chronic treatment of pc 12 cells with the 1,4-dihydropyridine ca2+ channel antagonist nifedipine [ 5 x 10-8m/5 days ] and the activator s bay k 8644 [ 5 x 10-7 m/5 days ] resulted in up- and down-regulation of 1,4-dihydropyridine binding site density by 29 and 24 % , respectively , without change in affinity .
C0028066
nifedipine
C0012315
dihydropyridine