Document Detail


Arterial chemoreceptor input to nucleus tractus solitarius.
MedLine Citation:
PMID:  1510176     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The arterial chemoreceptors play an important role in the reflex regulation of blood pressure and respiration. To investigate the initial integration of chemoreceptor inputs within the central nervous system, intracellular recordings were obtained in pentobarbital-anesthetized, paralyzed, and mechanically ventilated cats, from 58 cells within the nucleus of the tractus solitarius (NTS) that were depolarized by activation of the ipsilateral carotid body chemoreceptors. Close arterial injection of less than 100 microliters CO2-saturated bicarbonate evoked depolarizations of membrane potential with amplitudes of 2.2-4.6 mV and durations of 1.8-6.7 s in 46 cells. In 12 cells, activation of the carotid body chemoreceptors evoked a depolarization-hyperpolarization sequence. Electrical stimulation of the carotid sinus nerve (500 microA, 0.2 ms) evoked EPSPs [mean latency 6.4 +/- 0.5 (SE) ms; range 2.1-18.4 ms] in 46 cells and EPSP-IPSPs (7.3 +/- 0.8 ms; range 4.2-12.4 ms) in 12 cells. The distribution of EPSP latencies exhibited two peaks, one in the 2- to 4-ms range and another in the 7- to 8-ms range. Twenty-nine chemoreceptive cells were tested for the presence of convergent inputs from the ipsilateral carotid sinus baroreceptors. No evidence was found of a convergent postsynaptic inhibitory input from the baroreceptors within the NTS; however, seven cells were found that received an excitatory input from the baroreceptors. The observation that NTS neurons do not integrate chemoreceptor afferent inputs in a homogeneous manner suggests that the multiplicity of NTS unit responses might be related to the specific reflex function of an individual cell (e.g., vagal or sympathetic outflow, respiration).(ABSTRACT TRUNCATED AT 250 WORDS)
Authors:
S W Mifflin
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  The American journal of physiology     Volume:  263     ISSN:  0002-9513     ISO Abbreviation:  Am. J. Physiol.     Publication Date:  1992 Aug 
Date Detail:
Created Date:  1992-09-22     Completed Date:  1992-09-22     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  0370511     Medline TA:  Am J Physiol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  R368-75     Citation Subset:  IM    
Affiliation:
Department of Pharmacology, University of Texas Health Science Center, San Antonio 78284-7764.
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MeSH Terms
Descriptor/Qualifier:
Afferent Pathways / physiology
Animals
Arteries / physiology*
Bicarbonates / administration & dosage,  pharmacology
Carotid Body / physiology
Carotid Sinus / innervation
Cats
Chemoreceptor Cells / physiology*
Electric Stimulation
Electrophysiology
Female
Injections, Intra-Arterial
Male
Medulla Oblongata / cytology,  physiology*
Nervous System Physiological Phenomena
Neurons / physiology
Grant Support
ID/Acronym/Agency:
HL-41894/HL/NHLBI NIH HHS
Chemical
Reg. No./Substance:
0/Bicarbonates

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


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