Blood-brain barrier permeability to sucrose and dextran after osmotic opening

摘要: Regional cerebrovascular permeability-surface area (PA) products were calculated for two nonelectrolyte tracers differing considerably in molecular weight and size [( 14C]sucrose: mol wt 340 daltons, radius 5 A; [3H]dextran: approximately 79,000 65 A) control (uninfused) rats 6, 35, 55 min after the blood-brain barrier was opened by a 30-s infusion of 1.8 molal L(+)-arabinose into carotid artery. In brain regions, mean PA [14C]sucrose 10(-5) s-1, whereas not measurable [3H]dextran. Six minutes arabinose infusion, both substances increased dramatically to 10(-4) s-1 or more; then declined at 35 but more markedly [3H]dextran than [14C]sucrose. The results demonstrate size-dependent, differential rate closure osmotic opening. This is shown be consistent with pore model bulk flow permeability