Effects of ethanol on in vivo cystometry and in vitro whole bladder contractility in the rat

Purpose: It is known that acute ethanol intoxication can produce urinary retention in patients with benign prostatic hyperplasia. We evaluated the effects of ethanol on rat bladder function in vivo and in vitro. Materials and Methods: Infusion cystometry was performed under urethane anesthesia with or without intravenous injection of ethanol. Voided volume, maximum voiding pressure, residual urine, bladder capacity, the pressure at which micturition was induced and voiding efficacy were compared. Subsequently, the in vitro whole bladder pressure generated by field stimulation, bethanechol, adenosine triphosphate and KCl in the presence of ethanol 0 to 5.0% was investigated. Results: Intravenous administration of ethanol changed the in vivo cystometrogram. Bladder capacity and residual urine volume were significantly increased, and voiding pressure was decreased. Contractility of the isolated whole bladder to various kinds of stimulation in vitro was suppressed by ethanol in a dose-dependent manner. Washing the bladder and incubating it in normal Krebs' solution following exposure to 5% ethanol restored detrusor contractility. Conclusion: Ethanol significantly impairs detrusor contractility in the rat in vivo and in vitro.