Block of P-type Ca2+ channels in freshly dissociated rat cerebellar Purkinje neurons by diltiazem and verapamil.
We investigated the effects of organic Ca2+ channel blockers, diltiazem and verapamil, on the high voltage-activated P-type Ca2+ channels in freshly isolated rat Purkinje neurons. Both diltiazem and verapamil blocked P-type Ca2+ channel current without any change in the current-voltage relation. The block was concentration-dependent. In the presence of these agents, the inactivation curve was shifted to hyperpolarizing potentials. The characteristics of block of P-type Ca2+ channels by diltiazem and verapamil are similar to that of L-type Ca2+ channels. These results indicate that both benzothiazepine and phenylalkylamine react with P-type Ca2+ channels and suggest that some structural features common to which operate in both L-type and P-type Ca2+ channels may be involved in drug binding to these channels.
Ishibashi
H
H
Department of Physiology, Kyushu University Faculty of Medicine, Japan.
Yatani
A
A
Akaike
N
N
D000818:Animals; D015220:Calcium Channels / Q000187:drug effects*; D002531:Cerebellum / Q000187:drug effects*; D004110:Diltiazem / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D011689:Purkinje Cells / Q000187:drug effects; D051381:Rats; D017208:Rats, Wistar; D013997:Time Factors; D014700:Verapamil / Q000494:pharmacology*
D015220:Calcium Channels; D014700:Verapamil; D004110:Diltiazem