<正> The changes of blood-brain barrier（BBB）permeability following brain injury werestudied quantitatively by using colloidal gold（CG）particles of various sizes as tracers in 57 rab-bits.In addition

water content in brain tissues was determined.The brain-injured rabbits re-ceived intravenous injection of anisodamine in a dose of 0.3 mg/kg BW at 5rain or 3h after braininjury

and the effect of anisodamine on aherations of BBB permeability and water content of thebrain tissue after brain injury was investigated.The results indicated that an increase of BBBpermeability began at 30min after injury with only a few of 5nm CG tracers present in the endo-cytic pits and endothelial microvilli

and there were 10nm CG tracers passing through the BBB at3 h after brain injury.The increase of BBB permeability reached its peak at 6 h after brain in-jury.More 15nm CG tracers penetrated the BBB by way of pinocytotic vesicule transportationand opening of tight junctions between endothelial cells.The water content in the brain tissueincreased

which was closely correlated to the above-mentioned EBB permeability and giving ad-vantages to the treatment of traumatic brain edema in the present study.