Klyce S D
Am J Physiol. 1975 May;228(5):1446-52. doi: 10.1152/ajplegacy.1975.228.5.1446.
Theophylline (1 mM) produced a net transport of Na and Cl from aqueous humor to tears (.02-.04 mumol/cm2 h) in the isolated rabbit cornea denuded of endothlium and in the presence of normal resting potential (25-35 mV). The active transport of Na (tears to aqueous) and of Cl (aqueous to tears), estimated with the Goldman constant-field equations, was confirmed. A 10 degrees C rise in temperature produced changes close to those predicted for passive processes in both unidirectional fluxes of Na and in the tears-to-aqueous flux of Cl, but not for the aqueous-to-tears flux of Cl. Theophylline treatment doubled Cl permeability but did not significantly affect Na or urea permeability, suggestingspecificity of affect. In separate experiments it was shown that stromal thinning occurred in previously swollen corneas when the endothelium was blocked by silicone oil and the epithelium was treated with theophylline. These findings provide further support for the argument that the mammalian epithelium could have an active role in the regulation of corneal thickness in situ.
在分离的去除内皮且具有正常静息电位（25 - 35 mV）的兔角膜中，茶碱（1 mM）导致了从房水到泪液的钠和氯的净转运（0.02 - 0.04 μmol/cm²·h）。用戈德曼恒定场方程估算的钠（从泪液到房水）和氯（从房水到泪液）的主动转运得到了证实。温度升高10℃，钠的单向通量以及氯从泪液到房水的通量的变化接近被动过程预测的变化，但氯从房水到泪液的通量变化并非如此。茶碱处理使氯通透性增加一倍，但对钠或尿素通透性无显著影响，表明其作用具有特异性。在单独的实验中发现，当用硅油阻断内皮且用茶碱处理上皮时，先前肿胀的角膜会发生基质变薄。这些发现为哺乳动物上皮在原位角膜厚度调节中可能具有积极作用的观点提供了进一步支持。
