Depressive-like profile induced by MCH microinjections into the dorsal raphe nucleus evaluated in the forced swim test.

Antagonism of the melanin-concentrating hormone (MCH) receptor 1 (MCH-R1) has been recently shown to have antidepressant-like profile in rats. However, the mechanisms by which the MCHergic system participates in the modulation of emotional states are still to be determined. In the present study we confirmed the presence of MCHergic fibers within the dorsal raphe nucleus (DRN), a serotonergic nucleus involved in the physiopathology of major depression.