Oren R E, Rasool N A, Rubinstein E H
Stroke. 1987 Mar-Apr;18(2):441-4. doi: 10.1161/01.str.18.2.441.
The effects of intravenous ketamine (1 mg/kg) on cerebral cortical blood flow and O2 uptake were evaluated in 13 anesthetized, ventilated rabbits. Blood flow was measured either directly (Group 1) or by the H2 clearance method (Group 2). In those animals of Groups 1 and 2 with normal control arterial pH (pHa), ketamine produced a significant increase in cerebral cortical blood flow of 18 and 34%, respectively, but had no effect on cerebral cortical O2 uptake. However, in rabbits with low control pHa, ketamine caused an increase in blood flow (30%) accompanied by a significant increase in O2 uptake (22%). Ketamine produced nonsignificant changes in mean arterial blood pressure and arterial blood gases, except for a significant reduction in pressure in animals with low pHa. It is concluded that ketamine is a cerebral vasodilator without cerebral metabolic effect when mean arterial blood pressure and arterial PCO2, PO2, and pH are held constant at physiologic levels. The vasodilator effect of ketamine is probably due to direct dilating action or activation of a cholinergic cerebral vasodilator system.
在13只麻醉通气的兔子身上评估了静脉注射氯胺酮（1毫克/千克）对大脑皮质血流和氧气摄取的影响。血流通过直接测量（第1组）或氢气清除法（第2组）进行测定。在第1组和第2组中动脉pH值（pHa）处于正常对照水平的动物中，氯胺酮分别使大脑皮质血流显著增加了18%和34%，但对大脑皮质氧气摄取没有影响。然而，在对照pHa较低的兔子中，氯胺酮导致血流增加（30%），同时氧气摄取显著增加（22%）。氯胺酮使平均动脉血压和动脉血气发生无显著意义的变化，但在pHa较低的动物中血压有显著降低。得出的结论是，当平均动脉血压以及动脉血二氧化碳分压、氧分压和pH值在生理水平保持恒定时，氯胺酮是一种脑血管扩张剂，对脑代谢无影响。氯胺酮的血管扩张作用可能是由于直接扩张作用或激活了胆碱能脑血管扩张系统。
