Analysis of coronary vascular beta receptors in situ.
Observations were conducted in the isolated potassium-arrested dog heart to determine the direct vasodilator effects of adrenergic agonists and antagonists on the coronaryvascular beta receptors, independent of cardiac inotropic and chronotropic influences. Practocol (a selective beta-1-receptor antagonist) blocked coronary vasodilation activated by isoproternol (a combined beta-1-and beta-2-receptor agonist) only at the very high dose of 10-minus 3 M, whereas propranolol (a combined beta-1- and beta-2-receptor antagonist) blocked coronary vasodilation at 10-minus 7 to 10-minus 5 M.  Salbutamol (a selective beta-2-receptor agonist) was one-eighth as potent as isoproterenol in producing coronary vasodilation.  The potency ratio (1/8) is similiar to valuesreported for other beta receptors classified as type 2.  It is concluded that the coronary vasodilator beta receptors are type 2, similiar to those found in peripheral bloodvessels.
D000420:Albuterol / Q000494:pharmacology; D000818:Animals; D003250:Constriction; D003331:Coronary Vessels / Q000294:innervation*; D004106:Dilatation; D004285:Dogs; D004305:Dose-Response Relationship, Drug; D007545:Isoproterenol / Q000494:pharmacology; D008297:Male; D011217:Practolol / Q000494:pharmacology; D011941:Receptors, Adrenergic; D014666:Vasomotor System / Q000502:physiology
D011941:Receptors, Adrenergic; D007545:Isoproterenol; D000420:Albuterol; D011217:Practolol