Recording of dorsal raphe unit activity in vitro

The spontaneous electrical activity of single neurons of the midbrain dorsal raphe nucleus in the rat was recorded in vitro in 400 mum thick slices. The majority of raphe neurons exhibited the slow and regular discharge pattern that characterizes the activity of raphe neurons when recorded in vivo. The viability of these neurons in vitro thus provides a preparation for analyzing endogenous and exogenous factors that regulate the activity of these serotonin-containing neurons.