Figure 2. Effects of thapsigargin (TG) on vasopressin release in vitro.

A and C, repeated stimulation with high-K⁺ solutions results in repeatable responses in vasopressin release from isolated neural lobes (A) and SON (C). B and D, vasopressin release from isolated SON (D), and neural lobes (B) before and after thapsigargin (TG). E, release from the SON only, evoked by depolarization with high-K⁺ solutions, was strongly potentiated by thapsigargin; the potentiation was long-lasting and time dependent. F, release from the SON only, evoked by depolarization with high-K⁺ solutions, was strongly potentiated by thapsigargin, but not by caffeine or ryanodine. Data are means ± s.e.m., n = 4 per group for each experiment, *P < 0.05, t tests.