不同年龄大鼠血管反应性及磷酸肌醇代谢的比较

本实验采用3H-肌醇掺入、阴离子交换层析分离法及生物测定法比较了不同年龄大鼠主动脉平滑肌细胞胞浆中的肌醇含量变化以及在有或无Ca2 的Kreb’s液中苯肾上腺素（phenylephrine，PE）的量效曲线。结果表明：（1）两种年龄大鼠主动脉中的磷酸肌醇均以IP为主，约占总磷酸肌醇的67％-83％。在静息状态和PE激活状态下，老龄大鼠主动脉中IP、IP2和IP3含量均明显高于年轻大鼠（P＜0．05）。（2）在两种Kreys液中，对PE的量效曲线在老龄鼠均明显右移。提示血管平滑肌磷酸肌醇的代谢途径和方式与大鼠年龄密切相关，老龄鼠磷酸肌醇代谢明显活跃，血管反应性明显降低。

Contents of Inositol Phosphates and Response to Phenylephrine in Aorta from Both Young and Old Rats

The changes of contents of inositol phosphates in Phenylephrine stimulated contractionof aorta from both 3 month and 20 month Wistar rats were studied by means of Bioassaymethod, and L3H]-myo-inositol labelling, ion exchage chromatography. The results wereas follows: (1) In both resting and PE-activated arteries, IP took the greatest part (67%~83% ) in total amount of inositol phosphates and the contents of IP, IP, and IP, were signifi-cantly higher in 20 month rat aorta than that in 3 month rat. (2) There is an age-related re-duction in aortic contraction in Ca2 -free buffer and Ca2 -containing buffer. These resultssuggest that there is an age-related difference in IP metabolism pattern and pathway, andthat IP metabolism in old rat is obviously active, but the Vascular response is apparentlylow.