Male Reproductive Tract

Adenosine Triphosphatase Induces Ca²⁺ Signal in Epithelial Cells of the Mouse Caput Epididymis Through Activation of P2X and P2Y Purinergic Receptors

Abstract

In the present study, we developed a novel method to analyze calcium (Ca²⁺) signal in living slices of mouse caput epididymides, by applying calcium imaging on Fura-2 loaded vibratome slices. The data revealed that in epithelial cells of mouse caput epididymides, ATP induces a rapid Ca²⁺ signal that is sustained after 60 seconds. Pre-incubating the sections in Ca²⁺-free medium in the presence of EGTA did not affect the amplitude of the ATP induced Ca²⁺ signal, indicating the presence of P2Y type purinergic receptors and phospholipase C activity. Furthermore, ATP induced a similar Ca²⁺ signal in the different sub-regions of caput epididymides. The P2X type ion-gated purinergic receptors could also be responsible for the ATP induced Ca²⁺ signal as immunohistochemical and RT-PCR analyses showed the expression of at least P2X1, P2X2, P2X4 and P2X7, and P2Y1 and P2Y2 receptors in the epididymis. We propose that the P2X and P2Y receptor expression is vital for the normal function of epididymal epithelium and sperm maturation. Furthermore, the method developed allows us to analyze activity of various G-protein coupled receptors in intact epithelial cells of mouse epididymides, and other reproductive tissues as well.