Differential effects of fluoxetine and zimelidine on the uptake of 5-hydroxytryptamine and tryptamine by cortical slices and on responses of cortical neurones to stimulation of the nucleus raphe medianus.

Intravenous administration of fluoxetine inhibited the uptake of tryptamine and 5-hydroxytryptamine by cortical slices. In contrast, zimelidine inhibited the uptake of 4-hydroxytryptamine only. In vivo, inhibitory and excitatory response of cortical neurones to stimulation of raphe medianus were potentiated by fluoxetine whereas only excitatory responses were enhanced by zimelidine. The results are consistent with the suggestion that the inhibitory effects of raphe stimulation are mediated by tryptamine and the excitatory responses by 5-hydroxytryptamine.