Efflux transport of [3H]GABA across blood-brain barrier after cerebral ischemia-reperfusion in rats

AIM: To study whether the efflux transport of [H-3]GABA across the blood-brain barrier (BBB) would be enhanced after cerebral ischemia-reperfusion. METHODS: Brain efflux index (BEI) of [H-3]GABA tvas determined in ischemic-reperfused rats after [H-3]GABA or [H-3]GABA combined with unlabeled GABA or probenecid (Pro) was microinjected into the parietal cortex area 2 (Par 2), and brain uptake of Evans blue (EB) was assessed after iv EB. RESULTS: BEI in rats subjected to 10-min ischemia and 30-min, 2-h, 6-h, or 24-h reperfusion were 67%, 83%, 92%, and 87%, respectively, which were higher than that in control (58%). The brain uptake of EB was also considerably increased. Unlabeled GABA or Pro obviously decreased BEI in normal or 6-h reperfused rats, but GABA had no obvious effect on that in 5-min reperfused rats. CONCLUSION: The efflux transport of [H-3] GABA was markedly enhanced after cerebral ischemia-reperfusion in rats.