AJP - Cell Physiology, Vol 262, Issue 2 C501-C509, Copyright © 1992 by American Physiological Society

ARTICLES

Whole cell patch clamping of ciliary epithelial cells during anisosmotic swelling

R. E. Yantorno, D. A. Carre, M. Coca-Prados, T. Krupin and M. M. Civan
Department of Physiology, University of Pennsylvania, Philadelphia 19104.

Anisosmotic cell swelling triggers a regulatory volume decrease (RVD) in cell lines derived from human nonpigmented ciliary epithelium. Measurements of cell volume have indicated that the RVD reflects activation of K+ and/or Cl- channels. We have begun to characterize the putative channels by whole cell patch clamping. The results obtained by altering the external K+ and Cl- concentrations and by adding 20-50 microM quinidine or 1 mM Ba2+ indicate that K+ conductances contribute substantially and Cl- conductances contribute very little to the total membrane conductance (GT) under baseline isotonic conditions. Reducing the external osmolality by 20-50% reversibly and reproducibly increased GT by an order of magnitude. Data obtained from ion substitutions and the channel blockers quinidine and 5-nitro-2-(3-phenylpropylamino)-benzoate indicate that most of the hypotonicity-induced conductance reflects stationary Cl(-)-channel activity. The contribution of new K(+)-channel activity was small at intracellular free Ca2+ concentrations of 10 or 200 nM. We conclude that the RVD triggered by bath hypotonicity primarily reflects increased Cl(-)-channel activity.

This article has been cited by other articles:

				C.-W. Do, K. Peterson-Yantorno, C. H. Mitchell, and M. M. Civan cAMP-activated maxi-Cl- channels in native bovine pigmented ciliary epithelial cells Am J Physiol Cell Physiol, October 1, 2004; 287(4): C1003 - C1011. [Abstract] [Full Text] [PDF]

				C. W. McLaughlin, S. Zellhuber-McMillan, A. D. C. Macknight, and M. M. Civan Electron microprobe analysis of ouabain-exposed ciliary epithelium: PE-NPE cell couplets form the functional units Am J Physiol Cell Physiol, June 1, 2004; 286(6): C1376 - C1389. [Abstract] [Full Text] [PDF]

				D. A. Carre, C. H. Mitchell, K. Peterson-Yantorno, M. Coca-Prados, and M. M. Civan Similarity of A3-adenosine and swelling-activated Cl- channels in nonpigmented ciliary epithelial cells Am J Physiol Cell Physiol, August 1, 2000; 279(2): C440 - C451. [Abstract] [Full Text] [PDF]

				V. E. Walker, J. W. Stelling, H. E. Miley, and T. J. C. Jacob Effect of coupling on volume-regulatory response of ciliary epithelial cells suggests mechanism for secretion Am J Physiol Cell Physiol, June 1, 1999; 276(6): C1432 - C1438. [Abstract] [Full Text] [PDF]

				L. Chen, L. Wang, and T. J. C. Jacob Association of intrinsic pICln with volume-activated Cl- current and volume regulation in a native epithelial cell Am J Physiol Cell Physiol, January 1, 1999; 276(1): C182 - C192. [Abstract] [Full Text] [PDF]

				F. LANG, G. L. BUSCH, M. RITTER, H. VOLKL, S. WALDEGGER, E. GULBINS, and D. HAUSSINGER Functional Significance of Cell Volume Regulatory Mechanisms Physiol Rev, January 1, 1998; 78(1): 247 - 306. [Abstract] [Full Text] [PDF]

				M. B. Wax, I. Saito, T. Tenkova, T. Krupin, B. Becker, N. Nelson, D. Brown, and S. L. Gluck Vacuolar H+-ATPase in ocular ciliary epithelium PNAS, June 24, 1997; 94(13): 6752 - 6757. [Abstract] [Full Text] [PDF]

				J. FISCHBARG Mechanism of fluid transport across corneal endothelium and other epithelial layers: a possible explanation based on cyclic cell volume regulatory changes Br. J. Ophthalmol., January 1, 1997; 81(1): 85 - 89. [Full Text] [PDF]