Sparks D L, Thomas T N, Buckholtz N S
Neurosci Lett. 1981 Jan 20;21(2):201-6. doi: 10.1016/0304-3940(81)90382-7.
The activities of monoamine oxidase (MAO)-A and -B in subcellular fractions of bovine retina were determined using serotonin and beta-phenylethylamine, respectively, as substrates. The subcellular fractions were a P1 fraction containing photoreceptor cell synaptosomes and a P2 fraction enriched with small synaptosomes derived from the inner plexiform layer. MAO activities in the homogenate and P1 fraction were similar and lower than those in the P2 fraction for both MAO-A and -B. The activity of MAO-B was greater than that of MAO-A in all fractions, but the relative distribution of MAO-A and -B did not change in the different fractions. Studies using various MAO inhibitors showed effects which were generally similar to those seen in brain. These results provide further support for the localization of terminals of retinal monamine-containing neurons to the inner plexiform layer and suggest that pharmacological modification of MAO activity in the retina could play an important role in retinal function via changes in monoamine metabolism.
分别以血清素和β-苯乙胺为底物，测定了牛视网膜亚细胞组分中单胺氧化酶（MAO）-A和-B的活性。亚细胞组分包括一个含有光感受器细胞突触体的P1组分和一个富含源自内网状层的小突触体的P2组分。对于MAO-A和-B，匀浆和P1组分中的MAO活性相似且低于P2组分中的活性。在所有组分中，MAO-B的活性均大于MAO-A，但MAO-A和-B在不同组分中的相对分布没有变化。使用各种MAO抑制剂的研究显示出的效应通常与在脑中观察到的效应相似。这些结果进一步支持了含视网膜单胺神经元的终末定位于内网状层的观点，并表明通过单胺代谢的变化，视网膜中MAO活性的药理学修饰可能在视网膜功能中发挥重要作用。
