Expression of nucleotide P2X receptor subtypes during spermatogenesis in the adult rat testis

Abstract

The expression of ATP-gated ion channels (P2X receptors) was investigated in testes of adult rats by immunohistochemistry and Western blotting with antibodies against all seven P2X receptor subtypes. Immunoreactive cells were identified and monitored during germ cell maturation. Results of immunohistochemical and Western blotting experiments showed the expression of P2X(1), P2X(2), P2X(3), P2X(5) and P2X(7) receptors, while P2X(4) and P2X(6) receptors were absent from the testis. Blood vessels displayed immunostaining for P2X(1) and P2X(2) receptors; the P2X(1) receptors were present exclusively in blood vessels. P2X(2), P2X(3) and P2X(5) receptors were found to be expressed differentially in the various germ cell types throughout the different stages of the cycle of the seminiferous epithelium; P2X(2) and P2X(3) receptors were always observed together in the same cell types and at the same stages. Sertoli cells also showed differential staining for P2X(2) and P2X(3) receptors during the cycle of the seminiferous epithelium, whereas P2X(7) receptor expression was present throughout all stages. No immunostaining for P2X receptors was detected on Leydig cells. The possible roles of purinergic signalling in the control of germ cell maturation are discussed. In particular, it is suggested that purinergic signalling may play a role in controlling the maturation of germ cell subsets of different developmental ages that exist alongside each other in the adult testis.