Effects of middle cerebral artery occlusion on cerebral cortex choline and acetylcholine in rats

We measured regional cerebral blood flow and acetylcholine and choline concentrations in tissue fragments of normally perfused and ischemic cortical regions from 10 rats. Tissue uptake of [14C]iodoantipyrine was used to indicate regional cerebral blood flow, and gas chromatography-mass spectrometry was used to measure acetylcholine and choline concentrations. Cerebral cortical ischemia was induced by permanent occlusion of the middle cerebral artery, and variables were measured 2.5 or 24 hours later. A close correlation was found between tissue choline concentration and the reciprocal of regional cerebral blood flow. A large increase in tissue choline concentration was observed in the ischemic cortex. Choline production rate was estimated by plotting choline concentration against the reciprocal of regional cerebral blood flow. This rate was independent of choline concentration. Acetylcholine concentration, on the other hand, was constant in ischemic and normally perfused regions, except in the center of the ischemic region 2.5 hours after middle cerebral artery occlusion, where a significant decrease was observed.