5-Hydroxytryptamine stimulates the release of prostacyclin but not thromboxane A2 from isolated rat dental pulp

The effect of 5-hydroxytryptamine (5-HT) on the release of prostacyclin and thromboxane (TX) A2 from isolated rat dental pulp was evaluated. 5-HT (1-1,000 microM) caused a dose-dependent and marked stimulation of the release of prostacyclin but not TXA2. Of the 5-HT-related indolealkylamines tested, only tryptamine had a similar stimulatory effect while tryptophan and 5-hydroxytryptophan had no effect. Neither histamine (100 microM) nor bradykinin (100 microM) had such an effect. Our results suggest the possible involvement of 5-HT receptors in 5-HT-induced stimulation of prostacyclin production in rat dental pulp.