Experimental study of new cerebral protective substances - functional recovery of severe, incomplete ischaemic brain lesions pretreated with mannitol an fluorocarbon emulsion.

Using the "canine model of complete ischemic brain regulated with a perfusion method" in which it is possible to control the degree of blood flow to a cerebral hemisphere via a perfusion pump, the effects of mannitol (which acts as a free radical scavenger) and fluorocarbon emulsion (FC) (which has 0.1 micron of average particle size and a high oxygen-carrying capacity) on cerebral ischaemia were investigated. After pretreatment with the drugs, blood flow was reduced via the pump to 1/10 the normal state and 1 hour later, return to a normal state allowed. Subsequent changes in electrical activity were observed and the effectors of the drugs evaluated. In the control group, no recovery of electrical activity was seen, but in the animals treated with either mannitol or FC, incomplete, yet distinct recovery was apparent. In the animals administered mannitol together with FC, however, marked recovery was evident. These experimental results indicate that the combined administration of mannitol and FC is effective in protecting the brain from cerebral ischaemia.