Terbutaline increases open channel density of epithelial sodium channel (ENaC) in distal lung

Neonatal and adult vertebrate respiration is facilitated by alveolar fluid and sodium (Na+) absorption driven by apical sodium channels (ENaC). ENaC are characterized in Xenopus laevis lung (XLL) epithelia using voltage clamping and fluctuation analysis to non-invasively examine macroscopic transepithelial current and resistance (I-SC, R-T), single channel current (i(Na)) and total channel density (N-T) responses to a beta adrenergic agonist (Terbutaline). Terbutaline addition to the basolateral bath of XLL increased Na entry to > 200% of control reflecting a doubling of open channel density (N-o). These data are consistent with the notion that XLL can serve as a useful model for investigation of distal lung ENaC response to agents of physiological interest. (C) 1999 Elsevier Science B.V. All rights reserved.