Serotonin modulates muscimol- and baclofen-elicited inhibition of cerebellar Purkinje cells.

The present study was designed to test whether serotonin (5-HT) preferentially affects the GABAA or GABAB receptor subtypes in the cerebellum using muscimol and baclofen as the selective agonists. Serotonin significantly augmented baclofen- and muscimol-elicited inhibitions with minimal effects of 5-HT on the spontaneous activity. The magnitudes of augmentation of baclofen and muscimol effects seen in the presence of 5-HT were comparable. In summary, this study further describes the neuromodulatory role of serotonin on GABAergic inhibition and based upon the present study, it can be concluded that both GABAA and GABAB receptor subtypes are modulated by 5-HT.