Middle cerebral artery occlusion increases cerebral capillary permeability

AbstractOne hour after middle cerebral artery occlusion, the regional blood to brain transfer coefficient of α-aminoisobutyric acid was determined in eight barbiturate anaesthetized rats. The transfer coefficient (μl/min–1 /g–1) was significantly higher in the ischaemic cortex (10.6±2.3) than in the contralateral cortex (6.5 ±1.0). Cerebral regional capillary surface area was determined in another group of twelve rats using an alkaline phosphatase stain for the total capillary bed and fluorescein isothiocyanate-dextran to visualize the perfused capillaries. Perfused capillary surface area (cm2/cm3) was lower in the ischaemic cortex (141 ±31) than in the contralateral cortex (426 ±32). Using these values for the transfer coefficient, surface area and our previously published data of regional cerebral blood flow after middle cerebral artery occlusion, we calculated the extraction fraction of α-aminoisobutyric acid, the permeability-surface areapmduct and the permeability of cerebral regional capillary beds....