Distribution of P2X receptors in the urinary bladder and the ureter of the rat

Purpose: One means of assessing the presence of purinoceptors and their possible participation in signaling events in tissues is through use of specific antibodies and immunohistochemical methods. A thorough immunohistochemical screening for the presence of P2X receptors on bladder and ureter sections has been performed. Materials and Methods: Distribution of P2X receptor subtypes in rat bladder and ureter has been investigated using specific polyclonal antibodies to P2X(1) through to P2X(7) receptor subtypes with immunohistochemical methods. Results: In both the bladder detrusor muscle and the ureteral muscle (as well as the accompanying arteries) P2X(1) immunoreactivity was associated with the smooth muscle membranes. Non-membrane associated smooth muscle reactivity was seen with P2X(2)> P2X(5) = P2X(6). P2X(3) immunoreactivity was seen within nerve bundles in detrusor muscle only. The fine capillary network supplying bladder and ureter smooth muscle and lamina propria was visualized with P2X(4) immunoreactivity, membranes of urothelial cells gave a strong reaction with P2X(5), whereas P2X(6) immunostained the thin basement membrane beneath the urothelium. Nuclear staining was seen with P2X(7) in the urothelium tout more prominent in the bladder than in the ureter. Conclusions: Having established the distribution of P2X receptors in normal animal bladder and ureter tissue, it is now possible to perform comparable investigations on normal and diseased human tissue to establish a possible role of P2X receptors in pathogenic events.