Effects of sensory-motor cortical lesions on blood-brain permeability in guinea pigs

Effects of sensory-motor cortical lesions on the function of the blood-brain barrier in distant brain areas are poorly understood. Therefore a brain vascular perfusion method has been used to measure simultaneously the kinetics of entry of two inert polar molecules, D-[14C]mannitol (MW 180) and [3H]polyethylene glycol (PEG; MW 4000), into the parietal cortex, hippocampus, and caudate nucleus in guinea pigs with ipsilateral and contralateral sensory-motor cortical lesions. The graphically determined cerebral capillary unidirectional constant, Kin, indicated a marked increase in blood-to-brain transport of both molecules in all regions studied, the changes being significantly higher after contralateral lesion. The mannitol/PEG cerebrovascular permeability constant ratio, Pman/PPEG, suggested the opening up of channels that permit a flow of fluid carrying substances either with respect to (2 days after ipsilateral lesion) or irrespective of their molecular size, depending on the time after lesion. Amphetamine treatment in the guinea pigs with sensory-motor lesions induced more pronounced blood-brain barrier permeability changes for both molecules in distant brain areas.