Inhibitory effect of lomerizine, a diphenylpiperazine Ca2+-channel blocker, on Ba2+ current through voltage-gated Ca2+ channels in PC12 cells.
We investigated the effect of lomerizine, an anti-migraine drug, on the Ba2+ current through voltage-gated Ca2+ channels in rat pheochromocytoma (PC12) cells using a whole-cell voltage-clamp technique. Lomerizine inhibited the Ba2+ current with an IC50 value of 1.9 microM. Lomerizine and nicardipine were >4 times more potent than flunarizine, diltiazem, verapamil and dimetotiazine. The time course of inactivation induced by lomerizine was similar to that induced by nicardipine and flunarizine. These data indicate that lomerizine may inhibit the Ca2+ channel in a similar manner to nicardipine and flunarizine, and its potency is almost equal to that of nicardipine.
Watano
T
T
Department of Pharmacology, New Drug Discovery Research Laboratory, Osaka, Japan.
Hara
H
H
Sukamoto
T
T
D000818:Animals; D001464:Barium / Q000737:chemistry / Q000378:metabolism*; D002121:Calcium Channel Blockers / Q000494:pharmacology*; D007473:Ion Channels / Q000187:drug effects* / Q000378:metabolism; D016716:PC12 Cells; D018408:Patch-Clamp Techniques; D010640:Phenothiazines / Q000494:pharmacology; D010879:Piperazines / Q000494:pharmacology*; D051381:Rats
D002121:Calcium Channel Blockers; D007473:Ion Channels; D010640:Phenothiazines; D010879:Piperazines; C100113:fonazine; D001464:Barium; C052424:lomerizine