Bertuglia S, Colantuoni A
CNR Institute of Clinical Physiology, University of Pisa, Italy.
J Vasc Res. 1998 Jul-Aug;35(4):250-6. doi: 10.1159/000025591.
We investigated the effects of tyrosine kinase (TK) and nitric oxide synthase (NOS) inhibition on insulin-induced dilation of arterioles. We determined the arteriolar diameter, red blood cell velocity (VRBC) and blood flow changes in hamster cheek pouch microcirculation as affected by insulin in presence of TK and NOS inhibitors, genistein, piceatannol and NG-monomethyl-L-arginine (L-NMMA). Microvessels were visualized by a fluorescent microscopy technique. Arteriolar diameter and VRBC were measured after topical application of insulin and genistein or piceatannol or L-NMMA. Insulin (10 microU/ml) induced diameter and VRBC increase in A3 and A2 arterioles by 30 +/- 5 and 123 +/- 4%, 16 +/- 4 and 102 +/- 3%, as percent of baseline values, respectively. After genistein or piceatannol prior to insulin A3 and A2 arterioles dilated by 10 +/- 4, 5 +/- 2% and 9 +/- 4, 2 +/- 1%, respectively. After L-NMMA prior to insulin A2 and A3, arteriole diameters increased by 12 +/- 3 and 7 +/- 2%, respectively. VRBC increased significantly in all the cases. TK and NOS inhibitors applied together abolished insulin-induced dilation with a reduction in VRBC and blood flow. In conclusion, full insulin-induced dilation of hamster cheek pouch arterioles requires TK signaling pathways. Furthermore, activation of insulin receptors, as well as other TK receptors, appears to be required for vasomotor tone regulation.
我们研究了酪氨酸激酶（TK）和一氧化氮合酶（NOS）抑制对胰岛素诱导的小动脉扩张的影响。我们测定了在存在TK和NOS抑制剂染料木黄酮、 白藜芦醇和NG-单甲基-L-精氨酸（L-NMMA）的情况下，胰岛素对仓鼠颊囊微循环中小动脉直径、红细胞速度（VRBC）和血流变化的影响。通过荧光显微镜技术观察微血管。在局部应用胰岛素以及染料木黄酮、白藜芦醇或L-NMMA后，测量小动脉直径和VRBC。胰岛素（10微单位/毫升）使A3和A2小动脉的直径和VRBC分别增加，相对于基线值的百分比分别为30±5%和123±4%、16±4%和102±3%。在胰岛素之前应用染料木黄酮或白藜芦醇后，A3和A2小动脉分别扩张了10±4%、5±2%和9±4%、2±1%。在胰岛素之前应用L-NMMA后，A2和A3小动脉直径分别增加了12±3%和7±2%。在所有情况下VRBC均显著增加。同时应用TK和NOS抑制剂可消除胰岛素诱导的扩张，并使VRBC和血流减少。总之，胰岛素诱导的仓鼠颊囊小动脉完全扩张需要TK信号通路。此外，血管舒缩张力调节似乎需要胰岛素受体以及其他TK受体的激活。
