Figure 4.

Plasma ACTH (a) and corticosterone (b) concentrations after the forced swim test (x). Each mouse was placed for 0.5, 2, 4, 7, or 10 minutes in a glass beaker (12.5 cm in diameter, 14 cm in height) filled with tap water (23°C). Subsequently, the animals were returned to their home cages, and blood collection was performed by decapitation immediately after the end of stress exposure. Plasma ACTH and corticosterone concentrations were determined. Data are expressed as mean ± SEM (n = 8–10). *Statistically significant difference between genotypes (P < 0.05). White bars, V1bR+/+ male; black bars, V1bR–/– male.