A comparison of the expression and contractile function of α1-adrenoceptors in seminal vesicle and vas deferens from normotensive and hypertensive rats

Abstract

Because hypertension related alterations occur in the properties of α1-adrenoceptor in several mammalian tissues and hypertension may impact ejaculatory function, we investigated hypertension related alterations in the functional, biochemical and molecular properties of α1-adrenoceptor in the rat seminal vesicle and vas deferens. Spontaneous seminal emission in male spontaneously hypertensive rats (SHRs) and normotensive Wistar-Kyoto (WKY) rats was studied during the 3-day observation period. The characteristics of α1-adrenoceptor in the seminal vesicle and epididymal and prostatic portion of vas deferens of the two strains were determined using an isolated muscle bath, radioligand receptor binding and real-time reverse transcription-polymerase chain reaction techniques. SHRs had significantly higher serum testosterone than WKY rats. However, the daily mean number of ejaculatory plugs emitted and their dry weight in SHRs were significantly lower than those in WKY rats. Although there was no significant difference in the properties of α1-adrenoceptor in the prostatic portion of vas deferens between SHRs and WKY rats, the maximum contractile responses to phenylephrine, total α1-adrenoceptor density and expression of α1A-adrenoceptor mRNA were significantly higher in the seminal vesicle and epididymal portion of vas deferens of SHRs vs. WKY rats. Our data demonstrate the presence of hypertension related alterations in serum testosterone and in α1-adrenergic responsiveness of the rat seminal vesicle and vas deferens and suggest that ejaculatory function in SHRs does not mirror these hypertension related alterations.