Attenuated extracellular dopamine levels after stress and amphetamine in the nucleus accumbens of rats with neonatal ventral hippocampal damage

Summary. In vivo microdialysis was used to study the effects of restraint stress (30 min) and amphetamine (AMPH) (5 mg/kg, i.p.) in awake adult male rats with neonatal ventral hippocampal (VH) damage. Extracellular levels of dopamine (DA), dihydrophenylacetate (DOPAC), homovanillate (HVA) and 5-hydroxyindolacetate (5-HIAA) were measured in the nucleus accumbens (NA). There were no differences in the baseline levels of DA, DOPAC, HVA or 5-HIAA in the lesioned as compared to the sham rats. Release from restraint resulted in increased extracellular levels of DA in the sham but not in the lesioned animals. AMPH increased DA release in both sham operated and lesioned animals, but this increase was significantly attenuated in the lesioned rats. Our data suggest that this developmental lesion alters function of the dopaminergic system in response to environmental and pharmacological challenge. Received June 3, 1997; accepted August 10, 1998