PHOSPHATIDYL INOSITOL, PROSTAGLANDINS, AND EXCITATION

本提案的总体目标是阐明生理学 磷脂酰肌醇的意义及其生化机制 (PI)磷脂酸循环在不同的测试系统。 最初三 模型系统-胰腺外分泌对蓝斑、大脑皮层 和胰岛对乙酰胆碱（ACh）的反应， 高血糖-将用于检验假设的一般有效性 PI分解是前列腺素（PG）发生器，其反过来 调节激动剂诱发的反应。 我们也会详细研究 在这些系统中PI效应的生物化学方面。 基本技术 将用[14 C]花生四烯酸（AA）预标记，优选在 刺激条件下，用白蛋白猝灭， 第一激动剂（或洗涤），最后与第二激动剂孵育 (or洗涤后的第一激动剂）。 放射性的变化 的磷脂，中性脂质和PG将被确定（超过95%）。 回收的总脂质放射性）和编制的资产负债表。 在 这样，放射性从PI流向其它脂质和/或PG， 被确定。 磷脂酶C和磷脂酶A的贡献 将确定AA及其代谢物的释放途径。 的 阿司匹林样药物对胰岛素分泌的假定刺激将是 研究了 初步证明甘油三酯（TG）显示 用ACh刺激大脑皮层切片时AA大量释放， 与PGF 2 α形成的显著增加相关-将是 进一步研究。 胰岛素分泌可能的负反馈， PG和阿司匹林样药物对这种负反馈的阻断可能是 2型糖尿病的治疗方法有哪些 对大脑皮层的研究可能会揭示阿尔茨海默病， 脑皮质ACh缺乏。 由于刺激的PGE 2形成 来自PI通过导管扩张增加胰腺外分泌， 这些研究可能对急性胰腺炎有意义。

The overall aim in this proposal is to elucidate both the physiological significance and the biochemical mechanism of the phosphatidyl inositol (PI) phosphatidic acid cycle in different test systems. Initially three model systems-the exocrine pancreas in response to caeruleim, brain cortex in response to acetylcholine (ACh), and pancreatic islets in response to high glucose - will be used to test the general validity of the hypothesis that PI breakdown is a prostaglandin (PG) generator, which in turn modulates agonist-evoked responses. We will also study in detail biochemical aspects of the PI effect in these systems. The basic technique will be prelabelling with [14C]arachidonic acid (AA), preferably under stimulating conditions, quenching with albumin and an antagonist of the first agonist (or washing), and finally incubating with a second agonist (or the first agonist after washing). The changes in radioactivity in all of the phospholipids, neutral lipids, and PGs will be determined (over 95% of total lipid radioactivity recovered) and a balance sheet drawn up. In this way, the flow of radioactivity from PI to other lipids and/or PGs can be determined. The contribution of phospholipase C and phospholipase A pathways to the release of AA and its metabolites will be determined. The putative stimulation of insulin secretion by aspirin-like drugs will be studied. The preliminary demonstration that triglyceride (TG) shows a massive release of AA on stimulation of brain cortex slices with ACh - associated with a marked increase in the formation of PGF2Alpha - will be further studied. The possible negative feedback of insulin secretion by PGs and the blockade of this negative feedback by aspirin-like drugs may be important in our understanding and treatment of Type II diabetes mellitus. Studies in brain cortex may throw light on Alzheimer's disease, which shows deficiency of ACh in brain cortex. Since the stimulated PGE2 formation from PI augments secretion in the exocrine pancreas by dilation of ducts, these studies may have implications for acute pancreatitis.