Effects of ethanol on responses of isolated rabbit urinary bladder and urethra.

BACKGROUND

Acute ethanol ingestion increases the risk of urinary retention in patients with benign prostatic hyperplasia (BPH). To elucidate the mechanism of this effect, we investigated the in vitro effects of ethanol on lower urinary tract function in rabbits.

METHODS

The responses to various stimuli of muscle strips isolated from male rabbit bladder and urethra were determined in the presence of 0%, 0.5%, 1.0%, and 3.0% ethanol.

RESULTS

Basal tension of tissue strips taken from the bladder and the urethra was reduced by ethanol in a dose-dependent manner, as were bladder contractions induced by field stimulation, bethanechol, and ATP. Ethanol also reduced phenylephrine-induced contractions of the prostatic urethra. A high (3%) concentration of ethanol significantly reduced KCl-induced contraction of both the bladder and urethra, as well as urethral relaxation induced by field stimulation following contraction with 200 mumol/L phenylephrine.

CONCLUSION

Responsiveness of the rabbit lower urinary tract was significantly reduced by exposure to ethanol. A similar decrease in tonus and contractility of the detrusor and inhibition of relaxation in the prostatic urethra may lead to urinary retention in men following acute ingestion of ethanol.