The effect of exogenous prostaglandins F2 alpha and E2 and indomethacin on micturition.

The influence of exogeneous infusion of prostaglandins (PGs) of the F2 alpha and E2 series and of indomethacin on micturition cycles was investigated in 30 anaesthetised female dogs. In 30 other animals, urethrovesical disconnection was performed to study the action of PGs and of indomethacin without the muscle continuity factors. In the intact animal model during vesical distension, PGE2 produced a significant urethral pressure drop and a dose-dependent reduction in the threshold micturition volume. PGF2 alpha produced a significant urethral pressure rise. At doses higher than 0.3 micrograms/kg, PGF2 alpha reduced the threshold micturition volume. On the other hand, indomethacin significantly increased the threshold micturition volume and reduced the maximum intravesical pressure. In the disconnected model, PGE2 produced a dose-dependent decrease in the resting urethral pressure and hardly affected the intravesical pressure; PGF2 alpha produced a dose-dependent increase in both urethral and intravesical pressures. Thus it is suggested that endogenous PG release during vesical distension could play a facilitatory role in micturition.