The effects of serotonin related compounds on the urinary bladder motility in conscious rats

Recently new psychotropic drugs acting on the serotonin (5-HT) receptors are developed and used clinically. 5-HT has been known to affect the function of the lower urinary tract. However, the roles of the different subtypes of 5-HT receptors are not well known. We studied the effects of the 5-HT and the antagonists of the receptor subtypes on bladder motility in conscious rats. In male Wistar rats bladder contraction was reflexly induced by fluid infusion and drugs were injected through the intracerebroventricular cannula planted 2 days ago. In 5-HT (10-100), fluvoxamine (100), methysergide (10-100), WAY100635 (30, 100), ketanserin (10, 30), granisetron (5, 10), SB2040 (30) (dose：μg), 5-HT and methysergide shortend and WAY100635 and ketanserin prolonged the intercontraction interval, respectively. In reserpinized rats the inhibitory effects of WAY100635 was attenuated and serotonin caused overactivity. Now we think the blockade of the presynaptic 5-HT1 receptors in the neurons of the micturition reflex pathway exerts the inhibitory effect through the increase in the serotonin release.