| Effect of intermittent hypoxia on cardiovascular function, adrenoceptors and muscarinic receptors in Wistar rats. | |
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MedLine Citation:
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PMID: 12392109 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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The usual model of intermittent hypoxia (sleep apnoea) corresponds to repeated episodes of hypoxia from a few seconds to a few hours interspersed with episodes of normoxia. The aim of this study was to evaluate in rats the effect of two periods of intermittent exposure for 2 months to hypoxia (IHX1, 24 h in hypoxia (428 Torr), 24 h in normoxia; IHX2, 48 h in hypoxia (428 Torr), 24 h in normoxia) as a new model of hypoxia simulating intermittent exposure to high altitude experienced by Andean miners. We assessed the haematological parameters, time course of resting heart rate and systolic blood pressure. We also evaluated the expression of adrenergic and muscarinic receptors. IHX1 and IHX2 produced an increase in haematocrit, haemoglobin concentration and mean corpuscular volume as previously seen in most hypoxic models. IHX1 and IHX2 induced a similar sustained elevation of systolic blood pressure (132 +/- 2 and 135 +/- 3 mmHg, respectively, vs. the control level of 121 +/- 16 mmHg) after 10 days of exposure without change in heart rate. Right ventricular (RV) hypertrophy (225 +/- 13 and 268 +/- 15 mg g(-1), vs. 178 +/- 7 mg g(-1) and downregulation of alpha1-adrenoceptor (RV: 127 +/- 21 and 94 +/- 16 fmol mg(-1) vs. 157 +/- 8 fmol mg(-1); left ventricle (LV): 141 +/- 5 and 126 +/- 9 fmol mg(-1) vs. 152 +/- 5 fmol mg(-1)) have been found in both groups, with right ventricular hypertrophy being greater and alpha1-adrenoceptor density being lower in IHX2 than in HX1 groups. These data indicate that both parameters are related to the time of exposure to hypoxia. IHX1 and IHX2 produced the same magnitude of upregulation of muscarinic receptors (LV, 60%; RV, 40%), and no change in beta-adrenoceptors. In conclusion, exposure to intermittent hypoxia led to polycythaemia and RV hypertrophy as observed in other types of hypoxia. A specific cardiovascular response was seen, that is an increase in blood pressure without change in heart rate, which was different from the one observed in episodic and chronic hypoxia. Furthermore, this model involved specific modifications of alpha1-adrenergic and muscarinic expression. |
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Authors:
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R Germack; F Leon-Velarde; R Valdes De La Barra; J Farias; G Soto; J P Richalet |
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Publication Detail:
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Type: Comparative Study; Journal Article; Research Support, Non-U.S. Gov't |
Journal Detail:
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Title: Experimental physiology Volume: 87 ISSN: 0958-0670 ISO Abbreviation: Exp. Physiol. Publication Date: 2002 Jul |
Date Detail:
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Created Date: 2002-10-23 Completed Date: 2003-03-20 Revised Date: 2006-11-15 |
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: 453-60 Citation Subset: IM |
Affiliation:
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Laboratoire Réponses cellulaires et fonctionnelles à l'hypoxie, Université Paris XIII, Bobigny, France. |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Animals Anoxia / blood, complications, physiopathology* Blood Pressure Heart / physiopathology Heart Rate Hypertrophy, Left Ventricular / blood, etiology, metabolism*, physiopathology Hypertrophy, Right Ventricular / blood, etiology, metabolism*, physiopathology Male Rats Rats, Wistar Receptors, Adrenergic, alpha-1 / analysis, metabolism* Receptors, Adrenergic, beta / analysis, metabolism* Receptors, Muscarinic / analysis, metabolism* |
| Chemical | |
Reg. No./Substance:
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0/Receptors, Adrenergic, alpha-1; 0/Receptors, Adrenergic, beta; 0/Receptors, Muscarinic |
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