INFLUENCE OF SCROTAL NERVES ON THE PROSTATE GLAND FUNCTION IN MALE RATS

The prostate is a sexual gland producing decisive substances for the potency of sperms to fertilize eggs at the female reproductive tract. Its location influences several functions as those related to micturition, seminal emission and ejaculation, and has a differential role in its two regions, the dorsolateral and the ventral prostate. The two regions are organized in several alveoli surrounded by the stroma area, and each alveolus is arranged with a secretory epithelium that is in charge of the synthesis of prostatic secretions necessary for fertility. In order to accomplish its functions, the prostate is finely regulated by neural and hormonal mechanisms. Working with peripheral nerves supplying the reproductive organs in male rats, we observed that manipulation of afferent scrotal nerves in anesthetized subjects produces the expulsion of semen, and that the execution of sexual behavior by male rats includes an intense mechanical stimulation of the scrotal skin. Therefore, we hypothesized that scrotum stimulation during copulation reflexively activates the autonomic neural supply to the sexual glands in order to expel the appropriate content of semen during ejaculation. Thus, here we tested the hypothesis by analyzing the ejaculated semen parameters and the organization of the prostate gland in male rats with denervated scrotal nerves. Results show that transection of scrotal nerves did not modify neither motivation nor the normal execution of sexual behavior in male rats, but produces significant reductions in the volume of expelled semen, in the concentration of spermatozoa, and in the viability of ejaculated sperms when the semen is evaluated in the female reproductive tract immediately after male ejaculation. Also, denervated males showed a significant reduction and increase respectively in the alveolar area of the ventral and dorsolateral prostate. Thus, in addition to the endocrine regulation of sexual glands, the neural control has also a key role. Our data show that the mechanical stimulation activating scrotal nerves during copulation is important for the ejaculation of semen with the appropriate content for fertility, through the influence on prostate physiology. Whether the prostate is the only sexual gland reflexively activated, is a topic that deserves further research. (poster)