ENDOTHELIN EFFECTS ON RETINAL CELLS AND BLOOD FLOW

内皮素对视网膜细胞和血流的影响

• 批准号: 2162816
• 负责人: GEORGE L KING
• 金额: $ 26.43万
• 依托单位: JOSLIN DIABETES CENTER
• 依托单位国家: 美国
• 财政年份: 1992
• 资助国家: 美国
• 起止时间: 1992-01-01 至 1996-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2162816
• 关键词: angiotensin II; aorta; blood flow measurement; blood glucose; cardiovascular disorder; diabetes mellitus; diabetic retinopathy; diacylglycerols; endothelin; fluorescein angiography; gene expression; hormone receptor; hormone regulation /control mechanism; inositol phosphates; insulin; laboratory rat; macrophage; molecular cloning; phorbols; protein kinase C; protein purification; protein sequence; receptor expression; retina circulation; vascular endothelium; video recording system; vitreous body

The mechanisms by which hormones regulate retinal vascular circulation are not clear. Recently, a new and potent vasoactive hormone, endothelin, has been described and sequenced from vascular endothelial cells. The endothelin (ET) family consists of at least three hormones which have a vasoconstrictive effect on vascular smooth muscle cells. Recently, evidence has indicated that ET probably has a role in regulating retinal circulation since it has been identified in the retina and retinal vascular cells. Since retinal capillary cells have high affinity and specific receptor for ET-1, ET injected into rabbit vitreous was shown to induce vasoconstriction of retinal vessels. We have recently shown that the expression of ET-1 mRNA is regulated by insulin via its own receptor through a novel mechanism. In addition, we have shown that retinal pericytes have ET-1 receptors of 95 and 65 kD whereas smooth muscle cells only have the 60 kD receptor. Lastly, using image analysis of video fluorescein angiogram, the intravitreal bolus injection of 1 x 10 19 M of ET-1 induced vasoconstriction of retinal arteries and arterioles and increased retinal circulation times for as long as 20 min after infusion. We are proposing to study the following three Specific Aims: la) to determine the regulation of ET-1 in retinal and aortic endothelial cells by insulin at the DNA level; b) to characterize the role of high glucose level and protein kinase C in regulating ET-1 expression; c) to correlate the expression of ET-1 in the retina, aorta and kidney with vascular abnormalities in diabetic rats. 2a) To characterize, purify and sequence the receptors of ET-1 in retinal pericytes; b) to determine the biological effects of ET-1 in pericytes on the stimulation or activation of diacylglycerol, IP3, protein kinase C and calponin. 3) To evaluate the physiological actions of ET on retinal circulation in diabetic and non-diabetic rats. From these studies, we will be able to understand ET's expression and mode of action at the genetic, biochemical, cellular and physiological levels with special focus on its role in the development of retinal vascular dysfunctions in diabetes.

激素调节视网膜血管循环的机制是 不清楚。 最近，一种新的，有效的血管活性激素Endophelin具有 描述并从血管内皮细胞进行了测序。 这 内皮素（ET）家族至少由三种激素组成 血管收缩对血管平滑肌细胞的作用。 最近， 证据表明，ET可能在调节视网膜中起作用 循环由于已在视网膜和视网膜血管中鉴定出来 细胞。 由于视网膜毛细血管细胞具有高亲和力和特异性 ET-1的受体注射到兔玻璃体中诱导 视网膜血管的血管收缩。 我们最近表明 ET-1 mRNA的表达通过胰岛素通过其自身受体调节 通过一种新颖的机制。 此外，我们已经表明了视网膜 周细胞的ET-1受体为95和65 kD，而平滑肌细胞 只有60 kD受体。 最后，使用视频的图像分析 荧光素血管造影，玻璃体内注射1 x 10 19 m的 ET-1诱导视网膜和动脉的血管收缩以及 输注后长达20分钟的视网膜循环时间增加。 我们建议研究以下三个具体目标：la） 确定视网膜和主动脉内皮细胞中ET-1的调节 DNA水平的胰岛素； b）表征高葡萄糖水平的作用 和蛋白激酶C在调节ET-1表达中； c）关联 ET-1在视网膜，主动脉和肾脏中的表达 糖尿病大鼠异常。 2a）要表征，纯化和序列 视网膜周细胞中ET-1的受体； b）确定生物学 ET-1在周细胞中对刺激或激活的影响 二酰基甘油，IP3，蛋白激酶C和钙蛋白酶。 3）评估 ET对糖尿病和视网膜循环的生理作用 非糖尿病大鼠。 从这些研究中，我们将能够理解ET的 在遗传，生化，细胞和遗传上的作用方式 生理水平特别关注其在发展中的作用 糖尿病中的视网膜血管功能障碍。