Document Detail


Effect of intermittent hypoxia on cardiovascular function, adrenoceptors and muscarinic receptors in Wistar rats.
MedLine Citation:
PMID:  12392109     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
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.
Authors:
R Germack; F Leon-Velarde; R Valdes De La Barra; J Farias; G Soto; J P Richalet
Related Documents :
6508019 - Hypoxia-altitude simulation test. evaluation of patients with chronic airway obstruction.
2780259 - Pulmonary vascular and renal effects of cromakalim in anaesthetized dogs.
9134919 - Regression of hypoxic hypertension-induced changes in the elastic laminae of rat pulmon...
7449399 - Interaction of pulmonary and systemic hypertension. an experimental study.
23525529 - B-type natriuretic peptide is not a volume marker among patients on hemodialysis.
7964369 - Ventilatory responses to hypoxia in the toad bufo paracnemis before and after a decreas...
22129519 - Hypertension among tunisian adults: results of the tahina project.
12693799 - Breathing frequency and use of expiratory muscles do influence the dynamic positive end...
191299 - The renin-angiotensin system and the central nervous system.
Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Experimental physiology     Volume:  87     ISSN:  0958-0670     ISO Abbreviation:  Exp. Physiol.     Publication Date:  2002 Jul 
Date Detail:
Created Date:  2002-10-23     Completed Date:  2003-03-20     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  9002940     Medline TA:  Exp Physiol     Country:  England    
Other Details:
Languages:  eng     Pagination:  453-60     Citation Subset:  IM    
Affiliation:
Laboratoire Réponses cellulaires et fonctionnelles à l'hypoxie, Université Paris XIII, Bobigny, France.
Export Citation:
APA/MLA Format     Download EndNote     Download BibTex
MeSH Terms
Descriptor/Qualifier:
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:
0/Receptors, Adrenergic, alpha-1; 0/Receptors, Adrenergic, beta; 0/Receptors, Muscarinic

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


Previous Document:  Influence of castration on isoprenaline-induced amylase release in parotid gland from male rats.
Next Document:  Synchrony analysis between blood pressure and sympathetic nerve signal inhibited by atrial receptor ...