- Alomone Labs Verapamil HCl inhibits L-type Ca2+ currents in Xenopus oocytes.A. Time course of L-type channel (CaV1.2+α2δ1+β1a) activity before and during applications of 10 and100 μM Verapamil HCl (#V-100) and upon wash (Verapamil HCl application periods are indicated by the horizontal bars). Holding potential was -100 mV and currents were elicited every 10 seconds by 100 ms steps to -10 mV. X axis in minutes and Y axis in nA. B. Example current traces before and during applications of 10 and 100 μM Verapamil HCl (concentrations indicated are taken from the experiment described in A).
L-type (CaV1), voltage-gated Ca2+ channels are plasma membrane protein complexes which allow the passage of Ca2+ ions into cells following depolarization of the membrane potential. L-type channels are widely expressed in cardiac and smooth muscle in which they control contraction and therefore were recognized as a therapeutic target for cardiovascular diseases1,2.
Verapamil HCl is a phenylalkylamine that acts as a L-type, voltage-gated Ca2+ channel blocker and is used in the clinic to treat hypertension2-4. Verapamil is also effective in treating arrythmias2. Verapamil block of L-type channels is dependent on the membrane potential. The IC50 values at a holding potential of -80 or -40 mV are 250 and 15.5 µM, respectively5. In Xenopus oocytes, Verapamil inhibits L-type currents in an activity dependent manner6.