DECREASE IN BRAIN CHOLINE-CONTAINING COMPOUNDS FOLLOWING A SHORT-PERIOD OF GLOBAL-ISCHEMIA IN GERBILS AS DETECTED BY H-1-NMR SPECTROSCOPY IN-VIVO

Cerebral metabolism was studied in the postischaemic gerbil brain using surface coil P-31 and H-1 NMR spectroscopy. The ratio of choline-containing compounds (Cho) to total creatine (Cr) in the brain decreased from 0.46+/-0.02 to 0.32+/-0.02 by the fifth day following exposure to 5 min of global ischaemia and it remained at this low level for at least 19 days. The amounts of cerebral Cho as quantified by H-1 NMR in vivo were 1.70+/-0.15 and 1.09+/-0.22 mmol/kg in control and postischaemic animals, respectively. The T-2 of Cho was longer in the postischaemic cerebral cortex than in the control one. N-acetyl aspartate (NAA) as determined by H-1 NMR in vivo did not differ in the two animal groups. High-resolution H-1 NMR of acid-extracted brain cortices showed a decrease in total Cho (glycerophosphocholine, phosphocholine and choline) by 31%, but no changes in NAA, total creatine, taurine and myo-inositol, in the brain cortex seven days postischaemia relative to control animals. The decrease in acid extractable Cho was mainly due to the drop in glyceraphosphocholine concentration. P-31 NMR indicated normal energy state and phosphomonoester/phosphocreatine (PCr) and phosphodiester/PCr ratios in the in vivo brain 7 days postischaemia. Silver impregnation did not reveal neuronal degeneration but immunohistochemical staining showed a number of glial fibrillary acidic protein expressing astrocytes as indicators of reactive gliosis in the postischaemic cerebral cortex. These data show, for the first time, that a H-1 NMR decrease in Cho metabolites takes place as a consequence of brief ischaemic episode even in the absence of obvious neuronal degeneration.