Figure 6.
5-HT2CR knock-out mice displayed normal circadian CORT but did not respond to mCPP- or d-fen-stimulated CORT release. a, Wild-type (black bars) and 5-HT2CR knock-out (KO; white bars) mice displayed comparable levels of CORT measured in the plasma 1 h after the onset of the light and dark cycles. In contrast, a significant genotypic difference in CORT release was observed after HPA axis stimulation. b, c, Both mCPP (b) and d-fen (c) significantly increased in vivo release of CORT in wild-type mice but were ineffective in 5-HT2CR KO littermates. Data are expressed as mean ± SEM. #p < 0.05, drug versus 0.9% saline treatment; *p < 0.05, wild-type versus 5-HT2CR KO mice.