Glutamate transport across blood brain barrier after transient global ischemia/reperfusion in rats / 中国病理生理杂志

ABSTRACT

AIM: To study the change of glutamate (Glu) transport across blood brain barrier ( BBB ) in rat following forebrain ischemia/reperfusion. METHODS: BBB unidirectional transfer constant ( Ki ) for [3H] - Glu in rat hippocampus, cerebral cortex and striatum were determined after rats were subjected to cerebral ischemia 10 min ( two - carotid occlusion plus hypovolemic hypotension) followed by 0.17, 2, 6 and 24 h of reperfusion. The recovery of [3H] - Glu in cerebrum was also determined after intracerebral injection of [3H] - Glu in another experiment. RESULTS: Compared with control rat brain, Ki for [3H] -Glu significantly( P < 0.05) decreased at 10 ain cerebral ischemia followed by 0.17, 2 and 6 h of reperfusion. At 5 min after intracerebrally injecting [3H] - Glu , recovery of [3H] - Glu in control rat brain was 23.83%. The result indicted that there is a Glu efflux mechanism on BBB. This efflux was not significantly inhibited by pretreatment of 200 mg/L probenecid. After 10 ain cerebral ischemia followed by 2 h of reperfusion, the recovery( 13.13 % ) was significantly lower than contro( P < 0.05), its recovery was only 55 % of the control. The result indicated that cerebral ischemia/reperfusion may enhanced the effiux of [3H] -Glu from brain. CONCLUSION: Cerebral ischemia/reperfusion significantly reduced Glu BBB transport from plasma to brain and enhanced effiux of Glu from brain.