DISTRIBUTION OF N-ACETYLASPARTATE, N-ACETYLASPARTYLGLUTAMATE, FREE GLUTAMATE AND ASPARTATE FOLLOWING COMPLETE MESENCEPHALIC TRANSECTION IN RAT NEURAXIS

The distribution of N-acetylaspartate (NAA), N-acetylaspartylglutamate (NAAG), free glutamate (Glu) and aspartate (Asp) was studied in the neuraxis of rats 48h after complete transection of brain stem at the intercollicular level. NAA remained unchanged above the transection level but decreased in the neuraxis segments caudal to the lesion. Glu was strongly depressed both in the segments rostral to the transection and in the ones caudal to it. No significant change was found for NAAG and Asp. These findings are consistent with the hypothesis that NAA may be involved in neurotransmission processes and provide further evidence for Glu as transmitter of descending and ascending pathways. In addition, the data obtained do not suggest a direct metabolic or functional relationship between NAA and NAAG nor between these N-acetylderivates and free Glu and Asp. © 1990.