去甲肾上腺素促使血管平滑肌细胞内三磷酸肌醇含量的增加

Increase in inositol trisphosphate levels in norepinephrine-stimulated vascular smooth muscle cells

研究去甲肾上腺素（ＮＥ）对自发性高血压大鼠（ＳＨＲ）的主动脉血管平滑肌细胞（ＶＳＭＣｓ）内三磷酸肌醇（ＩｎｓＰ３）含量的影响，并与对照组京都威斯特大鼠（ＷＫＹ）相比较。结果显示，在基础状态下ＳＨＲ和ＷＫＹ的ＶＳＭＣｓ内ＩｎｓＰ３含量无明显差异。ＮＥ作用下，ＷＫＹ的ＶＳＭＣｓ内ＩｎｓＰ３值迅速增加，１０秒钟内即达高峰，而ＳＨＲ的ＶＳＭＣｓ内ＩｎｓＰ３的增加呈双相性，除快相峰值明显大于ＷＫＹ外，慢相峰值也显著大于对照组，并且ＩｎｓＰ３值增高后持续时间延长。ＧＴＰγＳ激活Ｇ蛋白后，ＳＨＲ的ＶＳＭＣｓ内ＩｎｓＰ３的增量显著大于ＷＫＹ。提示，ＳＨＲ的ＶＳＭＣｓ内α１肾上腺素受体－肌醇磷脂途径对激活剂的反应性过高，这一途径的一些成份数目、结构或功能可能存在着某些变异。

Effects of norepinephrine on levels of inositol-1,4,5-trisphosphate(InsP3)were studied in cultured vascular smooth muscle cells(VSMCs)from spontaneously hypertensive rats(SHR)and Wistar Kyoto rats(WKY).Under basal condition,there was no significant difference in InsP3 levels between VSMCs from SHR and that from WKY.InsP3 in VSMCs from WKY increased significantly within 10s of 10-5mol/L norepinephrine stimulation.A rapid biphasic InsP3 response,which were significantly higher than that of WKY,in VSMCs from SHR had beenobserved after norepinephrine stimulation.G proteins activated by GTPγS significantly raise InsP3 prodrction in VSMCs from SHR comparing to WKY.These results implied that there is a highly sensitive response in α1-adrenergic receptor,phosphoinositide turnover in VSMCs from SHR after agonist stimulation,and it is possible that number,substructure or funbtion of some components in this turnover were altered in SHR.