Proia A D, Chung S M, Klintworth G K, Lapetina E G
Invest Ophthalmol Vis Sci. 1986 Jun;27(6):905-8.
The cornea has one of the highest acetylcholine (ACh) concentrations of any tissue but the function of the ACh has remained enigmatic. During studies on corneal arachidonic acid metabolism, we observed that ACh stimulates formation of labeled phosphatidic acid in rat corneas whose phospholipids were prelabeled with [14C]arachidonate. ACh did not affect the metabolism of free [14C]arachidonate. [14C]Arachidonyl-phosphatidic acid formation was doubled after 10 min of incubation in the presence of ACh concentrations of 10(-4) M or greater. The stimulation by ACh could be completely blocked by atropine and scopolamine and partially blocked by d-tubocurarine. These studies suggest that intact rat cornea has muscarinic cholinergic receptors and that the enzymes of the inositol phospholipids pathway are present since phosphatidic acid is an obligatory intermediate in that cycle of reactions.
角膜是所有组织中乙酰胆碱（ACh）浓度最高的组织之一，但其功能一直成谜。在对角膜花生四烯酸代谢的研究中，我们观察到，在磷脂已用[14C]花生四烯酸盐预标记的大鼠角膜中，ACh会刺激标记磷脂酸的形成。ACh并不影响游离[14C]花生四烯酸的代谢。在10(-4)M或更高浓度的ACh存在下孵育10分钟后，[14C]花生四烯酰磷脂酸的形成增加了一倍。ACh的刺激作用可被阿托品和东莨菪碱完全阻断，被d-筒箭毒碱部分阻断。这些研究表明，完整的大鼠角膜具有毒蕈碱型胆碱能受体，并且存在肌醇磷脂途径的酶，因为磷脂酸是该反应循环中的一个必需中间体。
