Abstract
Abstract: :
Purpose. The isolated bovine ciliary epithelium transports Cl into the aqueous side (1) but it does not transport bicarbonate (2). This suggests that the bovine aqueous humor (AH) should contain Cl at a higher concentration than plasma (PL), as found in human. Thus, concentrations of Cl, Na and K were measured in bovine AH and PL. Methods. Blood and AH were obtained while the animals were unconscious before being sacrificed following the standard procedure of the slaughterhouse in Argentina. Electrolyte concentrations were determined by a Nova Electrolyte Analyzer (Nova Biomedical). Results. Samples of AH from one set of 30 eyes gave values of 114.4±0.8, 139.9±0.9 and 5.1±0.3 mM for Cl, Na and K respectively. In a different set of 23 eyes in which the AH was paired with the PL of the same animal the AH/P values for Cl, Na and K were 113.3±1.2/102.9±0.7, 137.7±1.4/152.0±1.2 and 3.3±0.1/4.1±0.1 respectively. Cl, in AH was significantly higher than in PL, p<0.001. There was no statistically significant difference between the electrolyte concentrations of both eyes. Na was significantly higher in PL than AH, p<0.001. K was also higher in PL, p<0.001. Conclusion. A Cl concentration in bovine AH higher than in PL is consistent with an active Cl transport in the blood-to-aqueous direction as found in the isolated ciliary epithelium from this species. Thus, the bovine tissue is an adequate model for ionic transport mechanisms in the human ciliary epithelium. 1. Do C-W and To C-H. Invest. Ophthalmol Vis Sci 41: 1853-1860, 2000. 2. To C-H, Do C-W, Zamudio AC and Candia OA. Am J Physiol 280: C1521-C1530, 2001.
Keywords: aqueous • aqueous • anterior chamber