Cytosolic factor(s) determines the impaired desensitization of beta-adrenoceptors in the myocardium of spontaneously hypertensive rats.
Loss of membrane-bound beta-receptors in the myocardium of spontaneously hypertensive rats has been explained on the basis of enhanced agonist-induced desensitization. However, in both cardiac myocytes and cell-free preparations, isoproterenol and cyclic AMP-dependent protein kinase are less effective in desensitizing beta-receptors from hypertensive compared to normotensive animals. Reconstitution of cardiac membrances from hypertensive rats with cytosol from normotensive controls restores the ability of isoproterenol and protein kinase A to desensitize beta-receptors. Impaired desensitization in spontaneously hypertensive rats is, therefore, not due to intrinsic defects of the beta-receptor but, rather, to absence of regulatory cytosolic factor(s).
Limas
C
C
Department of Laboratory Medicine and Pathology, University of Minnesota School of Medicine, Minneapolis.
Limas
C J
CJ
D000818:Animals; D002462:Cell Membrane / Q000378:metabolism; D003600:Cytosol / Q000502:physiology; D004082:Dihydroalprenolol / Q000378:metabolism; D007545:Isoproterenol / Q000494:pharmacology*; D007700:Kinetics; D008297:Male; D009206:Myocardium / Q000378:metabolism*; D011480:Protease Inhibitors / Q000494:pharmacology; D047428:Protein Kinase Inhibitors; D011494:Protein Kinases / Q000378:metabolism; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY; D011943:Receptors, Adrenergic, beta / Q000187:drug effects / Q000378:metabolism*
D011480:Protease Inhibitors; D047428:Protein Kinase Inhibitors; D011943:Receptors, Adrenergic, beta; D004082:Dihydroalprenolol; D011494:Protein Kinases; D007545:Isoproterenol