Hemodynamic effects of arotinolol in anesthetized dogs and its affinities for adrenoceptors in vitro.
Hemodynamic actions of arotinolol in anesthetized dogs and its effects on alpha- and beta-adrenoceptors were examined. Arotinolol produced dose-dependent decrease in mean blood pressure, heart rate, cardiac output, maximum rate of left ventricular pressure rise and coronary blood flow in a dose range of 1 microgram/kg-3 mg/kg. Total peripheral resistance (TPR) increased with arotinolol dose-dependently in a dose range of 1 microgram/kg-0.3 mg/kg, but at doses of 1 and 3 mg/kg the increase in TPR was less. Arotinolol at a dose of 10 micrograms/kg significantly inhibited the blood pressure and heart rate responses to isoproterenol. Propranolol at the same dose produced only a slight inhibition of these. Arotinolol at a dose of 3 mg/kg attenuated the pressor response to phenylephrine without any effect on the response to angiotensin-II in anesthetized dogs. Propranolol at the same dose produced only a slight inhibition of the response to phenylephrine. In the study of radioactive ligand binding assays, arotinolol showed high affinities for both beta 1- and beta 2-adrenoceptors. Arotinolol showed an affinity also for alpha 1-adrenoceptors which was comparable to the affinity of yohimbine. Thus, the present results support the idea that arotinolol possesses both alpha- and beta-adrenoceptors blocking effects.
D000319:Adrenergic beta-Antagonists / Q000378:metabolism / Q000494:pharmacology*; D000758:Anesthesia; D000804:Angiotensin II / Q000494:pharmacology; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D004285:Dogs; D004347:Drug Interactions; D005260:Female; D006168:Guinea Pigs; D006339:Heart Rate / Q000187:drug effects; D006439:Hemodynamics / Q000187:drug effects*; D066298:In Vitro Techniques; D007545:Isoproterenol / Q000494:pharmacology; D008297:Male; D010656:Phenylephrine / Q000494:pharmacology; D011412:Propanolamines / Q000378:metabolism / Q000494:pharmacology*; D011506:Proteins / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D011941:Receptors, Adrenergic / Q000378:metabolism*
D000319:Adrenergic beta-Antagonists; D011412:Propanolamines; D011506:Proteins; D011941:Receptors, Adrenergic; D000804:Angiotensin II; D010656:Phenylephrine; C024523:arotinolol; D007545:Isoproterenol