Differential Effect of Cerebral Ischemia on Monoamine Content of Discrete Brain Regions of the Mongolian Gerbil (Meriones unguiculatus)

Abstract

The effect of bilateral cerebral ischemia on noradrenaline [norepinephrine, NE], dopamine, and serotonin [5-hydroxytryptamine, 5-HT] concentrations in 6 brain regions (i.e., the cerebral cortex, striatum, hippocampus, midbrain-diencephalon, cerebellum and pons-medulla oblongata) was examined in the gerbil stroke model. The relative changes in regional cerebral blood flow after bilateral common carotid occlusion were also assessed using the radioactive microsphere technique. At 1 h after bilateral cartoid occlusion, a significant decrease of monoamine concentration was observed in the cerebral cortex, striatum, hippocampus, and midbrain-diencephalon whereas no significant change was detected in the cerebellum and pons-medulla oblongata. The fall in NE content was most prominent in the cerebral cortex and hippocampus, and percentage reductions of dopamine and 5-HT were greatest in the striatum and cerebral cortex, respectively. The monoamine neurons in various brain regions might have different vulnerabilities to ischemic insult and show no evidence of transtentorial diaschisis.