Role of cnp in human airways: cgmp-mediated stimulation of ciliary beat frequency. Geary, C. A., C. W. Davis, A. M. Paradiso, R. C. Boucher. Department of Medicine and 2Department of Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
APStracts 2:0019L, 1995.
Ciliated airway epithelial cells contribute to mucociliary transport systems via ciliary beating and electrolyte transport mechanisms. Both of these activities are regulated by agonists acting through intracellular calcium- and cAMP-dependent processes (5,15,18,27). This study examines the role of cGMP in the regulation of both ciliary beat frequency (CBF) and electrolyte transport in human airway epithelia (HAE). In a previous report, cGMP production in HAE was observed after stimulation with either C-type natriuretic peptide (CNP) or sodium nitroprusside (6). In this study, CNP was found to increase CBF by 30 +/- 6.9%, and this effect was mimicked by the cGMP analog, 8Br-cGMP, but not by sodium nitroprusside. CNP-induced increases in CBF do not appear to be mediated by changes in either intracellular calcium or cAMP levels. Using modified Ussing chambers, we also investigated CNP's potential modulation of sodium and chloride transport rates. Neither CNP, NP nor 8-Br-cGMP altered active ion transport rates. In conclusion, CNP regulates ciliary beat via cGMP-dependent mechanisms, whereas no effect of CNP or cGMP on ion transport was detected.

Received 1 August 1994; accepted in final form 25 January 1995.
APS Manuscript Number L215-4.
Article publication pending Am. J. Physiol. (Lung Cell. Mol.
Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 24 February 1995.