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 P2X₁, P2X₂, P2X₃, P2X₅ and P2X₇ receptors, while P2X₄ and P2X₆ receptors were absent from the testis. Blood vessels displayed immunostaining for P2X₁ and P2X₂ receptors; the P2X₁ receptors were present exclusively in blood vessels. P2X₂, P2X₃ and P2X₅ receptors were found to be expressed differentially in the various germ cell types throughout the different stages of the cycle of the seminiferous epithelium; P2X₂ and P2X₃ receptors were always observed together in the same cell types and at the same stages. Sertoli cells also showed differential staining for P2X₂ and P2X₃ receptors during the cycle of the seminiferous epithelium, whereas P2X₇ 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.