RT Journal Article
SR Electronic
T1 EFFECT OF 4-(2-HYDROXY-3-ISOPROPYLAMINOPROPOXY) ACETANILIDE (AY 21,011) ON THE MYOCARDIAL AND CORONARY VASCULAR RESPONSES TO ADRENERGIC STIMULATION
JF Journal of Pharmacology and Experimental Therapeutics
JO J Pharmacol Exp Ther
FD American Society for Pharmacology and Experimental Therapeutics
SP 200
OP 211
VO 176
IS 1
A1 BENEDICT R. LUCCHESI
A1 ROBERT J. HODGEMAN
YR 1971
UL http://jpet.aspetjournals.org/content/176/1/200.abstract
AB The effects of adrenergic stimulation upon hind-limb blood flow, myocardial contractile force, coronary blood flow and vascular resistance were studied in the anesthetized dog before and after the administration of 4-(2-hydroxy-3-isopropylaminopropoxy) acetanilide (AY 21,011; ICI 50,172; practolol). Simultaneous measurements of hind-limb blood flow and myocardial force showed dose-dependent increases to isoproterenol with only the latter being reduced significantly by AY 21,011, 1 mg/kg. AY 21,011 significantly reduced the positive inotropic and chronotropic responses to left stellate ganglion stimulation and changed the coronary vascular response from a vasodilatation to one of vasoconstriction. The intracoronary administration of norepinephrine or isoproterenol increased myocardial force and decreased coronary vascular resistance. After AY 21,011, the inotropic dose-response curves for norepinephrine and isoproterenol were shifted to the right. The coronary vascular responses to isoproterenol showed a similar shift to the right; the responses to norepinephrine became biphasic with an initial vasoconstriction followed by a vasodilatation. The results suggest that AY 21,011, in dosages which do not prevent beta receptor-mediated increases in hindlimb blood flow, effectively prevents the positive inotropic responses to adrenergic stimulation as well as the coronary vasodilatator effects due to stellate ganglion stimulation and the intracoronary administration of catecholamines. It is suggested that the beta adrenergic receptors in the myocardium and coronary vascular bed represent beta-1-receptors whereas those in the peripheral vascular bed are beta-2-receptors. © 1971, by The Williams & Wilkins Company