Non-neuronal cholinergic system in human bladder urothelium.

Area of Science:

• Urology
• Neuroscience
• Pharmacology

Background:

• Non-nerve-evoked acetylcholine (ACh) release is increasingly recognized for its role in various pathophysiological conditions.
• The non-neuronal cholinergic system's contribution to human bladder function remains incompletely understood.

Purpose of the Study:

• To investigate the presence and characteristics of the non-neuronal cholinergic system in the isolated human bladder.
• To determine the role of the urothelium in non-nerve-evoked ACh release.
• To evaluate the influence of age and mechanical stretch on ACh release.

Main Methods:

• Human bladder tissues from 15 patients were utilized.
• Bladder strips, with or without urothelium, were subjected to microdialysis and high-performance liquid chromatography to measure ACh release.
• Choline acetyltransferase (ChAT) immunohistochemistry was performed.
• The effects of age and varying resting tension (0-40 mN) on ACh release were assessed.

Main Results:

• ChAT-positive staining was prominent in the urothelium and suburothelial regions.
• Tetrodotoxin-insensitive, non-nerve-evoked ACh release was significantly higher in bladder strips containing urothelium.
• ACh release demonstrated a significant positive correlation with patient age.
• Mechanical stretching of bladder strips significantly increased non-nerve-evoked ACh release, with a more pronounced effect in urothelium-containing tissues.
• Stretch-induced ACh release also increased with age.

Conclusions:

• A non-neuronal cholinergic system, involving ACh release from the urothelium/suburothelium, is present in the human bladder.
• Age and mechanical stretch significantly modulate non-nerve-evoked ACh release.
• This system likely plays a role in both normal human bladder physiology and its associated pathologies.