The sequential change of local cerebral blood flow and local cerebral glucose metabolism after focal cerebral ischaemia and reperfusion in rat and the effect of MK-801 on local cerebral glucose metabolism

In order to investigate the time course change of local cerebral blood flow (1CBF) and local cerebral glucose metabolism (1CGM) and the effect of MK-801 (dizocilpine), an NMDA receptor antagonist on glucose metabolism in a middle cerebral artery occlusion-reperfusion model,14C-Iodo-antipyrine and14C-Deoxyglucose autoradiographic method have been used. The 1CBF was reduced to 0–10% of the control level in the ischaemic core and to 12–40% in the ischaemic penumbra between 60 and 120 min after the onset of the ischaemia. In the ischaemic core, the marked hyperfusion appeared at 15 min and maintained about 30 to 45 min following reperfusion. In the ischaemic penumbra, the hyperfusion during reperfusion was not found. Hypermetabolism occurred at 30 min and reached to the peak at 60 min after the middle cerebral artery (MCA) occlusion both in the ischaemic core and in the penumbra. The shift from hyper- to hypometabolism was observed during the ischaemia. The reperfusion following 2 hours of MCA occlusion facilitated the decrease of cerebral glucose metabolism in the ischaemic region. The pretreatment of MK-801 (0.4 mg/kg) inhibited both increased glucose metabolism during the ischaemia and decreased glucose metabolism during the reperfusion. The effect of limiting decreased glucose metabolism during the reperfusion by MK-801 was remarkable in the ischaemic penumbra. These findings support the hypothesis that excitation-induced hypermetabolism play a major role in the ischaemic insult following focal cerebral vascular occlusion.