Effects of beta-adrenergic blocking agents on peripheral vascular resistance.
The effects of the beta-adrenergic blocking agents propranolol, pindolol, atenolol, bunitrolol, and methypranol on the vascular resistance of isolated perfused hindlimbs of rats were investigated. At concentrations of 0.01 microgram/ml in the perfusate dl-propranolol and pindolol significantly increased vascular resistance by blockade of beta2-receptor mediated vasodilatation, whereas atenolol, bunitrolol and methypranol had no effect on peripheral resistance at this concentration. With increasing concentrations up to 10 microgram/ml all drugs, with the exception of atenolol, caused vasodilatation. We conclude that the specificity of beta-blocking agents can be established in the isolated perfused hindlimb vasculature of rats through its effect on vascular resistance. The lack of inhibition of vascular beta2-receptors at low concentrations of atenolol and also bunitrolol and methypranol show relative selectivity for beta1-receptors. The differential effects of beta-adrenergic agents on vascular resistance may have significance for the clinical use of the drugs.
D000319:Adrenergic beta-Antagonists / Q000494:pharmacology*; D000818:Animals; D001262:Atenolol / Q000494:pharmacology; D008297:Male; D010869:Pindolol / Q000494:pharmacology; D011412:Propanolamines / Q000494:pharmacology; D011433:Propranolol / Q000494:pharmacology; D051381:Rats; D014655:Vascular Resistance / Q000187:drug effects*
D000319:Adrenergic beta-Antagonists; D011412:Propanolamines; D001262:Atenolol; D011433:Propranolol; D010869:Pindolol