Constitutive GHSR1a activity inhibits by a long-term mechanism the CaV2 currents preserving CaV2 current inhibition by ghrelin-dependent GHSR1a activity. (A) Representative ICa traces (left) from HEK 293T cells expressing CaV2.1 (above) or CaV2.2 (below), CaVα2δ1, CaVβ3, and GHSR1a preincubated with 1 µM SPA, before (control) and after (+ghrelin) 500-nM ghrelin application, and averaged percentage of ICa inhibition by 500 nM ghrelin (right) from HEK 293T cells expressing CaV2.1 or CaV2.2, CaVα2δ1, CaVβ3, and GHSR1a preincubated with 1 µM SPA or GHSR1a-A204E as a control condition. (B) Time courses of peak CaV2 currents (left) with the acute application of 1 µM SPA (gray bars) from HEK 293T cells expressing CaV2.1 (above) or CaV2.2 (below), CaVα2δ1, CaVβ3, and GHSR1a, and the averaged CaV2.1 or CaV2.2 currents before (control) and after (+SPA) acute application of 1 µM SPA. Two sample (A) and paired (B) Student’s t tests. Error bars represent mean ± SE.
