RESUMO
BACKGROUND: Isolated brain of experimental animals is a useful model to study transport of substances, including drugs, across the blood-brain barrier, mechanisms of convulsive activity, ischemic and reperfusion brain injury. Normal functioning of neurons, especially cortical, in the central nervous system requires adequate supply of oxygen. Therefore oxygen carriers or fluorocarbon substances with high oxygen capacity are often used in animal brain perfusion experiments. NEW METHOD: In the present study of the in situ rat brain perfusion oxygen carriers were not used. The optimum oxygen capacity of the perfusion media (adequate to the arterio-venous difference) was achieved by a high oxygen tension (2400-2600â¯mm Hg) in the solution under normal barometric pressure. Perfusate was depressurized and delivered at normal rat systemic hydrostatic pressure to the brain via a cannula inserted transcardially into the ascending aorta, with both subclavian arteries ligated. Perfusate was delivered using normal hydrostatic pressure. RESULTS: In these experimental conditions of the brain perfusion the pattern of electrocorticogram has been stable in the course of 5â¯h and more. The release of lactic acid in the perfusion solution was 3 times less than in perfusion under partial oxygen tension of 900â¯mm Hg; excessive activation of the lipid peroxidation process in the brain tissue was not observed. CONCLUSION: The presented new model of the isolated brain perfusion may be used in experiments with other isolated organs and in studies of toxic effects of oxygen.
