a series of unsymmetrically substituted 4-phenyl-1,4-dihydropyridine calcium entry blockers were investigated for their ability to relax potassium-contracted rabbit aortic smooth muscle and to competitively displace [ 3h ] nitrendipine from its specific binding sites on guinea pig myocardial membranes in order to delineate the pharmacologically active conformer with respect to the position of the aromatic substituent ( synperiplanar or antiperiplanar ) .
C0012315
dihydropyridine
C0028127
nitrendipine