Alteration of dopamine metabolites in CSF and behavioral impairments induced by neonatal hippocampal lesions

Alterations of monoamine metabolites in CSF and behavioral abnormalities we re studied in rats with neonatal hippocampal lesions and controls. Lesions of the ventral hippocampus were produced bilaterally by ibotenic acid on po stnatal day 7. Lesion-induced neurochemical alterations and behavioral impa irments were examined concurrently when rats were 12 weeks old. CSF from th e cisterna magna was sampled repeatedly from freely moving rats. The levels of free 3,4-dihydroxyphenylacetic acid (DOPAC), homovanillic acid (HVA), a nd 5-hydroxyindoleacetic acid (5-HIAA) in CSF were determined. An exposure to a novel environment induced hyperexploratory behavior and elevated the l evel of free DOPAC in CSF in lesioned rats. Although a swim stress increase d the levels of free DOPAC and 5-HIAA in CSF in both control and lesioned g roups, rats with hippocampal lesions had a further elevation of free DOPAC in CSF and greater spontaneous activity relative to controls shortly after stress. Amphetamine (1.5 mg/kg, i.p.) induced hyperlocomotion in lesioned r ats compared to controls. For the control group, the levels of the three mo noamine metabolites in CSF were not significantly influenced by amphetamine . However, for the lesioned group, the level of DOPAC significantly decreas ed compared to preinjection of amphetamine. The results indicate that neona tal hippocampal lesion-induced impairments can be manifested by behavioral and neurochemical abnormalities. Alterations of monoamine metabolites in CS F may be determined quantitatively and used as indices for monitoring lesio n-impaired monoaminergic function in the central nervous system. (C) 1998 E lsevier Science Inc.