Interaction between propranolol and calcium channel blockers in cardiac and vascular smooth muscle.
The ability of the beta-receptor antagonist propranolol to influence the response of isolated cardiac and vascular smooth muscle to several classes of calcium channel blockers was examined. For comparison, the interactions between propranolol and other classes of negative inotropic and vasorelaxant agents was also evaluated. The results of these studies demonstrate that propranolol pre-treatment significantly enhances the in vitro response to the dihydropyridine calcium channel blocker nifedipine, but not the thiazapine calcium channel blocker diltiazem. This enhancement was unrelated to the negative inotropic or vasorelaxant properties of these agents. In addition, propranolol pre-treatment of rat cortical membranes also enhanced the affinity of nifedipine for the 3H-nitrendipine binding site, but did not alter the effect of diltiazem on 3H-nitrendipine binding. These observations suggest that a direct interaction may exist between beta-receptor antagonists and dihydropyrine-type calcium channel blockers. This interaction may be an important factor in selecting drug therapy for conditions such as hypertension and angina.
Weishaar
R E
RE
Department of Pharmacology, Parke-Davis Pharmaceutical Research Division, Warner-Lambert Company, Ann Arbor, MI 48105.
Quade
M M
MM
Pugsley
T A
TA
Shih
Y H
YH
Taylor
D G
DG
D000818:Animals; D002121:Calcium Channel Blockers / Q000378:metabolism* / Q000494:pharmacology; D004095:Dihydropyridines / Q000378:metabolism; D004347:Drug Interactions; D006168:Guinea Pigs; D006321:Heart / Q000187:drug effects; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000378:metabolism*; D009200:Myocardial Contraction / Q000187:drug effects; D009206:Myocardium / Q000378:metabolism*; D009568:Nitrendipine / Q000378:metabolism; D011433:Propranolol / Q000378:metabolism* / Q000494:pharmacology
D002121:Calcium Channel Blockers; D004095:Dihydropyridines; D009568:Nitrendipine; D011433:Propranolol