Role of 5HT in the modification of intestinal motility, in vitro study

ABSTRACT

To determine with the mechanism of action involved in the therapeutic potential of serotonin and its blocker on gastrointestinal motility. The standard method was used for obtaining the longitudinal and circular muscles strip of rabbit ileum for in vitro studies. Each muscle strip was exposed to serotonin and its blocker and the result obtained was recorded on polygraph apparatus. The effects were recorded in vice versa fashion i.e. agonist v/s antagonist and antagonist v/s agonist on longitudinal and circular muscle strip separately. Serotonin had depressant effect on the force of contraction. On addition of antagonist in the presence of agonist, the effects were increased. Longitudinal muscle showed more pronounced effect i.e. 52.7% with methysergide in comparison to circular muscle, which was 15.6%. Circular muscle showed reduction in the force of contraction with serotonin, which was increased on addition of antagonist, but still below the level of base line contraction. Serotonin when given from external source in vitro, decreased the force, however, there was minimal increase in the rate of contraction. Hence, serotonin decreases the intestinal motility giving an impression of having antispasmodic effect. The results of this study can be utilized in the development of new drug related to G.I. motility mediated through 5HT receptors