tritiated 1,4-dihydropyridines ( nimodipine , nitrendipine , nifedipine , pn 200-110 ) and [ 3h ] d-cis-diltiazem as well as [ 3h ] verapamil were employed to directly identify calcium channels in membranes for excitable tissues .
C0012315
dihydropyridines
C0028127
nitrendipine