Skarphedinsson J O, Thorén P
Acta Physiol Scand. 1987 Jan;129(1):27-34. doi: 10.1111/j.1748-1716.1987.tb08036.x.
The purpose of the study was to examine the effects of naloxone on signs of cerebral ischaemia during hypotensive haemorrhage in unanaesthetized spontaneously hypertensive rats. Mean arterial blood pressure (MAP), heart rate (HR) and somatosensory evoked potentials (SEP) were recorded. Arousal tests were also performed and the behavioural responses quantified. The SEP alone were a poor indicator of cerebral function in these unanaesthetized rats, because they were markedly influenced by changes in activity and arousal of the animals. Hypotensive haemorrhage resulted in a biphasic tachycardia response, an attenuation of the first SEP component and a reduction of the behavioural response score. Naloxone, 5 mg kg-1 i.v., induced transient bradycardia and a dramatic improvement in arousal test responses, while SEP were not clearly altered. The MAP was kept constant after naloxone injection by adjustments of bleeding and transfusion. Injection of naloxone in unbled control SHR also induced bradycardia but without any changes in SEP and the behavioural responses. The results indicate that naloxone can have beneficial effects in cerebral ischaemia. Possible mechanisms are discussed.
本研究的目的是检测纳洛酮对未麻醉的自发性高血压大鼠低血压性出血期间脑缺血体征的影响。记录平均动脉血压（MAP）、心率（HR）和体感诱发电位（SEP）。还进行了觉醒测试并对行为反应进行量化。在这些未麻醉的大鼠中，仅SEP并不是脑功能的良好指标，因为它们受到动物活动和觉醒变化的显著影响。低血压性出血导致双相心动过速反应、第一个SEP成分的衰减以及行为反应评分的降低。静脉注射5 mg/kg的纳洛酮可引起短暂性心动过缓，并使觉醒测试反应显著改善，而SEP没有明显改变。注射纳洛酮后，通过调整出血和输血使MAP保持恒定。在未出血的对照自发性高血压大鼠中注射纳洛酮也会引起心动过缓，但SEP和行为反应没有任何变化。结果表明，纳洛酮对脑缺血可能具有有益作用。文中讨论了可能的机制。
