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Prostanoids modulate reflex micturition by acting through capsaicin-sensitive afferents
C A Maggi1, S Giuliani, B Conte
1Pharmacology Department, A. Menarini Pharmaceuticals, Florence, Italy.
European Journal of Pharmacology
|January 12, 1988
Summary
Exogenous prostanoids activate reflex micturition in rats, an effect blocked by capsaicin desensitization. Endogenous prostanoids likely sensitize capsaicin-sensitive bladder mechanoreceptors, facilitating this reflex.
Area of Science:
- Urology
- Neuroscience
- Pharmacology
Background:
- Prostanoids, such as prostaglandin E2 (PGE2), play roles in various physiological processes.
- The micturition reflex involves complex neural pathways and sensory input from the bladder.
Purpose of the Study:
- To investigate the role of prostanoids in regulating the micturition reflex.
- To determine if prostanoids sensitize capsaicin-sensitive bladder afferents.
Main Methods:
- Rats were anesthetized with urethane.
- Exogenous prostanoids (PGE2, TBX B2) were applied topically to the bladder serosa or instilled intravesically.
- Systemic capsaicin desensitization was performed prior to experiments.
- Indomethacin was used as a prostanoid synthesis inhibitor.
- Cystometrograms were recorded to assess micturition reflex activity.
Main Results:
- Topical prostanoid application and intravesical PGE2 instillation activated reflex micturition.
- These prostanoid-induced effects were abolished by systemic capsaicin desensitization.
- Both indomethacin pretreatment and capsaicin desensitization increased the micturition threshold.
- Combined treatment did not yield additive effects on the micturition threshold.
Conclusions:
- Endogenous prostanoids appear to facilitate reflex micturition.
- Prostanoids likely stimulate or sensitize capsaicin-sensitive bladder mechanoreceptors.
- These findings elucidate a mechanism involving prostanoids and specific sensory pathways in bladder function.