AJP - Regulatory, Integrative and Comparative Physiology, Vol 268, Issue 4 963-R969, Copyright © 1995 by American Physiological Society

ARTICLES

Low-conductance anion channel activated by cAMP in teleost Cl- -secreting cells

W. S. Marshall, S. E. Bryson, A. Midelfart and W. F. Hamilton
Department of Biology, St. Francis Xavier University, Antigonish, Nova Scotia, Canada.

We studied characteristics and modulation of ion channels in primary cultures of opercular epithelium from the euryhaline marine killifish Fundulus heteroclitus. Primary cultures, 17-28 h old, retain mitochondria-rich Cl- cells identifiable by fluorescence microscopy. Cell-attached patches revealed frequent low-conductance 8.1 +/- 0.35 pS channels that usually became inactive on excision; high-conductance anion channels were not apparent. Ion substitution experiments demonstrated selectivity for Cl- over gluconate of 1:0.07. With addition of 1-isobutyl-3-methylxanthine (0.1 mM) and dibutyryladenosine 3',5'-cyclic monophosphate (1.0 mM) to the bath, incidence of the channel increased from 35.3 to 61.9% of total patches (n = 156 and 21, respectively), and incidence of patches with multiple copies of the channel increased markedly from 2.2 to 38.5%. Epithelial Cl- transport was inhibited by mucosally added diphenylamine-2-carboxylic acid (1.0 mM) but not by 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid (0.1-1.0 mM). The anion channel was absent from cultured killifish corneal epithelium, a tissue that lacks Cl- cells. We conclude that a low-conductance anion channel of Cl- cells, likely in the apical membrane, may account for adenosine 3',5'-cyclic monophosphate-activated Cl- secretion by marine fish.

This article has been cited by other articles:

				M. Avella, O. Ducoudret, D. F. Pisani, and P. Poujeol Swelling-activated transport of taurine in cultured gill cells of sea bass: physiological adaptation and pavement cell plasticity Am J Physiol Regulatory Integrative Comp Physiol, April 1, 2009; 296(4): R1149 - R1160. [Abstract] [Full Text] [PDF]

				D. H. Evans Teleost fish osmoregulation: what have we learned since August Krogh, Homer Smith, and Ancel Keys Am J Physiol Regulatory Integrative Comp Physiol, August 1, 2008; 295(2): R704 - R713. [Abstract] [Full Text] [PDF]

				D. H. Evans, P. M. Piermarini, and K. P. Choe The Multifunctional Fish Gill: Dominant Site of Gas Exchange, Osmoregulation, Acid-Base Regulation, and Excretion of Nitrogenous Waste Physiol Rev, January 1, 2005; 85(1): 97 - 177. [Abstract] [Full Text] [PDF]

				W. S. Marshall, E. M. Lynch, and R. R. F. Cozzi Redistribution of immunofluorescence of CFTR anion channel and NKCC cotransporter in chloride cells during adaptation of the killifish Fundulus heteroclitus to sea water J. Exp. Biol., May 1, 2002; 205(9): 1265 - 1273. [Abstract] [Full Text] [PDF]

				W. S. Marshall, J. A. Howard, R. R. F. Cozzi, and E. M. Lynch NaCl and fluid secretion by the intestine of the teleost Fundulus heteroclitus: involvement of CFTR J. Exp. Biol., March 15, 2002; 205(6): 745 - 758. [Abstract] [Full Text] [PDF]

				K. Daborn, R. R. F. Cozzi, and W. S. Marshall Dynamics of Pavement Cell-Chloride Cell Interactions During Abrupt Salinity Change in FUNDULUS HETEROCLITUS J. Exp. Biol., January 6, 2001; 204(11): 1889 - 1899. [Abstract] [Full Text] [PDF]

				T. D. Singer, S. J. Tucker, W. S. Marshall, and C. F. Higgins A divergent CFTR homologue: highly regulated salt transport in the euryhaline teleost F. heteroclitus Am J Physiol Cell Physiol, March 1, 1998; 274(3): C715 - C723. [Abstract] [Full Text] [PDF]