A Selective α1A-Adrenoceptor Antagonist Inhibits Detrusor Overactivity in a Rat Model of Benign Prostatic Hyperplasia

Purpose: α1-Adrenoceptor antagonists relax the obstructed prostatic urethra and suppress the irritative symptoms frequently observed in patients with benign prostatic hyperplasia. We investigated the effects of 3 α1-adrenoceptor antagonists on urodynamics in rats with hormone induced benign prostatic hyperplasia to determine which α1-adrenoceptor subtype selective antagonists would suppress irritative symptoms.Materials and Methods: Rats were treated with testosterone and 17β-estradiol by weekly intramuscular injections. After 4 weeks a pressure flow study was done and the effects of the α1-adrenoceptor antagonists KMD-3213 silodosin, tamsulosin and prazosin on urodynamics were compared. We especially investigated the involvement of the bladder and prostatic urethra to clarify the mechanism of detrusor overactivity expression.Results: Hormone treatment induced benign prostatic hyperplasia and resulted in detrusor overactivity, as determined by cystometry. Baseline perfusion urethral pressure and the pheny...