Figure 1.

Inhibitory action of BHQ on I_Ca(L). (a) Original recordings of whole-cell I_Ca(L) in rat tail artery myocytes elicited with 250 ms depolarizing voltage-clamp pulses from a V_h of −50 mV to test potentials of 5 mV measured in the absence (CTRL) or presence of BHQ (10 and 100 μM). I_Ca(L) suppression by 2 μM nifedipine is also shown. (b) Current-voltage relationships constructed before the addition of BHQ (CTRL) and in the presence of 10, 50 and 100 μM BHQ or 2 μM nifedipine. Data points are means±s.e.mean of three to 11 cells (n=3–11). *P<0.05, **P<0.01, Dunnett's post test. (c) Time course of I_Ca(L) inhibition induced by BHQ. BHQ (50 or 100 μM) was applied, at the time indicated by the arrow, by superfusion and peak currents were recorded during a typical depolarization from −50 to 5 mV applied every 30 s and subsequently normalized according to the current recorded just before BHQ application. Wash-out of drug allows for partial recovery of inhibition. Data points are means±s.e.mean of six cells (n=5).