Nuevas dihidropiridinas sintéticas con propiedades antagonistas del calcio vasoselectivas

the calcium antagonist properties of 2 new 1,4 synthetic dihydropyridines (i and ii) were studied. both compounds reduced in a great extent the contractions of rabbit's aorta rings, and they inhibited with less potency the papillary contractions of rat's right ventricle. they also shortened the duration of the heart action potential to 0 mv, and decreased the l calcium current in ventricular cardiomyocites isolated from rats. the inhibition of calcium l current depended on the potential, with an increase of the action potential in more than one order of concentration magnitude in partially depolarized cells (-50 mv). these results allow to conclude that 1,4 dihydropyridines i and ii have marked vasoselective calcium antagonist actions, and that this mechanism is due to the blockade of the calcium l current depending on the potential