MECHANISMS OF HORMONE AND TRANSMITTER SECRETION

我们的工作继续集中在导致融合的过程中 细胞胞吐过程中的颗粒和质膜，包括 嗜铬细胞、胰岛β细胞、神经末梢和 人结肠癌细胞分泌粘蛋白。接触与聚变事件 胞吐过程中可能受蛋白质联结蛋白的控制。我们有 最近通过蛋白质克隆并对此进行了cdna测序，并了解到 它是膜联蛋白基因家族的成员。我们已经表达了Synexin 在大肠杆菌中发现了表达这两种融合蛋白的重组蛋白 和频道属性。分泌机制也已在 完整的嗜铬细胞，在其中已发现证据支持 钙和钡通过不同的机制促进分泌的概念。 嗜铬细胞中的乙酰胆碱受体被发现是 不同于经典的尼古丁受体，因为它有 意想不到的毒枭角色。一种新的钙通道被发现 在人类β细胞中发现，它对葡萄糖和相关的 代谢物。这个通道被我们命名为“G型”钙通道， 可能在胰岛的葡萄糖活化中起核心作用。葡萄糖诱导 胰岛素的释放受乙酰胆碱的调节，药理分析 提示M受体类型为M1，而不是M2。这个 肾上腺髓质瘤为研究这种相互作用提供了一个易于处理的系统。 在内分泌细胞和贴壁毛细血管之间。内皮细胞有 MAO-A和各种类固醇影响该酶的表达， 而不影响仅存在于嗜铬细胞中的MAO-B。 库仑法测定抗坏血酸的新方法 电化学检测已经发展起来。该方法允许 维生素的测量，不仅在细胞中，如白细胞和 嗜铬细胞，还有人的血浆。两种抗坏血酸转运蛋白 在人类中性粒细胞中检测到了酸。毫摩尔浓度 在两个人的中性粒细胞中都检测到了游离的抗坏血酸。 和单核细胞。

Our work continues to focus on the processes leading to fusion between granule and plasma membranes during exocytosis in cells, including chromaffin cells, beta cells from islet of Langerhans, nerve terminals, and mucin secreting human colon carcinoma cells. The contact and fusion event during exocytosis may be controlled by the protein synexin. We have recently cloned and sequenced the cDNA for this by the protein, and learned that it is a member of the annexin gene family. We have expressed synexin in E. coli and have found the recombinant protein to express both fusion and channel properties. Secretion mechanisms have also been studied in intact chromaffin cells, in which evidence has been found to support the concept that calcium and barium promote secretion by separate mechanisms. The acetycholine receptor in chromaffin cells has been found to be different from the classical nicotinic receptor, inasmuch as it has unexpected muscarinic character. A novel calcium channel has been discovered in human beta cells, which responds to glucose and related metabolites. This channel is named by us the "G-type" calcium channel, and may play a central role in glucose activation if islets. Glucose induced insulin release is modulated by acetylcholine, and pharmacological analysis reveals that the muscarinic receptor type is M1 rather than M2. The adrenal medullas has provided a tractable system to study the interaction between endocrine cells and adherent capillaries. Endothelial cells have MAO-A, exclusively, and various steroids affect expression of this enzyme, without affecting the MAO-B which is exclusively found in chromaffin cells. A new method for measuring ascorbic acid using HPLC and coulometric electrochemical detection has been developed. The method allows measurement of the vitamin, not only in cells such as leucocytes and chromaffin cells, but also human plasma. Two transporters for ascorbic acid have been detected in human neutrophils. Millimolar concentrations of ascorbic acid have been detected in unbound form in both human neutrophils and monocytes.