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

Abstract

Animal experiments have shown that the bladder-cooling reflex is activated by cold stimulation of the bladder and urethra, causing a reflex bladder contraction. In this clinical experimental study, the bladder reflex responses to distension and cooling of the bladder neck and the proximal urethra were investigated. Twenty-one patients with overactive bladders and documented positive ice water tests were studied. Three patients (14%) responded with reflex bladder contraction by urethral infusion of ice water only, and another 4 patients responded to urethral distension with both warm and cold water. In 4 patients, bladder contraction was induced by a catheter pulling on the bladder neck. This study supports the existence of a cold-sensitive reflex system in the human urethra. However, in the experimental situation, both cold and tension-mediated reflexes were more difficult to evoke from the urethra than from the bladder.