Verapamil and diltiazem inhibit receptor-operated calcium channels and intracellular calcium oscillations in rat hepatocytes.
Fura-2 loaded rat hepatocytes were used to determine whether the L-type channel blockers, verapamil and diltiazem, affect receptor-operated calcium channels (ROCCs). The flux through ROCCs was followed by quenching of fura-2 fluorescence due to the influx of extracellular Mn2+ induced by vasopressin. Verapamil as well as diltiazem inhibited vasopressin-stimulated Mn2+ influx in a dose-dependent manner up to 60% at concentrations of 200-400 microM. Furthermore, both inhibitors decreased significantly the frequency of phenylephrine-induced oscillation of [Ca2+]i. The experimental findings indicate that L-type channel blockers inhibit ROCCs in rat hepatocytes.
Striggow
F
F
Institut für Biochemie, Medizinische Akademie Magdeburg, Germany.
Bohnensack
R
R
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D015220:Calcium Channels / Q000187:drug effects*; D004110:Diltiazem / Q000494:pharmacology*; D005456:Fluorescent Dyes; D016257:Fura-2; D008099:Liver / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D008345:Manganese / Q000378:metabolism; D010656:Phenylephrine / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D011956:Receptors, Cell Surface / Q000502:physiology*; D014667:Vasopressins / Q000494:pharmacology; D014700:Verapamil / Q000494:pharmacology*
D015220:Calcium Channels; D005456:Fluorescent Dyes; D011956:Receptors, Cell Surface; D014667:Vasopressins; D010656:Phenylephrine; D008345:Manganese; D014700:Verapamil; D004110:Diltiazem; D002118:Calcium; D016257:Fura-2