Epithelial P2X purinergic receptor channel expression and function

P2X purinergic receptor (P2XR) channels bind ATP and mediate Ca2+ influx - 2 signals that stimulate secretory Cl- transport across epithelia. We teste d the hypotheses that P2XR channels are expressed by epithelia and that P2X Rs transduce extracellular ATP signals into stimulation of Cl- transport ac ross epithelia. Electrophysiological data and mRNA analysis of human and mo use pulmonary epithelia and other epithelial cells indicate that multiple P 2XRs are broadly expressed in these tissues and that they are active on bot h apical and basolateral surfaces. Because P2X-selective agonists bind mult iple P2XR subtypes, and because P2X agonists stimulate C-l- transport acros s nasal mucosa of cystic fibrosis (CF) patients as well as across non-CF na sal mucosa, P2XRs may provide novel targets for extracellular nucleotide th erapy of CF.