ROLE OF EXCITATORY AMINO-ACIDS IN NEONATAL HYPOGLYCEMIA

Background: In many neurological disorders, injury to neurons may be d ue in part to overstimulation of the receptors for the excitatory amin o acids glutamate and aspartate. The same excitotoxic mechanism and hi gh aspartate levels in experimental studies led to this study of the c oncentrations of glutamate and aspartate and zinc, copper, and magnesi um levels in the cerebrospinal fluid (CSF) of hypoglycemic newborns. M ethods: Aspartate and glutamate were determined by high-performance Li quid chromatography, and magnesium, zinc and copper by atomic absorpti on spectrophotometer. Results: The CSF levels of aspartate (3.98 +/- 1 .77 mu mol/L) and glutamate (1.7 +/- 1.05 mu mol/L) in 20 hypoglycemic newborns were significantly higher when compared with the values of a spartate (2.19 +/- 0.6 mu mol/L) and glutamate (0.77 +/- 0.34 mu mol/L ) of 10 control newborns. In the hypoglycemic patients, the concentrat ion of zinc (0.57 +/- 0.13 mu g/mL), but not copper (0.39 +/- 0.40 mu g/mL) was significantly lower when compared with the control values. T here was no difference in the magnesium levels between the two groups. Conclusions: The higher levels of excitatory amino acids found in the CSF of hypoglycemic infants than in controls were consistent with pre vious animal studies, which may indicate the role of excitatory amino acids in the late biochemical effects of hypoglycemia in newborn brain metabolism.