P2X receptor immunoreactivity in the male genital organs of the rat

Abstract.

The distribution of ATP ionotropic P2X receptors in the genital organs of the male rat has been investigated with immunohistochemical techniques using specific antibodies to P2X_1–7 receptors. In the excretory ducts of the testis (ductus epididymidis, vas deferens and its associated seminal vesicles), the major signals were seen with antibodies to P2X₁ and P2X₂ in the membranes of the smooth muscle layer, suggesting that these receptors are involved in the process of sperm transport and ejaculation. In the penis body, strong P2X₁ and weaker P2X₂ immunoreactivity was seen in the smooth muscle of blood vessels and the corpus cavernosum, suggesting a participation in the detumescence process. P2X₅ immunoreactivity, a marker for differentiating cells in stratified squamous epithelia, was observed in the epithelia of the terminal urethra, the "horny spur" (spine-studded epithelium of the glans) and the inner surface of the prepuce. Antibodies to P2X₃ reacted with nerve fibres in the adventitia of vas deferens, and the P2X₆ receptor was localised in the basal lamina of the epithelium. In the prostate, there was immunostaining of the smooth muscle between the tubules with antibody for P2X₁, but not with P2X₂; P2X₃ immunostaining of nerves and strong P2X₇ immunostaining of the glandular epithelium of the prostate were also present.