Effects of increasing serotonergic receptor activity in brain on analgesic activity in rats

In the rat, increasing serotonergic receptor activity or functional serotonin in the brain with inhibitors of serotonin reuptake (such as fluoxetine and chlorimipramine), with serotonin, or with the serotonin precursor, 5-hydroxytryptophan, in combination with the peripheral decarboxylase inhibitor benserazide had a significant analgesic effect shown by an increase in the latency to hind-paw lick in the hot plate test. The data indicate that activation of central serotonergic receptors with inhibitors of serotonin reuptake, serotonin, or the serotonin precursor produced pain inhibition.