title: Cardiac alpha- and beta-adrenergic receptor alterations in diabetic cardiomyopathy.
abstract: The effect of chronic experimental diabetes on the adrenergic receptors in the rat heart was investigated. Diabetes was induced by streptozotocin (65 mg/kg; i.v.) administration, animals were sacrificed 8 weeks later, and positive as well as negative dF/dt values were determined in isolated papillary muscle preparations. Stimulation of the contractile force generation by isoproterenol and methoxamine was attenuated in diabetic preparations. Beta- and alpha-adrenergic receptor bindings were determined in cardiac membranes by employing 3H-dihydroalprenolol and 3H-dihydroergocryptine respectively. Reduced number of beta- and alpha-receptor binding sites without changes in the affinity constants were observed in diabetic myocardium. Such a decrease in alpha- and beta-receptor density in the heart may account for the depressed contractile responsiveness to adrenergic stimuli in diabetic cardiomyopathy.
mesh_terms: D000818:Animals; D009202:Cardiomyopathies / Q000378:metabolism*; D003921:Diabetes Mellitus, Experimental / Q000378:metabolism*; D004082:Dihydroalprenolol / Q000378:metabolism; D004088:Dihydroergotoxine / Q000378:metabolism; D007700:Kinetics; D008297:Male; D008729:Methoxamine / Q000494:pharmacology; D009200:Myocardial Contraction / Q000187:drug effects; D009206:Myocardium / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D011941:Receptors, Adrenergic / Q000378:metabolism*; D011942:Receptors, Adrenergic, alpha / Q000378:metabolism*; D011943:Receptors, Adrenergic, beta / Q000378:metabolism*
chemical_list: D011941:Receptors, Adrenergic; D011942:Receptors, Adrenergic, alpha; D011943:Receptors, Adrenergic, beta; D004088:Dihydroergotoxine; D004082:Dihydroalprenolol; D008729:Methoxamine