DIFFERENTIAL-EFFECTS OF VARIOUS CA-2+ ANTAGONISTS

1. The effects of various Ca antagonists (nicardipine, nifedipine, verapamil, diltiazem, flunarizine, cinnarizine, lidoflazine and papaverine) were studied in one in vitro (inhibition of CaCl2 induced contractions in isolated rat aorta) and two in vivo tests [survival after BaCl2 in the rat and survival after arachidonic acid (AA) in the mouse]. 2. Test substances behave in different ways, thus suggesting varying mechanisms of action. 3. The three tests used are very simple and quick to perform, but taken together give a good preliminary information which allows classification of the products during the screening phase into four subgroups: dihydropyridines, verapamil, diltiazem and diphenylalkylamines.