Fig. 5.

Effects of 30 µM dehydroepiandrosterone (DHEA) on current-voltage (I-V), quasi-steady-state inactivation curve (f_∞-V), and window current (I_WD)-V relationships. a and b: Typical current traces before (a) and after (b) application of 30 µM DHEA. Inset: pulse protocol. c and d: Typical records for control (c) and 30 µM DHEA (d). Inset: pulse protocol with 2-s conditioning pulses and 500-ms test pulse. Currents after the conditioning pulses to −40 mV and −30 mV are shown by black traces. A: I-V relationship of peak L-type Ca²⁺ current (I_Ca,L,peak) in the presence and absence of 30 µM DHEA with fitting by the Boltzmann’s equation. B: f_∞-V relationship before and after application of 30 µM DHEA. Plots were fitted with the Boltzmann’s equation (Table 3). C: voltage-dependent changes of I_WD obtained as a product of I-V (A) and f_∞-V (B) in the absence and presence of 30 µM DHEA. Con, control.