REGULATORY MECHANISMS OF VASCULAR CONTRACTION AND CELL PROLIFERATION IN DIABETES MELLITUS

本研究旨在探讨糖尿病血管收缩和细胞增殖调节异常的机制。1.血管平滑肌细胞的增殖：建立了在单细胞水平上测定原代培养的血管平滑肌细胞的细胞周期时相的方法。结果发现：（1）血小板源性生长因子（PDGF）刺激细胞从G_0期进入G_1期不需要胞浆Ca^<2+>瞬变;（2）高糖对G_0期细胞周期无刺激作用，而对PDGF预处理的G_1期细胞周期有刺激作用，使其进入S期和M期，内皮素-1（endothelin-1，ET-1）可使内皮细胞内[Ca^<2+>]i B升高，而细胞内[Ca^<2+>]i无明显升高。2.内皮细胞的钙瞬变 ...更多信息 y既刺激Ca^2+内流又刺激细胞内Ca^2+释放; 2）Ca^2+内流受百日咳毒素敏感性G蛋白调节，而细胞内Ca^2+释放不受其调节。（1）通过RT-PCR和Fura-2显微荧光分析发现，血管紧张素II（AT-II）、蛋白激酶C和蛋白激酶A调节AT-II受体mRNA的表达，并且mRNA水平的增加伴随着生理反应性的增加。(2)用Fura-2荧光法和猪冠状动脉条研究发现，ET-3主要通过细胞外Ca^<2 +>内流增加[Ca^<2 +>]i引起血管收缩，并且在ET-1和ET-3引起的血管收缩反应中，Ca^<2+>敏感性的时间依赖性调节机制不同。(3)It结果发现去甲肾上腺素可引起收缩器的Ca^<2+>敏感性增加，而5-羟色胺对收缩器的Ca^<2+>敏感性几乎没有增强作用。少

The purpose of this research is to investigate the mechanisms of abnormal regulation of vascular contraction and cell proliferation in diabetes mellitus. The following results were obtained :1.CELL PROLIFERATION OF VASCULAR SMOOTH MUSCLE CELLS.I developed the method to determine the phase of the cell cycle of vascular smooth muscle cells in primary culture at the single cell level. It was found that : (1)cytosolic Ca^<2+> transients are not required for platelet-derived growth factor (PDGF) to stimulate the cell cycle progression from the G_0 phase to the G_1 phase ; and (2)high glucose does not stimulate the cell cycle of the G_0 cells, whereas it stimulates the cell cycle of the PDGF-pretreated G_1 cells to the S and M phases, without any increase of cytosolic Ca^<2+> concentration ([Ca^<2+>]i).2.CALCIUM TRANSIENTS OF ENDOTHELIAL CELLS.Using front-surface fluorometry and fura-2-loaded valvular endothelial cells in situ, it was found that : (1)endothelin-1 (ET-1) elevates [Ca^<2+>]i b … More y the stimulation of both Ca^<2+> influx and intracellular Ca^<2+> release ; and 2)the Ca^<2+>influx is regulated by an pertussis toxin-sensitive G-protein, while the release of intracellular Ca^<2+> is not.3.VASCULAR CONTRACTION.(1)Using RT-PCR and fura-2 microfluorometry, it was found that angiotensin II (AT-II), protein kinase C,and protein Kinase A regulate the expression of AT-II receptor mRNA,and the increase in mRNA level is accompanied by an increase in physiological responsiveness. (2) Using fura-2-front-surface fluorometry and porcine coronary arterial strips, it was found that ET-3 induced vasoconstriction by increasing [Ca^<2+>]i mainly through the influx of extracellular Ca^<2+>, and that distinct mechanisms of time-dependent modulation of the Ca^<2+>-sensitivity function in the vasoconstrictor responses to ET-1 and ET-3. (3)It was found that norepinephrine induced increase in the Ca^<2+>-sensitivity of contractile apparatus, while serotonin demonstrates little enhancement of the Ca^<2+>-sensitivity of contractile apparatus. Less