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Mechanical Stimulation-induced Calcium Wave Propagation in Cell Monolayers: The Example of Bovine Corneal Endothelial Cells
Published on: July 16, 2013
Functional coupling in bovine ciliary epithelial cells is modulated by carbachol
1Physiology Unit, University of Wales, Cardiff, United Kingdom.
The American Journal of Physiology
|January 22, 1998
Summary
Functional coupling between pigmented and nonpigmented ciliary epithelial cells was studied. Agents like carbachol and increased calcium uncoupled these cells, suggesting a mechanism to control eye secretion.
Area of Science:
- Ophthalmology
- Cell Biology
- Physiology
Background:
- The ciliary epithelium plays a crucial role in ocular fluid dynamics and solute transport.
- Understanding the functional coupling between pigmented ciliary epithelial (PCE) and nonpigmented ciliary epithelial (NPCE) cells is key to comprehending ocular secretion.
- Gap junctions are known to mediate intercellular communication and are vital for coordinated cellular function.
Purpose of the Study:
- To investigate the functional and electrical coupling between isolated pairs of PCE and NPCE cells.
- To determine the effects of specific agents and conditions on the coupling status of these cells.
- To explore the potential of modulating this coupling for controlling ciliary epithelium secretion.
Main Methods:
- Whole-cell patch clamp technique was employed to measure electrical coupling.
- Lucifer yellow dye was used to confirm cell coupling via fluorescence microscopy.
- Capacitance measurements, using a supercell model, quantified the degree of coupling.
- Exposure to octanol, carbachol (CCh), and varying extracellular calcium concentrations ([Ca2+]o) assessed uncoupling effects.
Main Results:
- Coupled PCE-NPCE cell pairs exhibited significantly higher capacitance (79.8 pF) compared to single cells (approx. 38 pF).
- Octanol, CCh, and increased [Ca2+]o effectively reduced cell pair capacitance, indicating uncoupling.
- CCh-induced uncoupling was dose-dependent and reversible, with recoupling observed after agent washout.
- Optical confirmation with lucifer yellow corroborated the electrical coupling measurements.
Conclusions:
- The ciliary epithelium functions as a syncytium, with gap junctional communication between PCE and NPCE cells.
- Modulation of this intercellular coupling, particularly by agents like CCh and calcium, provides a potential mechanism to regulate ocular fluid and solute secretion.
- These findings offer insights into the physiological control of the eye's internal environment and potential therapeutic targets.
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