2020 Volume 69 Issue 4 Pages 382-387
Our early weaning schedule was associated with the emergence of trait anxiety in male rodents performing an elevated plus maze but not an open-field test. We previously reported that early weaning weakened excitatory neurotransmission to the amygdala from the prefrontal cortex, where the mesocorticolimbic dopaminergic (DAergic) fiber terminates on each. In this study, we investigated DAergic transmission in both these brain regions. The extracellular levels of amygdalar DA in adulthood were two times higher in rats weaned at 16 days compared to those weaned at 30 days in both the home cage and the open-field. This difference in extracellular DA levels was not apparent in the prefrontal cortex. The concurrently measured locomotor and rearing behaviors did not vary according to the weaning period and the probe-implanted region, respectively. These results suggest that the effects of early weaning on DA tone appear to be specific to the amygdala and do not represent ubiquitous upregulation as these changes were not observed in the prefrontal cortex.