Selective damage in striatum and hippocampus with in vitro anoxia

Abstract

An in vitro model of anoxia-induced brain damage was utilized to help elucidate the biochemical basis of cell damage due to reduced oxygen availability. Previous studies suggest that anoxia-induced damage may vary presynaptically, post-synaptically or in the cell body. Thus, the consequences of an anoxic treatment incubation were examined with hippocampal slices, which contain cholinergic nerve terminals but not cell bodies, and with slices from whole striatum or its subregions, which contain both cholinergic cell bodies and nerve terminals. Slices were preincubated with either oxygen or nitrogen (treatment incubation) and the persistent effects of this treatment on [14C]acetylcholine and 14CO2 production from [U-14C]glucose were assessed in a subsequent incubation under optimal conditions (test incubation). An anoxic treatment incubation reduced the subsequent test incubation production of CO2 about 40% in the hippocampus and striatum. The anoxic treatment incubation diminished ACh production by 46% in the striatum, but only minimally affected that in the hippocampus. Anoxic treatment incubations of synaptosomes did not alter test-incubation ACh synthesis or CO2 production. Omission of calcium from the anoxic treatment incubation increased striatal ACh synthesis by 88% and CO2 production in both regions. These results suggest that anoxia produces persistent changes in postsynaptic processes or cell bodies (in this model cholinergic ones) that differ from those in nerve terminals and that calcium is important in the production of these deficits.