Biomaterial Database

Swelling activated chloride channels in cultured bovine corneal endothelial cells. 1999

S P Srinivas, and Y Guan, and J A Bonanno

Morton D. Sarver Center for Cornea and Contact Lens Research, University of California, School of Optometry, Berkeley, CA, 94720, USA.

Swelling induced enhancement of anion permeability was investigated using the halide-sensitive fluorescent dye SPQ in cultured bovine corneal endothelial cells (BCEC). Rates of anion influx were quantified in terms of the rate of change of SPQ fluorescence during exposure to short duration pulses of Cl-, I-or NO3-while the cells were being perfused with I-, NO3-or Cl-Ringer, respectively. Since SPQ fluorescence is quenched to different extents by these anions, their influx or efflux causes significant changes in fluorescence. The ratio of the maximum rate of change of fluorescence during the pulse period under hyposmotic conditions to that under isosmotic conditions, referred to as the enhancement ratio (ER), was calculated as a measure of the increase in anion permeability. When cells were perfused with NO3-Ringer, exposure to I-pulses yielded an ER=9.0+/-2.6 for 110+/-5 mosmhyposmotic shock. This was higher than with Cl-/I-(6.4+/-0.7) or NO3-/Cl-(3.2+/-0.8) anion-pairs for the same level of shocks. In all cases, the enhancement occurred within approximately 100 seconds after swelling but decreased with continued progress of regulatory volume decrease (RVD). ER returned to approximately 1 within 4 minutes after returning to isosmotic conditions. The membrane potential (Em) depolarized immediately after hyposmotic shock. When cells were depolarized prior to the shocks by high [K+], changes in Emwere relatively small. ER, for the NO3-/I-anion-pair, was significantly reduced by DIDS (100% at 500 microm), NPPB ( approximately 80% at 100 microm) and tamoxifen (approximately 85% at 12 microm). Tamoxifen and NPPB also inhibited swelling induced depolarization. Increasing cationic conductance with Gramicidin D at approximately 2 minutes following hyposmotic shock induced NPPB-inhibitable secondary swelling or accelerated RVD under normal or low Na+conditions, respectively. These results demonstrate that BCEC express swelling activated Cl-channels, which facilitate RVD by enhancing anionic permeability and also by providing a favorable electrical gradient for K+efflux.

UI	MeSH Term	Description	Entries
D007454	Iodides	Inorganic binary compounds of iodine or the I- ion.	Iodide
D008564	Membrane Potentials	The voltage differences across a membrane. For cellular membranes they are computed by subtracting the voltage measured outside the membrane from the voltage measured inside the membrane. They result from differences of inside versus outside concentration of potassium, sodium, chloride, and other ions across cells' or ORGANELLES membranes. For excitable cells, the resting membrane potentials range between -30 and -100 millivolts. Physical, chemical, or electrical stimuli can make a membrane potential more negative (hyperpolarization), or less negative (depolarization).	Resting Potentials,Transmembrane Potentials,Delta Psi,Resting Membrane Potential,Transmembrane Electrical Potential Difference,Transmembrane Potential Difference,Difference, Transmembrane Potential,Differences, Transmembrane Potential,Membrane Potential,Membrane Potential, Resting,Membrane Potentials, Resting,Potential Difference, Transmembrane,Potential Differences, Transmembrane,Potential, Membrane,Potential, Resting,Potential, Transmembrane,Potentials, Membrane,Potentials, Resting,Potentials, Transmembrane,Resting Membrane Potentials,Resting Potential,Transmembrane Potential,Transmembrane Potential Differences
D009997	Osmotic Pressure	The pressure required to prevent the passage of solvent through a semipermeable membrane that separates a pure solvent from a solution of the solvent and solute or that separates different concentrations of a solution. It is proportional to the osmolality of the solution.	Osmotic Shock,Hypertonic Shock,Hypertonic Stress,Hypotonic Shock,Hypotonic Stress,Osmotic Stress,Hypertonic Shocks,Hypertonic Stresses,Hypotonic Shocks,Hypotonic Stresses,Osmotic Pressures,Osmotic Shocks,Osmotic Stresses,Pressure, Osmotic,Pressures, Osmotic,Shock, Hypertonic,Shock, Hypotonic,Shock, Osmotic,Shocks, Hypertonic,Shocks, Hypotonic,Shocks, Osmotic,Stress, Hypertonic,Stress, Hypotonic,Stress, Osmotic,Stresses, Hypertonic,Stresses, Hypotonic,Stresses, Osmotic
D002417	Cattle	Domesticated bovine animals of the genus Bos, usually kept on a farm or ranch and used for the production of meat or dairy products or for heavy labor.	Beef Cow,Bos grunniens,Bos indicus,Bos indicus Cattle,Bos taurus,Cow,Cow, Domestic,Dairy Cow,Holstein Cow,Indicine Cattle,Taurine Cattle,Taurus Cattle,Yak,Zebu,Beef Cows,Bos indicus Cattles,Cattle, Bos indicus,Cattle, Indicine,Cattle, Taurine,Cattle, Taurus,Cattles, Bos indicus,Cattles, Indicine,Cattles, Taurine,Cattles, Taurus,Cow, Beef,Cow, Dairy,Cow, Holstein,Cows,Dairy Cows,Domestic Cow,Domestic Cows,Indicine Cattles,Taurine Cattles,Taurus Cattles,Yaks,Zebus
D002463	Cell Membrane Permeability	A quality of cell membranes which permits the passage of solvents and solutes into and out of cells.	Permeability, Cell Membrane
D002712	Chlorides	Inorganic compounds derived from hydrochloric acid that contain the Cl- ion.	Chloride,Chloride Ion Level,Ion Level, Chloride,Level, Chloride Ion
D004728	Endothelium, Corneal	Single layer of large flattened cells covering the surface of the cornea.	Anterior Chamber Epithelium,Corneal Endothelium,Endothelium, Anterior Chamber,Epithelium, Anterior Chamber,Anterior Chamber Endothelium
D006706	Homeostasis	The processes whereby the internal environment of an organism tends to remain balanced and stable.	Autoregulation
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D048429	Cell Size	The quantity of volume or surface area of CELLS.	Cell Volume,Cell Sizes,Cell Volumes,Size, Cell,Sizes, Cell,Volume, Cell,Volumes, Cell