Figure 5.

GnRH-induced activation of a Ca²⁺-conducting inward current in GT1 cells. (A) Effects of extracellular Ca²⁺ depletion (shaded area) on GnRH-induced current and [Ca²⁺]_i in a cell voltage-clamped at –60 mV. (B) Application of 100 nM GnRH in the presence or absence of Ca²⁺-deficient medium in cells voltage-clamped at –85 mV. In A and B, the bath contained 1 μM nifedipine, 50 μM Ni²⁺, and 100 nM apamin. Simultaneous measurements of current and [Ca²⁺]_i were performed by using perforated-patch, voltage-clamp recording techniques.