Differential effects of verapamil and flunarizine on cardiac L-type and T-type Ca channels.
Whole cell experiments were used to study whether the L-type and the T-type Ca channel in guinea-pig ventricular myocytes are blocked similarly by verapamil and flunarizine. The L-type current is blocked by 5 mumol/l verapamil and 5 mumol/flunarizine in a use-dependent way, and block can be relieved by hyperpolarizing pulses in a potential-dependent way. The T-type current is not affected by 10 mumol/l verapamil while it is blocked by 10 mumol/l flunarizine in a use-dependent way. Verapamil selectively blocks the L-type channel in contrast to flunarizine.
Tytgat
J
J
Laboratory of Physiology, KU Leuven, Gasthuisberg, Belgium.
Vereecke
J
J
Carmeliet
E
E
D000818:Animals; D015220:Calcium Channels / Q000187:drug effects*; D005444:Flunarizine / Q000494:pharmacology*; D006168:Guinea Pigs; D006321:Heart / Q000187:drug effects; D066298:In Vitro Techniques; D009206:Myocardium / Q000378:metabolism*; D015221:Potassium Channels / Q000187:drug effects / Q000378:metabolism; D014700:Verapamil / Q000494:pharmacology*
D015220:Calcium Channels; D015221:Potassium Channels; D014700:Verapamil; D005444:Flunarizine