Studies on Effects of Analgesics in the Central Nervous System Using the Technique of Metabolic Mapping.

结果与讨论1.静脉注射吗啡10 mg/kg后，测定大鼠脑和脊髓局部葡萄糖利用率。与清醒大鼠的葡萄糖利用相比，给予吗啡后，只有5个结构的代谢受到抑制。腰髓脚间核、蓝斑、油上核、外侧白质和腹侧白质的葡萄糖利用率下降17-24%。在中脑导水管周围灰质、中缝核、巨细胞网状核、旁巨细胞核和脊髓灰质各层等结构中，葡萄糖的利用没有改变。2.大鼠静脉注射吗啡10 mg/kg后，对肢体疼痛等伤害性刺激无反应，电刺激坐骨神经可引起大脑皮层后肢投影区代谢激活。在深度安氟醚麻醉期间，未观察到皮质的这种代谢反应。3.测量腰部硬膜外注射吗啡后，脊髓局部葡萄糖利用率的变化。与清醒大鼠相比，硬膜外吗啡对脊髓任何区域的葡萄糖利用均无影响。

Effects of analgesics in the central nervous system were studied in rats, using the technique of metabolic mapping.Results and Discussion1.Local glucose utilization in the brain and spinal cord was measured after intravenous administration of morphine, 10mg/kg. Compared with glucose utilization in awake rats, metabolism was depressed after morphine administration in the following only 5 of 62 structures studied. Glucose utilization in the interpeduncular nucleus, locus coeruleus, superior oilive nucleus and lateral and ventral white matter in the lumbar spinal cord was decreased by 17-24%. In other structures including periaqueductal gray matter, raphe nuclei, giantocellular reticular nucleus, paragiantocellular nucleus and all layers in the spinal gray matter, glucose utilization remained unchanged.2.Althogh rats showed no responses to noxious stimuli such as pinch of extremities after intravenous administration of morphine, 10mg/kg, electrical stimulation of sciatic nerve induced metabolic activation in the hindlimb projection area in the cerebral cortex. Such metabolic response in the cortex was not observed during deep enflurane anesthesia.3.The local glucose utilization in the spinal cord was measured after epidural administraion of morphine in the lumbar region, which induced analgesia in lower extremities. Epidural morphine does not affect the glucose utilization in any areas of spinal cord compared with that observed in awake rats.