Dohi S, Jones M D, Hudak M L, Traystman R J
Institute of Basic Medical Sciences, University of Tsukuba, Japan.
Stroke. 1990 Dec;21(12):1710-4. doi: 10.1161/01.str.21.12.1710.
We used the closed cranial window technique to observe the responses of pial arterioles to topical application of cocaine in 29 anesthetized cats. Alterations in arteriolar diameter were dependent on the concentration of cocaine applied. Cocaine dissolved in artificial cerebrospinal fluid at concentrations of 10(-8) or 10(-7) M was without effect. Concentrations of 10(-6) and 10(-5) M produced dilation (4.9 +/- 1.5% [mean +/- SEM] and 5.9 +/- 2.0%, respectively) in large arterioles (greater than 100 microns) but no significant change in the diameter of small arterioles (less than 100 microns). A concentration of 10(-4) M dilated both large and small arterioles (20.3 +/- 3.1% and 12.0 +/- 7.1%, respectively). Pretreatment with 1 mg/kg i.v. propranolol blocked the increase in pial arteriolar diameter after application of 10(-4) M cocaine and produced significant vasoconstriction in small arterioles (-8.3 +/- 3.1%). Cocaine produces vasodilation of cat cerebral arterioles. This effect appears to be mediated, at least in part, by mechanisms that depend on stimulation of beta-adrenergic receptors.
我们采用封闭颅窗技术，观察了29只麻醉猫软脑膜小动脉对局部应用可卡因的反应。小动脉直径的改变取决于所应用可卡因的浓度。溶解于人工脑脊液中的10^(-8)或10^(-7) M浓度的可卡因无作用。10^(-6)和10^(-5) M浓度的可卡因使大的小动脉（大于100微米）扩张（分别为4.9±1.5%[平均值±标准误]和5.9±2.0%），但对小的小动脉（小于100微米）直径无显著影响。10^(-4) M浓度的可卡因使大、小动脉均扩张（分别为20.3±3.1%和12.0±7.1%）。静脉注射1 mg/kg普萘洛尔预处理可阻断应用10^(-4) M可卡因后软脑膜小动脉直径的增加，并使小动脉产生显著的血管收缩（-8.3±3.1%）。可卡因可使猫脑小动脉扩张。这种作用似乎至少部分是由依赖于β-肾上腺素能受体刺激的机制介导的。
