Region and age dependent differences in α1-adrenergic responsiveness of rat seminal vesicle and vas deferens

Because age dependent differences occur in the incidence of ejaculatory dysfunction with α1-adrenoceptor antagonists used to treat lower urinary tract symptoms secondary to benign prostatic hyperplasia, we investigated age related changes in the functional, biochemical and molecular properties of α1-adrenoceptor in the rat seminal vesicle and vas deferens. The characteristics of α1-adrenoceptor in the seminal vesicle and epididymal and prostatic portion of vas deferens of 3 and 22-month-old rats were determined using an isolated muscle bath, radioligand receptor binding and real-time reverse transcription-polymerase chain reaction techniques. Old rats had significantly higher body weight and lower testosterone than young rats. Although there was no significant age dependent difference in the properties of α1-adrenoceptor in the prostatic portion of vas deferens, the maximum contractile responses to phenylephrine, total α1-adrenoceptor density and mRNA expression of all 3 α1-adrenoceptor subtypes were significantly lower in the seminal vesicle and epididymal portion of vas deferens of 22 vs 3-month-old rats. Age dependent differences in the molecular, biochemical and functional properties of α1-adrenoceptors in the rat seminal vesicle and vas deferens may indicate potential differences in the response to α1-adrenoceptor antagonists with aging.