Ding L H, Xi G H, Ding D Y, Yu B, Zhou J F, Wu M
Institute of Clinical Pharmacology, Second Hospital of Zhejiang Medical University, Hangzhou, China.
Zhongguo Yao Li Xue Bao. 1991 Jul;12(4):312-5.
The effects of naloxone on local tissue oxygen partial pressure (pO2) and on the somatosensory evoked potentials (SEP) were studied in the brain of cat during focal cerebral ischemia. Ischemia, produced by clamping of the middle cerebral artery (MCA) by a transorbital approach, was performed in two series of cats for 3 h. In one group of cats (n = 5), naloxone 5 mg.kg-1 was injected i.v. 0.5 h after clamping. The pO2 was continuously recorded on different depths (0-5000 microns) of the median gyrus by a polarographic oxygen microelectrode. After MCA clamping, pO2 (depth of 0-1000 microns) decreased markedly and hypoxia occurred in the ischemic area. But in the deeper brain (1001-5000 microns) pO2 did not change significantly. The amplitude of SEP decreased after MCA clamping, while the conduction time of SEP did not significantly decrease. The mean pO2 values in the ischemic area were increased as compared to the control group after naloxone, especially at the depths of 0-1000 microns, and the hypoxia was improved. The amplitude of SEP was increased after naloxone in comparison to the situation of ischemia without naloxone. The conduction time of SEP was not improved significantly. We conclude that naloxone can improve the oxygen supply and the electrical activity of neurons in the ischemic region of the brain.
在猫脑局灶性脑缺血期间，研究了纳洛酮对局部组织氧分压（pO₂）和体感诱发电位（SEP）的影响。采用经眶入路夹闭大脑中动脉（MCA）造成缺血，分两组猫进行，每组缺血3小时。在一组猫（n = 5）中，夹闭MCA 0.5小时后静脉注射5 mg·kg⁻¹纳洛酮。用极谱氧微电极连续记录中央回不同深度（0 - 5000微米）的pO₂。夹闭MCA后，缺血区0 - 1000微米深度处的pO₂明显下降，出现缺氧，但脑深部（1001 - 5000微米）的pO₂无明显变化。夹闭MCA后SEP波幅下降，而SEP传导时间无明显下降。与对照组相比，纳洛酮处理后缺血区的平均pO₂值升高，尤其是在0 - 1000微米深度处，缺氧情况得到改善。与未用纳洛酮的缺血情况相比，纳洛酮处理后SEP波幅升高，SEP传导时间无明显改善。我们得出结论，纳洛酮可改善脑缺血区的氧供应和神经元的电活动。
