EXCITATORY AMINO-ACIDS AND MONOAMINES IN PARAHIPPOCAMPAL GYRUS AND FRONTAL CORTICAL POLE OF ADULTS WITH DOWN-SYNDROME

Aspartate (ASP), glutamate (GLU), noradrenaline (NA), dopamine (DA) an d its acidic metabolites DOPAC and HVA, serotonin (5-HT) and its metab olite 5-HIAA were simultaneously investigated in post-mortem tissue sa mples from right parahippocampal gyrus (temporal cortex) and frontal c ortical pole (frontal cortex) of adults with Down syndrome (DS), and o f neurologically healthy controls by use of high performance liquid ch romatography (HPLC). In parahippocampal gyrus, ASP, GLU, NA, DOPAC and 5-HT levels were significantly decreased in patients with DS, compare d to levels found in control subjects (approximate to 50%). No signifi cant changes were observed in frontal pole. ASP and GLU levels were si gnificantly lower in parahippocampal gyrus than in frontal pole of DS, a regional distribution that could not be observed in control subject s. In conclusion, the results of this study suggest that the temporal cortex would be more affected than the frontal cortex in adult patient s with DS, a finding in line with reports showing a marked hypometabol ism and extensive cell loss in temporal cortex of DS, and with those s howing that parahippocampal gyrus abnormality may correlate with the e xtent of mental retardation affecting this type of patients.