Consequently, it was demonstrated in the present study that nimodipine and nitrendipine inhibit both L- and N-type calcium channels and thus seem to be unique among the dihydropyridines examined in their effects on calcium channels in dibutyryl cAMP-differentiated neuroblastoma x glioma hybrid NG 108-15 cells, whereas nifedipine and niguldipine appear to block mainly L-type calcium channels