| Role of the pons in the carotid sympathetic chemoreflex. | |
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MedLine Citation:
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PMID: 8067462 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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The mass discharges of the splanchnic sympathetic (SND) and phrenic nerves (PND) were recorded in urethananesthetized rats with resected vagal and aortic nerves. Carotid chemoreceptor (CC) stimulation with N2 inhalation (4-12 s) or cyanide (50-100 micrograms/kg iv) activated SND in bursts synchronized with the postinspiratory phase (mean SND increase: 105 +/- 8%), raised AP, and increased PND rate and amplitude (n = 40). Brain transection at superior collicular level produced no effect. The sympathetic (SChR) and respiratory chemoreflexes (RChR) were reduced after transections through the pons. Lesions of the dorsolateral pons (dl-pons) produced CO2-dependent apneusis and/or tachypnea at rest. After such lesions, CC stimulation produced expiratory apnea and a 30% increase in SChR due to tonic activation of SND. In contrast, bilateral lesions of the ventrolateral pons (vl-pons) reduced the SChR by 54-76%. Muscimol (Mus) injections (bilateral, 175 pmol/side) into vl-pons did not change resting SND, MAP, baroreflex, and RChR but reduced the SChR (54-82%). In conclusion, under anesthesia: 1) the pathway of the carotid chemoreflex is confined to the pons and medulla, 2) the dl-pons exerts indirect control over the SChR via its role in respiratory rhythmogenesis, and 3) neurons in the vl-pons contribute selectively to the SChR but not to PND activation during CC activation. |
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Authors:
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N Koshiya; P G Guyenet |
Publication Detail:
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Type: Journal Article |
Journal Detail:
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Title: The American journal of physiology Volume: 267 ISSN: 0002-9513 ISO Abbreviation: Am. J. Physiol. Publication Date: 1994 Aug |
Date Detail:
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Created Date: 1994-09-21 Completed Date: 1994-09-21 Revised Date: 2008-11-21 |
Medline Journal Info:
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Nlm Unique ID: 0370511 Medline TA: Am J Physiol Country: UNITED STATES |
Other Details:
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Languages: eng Pagination: R508-18 Citation Subset: IM |
Affiliation:
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Department of Pharmacology, University of Virginia Health Sciences Center, Charlottesville 22908. |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Animals Brain Stem / physiology Carotid Arteries / innervation* Chemoreceptor Cells / physiology* Denervation Electrophysiology Injections Male Muscimol / pharmacology Neural Inhibition Neurons / drug effects Pons / cytology, drug effects, physiology* Rats Rats, Sprague-Dawley Reflex / physiology* Sympathetic Nervous System / physiology* |
| Chemical | |
Reg. No./Substance:
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2763-96-4/Muscimol |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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