Induction by Cocaine of the Serotonergic 5-HT3 Receptor in Rat Cerebellum

: The expression of the 5‐HT3 receptor, a member of the serotonin receptor family, was examined in rat cerebellum of saline‐ or cocaine‐treated rats. Both immunohistochemistry and Western blot analysis were used. We found that the expression of this serotonin receptor subtype was increased in the cerebellum of rats injected either acutely or repeatedly (1 injection/day for 10 days) with cocaine. The stimulation was more pronounced after a single injection than after a series of 10 injections. Surprisingly, the expression of the 5‐HT3 receptor was mainly localized in Bergmann glial cells, as assessed from the co‐localization of the receptor with the glial cell marker glial fibrillary acidic protein (GFAP). Our data emphasize the importance of the 5‐HT3 receptor induction in the cerebellum as part of the neuroadaptations taking place in rat brain in response to the psychostimulant cocaine.