GABA(A) receptor modulation of 5-HT neuronal firing in the median raphe nucleus: implications for the action of anxiolytics.

5-HT neurones in the median raphe nucleus (MRN) are involved in anxiety and the sleep/wake cycle. Here, using in vitro electrophysiology, we examined if the firing of MRN 5-HT neurones is regulated by GABA(A) receptors. The GABA(A) receptor agonists THIP and muscimol caused concentration dependent inhibition of MRN 5-HT neurones.