Shahidullah Mohammad, Wilson William S, Yap Maurice, To Chi-ho
Laboratory of Experimental Optometry, Department of Optometry and Radiography, The Hong Kong Polytechnic University, Kowloon, Hong Kong.
Invest Ophthalmol Vis Sci. 2003 Mar;44(3):1185-91. doi: 10.1167/iovs.02-0397.
To investigate the role of active chloride secretion by the ciliary epithelium in the formation of aqueous humor (AH), by using the in vitro perfused eye.
Bovine eyes collected from an abattoir were cannulated through the ophthalmic artery and perfused with oxygenated Krebs' solution at 37 degrees C. Aqueous humor formation (AHF) was measured by the fluorescein-dilution technique. Drugs were added to the perfusate and/or to the anterior chamber.
NaK-adenosine triphosphatase (ATPase) inhibitor, ouabain (1.0 mM), produced a significant reduction in AHF by 46% and 42% when added to the stromal or aqueous side, respectively. When added to both sides (1.0 mM), it produced a reduction of 61%. Bumetanide (0.1 mM), a specific inhibitor of Na-K-2Cl cotransport, and furosemide (0.1 mM), a nonspecific anion transport inhibitor, produced 35% and 45% reductions when applied to the stromal side. DIDS (0.001-0.1 mM), which is believed to inhibit the Cl-HCO(3) exchanger, Na-HCO(3) cotransporter, and chloride channel, produced a dose-dependent reduction when added to the stromal side. The inhibition was 55% by the highest concentration used. 5-Nitro-2-(3-phenylpropylamino)-benzoic acid (NPPB; 0.1 mM), a chloride channel blocker in the nonpigmented cells, produced a 25% reduction when applied to the aqueous side. Acetazolamide (0.1 mM), a carbonic anhydrase inhibitor, applied to the stromal side, produced 31% reduction.
At least 60% of the AH is formed by active secretion in bovine eyes. Transport of anions through the ciliary epithelium (CE), particularly the chloride ion, plays a crucial role in AHF.
通过使用体外灌注眼，研究睫状体上皮主动分泌氯离子在房水形成中的作用。
从屠宰场收集的牛眼经眼动脉插管，并在37℃下用含氧的 Krebs 溶液灌注。采用荧光素稀释技术测量房水生成（AHF）。将药物添加到灌注液和/或前房中。
NaK - 腺苷三磷酸酶（ATPase）抑制剂哇巴因（1.0 mM），当添加到基质侧或房水侧时，分别使AHF显著降低46%和42%。当两侧都添加（1.0 mM）时，降低了61%。布美他尼（0.1 mM），一种Na - K - 2Cl共转运的特异性抑制剂，以及呋塞米（0.1 mM），一种非特异性阴离子转运抑制剂，应用于基质侧时分别使AHF降低35%和45%。二氮嗪（DIDS，0.001 - 0.1 mM），据信可抑制Cl - HCO(3)交换体、Na - HCO(3)共转运体和氯离子通道，添加到基质侧时产生剂量依赖性降低。所用最高浓度时抑制率为55%。5 - 硝基 - 2 -（3 - 苯丙基氨基）苯甲酸（NPPB，0.1 mM），一种非色素细胞中的氯离子通道阻滞剂，应用于房水侧时使AHF降低25%。碳酸酐酶抑制剂乙酰唑胺（0.1 mM）应用于基质侧时使AHF降低31%。
在牛眼中，至少60%的房水由主动分泌形成。阴离子通过睫状体上皮（CE）的转运，特别是氯离子的转运，在AHF中起关键作用。
