| Sympathoexcitatory response to peripheral chemoreflex activation is enhanced in juvenile rats exposed to chronic intermittent hypoxia. | |
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MedLine Citation:
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PMID: 16959820 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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In the present study, we tested the hypothesis that chronic intermittent hypoxia (CIH) produces changes in the autonomic and respiratory responses to acute peripheral chemoreflex activation. To attain this goal, 3-week-old rats were exposed to 10 days of CIH (6% O(2) for 40 s at 9 min intervals; 8 h day(-1)). They were then used to obtain a working heart-brainstem preparation and, using this unanaesthetized experimental preparation, the chemoreflex was activated with potassium cyanide (0.05%, injected via the perfusion system), and the thoracic sympathetic nerve activity (tSNA), heart rate and phrenic nerve discharge (PND) were recorded. Rats subjected to CIH (n = 12), when compared with control animals (n = 12), presented the following significant changes in response to chemoreflex activation: (a) an increase in tSNA (78 +/- 4 versus 48 +/- 3%); (b) a long-lasting increase in the frequency of the PND at 20 (0.52 +/- 0.03 versus 0.36 +/- 0.03 Hz) and 30 s (0.40 +/- 0.02 versus 0.31 +/- 0.02 Hz) after the stimulus; and (c) a greater bradycardic response (-218 +/- 20 versus -163 +/- 16 beats min(-1)). These results indicate that the autonomic and respiratory responses to chemoreflex activation in juvenile rats previously submitted to CIH are greatly increased. |
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Authors:
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Valdir A Braga; Renato N Soriano; Benedito H Machado |
Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't Date: 2006-09-07 |
Journal Detail:
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Title: Experimental physiology Volume: 91 ISSN: 0958-0670 ISO Abbreviation: Exp. Physiol. Publication Date: 2006 Nov |
Date Detail:
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Created Date: 2006-11-19 Completed Date: 2006-12-19 Revised Date: 2008-11-21 |
Medline Journal Info:
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Nlm Unique ID: 9002940 Medline TA: Exp Physiol Country: England |
Other Details:
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Languages: eng Pagination: 1025-31 Citation Subset: IM |
Affiliation:
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Department of Physiology, School of Medicine of Ribeirão Preto, University of São Paulo, 14049-900, Ribeirão Preto, SP, Brazil. |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Animals Animals, Newborn Anoxia / physiopathology* Autonomic Nervous System / physiology Body Weight / physiology Bradycardia / physiopathology Chemoreceptor Cells / drug effects, physiology* Enzyme Inhibitors / pharmacology Heart Rate / physiology Peripheral Nervous System / physiology* Phrenic Nerve / physiology Potassium Cyanide / pharmacology Rats Respiratory System / drug effects Sympathetic Nervous System / physiology* |
| Chemical | |
Reg. No./Substance:
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0/Enzyme Inhibitors; 151-50-8/Potassium Cyanide |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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