Document Detail


Differential chemoreceptor reflex responses of adrenal preganglionic neurons.
MedLine Citation:
PMID:  11705767     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Adrenal sympathetic preganglionic neurons (ADR SPNs) regulating the chromaffin cell release of epinephrine (Epi ADR SPNs) and those controlling norepinephrine (NE ADR SPNs) secretion have been distinguished on the basis of their responses to stimulation in the rostral ventrolateral medulla, to glucopenia produced by 2-deoxyglucose, and to activation of the baroreceptor reflex. In this study, we examined the effects of arterial chemoreceptor reflex activation, produced by inhalation of 100% N(2) or intravenous injection of sodium cyanide, on these two groups of ADR SPNs, identified antidromically in urethane-anesthetized, artificially ventilated rats. The mean spontaneous discharge rates of 38 NE ADR SPNs and 51 Epi ADR SPNs were 4.4 +/- 0.4 and 5.6 +/- 0.4 spikes/s at mean arterial pressures of 98 +/- 3 and 97 +/- 3 mmHg, respectively. Ventilation with 100% N(2) for 10 s markedly excited all NE ADR SPNs (+222 +/- 23% control, n = 36). In contrast, the majority (40/48; 83%) of Epi ADR SPNs were unaffected or slightly inhibited by ventilation with 100% N(2) (population response: +6 +/- 10% control, n = 48). Similar results were obtained after injection of sodium cyanide. These observations suggest that the network controlling the spontaneous discharge of NE ADR SPNs is more sensitive to brief arterial chemoreceptor reflex activation than is that regulating the activity of Epi ADR SPNs. The differential responsiveness to activation of the arterial chemoreceptor reflex of the populations of ADR SPNs regulating epinephrine and norepinephrine secretion suggests that their primary excitatory inputs arise from separate populations of sympathetic premotor neurons and that a fall in arterial oxygen tension is not a major stimulus for reflex-mediated adrenal epinephrine secretion.
Authors:
W H Cao; S F Morrison
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  American journal of physiology. Regulatory, integrative and comparative physiology     Volume:  281     ISSN:  0363-6119     ISO Abbreviation:  Am. J. Physiol. Regul. Integr. Comp. Physiol.     Publication Date:  2001 Dec 
Date Detail:
Created Date:  2001-11-13     Completed Date:  2002-01-02     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  100901230     Medline TA:  Am J Physiol Regul Integr Comp Physiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  R1825-32     Citation Subset:  IM    
Affiliation:
Department of Physiology, Northwestern University Medical School, 303 E. Chicago Ave., Chicago, IL 60611, USA.
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MeSH Terms
Descriptor/Qualifier:
Adrenal Glands / innervation*
Animals
Aorta, Thoracic / innervation
Chemoreceptor Cells / drug effects,  physiology*
Deoxyglucose / pharmacology
Electric Stimulation
Epinephrine / pharmacology,  secretion
Ganglia, Sympathetic / physiology*
Male
Neurons / physiology*
Norepinephrine / pharmacology,  secretion
Phrenic Nerve / physiology
Rats
Rats, Sprague-Dawley
Reaction Time / physiology
Reflex / physiology*
Respiratory Mechanics / physiology
Sodium Cyanide / pharmacology
Grant Support
ID/Acronym/Agency:
HL-56365/HL/NHLBI NIH HHS
Chemical
Reg. No./Substance:
143-33-9/Sodium Cyanide; 154-17-6/Deoxyglucose; 51-41-2/Norepinephrine; 51-43-4/Epinephrine

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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