In contrast to the thirty minute acidosis treatment that caused both apoptosis and necrosis, a fifteen minute treatment produced only apoptosis. These results indicate that acidosis is neurotoxic in vitro and suggests that acidosis contributes to both necrotic and apoptotic neuronal loss following cerebral ischemia. We have developed a method to place slices of adult hippocampus into long-term culture. Experimental parameters that confound in vivo studies are avoided such as variations in cerebral microcirculation, brain temperature, and trauma due to survival surgery. The adult slice culture model will be a valuable tool to determine the molecular mechanism of ischemic injury as well to test potential neuroprotective therapies.
Caspase activation is believed to be necessary for apoptosis.
Specific caspase inhibitors have been developed that block apoptosis. Experiments in the first specific aim will examine when caspases are activated following hypoxia and determine the necessity of caspase activation for apoptosis. Glutamate is the major excitatory neurotransmitter in the central nervous system. The glutamate agonist kainate is thought to trigger limbic seizures by activating kainate receptors in the CA3 region of the hippocampus. Increased expression of kainate receptors may result in chronic hyperexcitability in the epileptic brain.