Transmembrane Signaling

本项目旨在阐明从膜受体到生理细胞反应的信号转导途径。第一年（1989）：我们研究肌肉细胞的信号转导通路。(1)研究了lyotonin在平滑肌收缩中的作用。(2)研究了肌醇代谢物在骨骼肌钙瞬变中的作用。(3)对牛蛙骨骼肌Ca瞬态进行Fura-2可视化。咖啡因刺激钙释放的阈值测量为1-2 mm。第二年（1990）：研究外分泌腺和抗通道药物。(1)在结肠杯状细胞中，冈田酸阻断了毒蕈碱刺激引起的分泌和Ca反应的后期。因此，毒蕈碱受体的磷酸化介导了这些细胞反应的脱敏。(2) DIC显微镜下观察到兔兔唾液腺分泌反应清晰。水的分泌表现为顶膜的周期性运动。毒蕈碱类兴奋剂和三磷酸腺苷是有效的，而β类兴奋剂在诱导舌下腺分泌反应方面没有作用。(3) Toosendainine对NG108细胞Ca通道活性有抑制作用。(4)从蝎子毒液中纯化出一种能特异性阻断昆虫钠离子通道的神经毒素。第三年（1991）：研究了大涎腺的刺激-分泌偶联和视网膜水平细胞的谷氨酸反应。(1)多种蛋白激酶C激活剂和k去极化剂均不能有效诱导唾液腺分泌反应。这表明唾液腺的跨膜信号是由a激酶和c激酶以外的第二信使系统介导的。(2)在水平细胞中研究kinate诱导电流。多巴胺以剂量依赖的方式调节动蛋白电流。氟哌啶醇抑制了多巴胺对运动电流的影响。这些调节作用被认为是由cGMP信使系统的改变引起的。少

This project aimed at elucidation of signal transduction pathway from membrane receptors to physiological cellular responses.1. First Year (1989) : We studied signal transduction pathway in muscle cells.(1) Involvement of lyotonin in contraction of smooth muscles was studied.(2) Involvement of inositol metabolites in Ca transients in skeletal muscles was studied.(3) Fura-2 visualization of Ca transients in bull-frog skeletal muscles was done.The threshold for caffeine stimulation for Ca release was measured to be 1-2 mM.2. Second Year (1990) : We studied exocrine glands and anti-channel drugs.(1) In colonic goblet cells, okadaic acid blocked the late part of the secretory and Ca responses induced by muscarinic stimulation. Thus, phosphorylation of muscarinic receptors mediates desensitization of these cellular responses.(2) Exocytotic responses in salivary gland of tupai were clearly detected by DIC microscopy. Water secretion was visualized as periodical movements of the apical membra … More ne of acinar cells. Muscarinic stimulants and ATP were effective but BETA stimulants were not in inducing secretory responses in the sublingual gland.(3) Toosendainine was found to suppress the Ca channel activity in NG108 cells.(4) A neurotoxin that specifically blocks the Na channel in insects was purified from the scorpion venom.3. Third Year (1991) : Stimulation-secretion coupling in tupai salivary gland and glutamate responses in retinal horizontal cells were studied.(1) Either various activators of protein kinase C nor K-depolarization were not effective in inducing secretory response in the salivary gland. These suggested that transmembrane signaling in salivary gland is mediated by a 2nd messenger system other than A-kinase and C-kinase systems.(2) Kinate-induced currents were studied in horizontal cells. Dopamine modulated the kinate current in a dose-dependent manner. Haroperidol suppressed the effect of dopamine on the kinate current. These modulatory effects are thought to arise from alteration of cGMP messenger system. Less