| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
Biophysical Journal 63: 518-529 (1992)
© 1992 the Biophysical Society
Department of Physiology & Biophysics, State University of New York, Stony Brook 11794-8661.
ABSTRACT
We have used linear frequency domain techniques to measure impedance at various locations and depths in the intact rat lens. The data are used to obtain best-fit solutions to a new electrical model based on lens structure, allowing us to estimate localized conductances of surface cell membranes (Gs), fiber cell membranes (gm), and gap junctions (Gj) as functions of position. We find that gm is small and fairly uniform throughout the lens (2.02 +/- 0.58 microS/cm2); for the anterior surface-epithelial cells Gs = 1.26 +/- 0.19 mS/cm2; for the posterior surface differentiating fiber cells Gs = 0.46 +/- 0.04 mS/cm2. Thus, Gs varies about the equator in a stepwise fashion. Gj between fiber cells at locations interior to 80% of the radius is fairly uniform (0.75 S/cm2); but in the outer 20% Gj varies smoothly and symmetrically from both poles (0.66 S/cm2) to equator (5.95 S/cm2). This pattern of variation in Gj is similar to the pattern of inward and outward currents reported by Robinson and Patterson (1983. Curr. Eye Res. 2:843-847). We therefore suggest that the nonuniform distribution of functional gap junctions, not the surface cell conductance or Na/K pumps, may be responsible for directing these current flows. Gap junctional uncoupling during exposure to elevated calcium and acidification was also examined. High calcium (20 mM, with the calcium ionophore A23187) produced modest (twofold) irreversible uncoupling along with large, irreversible decreases in membrane potential. We did not pursue this further. Acidification with 20 and 100% CO2-bubbled Tyrode's produced 5- and 15-fold reversible uncoupling, respectively, only in the outer 20% of the lens radius. The remaining inner 80% of the lens gap junctions seemed resistant to the acidification and did not uncouple.
This article has been cited by other articles:
 |
|
 |
|
  B. A. Boswell, P. J. Lein, and L. S. Musil Cross-Talk between Fibroblast Growth Factor and Bone Morphogenetic Proteins Regulates Gap Junction-mediated Intercellular Communication in Lens Cells Mol. Biol. Cell, June 1, 2008; 19(6): 2631 - 2641. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 K. F. Webb and P. J. Donaldson Differentiation-dependent changes in the membrane properties of fiber cells isolated from the rat lens Am J Physiol Cell Physiol, May 1, 2008; 294(5): C1133 - C1145. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 F. J. Martinez-Wittinghan, C. Sellitto, T. W. White, R. T. Mathias, D. Paul, and D. A. Goodenough Lens Gap Junctional Coupling Is Modulated by Connexin Identity and the Locus of Gene Expression Invest. Ophthalmol. Vis. Sci., October 1, 2004; 45(10): 3629 - 3637. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. D. Jacobs, C. Soeller, A. M. G. Sisley, M. B. Cannell, and P. J. Donaldson Gap Junction Processing and Redistribution Revealed by Quantitative Optical Measurements of Connexin46 Epitopes in the Lens Invest. Ophthalmol. Vis. Sci., January 1, 2004; 45(1): 191 - 199. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 V. I. Shestopalov and S. Bassnett Development of a macromolecular diffusion pathway in the lens J. Cell Sci., October 15, 2003; 116(20): 4191 - 4199. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
O. A. Candia and A. C. Zamudio Regional distribution of the Na+ and K+ currents around the crystalline lens of rabbit Am J Physiol Cell Physiol, February 1, 2002; 282(2): C252 - C262. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
T. W. White, C. Sellitto, D. L. Paul, and D. A. Goodenough Prenatal Lens Development in Connexin43 and Connexin50 Double Knockout Mice Invest. Ophthalmol. Vis. Sci., November 1, 2001; 42(12): 2916 - 2923. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A.-C. N. Le and L. S. Musil A novel role for FGF and extracellular signal-regulated kinase in gap junction-mediated intercellular communication in the lens J. Cell Biol., July 9, 2001; 154(1): 197 - 216. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 P. Donaldson, J. Kistler, and R. T. Mathias Molecular Solutions to Mammalian Lens Transparency Physiology, June 1, 2001; 16(3): 118 - 123. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
V. M. Berthoud, E. M. Westphale, A. Grigoryeva, and E. C. Beyer PKC Isoenzymes in the Chicken Lens and TPA-Induced Effects on Intercellular Communication Invest. Ophthalmol. Vis. Sci., March 1, 2000; 41(3): 850 - 858. [Abstract] [Full Text]
|
|
|
|
|
|
Q. Cheng, D. Lichtstein, P. Russell, and J. S. Zigler Jr Use of a Lipophilic Cation to Monitor Electrical Membrane Potential in the Intact Rat Lens Invest. Ophthalmol. Vis. Sci., February 1, 2000; 41(2): 482 - 487. [Abstract] [Full Text]
|
|
|
|
 |
|
 K. Stergiopoulos, J. L. Alvarado, M. Mastroianni, J. F. Ek-Vitorin, S. M. Taffet, and M. Delmar Hetero-Domain Interactions as a Mechanism for the Regulation of Connexin Channels Circ. Res., May 28, 1999; 84(10): 1144 - 1155. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 X. Gong, G. J. Baldo, N. M. Kumar, N. B. Gilula, and R. T. Mathias Gap junctional coupling in lenses lacking alpha 3 connexin PNAS, December 22, 1998; 95(26): 15303 - 15308. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
