Brain-derived neurotrophic factor (BDNF), Wnt2 and 15-Deoxy-delta12,14-prostaglandin J2 (15d-PGJ2) are secreted by serotonergic neurons in response to fluoxetine and are increased in cerebrospinal fluid (CSF) of mice or depressed patients following fluoxetine treatment. (a–c) Treatment of 1C115−HT cells with fluoxetine (50 n, 2 days) induced the release of BDNF (a), Wnt2 (b) and 15d-PGJ2 (c) (n=6). (d–i), Treatment of mice (d–f) or depressed patients (g–i) with fluoxetine induced an increase of BDNF (d, g), Wnt2 (e, h) and 15d-PGJ2 (f, i) in CSF. The values are the means±s.e.m (n=5 for mice, n=7 for patients), *P<0.01 vs control.