FIGURE 2.

P2 receptor expression in the renal epithelium. Most P2X and P2Y receptor subtypes can be found throughout the nephron, although their relative expression has been difficult to define, as well as their exact function in each nephron segment. There is clearly some overlap in function and even between P2X and P2Y receptors. Message (mRNA in red) detection has been easier than protein (in black) by immunohistochemistry. Also shown are the corresponding renal tubular segment expression patterns for Na⁺-K⁺-2Cl⁻ cotransporter (NKCC2), Na⁺-Cl⁻ cotransporter (NCC), and epithelial sodium channel (ENaC), which have been proposed to be P2 receptor regulated. [Modified from Shirley et al. (474), with permission from Elsevier.]