TRPM8 agonists modulate contraction of the pig urinary bladder

Area of Science:

• Urology
• Physiology
• Molecular Biology

Background:

• The transient receptor potential melastin-8 (TRPM8) channel, activated by cooling agents, is linked to overactive bladder.
• Its role in normal bladder function remains unclear.

Purpose of the Study:

• To investigate TRPM8 channel distribution in pig bladder.
• To determine the effect of TRPM8 agonists on bladder contractile function.

Main Methods:

• Immunohistochemistry to detect TRPM8 expression.
• Organ bath studies on pig bladder strips (detrusor and mucosa).
• Measurement of whole bladder contractions in response to TRPM8 agonists (menthol, icilin) and carbachol.

Main Results:

• TRPM8 immunoreactivity was observed on pig urothelium.
• Intravascular menthol/icilin decreased whole bladder contractions.
• Vesical menthol/icilin increased whole bladder contractions.
• Menthol/icilin inhibited carbachol-induced contractions in detrusor and mucosal strips.

Conclusions:

• TRPM8 channels are present on the pig bladder urothelium.
• Urothelial TRPM8 activation enhances bladder contractility.
• Direct activation of detrusor/mucosal TRPM8 inhibits contractility.