Figure 1.

The cortical flash depends on the Ca²⁺ influx via L-type Ca²⁺ channels. (A) The eggs fertilized in the ASW with 1 mM Ca²⁺ (brown curves) displayed virtually the same Ca²⁺ response as in control eggs (ASW with 10 mM Ca²⁺, green curves), but the CFs were severely suppressed. (B-C) P. lividus eggs were pretreated with either diltiazem or verapamil for 40 minutes, and their Ca²⁺ responses at fertilization were compared with that of control eggs (FSW) in the same batch. The trajectories of the Ca²⁺ levels in the fertilized eggs that had been pretreated with 50 µM diltiazem or 10 µM verapamil were shown in brown curves, whereas the responses in the control eggs were presented in green curves. (D) The dose-dependent effects of diltiazem and verapamil on the Ca²⁺ signalling in fertilized eggs. The peak amplitudes of the CF (red line) and the global Ca²⁺ increase (blue line) in the eggs pretreated with varied amount of diltiazem and verapamil were normalized with the corresponding average levels in the control eggs of the same batch.