| This dissertation describes gap junctional intercellular communication in rabbit and human corneal epithelium and endothelium. Furthermore, it demonstrates the ability of bicarbonate and bicarbonate structural analogs to promote gap junctional intercellular communication in both the epithelium and endothelium.; Microelectrode injection of fluorescent dye was employed to investigate gap junctional communication in both the epithelium and endothelium. It was demonstrated that gap junctions in the epithelium and endothelium of human corneas, and the epithelium of rabbit corneas are functional. It was also determined, that in the absence of bicarbonate or one of its structural analogs (bisulfite, nitrate, and carbamate), dye couplings did not occur in the two superficial most layers of the corneal epithelium. Coupling in the second layer could be re-established in the presence of bicarbonate or one of its structural analogs. Furthermore, it was demonstrated that bicarbonate or one of its structural analogs has the effect of increasing dye spread coefficients in the corneal endothelium, which indicates an increase in gap junctional conductance. This effect of bicarbonate was determined to be independent of intracellular pH or transmembrane voltage. The ability of bicarbonate structural analogs to induce similar effects on gap junctional communication in both the epithelium and endothelium may indicate that a molecular interaction is involved.; These findings may hold promise for the development of new classes of bicarbonate-free, pH stable, artificial tears and intraocular irrigation solutions that make use of bicarbonate structural analogs to mimic the beneficial effects of bicarbonate. |
