Takayasu M, Dacey R G
Division of Neurological Surgery, University of North Carolina, Chapel Hill 27599-7060.
Stroke. 1989 Jun;20(6):778-82. doi: 10.1161/01.str.20.6.778.
The purpose of our study was to determine in rats the dependence of constrictor responses of intracerebral (parenchymal) penetrating arterioles on extracellular calcium. Vessel diameter was monitored in vitro, after spontaneous tone had developed. When the organ bat solution was changed from a physiological solution to a Ca2+-free one containing 0.5 mM EGTA, these vessels showed rapid and marked vasodilation to a mean +/- SEM of 159.8 +/- 8.2% of control (p = 0.018). After 3 minutes of pretreatment with Ca2+-free solution, constrictor responses to solutions of 140 mM KCl, pH 8.0, or 10(-4) M prostaglandin F2 alpha, were completely abolished, except for small transient contractions with the latter (6.6 +/- 1.8%). When vasoconstrictors were applied simultaneously with the Ca2+-free solution, all vessels still dilated to 159.8 +/- 8.4% (KCl), 146.7 +/- 6.1% (pH 8.0), and 124.3 +/- 9.1% (prostaglandin 2 alpha) of control (p = 0.018). Our results suggest that both vasomotor tone and constrictor responses in intracerebral arterioles are highly dependent upon activation from an extracellular calcium source.
我们研究的目的是确定大鼠脑内（实质）穿透性小动脉的收缩反应对细胞外钙的依赖性。在自发张力形成后，于体外监测血管直径。当器官浴液从生理溶液更换为含0.5 mM乙二醇双四乙酸（EGTA）的无钙溶液时，这些血管迅速且显著地舒张，达到对照值的平均±标准误为159.8±8.2%（p = 0.018）。在用无钙溶液预处理3分钟后，对140 mM氯化钾溶液（pH 8.0）或10⁻⁴ M前列腺素F2α溶液的收缩反应完全消失，不过对后者有小的短暂收缩（6.6±1.8%）。当血管收缩剂与无钙溶液同时应用时，所有血管仍舒张至对照值的159.8±8.4%（氯化钾）、146.7±6.1%（pH 8.0）和124.3±9.1%（前列腺素2α）（p = 0.018）。我们的结果表明，脑内小动脉的血管运动张力和收缩反应都高度依赖于细胞外钙源的激活。
