Interaction of amitriptyline and imipramine with serotonin receptors in rat uterus and stomach

ABSTRACT

Tricyclic antidepressants are known to bind with serotonin receptors in brain. We studied the in vitro interaction of amitriptyline and imipramine with serotonin receptors in rat uterus and stomach fundus preparations. In uterus, both amitriptyline and imipramine inhibited the contractile responses to serotonin. Similarly, in stomach, these antagonists also inhibited serotonin-induced contractions but blockade was seen only at very high concentrations of antagonists. Based on antagonist potencies, amitriptyline and imipramine were found to exhibit 150-500 fold higher affinity for uterine serotonin receptors than for those in the stomach. This suggests that these antidepressant drugs can discriminate between serotonin receptors located in uterus and stomach