The Effects of Pyridostigmine and Levosulpiride on the Contraction of Rabbit Urinary Bladders

Ko, Young Hwii; Lee, Jeong Gu

Abstract

PURPOSE: This study was performed to identify the effects of bethanechol, pyridostigmine and levosulpiride, on the contraction of rabbit bladder strip tissue in a single agent administration, and to investigate the synergistic effects in a mixed administration.
MATERIALS AND METHODS
Smooth muscle strips of bladder were prepared using female, New Zealand white, rabbits. After an equilibration period, dose response curves to each agent, with cumulative administration, were performed in the basal tension state of the strips. Each strip was then pretreated with the agent at the maximal concentration that would not induce a bladder contraction, and second dose-response curves for the other agents were obtained. Following this, the maximal stimulation with bethanechol was performed, and during the tonic response, pyridostigmine or levosulpiride was administrated to observe any synergistic effects of the agents. Similar experiments were repeated for the pyridostigmine and levosulpiride.
RESULTS
Each agent elicited a dose-dependent contractile response, in the order; bethanechol (0-4.49g/100mg tissue), pyridostigmine (0-1.58g/100mg tissue) and levosulpiride (0-0.44g/100mg tissue). In the presence of pyridostigmine (3x10(-6)M) or levosulpiride (10(-4)M), no additive effects were noted after the cumulative stimulation with bethanechol (10(-10)-10(-4)M). During the tonic response of bethanechol (10(-4)M) or pyridostigmine (10(-2)M), the addition of levosulpiride (10(-2)M) induced a significant increase in the bladder strip contractions, but the addition of pyridostigmine (10(-2)M) or bethanechol (10(-4)M) decreased the maximal response (p<0.05).
CONCLUSIONS
These results imply that pyridostigmine may be useful for impaired detrusor contractility management. Synergistic effects can also be expected when administrating levosulpiride, in addition to bethanechol, in improving bladder contractility.