Riley M V, Kishida K
Exp Eye Res. 1986 Jun;42(6):559-68. doi: 10.1016/0014-4835(86)90046-1.
The distribution of ion-stimulated ATPases of the ciliary epithelium has been examined in tissues from bovine and rabbit eyes. In homogenates of tissues from both species, both Na,K- and anion-stimulated enzyme activities were found, but no K,H-stimulated activity was detected. The anion ATPase had a broad specificity for a number of anions, and was strongly inhibited by thiocyanate. Following separation of pigmented (outer) and non-pigmented (inner) layers of the bovine ciliary epithelium and isolation of the two cell types on density gradients, higher activities of both Na,K- and anion ATPases were found in the non-pigmented cells. Subcellular fractionation of a mixed population of cells showed that the anion ATPase was almost exclusively associated with a mitochondrial fraction, rather than with the plasma-membrane fraction containing the Na,K-ATPase. These results confirm histochemical studies of the distribution of Na,K-ATPase in the ciliary epithelium and support the concept that the inner, non-pigmented cell layer is chiefly responsible for the active transport of ions into the posterior chamber. It is concluded that this transepithelial transport can be driven only by the energy derived via the Na,K-ATPase, and that any subsequent anion or proton transport in the formation of aqueous humor is driven by the sodium gradient through exchange mechanisms.
已经对牛和兔眼组织中睫状上皮的离子刺激ATP酶的分布进行了研究。在这两个物种组织的匀浆中，均发现了钠钾刺激和阴离子刺激的酶活性，但未检测到钾氢刺激的活性。阴离子ATP酶对多种阴离子具有广泛的特异性，并受到硫氰酸盐的强烈抑制。在分离牛睫状上皮的色素层（外层）和非色素层（内层）并通过密度梯度分离这两种细胞类型后，发现非色素细胞中钠钾ATP酶和阴离子ATP酶的活性均较高。对混合细胞群体进行亚细胞分级分离显示，阴离子ATP酶几乎完全与线粒体部分相关，而不是与含有钠钾ATP酶的质膜部分相关。这些结果证实了睫状上皮中钠钾ATP酶分布的组织化学研究，并支持了内层非色素细胞层主要负责将离子主动转运到后房的观点。得出的结论是，这种跨上皮运输只能由通过钠钾ATP酶产生的能量驱动，并且在房水形成过程中任何随后的阴离子或质子运输都是由通过交换机制的钠梯度驱动的。
