Neuroprotectants Effects on the Gerbil Brain

Temporary interruption or reduction of cerebral blood flow (CBF) during cerebrovascular surgery may rapidly result in ischemia or cerebral infarction. Nimodipine and thiopental have been shown to have cerebroprotective effects. The studies in this chapter were performed in order to examine whether the multiprobe assembly (MPA), which measures energy metabolism by CBF and mitochondrial NADH as well as extracellular ion concentrations (K+), can shed light on the mechanism of the cerebroprotective effects of Nimodipine or thiopental. The MPA was placed on the brain of Mongolian gerbils, and cerebral ischemia was induced by occlusion of carotid arteries. Burst suppression of the electrocorticogram (ECoG) after thiopental was accompanied by a significant decrease in cerebral blood flow. In animals that received thiopental prior to ischemia, NADH increased to a lesser degree and extracellular potassium ion concentration increased to a lesser degree than in the control animals, indicating that thiopental affords protection of the brain under ischemic conditions due to improved energy metabolism. This study also demonstrates that the MPA can monitor changes occurring in the cerebral cortex even after the ECoG can no longer be used.