Reflex interaction between the proximal urethra and the bladder. A clinical experimental study

Area of Science:

• Urology
• Neuroscience
• Physiology

Background:

• Animal studies indicate a bladder-cooling reflex triggered by cold stimulation of the bladder and urethra, leading to bladder contractions.
• The precise mechanisms and human relevance of these reflexes require further clinical investigation.

Purpose of the Study:

• To investigate bladder reflex responses to distension and cooling of the bladder neck and proximal urethra in humans.
• To explore the existence and characteristics of cold-sensitive reflexes in the human urethra.

Main Methods:

• Clinical experimental study involving 21 patients with overactive bladders.
• Utilized ice water tests, urethral distension with warm and cold water, and catheter-induced bladder neck stimulation.

Main Results:

• Three patients (14%) exhibited reflex bladder contraction solely from urethral cold water infusion.
• Four patients responded to urethral distension with both warm and cold water.
• Catheter traction on the bladder neck induced bladder contraction in four patients.

Conclusions:

• The study provides clinical evidence supporting a cold-sensitive reflex system within the human urethra.
• Reflexes mediated by cold and distension from the urethra were observed to be less easily evoked compared to those from the bladder in this experimental setup.