periodic breathing are the hallmarks of breathing for the infant who is born prematurely. Sustained respiration is obtained through modulation of respiratory-related neurons with inputs from the periphery. The peripheral arterial chemoreceptors, uniquely and reflexly change ventilation in response to changes in oxygen tension. The chemoreflex in response to hypoxia is hyperventilation, bradycardia and vasoconstriction. The fast response time of the peripheral arterial chemoreceptors to changes in oxygen and carbon dioxide tension increases the risk of more periodicity in the breathing pattern. As a result of baseline hypoxaemia, peripheral arterial chemoreceptors contribute more to baseline breathing in premature than in term infants. While premature infants may have an augmented chemoreflex, infants who develop bronchopulmonary dysplasia have a blunted chemoreflex at term gestation. The development of chemosensitivity of the peripheral arterial chemoreceptors and environmental factors that might cause maldevelopment of chemosensitivity with continued maturation are reviewed in an attempt to help explain the physiology of apnoea of prematurity and the increased incidence of sudden infant death syndrome (SIDS) in infants born prematurely and those who are exposed to tobacco smoke.
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Affiliation(s)
- Estelle B Gauda
- Department of Pediatrics, Johns Hopkins Medical Institutions, Baltimore, MD 21287-3200, USA.
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Agassandian K, Fazan VPS, Margaryan N, Dragon DN, Riley J, Talman WT. A novel central pathway links arterial baroreceptors and pontine parasympathetic neurons in cerebrovascular control. Cell Mol Neurobiol 2004; 23:463-78. [PMID: 14514008 DOI: 10.1023/a:1025059710382] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
1. We tested the hypothesis that arterial baroreceptor reflexes modulate cerebrovascular tone through a pathway that connects the cardiovascular nucleus tractus solitarii with parasympathetic preganglionic neurons in the pons. 2. Anesthetized rats were used in all studies. Laser flowmetry was used to measure cerebral blood flow. We assessed cerebrovascular responses to increases in arterial blood pressure in animals with lesions of baroreceptor nerves, the nucleus tractus solitarii itself, the pontine preganglionic parasympathetic neurons, or the parasympathetic ganglionic nerves to the cerebral vessels. Similar assessments were made in animals after blockade of synthesis of nitric oxide, which is released by the parasympathetic nerves from the pterygopalatine ganglia. Finally the effects on cerebral blood flow of glutamate stimulation of pontine preganglionic parasympathetic neurons were evaluated. 3. We found that lesions at any one of the sites in the putative pathway or interruption of nitric oxide synthesis led to prolongation of autoregulation as mean arterial pressure was increased to levels as high as 200 mmHg. Conversely, stimulation of pontine parasympathetic preganglionic neurons led to cerebral vasodilatation. The second series of studies utilized classic anatomical tracing methods to determine at the light and electron microscopic level whether neurons in the cardiovascular nucleus tractus solitarii, the site of termination of baroreceptor afferents, projected to the pontine preganglionic neurons. Fibers were traced with anterograde tracer from the nucleus tractus solitarii to the pons and with retrograde tracer from the pons to the nucleus tractus solitarii. Using double labeling techniques we further studied synapses made between labeled projections from the nucleus tractus solitarii and preganglionic neurons that were themselves labeled with retrograde tracer placed into the pterygopalatine ganglion. 4. These anatomical studies showed that the nucleus tractus solitarii directly projects to pontine preganglionic neurons and makes asymmetric, seemingly excitatory, synapses with those neurons. These studies provide strong evidence that arterial baroreceptors may modulate cerebral blood flow through direct connections with pontine parasympathetic neurons. Further study is needed to clarify the role this pathway plays in integrative physiology.
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Affiliation(s)
- Khristofor Agassandian
- Laboratory of Neurobiology, Department of Neurology, University of Iowa, Iowa City, Iowa 52242, USA
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16
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Kopczyńska B, Szereda-Przestaszewska M. Supranodose vagotomy precludes reflex respiratory responses to serotonin in cats. J Biomed Sci 2003; 10:718-24. [PMID: 14631110 DOI: 10.1007/bf02256323] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2003] [Accepted: 07/25/2003] [Indexed: 11/28/2022] Open
Abstract
Mediation of the respiratory reflex effects of an exogenous serotonin challenge goes beyond the lung vagi and is suggested to involve the nodose ganglia. In the present experiments the effects of an intravenous serotonin challenge on breathing pattern were studied in 8 pentobarbitone-chloralose anaesthetised cats. Bolus injection of serotonin oxalate (50 microg/kg) into the right femoral vein evoked prompt apnoea of 19.2 (+/- 2.4)-second duration in all 8 cats while intact; the apnoea was much shorter after midcervical vagal section (8.1 +/- 0.9 s, p < 0.001), and was abolished by supranodose vagotomy. In post-apnoeic breaths, the tidal volume was reduced from a baseline of 34.1 +/- 4.0 to 13.5 +/- 1.1 ml (p < 0.001) prior to, and from a baseline of 43.9 +/- 5.4 to 33.8 +/- 6.6 ml (p < 0.01) after midcervical vagotomy; the serotonin challenge did not affect tidal volume following supranodose vagal section (p = 0.4). The increase in respiratory rate found in intact (p < 0.001) and midcervically vagotomised cats (p < 0.01) was eliminated by the neurotomy above the nodose ganglia. Supranodose vagotomy altered cardiovascular response to serotonin by replacing the fall in blood pressure with an increase. These data suggest that the sequelae of serotonin-induced pulmonary chemoreflex, i.e. respiratory arrest, cardiovascular changes and post-apnoeic pattern of breathing require intact nodose ganglia.
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Affiliation(s)
- Beata Kopczyńska
- Laboratory of Respiration Physiology, PAS Medical Research Centre, 5 Pawińskiego Street, PL-02-106 Warsaw, Poland.
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17
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Heslop DJ, Keay KA, Bandler R. Haemorrhage-evoked compensation and decompensation are mediated by distinct caudal midline medullary regions in the urethane-anaesthetised rat. Neuroscience 2002; 113:555-67. [PMID: 12150776 DOI: 10.1016/s0306-4522(02)00161-6] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Previous research using microinjections of excitatory amino acids suggested that the caudal midline medulla (including nucleus raphe obscurus and nucleus raphe pallidus) contained a mixed population of sympathoexcitatory and sympathoinhibitory neurones. The results of this study indicate that different anaesthetic regimes (urethane versus halothane) determine whether sympathoexcitatory (urethane only) or sympathoinhibitory (halothane only) responses are evoked by stimulation within distinct caudal midline medullary regions. In addition, anaesthetic regimes also affect the caudal midline medullary-mediated response to haemorrhage. Specifically, under conditions of urethane anaesthesia, inactivation (lignocaine) of the midline medullary region immediately caudal to the obex, prematurely triggered and dramatically potentiated the hypotension and bradycardia evoked by 15% haemorrhage; whereas under halothane anaesthesia, inactivation of the same region had no effect. In contrast, under urethane anaesthesia, inactivation of the midline medullary region immediately rostral to the obex, delayed the onset of the hypotension and bradycardia to 15% haemorrhage; inactivation of the same region under halothane anaesthesia blocked haemorrhage-evoked hypotension and bradycardia. Our findings indicate that topographically distinct parts of the caudal midline medulla contain neurones (i) that differentially regulate the timing and magnitude of the compensatory (normotensive) versus decompensatory (hypotensive) phases of the response to haemorrhage; and (ii) whose activity is altered by urethane versus halothane anaesthesia.
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Affiliation(s)
- D J Heslop
- Department of Anatomy and Histology, The University of Sydney, Sydney, NSW 2006, Australia
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Chan RK, Jarvina EV, Sawchenko PE. Effects of selective sinoaortic denervations on phenylephrine-induced activational responses in the nucleus of the solitary tract. Neuroscience 2001; 101:165-78. [PMID: 11068145 DOI: 10.1016/s0306-4522(00)00332-8] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Intravenous administration of phenylephrine provokes a pattern of cellular activation in the nucleus of the solitary tract that resembles the central distributions of primary baroreceptor afferents supplied by the carotid sinus and aortic depressor nerves. Transganglionic transport and denervation methods were used in an experimental setting to test the dependence of phenylephrine-induced Fos immunoreactivity on the integrity of buffer nerve afferents, and to identify the subregions of the nucleus of the solitary tract supplied by each. Cholera toxin B-horseradish peroxidase injections into either or both nerves revealed terminal labeling concentrated in, but not restricted to, the dorsal commissural part of the nucleus of the solitary tract at the level of the apex of calamus scriptorius, and extending into the dorsal subnucleus at the level of the area postrema. Preferential ramifications of carotid sinus and aortic depressor nerve afferents at the levels of the commissural part of the nucleus and the area postrema, respectively, were reflected in the extent to which labeled fibers comingled with neurons exhibiting phenylephrine-induced Fos in dual labeling experiments. Complete sinoaortic denervation reduced by 90% the number of neurons exhibiting drug-induced Fos expression. Selective carotid and aortic sinus denervations effected partial reductions manifest preferentially in the caudal and rostral foci of the distribution, respectively. Reduced activational responses at the level of the area postrema of aortic sinus-denervated rats were accompanied by a reduction in cellular nicotinamide adenine dinucleotide phosphate-diaphorase activity in this region. Animals killed 30 days after complete sinoaortic denervation displayed no evidence of recovery of phenylephrine-induced Fos, while the strength and distribution of the response in rats that received selective carotid sinus denervation were indistinguishable from those seen in controls. These findings (i) support the dependence of phenylephrine-induced Fos expression on the integrity of carotid sinus and aortic depressor nerve afferents, (ii) provide anatomical and functional evidence that the two buffer nerves distribute differentially within the nucleus of the solitary tract, and (iii) implicate central reorganization as a likely basis for functional recovery of baroreflex mechanisms following partial sinoaortic denervation.
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Affiliation(s)
- R K Chan
- Laboratory of Neuronal Structure and Function, The Salk Institute for Biological Studies, La Jolla, CA 92037, USA
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Massari VJ, Shirahata M, Johnson TA, Lauenstein JM, Gatti PJ. Substance P immunoreactive nerve terminals in the dorsolateral nucleus of the tractus solitarius: roles in the baroreceptor reflex. Brain Res 1998; 785:329-40. [PMID: 9518676 DOI: 10.1016/s0006-8993(97)01335-8] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Physiological and light microscopic evidence suggest that substance P (SP) may be a neurotransmitter contained in first-order sensory baroreceptor afferents; however, ultrastructural support for this hypothesis is lacking. We have traced the central projections of the carotid sinus nerve (CSN) in the cat by utilizing the transganglionic transport of horseradish peroxidase (HRP). The dorsolateral subnucleus of the nucleus tractus solitarius (dlNTS) was processed for the histochemical visualization of transganglionically labeled CSN afferents and for the immunocytochemical visualization of SP by dual labeling light and electron microscopic methods. Either HRP or SP was readily identified in single-labeled unmyelinated axons, myelinated axons, and nerve terminals in the dlNTS. SP immunoreactivity was also identified in unmyelinated axons, myelinated axons, and nerve terminals in the dlNTS, which were simultaneously identified as CSN primary afferents. However, only 15% of CSN terminals in the dlNTS were immunoreactive for SP. Therefore, while the ultrastructural data support the hypothesis that SP immunoreactive first-order neurons are involved in the origination of the baroreceptor reflex, they suggest that only a modest part of the total sensory input conveyed from the carotid sinus baroreceptors to the dlNTS is mediated by SP immunoreactive CSN terminals. Five types of axo-axonic synapses were observed in the dlNTS. SP immunoreactive CSN afferents were very rarely involved in these synapses. Furthermore, SP terminals were never observed to form the presynaptic element in an axo-axonic synapse with a CSN afferent. Therefore, SP does not appear to be involved in the modulation of the baroreceptor reflex in the dlNTS.
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Affiliation(s)
- V J Massari
- Dept. of Pharmacology, Howard University, College of Medicine, Washington, DC 20059, USA
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20
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Blinder KJ, Gatti PJ, Johnson TA, Lauenstein JM, Coleman WP, Gray AL, Massari VJ. Ultrastructural circuitry of cardiorespiratory reflexes: there is a monosynaptic path between the nucleus of the solitary tract and vagal preganglionic motoneurons controlling atrioventricular conduction in the cat. Brain Res 1998; 785:143-57. [PMID: 9526069 DOI: 10.1016/s0006-8993(97)01258-4] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
We have tested the hypothesis: (1) that presumptive negative dromotropic vagal preganglionic neurons in the ventrolateral nucleus ambiguus (NA-VL) can be selectively labelled from the heart, by injecting one of two fluorescent tracers into the two intracardiac ganglia which independently control sino-atrial (SA) rate or atrioventricular (AV) conduction; i.e., the SA and AV ganglia, respectively. The NA-VL was examined for the presence of single and/or double labelled cells. Over 91% of vagal preganglionic neurons in the NA-VL projecting to either intracardiac ganglion did not project to the second ganglion. Consequently, we also tested the hypothesis: (2) that there is a monosynaptic connection between neurons of the medial, and/or dorsolateral nucleus of the solitary tract (NTS), rostral to obex, and negative dromotropic neurons in the NA-VL. An anterograde tracer was injected into the NTS, and a retrograde tracer into the AV ganglion. The anterograde marker was found in both myelinated and unmyelinated axons in the NA-VL, as well as in nerve terminals. Axo-somatic and axo-dendritic synapses were detected between terminals labelled from the NTS, and retrogradely labelled negative dromotropic neurons in the NA-VL. This is the first ultrastructural demonstration of a monosynaptic pathway between neurons in the NTS and functionally associated (negative dromotropic) cardioinhibitory neurons. The data are consistent with the hypothesis that the neuroanatomical circuitry mediating the vagal baroreflex control of AV conduction may be composed of as few as four neurons in series, although interneurons may also be interposed within the NTS.
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Affiliation(s)
- K J Blinder
- Dept. of Pharmacology, Howard University College of Medicine, Washington, DC 20059, USA
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21
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Buller KM, Bolter CP. Carotid bifurcation pressure modulation of spontaneous activity in external and internal carotid nerves can occur in the superior cervical ganglion. JOURNAL OF THE AUTONOMIC NERVOUS SYSTEM 1997; 67:24-30. [PMID: 9470141 DOI: 10.1016/s0165-1838(97)00088-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Previous reports have suggested that a peripheral pressure-modulated reflex operates at the level of the superior cervical ganglion to alter evoked activity in the postganglionic nerves of the ganglion in both the cat and rabbit. In the present study we have examined if spontaneous activity of the external and internal carotid nerves of the rabbit superior cervical ganglion can be modulated during changes of the carotid bifurcation pressure (CBP), independent of central nervous system (CNS) integration. For external carotid nerve recordings increases in CBP resulted in a reduction in spontaneous activity while decreases in CBP were associated with an increase in spontaneous activity. For internal carotid nerve recordings similar effects were observed in the majority of recordings although a subset of recordings showed opposite effects or were not responsive to changes in pressure. To determine if vagus nerve afferents contribute to the observed pressure-modulated spontaneous activity effects, the influence of CBP on external carotid nerve recordings was examined before and after section of the vagus nerve rostral to the nodose ganglion. We found that even following section of the vagus nerve the external carotid nerve response to an increase in pressure remained intact. These results demonstrate that, after section of centrally-projecting afferent pathways from the carotid bifurcation to the CNS, changes in CBP can still modify spontaneous sympathetic activity of the rabbit superior cervical ganglion. The data reinforce previous findings related to evoked responses in the postganglionic nerves and also suggest that a pressure-modulated reflex, integrated at the level of the superior cervical ganglion, can influence ongoing sympathetic nervous outflow from the superior cervical ganglion in the rabbit.
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Affiliation(s)
- K M Buller
- Department of Physiology, University of Otago, Dunedin, New Zealand
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Ciriello J, Zhang TX. Cardiovascular effects of neurotensin microinjections into the nucleus of the solitary tract. Brain Res 1997; 749:35-43. [PMID: 9070625 DOI: 10.1016/s0006-8993(96)01176-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Neurotensin (NT) immunoreactivity and binding sites have been demonstrated to be extensively distributed throughout the caudal nucleus of the solitary tract (NTS). In this study, the cardiovascular effects of microinjecting the tridecapeptide neurotensin (NT) or its analogues NT 1-8 and [D-Trp11]NT into NTS were investigated in the chloralose-anesthetized, paralyzed and artificially ventilated rat. Microinjection of NT (10 pmol) elicited decreases in arterial pressure (AP) (-34 +/- 3 mm Hg) and heart rate (HR) (-28 +/- 2 beats/min), whereas microinjection of equimolar amounts of the NT fragment NT 1-8 elicited a significantly smaller depressor response (-14 +/- 3 mm Hg), but the bradycardic (-22 +/- 4 beats/min) response was similar in magnitude to that elicited by NT. On the other hand, microinjection of [D-Trp11]NT did not elicit cardiovascular responses from sites in NTS. In addition, the prior injection of [D-Trp11]NT into cardiovascular responsive sites in the NTS did not significantly reduce the AP or HR response to NT. The depressor response elicited by NT was not affected by bilateral vagotomy but was abolished by either C1-C2 spinal cord transection or the i.v. administration of the nicotinic receptor blocker hexamethonium bromide. The cardiac slowing was partially attenuated by either bilateral vagotomy (-19 +/- 2 beats/min), i.v. administration of atropine methyl bromide (-17 +/- 4 beats/min), i.v. administration of hexamethonium bromide (-11 +/- 4 beats/min) or by spinal cord transection (-12 +/- 3 beats/min), and completely abolished after total autonomic blockade or by combined bilateral vagotomy and spinal cord transection. These data have demonstrated that within a restricted region of the caudal NTS NT activates neurons that contribute to vasodepressor responses as a result of sympatho-inhibition and to bradycardia responses as a result of vagal excitation and sympatho-inhibition. Furthermore, these data suggest that NT may act as a neurotransmitter or modulator in central cardiovascular reflex pathways.
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Affiliation(s)
- J Ciriello
- Department of Physiology, Health Sciences Centre, University of Western Ontario, London, Canada.
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23
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Massari VJ, Shirahata M, Johnson TA, Gatti PJ. Carotid sinus nerve terminals which are tyrosine hydroxylase immunoreactive are found in the commissural nucleus of the tractus solitarius. JOURNAL OF NEUROCYTOLOGY 1996; 25:197-208. [PMID: 8737172 DOI: 10.1007/bf02284796] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Tyrosine hydroxylase immunoreactive sensory neurons in the petrosal ganglion selectively innervate the carotid body via the carotid sinus nerve. Central projections of the carotid sinus nerve were traced with horseradish peroxidase. The commissural nucleus of the tractus solitarius was examined by dual labelling light and electron microscopy. Dense bilateral labelling with horseradish peroxidase was found in the tractus solitarius and commissural nucleus of the tractus solitarius. Horseradish peroxidase was found in unmyelinated axons, myelinated axons, and nerve terminals. About 88% of horseradish peroxidase-labelled carotid sinus nerve axons were unmyelinated. Tyrosine hydroxylase immunoreactivity was identified in unmyelinated axons, myelinated axons, dendrites, perikarya, and nerve terminals. Most tyrosine hydroxylase immunoreactive axons (93%) in the commissural nucleus of the tractus solitarius were unmyelinated. Tyrosine hydroxylase immunoreactivity was simultaneously identified in carotid sinus nerve unmyelinated axons, myelinated axons, and nerve terminals. These double-labelled terminals comprised 28% of the number of tyrosine hydroxylase immunoreactive terminals in the commissural nucleus of the tractus solitarius, and 55% of transganglionically-labelled terminals. Therefore, there are both central and peripheral sources of tyrosine hydroxylase immunoreactive nerve terminals in the commissural nucleus of the tractus solitarius. These data support the hypothesis that peripheral tyrosine hydroxylase immunoreactive neurons are involved in the origination of the chemoreceptor reflex. Axo-axonic synapses between peripheral carotid sinus nerve afferent terminals and central terminals containing tyrosine hydroxylase immunoreactivity were observed in 22% of the axo-axonic synapses observed. Thus, central tyrosine hydroxylase immunoreactivity neurons are involved in the modulation of the chemo-and/or baroreceptor reflexes. Synaptic contacts were not observed between carotid sinus nerve afferents and tyrosine hydroxylase immunoreactive perikarya of dendrites. Catecholaminergic neurons are thus unlikely to be the second order neurons of either the chemo-or baroreceptor reflex in the commissural nucleus of the tractus solitarius.
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Affiliation(s)
- V J Massari
- Department of Pharmacology, Howard University, College of Medicine, Washington, DC 20059, USA
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24
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Torrealba F, Müller C. Glutamate immunoreactivity of insular cortex afferents to the nucleus tractus solitarius in the rat: a quantitative electron microscopic study. Neuroscience 1996; 71:77-87. [PMID: 8834393 DOI: 10.1016/0306-4522(95)00426-2] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Corticosolitary axons and their terminals were labeled by the anterograde transport of wheat germ agglutinin conjugated to horseradish peroxidase, after injections into the rat insular cortex. The ultrastructure of these cortical afferents was analysed in the medial and commissural subnuclei of the nucleus tractus solitarius. Cortical terminals had a mean area of 0.36 microns 2, and were among the smallest terminals in the nucleus. They made single, asymmetric synaptic contacts with thin dendritic stems or with spines. The average diameter of the dendrites postsynaptic to cortical axons was 0.59 microns, and significantly smaller (P < 0.01, Kolmogorov-Smirnov test) than the mean (0.87 microns) of the population of dendrites in the same region of the nucleus tractus solitarius. Cortical boutons contained closely packed round and clear synaptic vesicles of diameter ca. 28 nm, a few mitochondria, and no dense core vesicles. Postembedding immunogold analysis showed that the anterogradely labeled cortical axon terminals were immunoreactive to glutamate, but not to GABA. Cortical afferents had on average four times the glutamate immunoreactivity (assessed by gold particle density) than local dendrites or terminals making symmetric synaptic contacts. Similarly, most of the unlabeled axon terminals participating in asymmetric synaptic contacts were highly enriched in glutamate immunoreactivity, suggesting that glutamate may be a most prevalent transmitter in the nucleus tractus solitarius. Terminals immunoreactive to GABA always made symmetric synapses, mostly with dendritic shafts and perikarya. We concluded that insular cortex axons made single, asymmetric synaptic contacts with thin, probably distal dendrites in the nucleus tractus solitarius. Cortical terminals are immunoreactive to glutamate, and morphologically different from primary afferents and from terminals immunoreactive to GABA.
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Affiliation(s)
- F Torrealba
- Departamento de Ciencias Fisiológicas, Pontificia Universidad Católica de Chile, Santiago
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25
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Dev BR, Philip L. Extracellular catechol and indole turnover in the nucleus of the solitary tract of spontaneously hypertensive and Wistar-Kyoto normotensive rats in response to drug-induced changes in arterial blood pressure. Brain Res Bull 1996; 40:111-6. [PMID: 8724428 DOI: 10.1016/0361-9230(95)02145-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Drug-induced alterations in arterial blood pressure are reflected in the extracellular fluid neurotransmitter levels of the nucleus of the solitary tract (NTS). Urethane-anesthetized spontaneously hypertensive rats (SHRs) and Wistar-Kyoto normotensive (WKY) rats were used in this study. The extracellular neurochemical profile of the NTS was quantified using the in vivo microdialysis technique. In SHR, phenylephrine-induced hypertension produced no significant changes in the extracellular norepinephrine (NE) and dihydroxyphenylacetic acid concentrations, whereas a significant increase in the serotonin metabolite 5-hydroxyindoleacetic acid (5-HIAA) concentration was observed. Wistar normotensive rats, in response to phenylephrine-induced hypertension, showed a significant increase in extracellular NE and 5-HIAA concentrations. Hypotension produced by the intravenous infusion of nitroprusside failed to show significant changes in the extracellular neurotransmitters in both SHR and WKY rats. However, there was a significant increase in 5-HIAA concentration in SHRs during the rebound hypertension, which followed the nitroprusside-infused hypotension. No such change was observed in the case of the WKY rats. These results suggest the possible involvement of the serotonergic mechanisms of NTS in the regulation of normal arterial blood pressure in these two rat strains.
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Affiliation(s)
- B R Dev
- Department of Physiology, Faculty of Medicine, Kuwait University, Safat, Kuwait
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26
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Gatti PJ, Shirahata M, Johnson TA, Massari VJ. Synaptic interactions of substance P immunoreactive nerve terminals in the baro- and chemoreceptor reflexes of the cat. Brain Res 1995; 693:133-47. [PMID: 8653401 DOI: 10.1016/0006-8993(95)00728-9] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The neurochemical anatomy and synaptic interactions of morphologically identified chemoreceptor or baroreceptor afferents in the nucleus of the solitary tract (NTS) are poorly understood. A substantial body of physiological and light microscopic evidence suggests that substance P (SP) may be a neurotransmitter contained in first order sensory chemo- or baroreceptor afferents, however ultrastructural support of this hypothesis is lacking. In the present report we have traced the central projections of the carotid sinus nerve (CSN) in the cat by utilizing the transganglionic transport of horseradish peroxidase. Medullary tissues including the commissural NTS (cNTS) were processed for the histochemical visualization of transganglionically labeled CSN afferents and for the immunocytochemical detection of SP by dual labeling light and electron microscopic methods. At the light microscopic level, dense bilateral labeling with TMB was found in the tractus solitarius (TS) and cNTS, caudal to the obex. Rostral to the obex, significant ipsilateral TMB labeling was detected in the dorsal, dorso-lateral, and medial subnuclei of the NTS, as well as in the TS. Significant staining of SP immunoreactive processes was detected in most subnuclei of the NTS. The cNTS was examined by electron microscopy. Either HRP or SP were readily identified in single labeled unmyelinated axons, myelinated axons, and nerve terminals in the cNTS. SP immunoreactivity was also identified in unmyelinated axons, myelinated axons, and nerve terminals in the cNTS which were simultaneously identified as CSN primary afferents. These ultrastructural data support the hypothesis that SP immunoreactive first order neurons are involved in the origination of the chemo- and baroreceptor reflexes. Axo-axonic synapses were observed between CSN primary afferent terminals and: (a) unlabeled nerve terminals; (b) other CSN primary afferent terminals; and (c) terminals containing SP. Axo-axonic synapses were also observed between CSN primary afferents which contained SP, and other SP terminals. These observations may mediate the morphological bases for multiple forms of presynaptic inhibition in the cNTS, including those involved in cardiorespiratory integration. In conclusion, our results indicate that SP immunoreactive nerve terminals may be important in both the origination and the modulation of the chemo- and/or baroreceptor reflexes.
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Affiliation(s)
- P J Gatti
- Department of Pharmacology, Howard University, College of Medicine, Washington, DC 20059, USA
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27
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Grimes PA, Mokashi A, Stone RA, Lahiri S. Nitric oxide synthase in autonomic innervation of the cat carotid body. JOURNAL OF THE AUTONOMIC NERVOUS SYSTEM 1995; 54:80-6. [PMID: 7594214 DOI: 10.1016/0165-1838(95)00006-j] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
In the cat carotid body, nitric oxide synthase (NOS) immunoreactivity and NADPH diaphorase activity localize in nerve fibers mainly associated with blood vessels and occasionally lying close to glomus cells. The NOS-positive innervation originates in part from multipolar ganglion cells scattered in and around the carotid body and in the glossopharyngeal nerve. In the superior cervical ganglion, NOS and diaphorase staining localizes to many preganglionic axons and also to a small population of vasoactive intestinal peptide-positive, presumably cholinergic, ganglion cells. Positively stained ganglion cells are absent in the petrosal ganglion and very rare in the nodose ganglion, although both sensory ganglia display characteristic distributions of cells immunoreactive for calcitonin gene-related peptide, substance P and tyrosine hydroxylase. The NOS-positive innervation of the carotid body thus appears to be autonomic, originating mainly from a population of dispersed ganglion cells, and probably parasympathetic in nature. The superior cervical ganglion also may supply some pre- or postganglionic NOS-positive axons. Nitric oxide released from these nerves could affect glomus cell activity directly or indirectly by vasoregulation.
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Affiliation(s)
- P A Grimes
- Department of Ophthalmology, University of Pennsylvania, Philadelphia 19104-6075, USA
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28
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Satoda T, Takahashi O, Uchida T, Mizuno N. An anterograde-retrograde labeling study of the carotid sinus nerve of the Japanese monkey (Macaca fuscata). Neurosci Res 1995; 22:381-7. [PMID: 7478303 DOI: 10.1016/0168-0102(95)00918-j] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The sites of origin and termination of efferent and afferent fibers in the carotid sinus nerve (CSN) were investigated in the Japanese monkey. After application of a mixture of horseradish peroxidase (HRP) and wheat germ aggulutinin-conjugated HRP to the central cut end of the CSN, sensory ganglion neurons were labeled in the jugular ganglion of the vagus nerve, as well as in the superior and petrosal ganglia of the glossopharyngeal nerve. Many sympathetic ganglion neurons were also labeled retrogradely in the superior cervical ganglion. In the brain, many labeled terminals were seen ipsilaterally in the lateral division of the nucleus of the solitary tract (NST). A few neuronal cell bodies were also labeled ipsilaterally in a reticular region dorsomedial to the caudal one-third of the facial nucleus. The results indicate that the CSN of the Japanese monkey is composed mainly of afferent fibers terminating in the NST, that the afferent fibers in the CSN originate not only from the superior and petrosal ganglia of the glossopharyngeal nerve but also from the jugular ganglion of the vagus nerve, and that efferent fibers contained in the CSN arise from the medullary reticular formation and superior cervical ganglion.
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Affiliation(s)
- T Satoda
- Department of Oral Anatomy (2nd division), School of Dentistry, Hiroshima University, Japan
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29
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Ruiz-Pesini P, Tomé E, Balaguer L, Romano J, Yllera M. The localization of neurons innervating the carotid sinus in the dog. JOURNAL OF THE AUTONOMIC NERVOUS SYSTEM 1995; 50:291-7. [PMID: 7536226 DOI: 10.1016/0165-1838(94)00100-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The localization of neurons innervating the carotid sinus of the dog was studied by horseradish peroxidase histochemistry following microinjection of wheat germ agglutinin-horseradish peroxidase (WGA-HRP) under the adventitia of the carotid sinus. Labeled cell bodies were found in the petrosal (198 +/- 108; mean +/- S.D.) and superior cervical ganglia (SCG) (890 +/- 354 mean +/- S.D.) supporting the existence of both a sensory afferent and a sympathetic efferent innervation of the carotid sinus. Labeled neurons in the petrosal ganglion were round pseudounipolar neurons of variable size. Labeled neurons in the SCG were multipolar and appeared distributed over the whole ganglion, but with a higher density toward its caudal half. No labeled perikarya appeared either in the brainstem or in the nodose or jugular ganglia, suggesting that in the dog a vagal pathway for carotid sinus baroreceptor afferents does not exist.
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Affiliation(s)
- P Ruiz-Pesini
- Departmento de Anatomía, Facultad de Veterinaria, Universidad de Santiago, Lugo, Spain
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30
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Ruiz-Pesini P, Tomé E, Balaguer L, Romano J, Yllera M. The projections to the medulla of neurons innervating the carotid sinus in the dog. Brain Res Bull 1995; 37:41-6. [PMID: 7541699 DOI: 10.1016/0361-9230(94)00255-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The localization and brain stem projections of neurons innervating the carotid sinus of the dog were studied by horseradish peroxidase histochemistry following microinjection of wheat germ agglutinin-horseradish peroxidase (WGA-HRP) under the adventitia of the carotid sinus. Within the brain stem, labeled afferent fibers and presumptive terminals were found bilaterally in the caudal nucleus tractus solitarius (nTS), the area postrema (AP), and the lateral tegmental field (LTF), reaching the area of the nucleus ambiguus (nA). Sparse labeling was also seen in the ipsilateral spinal trigeminal nucleus (SpV) and lateral cuneatus nucleus (LCn). These findings suggest the existence of multiple pathways by which peripheral baroreceptor inputs may influence central cardiovascular-related neurons. In addition to classically defined relay in the nTS, carotid sinus afferents may also interact more directly with these neurons in other brain stem regions.
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Affiliation(s)
- P Ruiz-Pesini
- Departamento de Anatomia, Facultad de Veterinaria, Universidad de Santiago, Lugo, Spain
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31
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Hochstenbach SL, Ciriello J. Cardiovascular effects of NaCl microinjections into the nucleus of the solitary tract. Brain Res 1994; 644:233-42. [PMID: 8050035 DOI: 10.1016/0006-8993(94)91685-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The nucleus of the solitary tract (NTS) was systematically explored in the alpha-chloralose-anesthetized rat for sites that elicited changes in mean arterial pressure (MAP) and heart rate (HR) during microinjections (20 nl) of phosphate-buffered saline (PBS; pH 7.2-7.4) or NaCl solutions containing various concentrations of NaCl (104-326 mM). Decreases in MAP (range 7-83 mmHg) and HR (range 10-70 bpm) were consistently elicited from sites in the caudal medial and commissural subnuclei of NTS. Microinjection of PBS or NaCl into other NTS subnuclei or area postrema did not elicit cardiovascular responses. Microinjection of LiCl in PBS elicited cardiovascular responses that were significantly smaller than those elicited by microinjection of NaCl in PBS at the same NTS site. Injections of either a hyperosmotic (400 mOsm/kg) or a hyposmotic (204 mOsm/kg) solution of mannitol into NaCl-sensitive sites did not elicit cardiovascular responses. Finally, most of the sites in NTS that elicited cardiovascular responses during microinjection of glutamate (1 M) did not respond to microinjections of PBS. Administration of atropine methyl bromide had no effect on the magnitude of the depressor response to injections of PBS into NTS, but significantly attenuated (32%) the HR response. Subsequent administration of the ganglionic blockers hexamethonium bromide or arfonad abolished both the depressor and bradycardic responses. These data suggest that within a restricted region of the caudal NTS there exists a pool of neurons sensitive to changes in extracellular Na+ concentrations that, when activated by the sodium, elicit vasodepressor responses as a result of sympathoinhibition and bradycardia as a result of vagal excitation and sympathoinhibition.
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Affiliation(s)
- S L Hochstenbach
- Department of Physiology, Health Sciences Centre, University of Western Ontario, London, Canada
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32
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Larnicol N, Wallois F, Berquin P, Gros F, Rose D. c-fos-like immunoreactivity in the cat's neuraxis following moderate hypoxia or hypercapnia. JOURNAL OF PHYSIOLOGY, PARIS 1994; 88:81-8. [PMID: 8019526 DOI: 10.1016/0928-4257(94)90094-9] [Citation(s) in RCA: 58] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The overall pattern of c-fos immunoreactivity was studied in the brainstem and spinal cord of cats subjected to moderate hypoxia or hypercapnia. In control cats (normoxic, normocapnic), c-fos was expressed mainly in pontine and periaqueductal grey but not in brainstem structures engaged in respiratory control nor in the spinal cord. Both hypoxia and hypercapnia induced c-fos expression in the parabrachial area (pneumotaxic center). In the retrotrapezoid nucleus, a structure involved in respiratory rhythmogenesis and chemoreception, immunoreactivity was detected in hypoxic but not in hypercapnic cats. Neurons in the nucleus raphe pallidus preferentially expressed c-fos in response to hypercapnia. Labelled neurons were concentrated in the dorsal and gelatinosus subnuclei of the solitary tract following hypoxia and hypercapnia, respectively. Our data suggest that some neurons that express c-fos in hypoxic or hypercapnic cats may be involved in coordination of cardiovascular and respiratory function.
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Affiliation(s)
- N Larnicol
- Laboratoire de Neurophysiologie, CNRS-URA 1331, Université de Picardie, Amiens, France
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33
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Buller KM, Bolter CP. The localization of sympathetic and vagal neurones innervating the carotid sinus in the rabbit. JOURNAL OF THE AUTONOMIC NERVOUS SYSTEM 1993; 44:225-31. [PMID: 8227957 DOI: 10.1016/0165-1838(93)90035-s] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The distribution of neurones innervating the carotid sinus of the rabbit was determined by inserting chips of horseradish peroxidase (HRP) into the adventitial layer of the carotid sinus. Labelled neurones were found in the superior cervical ganglion, along the cervical sympathetic trunk and in the nodose ganglion (mean counts of 1876, 139 and 232, respectively). No labelled neurones were located in the middle cervical ganglion or the stellate ganglion. Within the superior cervical ganglion, the fraction of labelled neurones found in equal longitudinal quadrants of the ganglion were, from rostral to caudal, 2%, 12%, 42% and 44%. Thus the majority of neurones were located in the caudal region of the superior cervical ganglion. The primary pathway for sympathetic fibres innervating the carotid sinus was shown to be in branches of the external carotid nerve. The greatest number of labelled neurones in the nodose ganglion were located in the most rostral quadrants of the ganglion.
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Affiliation(s)
- K M Buller
- Department of Physiology, Otago Medical School, Dunedin, New Zealand
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34
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Schmitt P, Pequignot J, Hanchin F, Pujol JF, Pequignot JM. Regional specificity of long-term regulation of tyrosine hydroxylase in some catecholaminergic rat brainstem areas. II. Effect of a chronic dihydralazine treatment. Brain Res 1993; 611:61-6. [PMID: 8100176 DOI: 10.1016/0006-8993(93)91777-p] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Dihydralazine, which is used in the treatment of hypertension, causes a long-lasting hypotensive action by a direct vasodilator effect on arteriolar smooth muscle. The present study was carried out to investigate the effect of a daily single injection of dihydralazine (20 mg/kg, s.c.) for 14 days on the tyrosine hydroxylase (TH) protein quantity in some catecholaminergic rat brainstem areas such as the dorsomedial medulla (DMM), the ventrolateral medulla (VLM) and the locus coeruleus (LC). This study demonstrates that the dihydralazine produced (1) an 85% increase in TH protein quantity exclusively in the rostral part of DMM, (2) a 58% increase of TH protein content exclusively in the rostral part of the LC, and (3) a 37% increase of the TH protein quantity in VLM catecholaminergic area. To determine whether the increase in TH protein quantity could be related to a change in norepinephrine (NE) content, the rate constant of disappearance (k) of NE was measured in the catecholaminergic regions of the same rats treated with dihydralazine. Our results show that dihydralazine causes an increase of the TH protein, in addition to an elevation of NE content, within the subpopulations of catecholaminergic structures. These data suggest a selective response of the TH regulation to dihydralazine within the rostral DMM area which receives barosensory inputs.
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Affiliation(s)
- P Schmitt
- Laboratoire de Neuropharmacologie Moléculaire, UMR 105 CNRS-UCB, Faculté de Médecine Alexis Carrel, Lyon, France
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35
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36
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Schamel A, Verna A. Localization of dopamine D2 receptor mRNA in the rabbit carotid body and petrosal ganglion by in situ hybridization. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 1993; 337:85-91. [PMID: 8109435 DOI: 10.1007/978-1-4615-2966-8_13] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- A Schamel
- Laboratoire de Cytologie, Université de Bordeaux II, Talence, France
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37
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McKinley MJ, Badoer E, Oldfield BJ. Intravenous angiotensin II induces Fos-immunoreactivity in circumventricular organs of the lamina terminalis. Brain Res 1992; 594:295-300. [PMID: 1450955 DOI: 10.1016/0006-8993(92)91138-5] [Citation(s) in RCA: 142] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Conscious rats were infused intravenously with either angiotensin II (30-55 pmol/kg/min), isotonic saline or phenylephrine for 2 h, then killed. Fos was identified by immunohistochemistry in the brains. Fos expression occurred in many neurons of the subfornical organ and organum vasculosum of the lamina terminalis (OVLT) with angiotensin infusion but not with isotonic NaCl or phenylephrine. Fos immunoreactivity was induced in cells in several medullary, hypothalamic and limbic structures with infusions of angiotensin II or phenylephrine at pressor doses. The results suggest that blood-borne angiotensin II at physiological levels causes angiotensin receptive neurons in the subfornical organ and OVLT to express Fos. Activation of baroreceptor pathways may also induce Fos expression at several other sites.
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Affiliation(s)
- M J McKinley
- Howard Florey Institute of Experimental Physiology and Medicine, University of Melbourne, Parkville, Vic., Australia
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38
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Torrealba F. Calcitonin gene-related peptide immunoreactivity in the nucleus of the tractus solitarius and the carotid receptors of the cat originates from peripheral afferents. Neuroscience 1992; 47:165-73. [PMID: 1579206 DOI: 10.1016/0306-4522(92)90129-p] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The presence and distribution of the calcitonin gene-related peptide was studied, using immunohistochemical techniques, in carotid receptors, in the nodose and glossopharyngeal ganglia and in the nucleus tractus solitarii of the cat. Seventy-seven per cent of the 42% of the nodose ganglion cells were labeled. Fine, sparsely branched immunoreactive terminal axonal arborizations were found in the carotid body; they disappeared after petrosal ganglionectomy. The intense immunoreactivity present in fibers in the commissural, medial, interstitial, gelatinosus, dorsal, intermediate and rostral gustatory subnuclei of the nucleus tractus solitarius was drastically reduced after removal of the ipsilateral nodose and petrosal ganglia. The central distribution of the immunoreactive axons, the morphology of the terminals in the carotid receptors and their dependence on an intact peripheral innervation are consistent with the idea that in the cat the calcitonin gene-related peptide is present in a high proportion of the primary visceral afferents, most of them unmyelinated.
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Affiliation(s)
- F Torrealba
- Departamento de Ciencias Fisiológicas, Facultad de Ciencias, Biológicas, Universidad Católica de Chile, Santiago
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39
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Finley JC, Katz DM. The central organization of carotid body afferent projections to the brainstem of the rat. Brain Res 1992; 572:108-16. [PMID: 1611506 DOI: 10.1016/0006-8993(92)90458-l] [Citation(s) in RCA: 330] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Despite increasing focus on brainstem respiratory control mechanisms in the rat, relatively little is known about the central organization of chemoreceptor pathways in this species. To approach this issue, the present study sought to selectively define the central projections of primary sensory neurons that innervate the carotid body. Afferent projections were visualized by horseradish peroxidase histochemistry following microinjection of wheat germ agglutinin-horseradish peroxidase into the vascularly isolated carotid body in situ. Labeled afferent fibers were found in several discrete regions of the dorsomedial and ventrolateral medulla. Heaviest labeling was seen bilaterally in the commissural and medial subnuclei of the caudal nucleus tractus solitarius (nTS); more moderate labeling was found bilaterally in the intermediate, interstitial, and dorsolateral subnuclei and ipsilaterally in the ventrolateral subnuclei. In addition, we observed a prominent projection to the caudal ventrolateral medulla in the region of the nucleus retroambigualis. Sparse labeling was also seen in the dorsal motor nucleus of the vagus nerve and the area postrema. These findings support the existence of multiple pathways by which peripheral chemoreceptor inputs may influence central respiratory neurons. In addition to the classically defined relay in nTS, carotid body afferents may also interact more directly with respiratory- or cardiovascular-related neurons in other regions such as the ventrolateral medulla.
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Affiliation(s)
- J C Finley
- Department of Medicine, University Hospitals of Cleveland, OH 44106
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40
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Chen IL, Weber JT, Rieck RW, Yates RD. Synaptic connections of central carotid sinus afferents in the nucleus of the tractus solitarius of the rat. I. An electron microscopic study. JOURNAL OF NEUROCYTOLOGY 1992; 21:137-47. [PMID: 1560250 DOI: 10.1007/bf01189012] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
A transganglionic transport technique was used to study the synaptic connections of the central carotid sinus afferents in the nucleus of the tractus solitarius of the rat by electron microscopy. The caudal part of the nucleus was profusely innervated. Labelled fibres extended to the contralateral nucleus, and to the ipsilateral dorsal motor nucleus of the vagus nerve, nucleus ambiguus, spinal nucleus of the trigeminal nerve and the area postrema. The labelled terminals were densely packed with clear, predominantly spherical vesicles about 50 nm in diameter and a few often swollen mitochondria. The terminals synapsed on dendrites of various calibres, spindle- or pear-shaped somal profiles with short axes lesser than 8 microns, and axon terminals. In axo-axonal synapses, most labelled terminals appeared to be presynaptic. Frequently, profiles of labelled terminals were in direct apposition with one another. The latter may represent the morphological substrate of the interaction between baro- and chemoreceptor inputs in the nucleus of the tractus solitarius and warrants further study. The present results indicate that in addition to direct inputs, the carotid sinus afferents are able to influence second-order neurons in the nucleus of the tractus solitarius indirectly through presynaptic modulation.
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Affiliation(s)
- I L Chen
- Department of Anatomy, Tulane Medical School, New Orleans, LA 70112
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41
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Roder S, Ciriello J. Caudal ventrolateral medullary projections to the nucleus of the solitary tract in the cat. Neurosci Lett 1992; 134:161-4. [PMID: 1375350 DOI: 10.1016/0304-3940(92)90506-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The projections of neurons, in and around the A1 noradrenergic cell group of the caudal ventrolateral medulla (VLM), to nucleus of the solitary tract (NTS) were studied in the cat using the anterograde transport of Phaseolus vulgaris leucoagglutinin (PHA-L). PHA-L was micro-iontophoresed into the region of the A1 noradrenergic cell group and after a 7-17 day survival period animals were sacrificed and brainstem sections were processed for PHA-L or tyrosine hydroxylase (TH) immunoreactivity. PHA-L injections within the region of the A1 cell group resulted in labelled fibers with their presumptive terminal boutons primarily in the ipsilateral commissural and medial subnuclei of NTS. A light projection to the ipsilateral parvocellular lateral and ventrolateral subnuclei of the NTS complex was also observed. These data demonstrate that neurons in the region of the A1 noradrenergic cell group project to regions of NTS that receive cardiovascular afferent inputs and suggest that VLM may influence the activity of neurons in NTS involved in the reflex regulation of the circulation.
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Affiliation(s)
- S Roder
- Department of Physiology, University of Western Ontario, London, Canada
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42
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Gieroba ZJ, Li YW, Wesselingh SL, Blessing WW. Transneuronal labeling of neurons in rabbit brain after injection of herpes simplex virus type 1 into the aortic depressor nerve. Brain Res 1991; 558:264-72. [PMID: 1685933 DOI: 10.1016/0006-8993(91)90777-s] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Herpes simplex virus type 1 (HSV1) was injected into either the aortic depressor nerve or the vagus nerve in the rabbit. Four or 5 days after injection of virus, the rabbit brain was processed immunohistochemically to demonstrate viral antigen. After injection into the aortic nerve HSV1 positive cells were found principally ipsilaterally within the nucleus tractus solitarius, area postrema, caudal and rostral ventrolateral medulla oblongata, the spinal trigeminal complex, raphe nuclei, A5 area, locus coeruleus, parabrachial nucleus, periaqueductal gray, ventrolateral hypothalamic area, paraventricular nucleus, amygdala, bed nucleus of the stria terminalis and insular cortex. Double labeling studies indicated that approximately 85% of the virus-containing neurons in the ventrolateral medulla, and virtually all the HSV-positive neurons in the A5 area and locus coeruleus also contained tyrosine hydroxylase. In the raphe nuclei and parapyramidal region approximately 33% of virus-containing cells reacted positively with PH8 antibody, a marker for serotonin synthesis. After injection of HSV1 into the vagus nerve labeled cells were found in similar brain areas, with a more bilateral distribution. The HSV-positive neurons may be involved in the processing of baroreceptor-derived information.
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Affiliation(s)
- Z J Gieroba
- Department of Physiology, Flinders University of South Australia, Bedford Park, Australia
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Kubin L, Kimura H, Davies RO. The medullary projections of afferent bronchopulmonary C fibres in the cat as shown by antidromic mapping. J Physiol 1991; 435:207-28. [PMID: 1770435 PMCID: PMC1181458 DOI: 10.1113/jphysiol.1991.sp018506] [Citation(s) in RCA: 58] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
1. The activity of eighty-seven bronchopulmonary vagal afferent neurones with unmyelinated axons (C fibres) was recorded extracellularly in the nodose ganglia of decerebrate, paralysed and artificially ventilated cats. On the basis of their response latencies following the right atrial injection of capsaicin or phenyldiguanide, the cells were classified as having their receptor endings within the reach of pulmonary (latency less than 3.5 s) or bronchial (latency above 3.5 s) circulation. 2. Pulmonary and bronchial receptor cells differed only slightly in their response characteristics (firing rate, burst duration) and the conduction velocity of their peripheral axons. Bronchial C fibres represented about 70% of the population studied. 3. The medullary distributions of the central branches of six pulmonary and six bronchial C fibres were determined by means of the antidromic mapping technique. The two receptor subtypes did not differ in their central projection patterns. 4. Rostral to the obex, the central branches of the bronchopulmonary C fibres were localized within the medial portions of the nucleus tractus solitarii (NTS) and area postrema, and were most densely distributed along the borders of the parvicellular subnucleus of the NTS. Caudal to the obex, the most dense branching was found in the dorsal portion of the commissural subnucleus. Projections to the contralateral NTS were found, but these were of a much lower density. 5. The central distribution of bronchopulmonary C fibres is compared to the projection patterns of vagal and glossopharyngeal afferents of other modalities that are involved in respiratory and cardiovascular control. This is discussed in relation to the concept of a modality-specific organization of the NTS.
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Affiliation(s)
- L Kubin
- Department of Animal Biology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia
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Claps A, Torrealba F, Calderón F. Segregation of coarse and fine glossopharyngeal axons in the visceral nucleus of the tractus solitarius of the cat. Brain Res 1989; 489:80-92. [PMID: 2472856 DOI: 10.1016/0006-8993(89)90010-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The projections of coarse and fine axons of the glossopharyngeal (IX) nerve upon the caudal two thirds of the nucleus of the tractus solitarius (NTS) were studied in the cat. These afferents convey the chemo- and baroreceptor activities from the carotid receptors. We applied the Fink-Heimer method on brainstem sections, at different survival times, after a petrosal ganglionectomy. A segregation of fine and coarse fibered components was observed. Degeneration of coarse axons was mostly found in the lateral NTS, while fine fiber degeneration was predominant in regions of the medial and commissural NTS. The injection of WGA-HRP in the different NTS divisions demonstrated that the lateral NTS was mainly innervated by the set of largest neurons of the petrosal ganglion and that the medial and the commissural NTS were innervated by the set of smaller neurons of the ganglia. These results were discussed in relation to cytoarchitecture, myeloarchitecture, distribution of normal axons, and known central connectivity of the different NTS divisions. We concluded that coarse and fine visceral afferents of the IX nerve, which includes the afferents of the carotid body and the carotid sinus, represent different afferent populations that project to particular divisions of the NTS and connect to different central pathways.
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Affiliation(s)
- A Claps
- Departamento de Ciencias Fisiológicas, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
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Abstract
Previous neuroanatomical studies described the central representation of the carotid sinus nerve, but did not differentiate the projections of the baroreceptors from the chemoreceptors present in the carotid bifurcation. In this research we investigated the individual territories occupied by the primary afferents from the carotid body in the brainstem of the cat. We also studied the distribution of afferent and efferent neurons to the carotid body. We injected into the carotid body lectin coupled to horseradish peroxidase. We found labeled axons only in the nucleus of the tractus solitarius; in particular, we found strong projections to the following ipsilateral subnuclei: dorsal, interstitial, and medial part of the commissural subnucleus. Moderate labeling was found in the ipsilateral medial and intermediate subnuclei and in the contralateral dorsal subnucleus and the medial region of the commissural subnucleus. We found a mean of 256 +/- 79 (S.E.M.) labeled afferent ganglion cells in the petrosal ganglia, and no evidence of efferent neurons in the brainstem that innervate the carotid body; conversely, about 4000 efferent neurons of the superior cervical ganglion send terminals to the ipsilateral carotid body.
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Affiliation(s)
- A Claps
- Laboratorio de Neurobiologia, Facultad de Ciencias Biológicas Universidad Católica de Chile, Santiago
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