Figure 4.

Insulin delivers new channels to the oocyte surface via regulated exocytosis. (A–C) Microinjection of the light chain of BoNT A (50 ng) into oocytes 5 h before recording reduced insulin potentiation of NMDA-elicited currents by about 70%. (A) Representative NMDA-elicited currents before and after insulin treatment for a control oocyte as in Fig. 1, but in Ca²⁺-free (Ba²⁺) Ringer's solution. (B) BoNT A reduced the degree of insulin potentiation. (C) Summary of experiments showing reduction of insulin potentiation by BoNT A.