Effects of a short-chain phospholipid on ion transport pathways in rabbit nasal airway epithelium

We investigated the mechanism of interference of mucosal application of the short-chain phospholipid didecanoyl-L-alpha-phosphatidylcholine (DDPC; 0.1-0.5%) with ion transport pathways in isolated rabbit nasal airway epithelium (RNAE). Transports of Na+ and Cl- were evaluated from tracer ion fluxes, short-circuit current (Isc), and epithelial conductance (Gt) under short-circuit conditions in Ussing chambers. DDPC rapidly and reversibly abolished net Na+ absorption, reduced control Isc (approximately 110 microA/cm2) by approximately 80%, and induced a small Cl secretion. Intracellular Ca2+ concentration ([Ca2+]i) increased dose dependently and transiently (measured by fura 2 in cultured rabbit airway epithelium), but ionomycin failed to mimic the decrease in Isc. The rise in [Ca2+]i may explain a Ba(2+)-sensitive transient activation of a basolateral K+ conductance. Indomethacin-sensitive prostaglandin E2 production in RNAE increased severalfold, but cyclooxygenase and lipoxygenase inhibitors did not prev...