Cutcliffe N, Osborne N N
Nuffield Laboratory of Ophthalmology, University of Oxford, U.K.
Brain Res. 1987 Sep 22;421(1-2):95-104. doi: 10.1016/0006-8993(87)91279-0.
A direct assay which involves prelabelling with [3H]inositol has been performed to characterize receptor-mediated breakdown of inositol phospholipids in the rabbit retina. In the presence of 10 mM lithium, the receptor agonists, carbachol and serotonin (5-HT), evoked an increase in the accumulation of tritiated inositol phosphates in a dose-dependent manner. A variety of 5-HT and other antagonists were used to show that at least part of the 5-HT-induced response is mediated by 5-HT2 receptor sites, adding weight to the theory that 5-HT plays a neurotransmitter role in the mammalian retina. The very high rate of carbachol-stimulated inositol phosphate accumulation observed in retinas from young animals (10 days) decreases significantly during development of the rabbit to the adult stage. In contrast 5-HT only induces significant stimulation of inositol phosphate accumulation in retinas of animals matured to at least 17 days. Separation of total accumulated inositol phosphates (after stimulation with both carbachol and 5-HT) showed that the vast majority of tritium label was associated with the monophosphate fraction.
已进行了一项直接测定，该测定涉及用[3H]肌醇进行预标记，以表征兔视网膜中受体介导的肌醇磷脂分解。在10 mM锂存在的情况下，受体激动剂卡巴胆碱和5-羟色胺（5-HT）以剂量依赖的方式引起氚化肌醇磷酸积累增加。使用了多种5-HT和其他拮抗剂来表明，5-HT诱导的反应至少部分是由5-HT2受体位点介导的，这进一步支持了5-HT在哺乳动物视网膜中起神经递质作用的理论。在幼龄动物（10天）的视网膜中观察到的卡巴胆碱刺激的肌醇磷酸积累的非常高的速率在兔子发育到成年阶段的过程中显著降低。相比之下，5-HT仅在至少成熟17天的动物视网膜中诱导肌醇磷酸积累的显著刺激。对总积累的肌醇磷酸（在用卡巴胆碱和5-HT刺激后）进行分离表明，绝大多数氚标记与单磷酸部分相关。
