Increased brain-derived neurotrophic factor (BDNF) protein concentrations in mice lacking brain serotonin
The interplay between BDNF signaling and the serotonergic system remains incompletely understood. Using a highly sensitive enzyme-linked immunosorbent assay, we studied BDNF concentrations in hippocampus and cortex of two mouse models of altered serotonin signaling: tryptophan hydroxylase (Tph)2-deficient (Tph2−/−) mice lacking brain serotonin and serotonin transporter (SERT)-deficient (SERT−/−) mice lacking serotonin re-uptake. Surprisingly, hippocampal BDNF was significantly elevated in Tph2−/− mice, whereas no significant changes were observed in SERT−/− mice. Furthermore, BDNF levels were increased in the prefrontal cortex of Tph2−/− but not of SERT−/− mice. Our results emphasize the interaction between serotonin signaling and BDNF. Complete lack of brain serotonin induces BDNF expression.