The present study was carried out to determine, first, the cardiac -adrenergic receptor characteristics of normal chickens and chickens with heart failure and, second, the characteristics of myocardial -adrenergic receptors in non-hypertrophied hearts in broilers exposed to two different altitude and temperature programmes. The density of -adrenergic receptors was significantly lower in myocardial cells in right ventricular failure birds compared with healthy birds. The binding capacity of -adrenergic receptors was reduced in the non-hypertrophied ventricles after exposure to high altitude in the younger but not in older chickens. At both altitudes, -adrenergic receptor binding capacity was not significantly different in low temperature compared with normal temperature birds. These data support the hypothesis of -adrenergic receptor downregulation as one of the mechanisms of cardiac cell adaptation to hypertrophy or hypoxia. Second, the acclimatization to high altitude in older chickens resulted in a normalization of -receptor capacity in those broilers that were not affected by right ventricular failure and ascites.
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Document Type: Original Article
Department of Poultry Diseases, Faculty of Veterinary Medicine, University of Tehran, P.O. Box 14155–6453, Tehran, Iran
Laboratory for Physiology and Immunology of Domestic Animals, K.U. Leuven, Kardinaal Mercierlaan 92, B– 3001 Heverlee, Belgium
Publication date: April 1, 2001
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