Changes in limbic dopamine metabolism following quinolinic acid lesions of the left entorhinal cortex in rats.

To examine the effects of lesions of the entorhinal cortex on limbic dopamine (DA) metabolism, DA and its metabolites were assayed in five brain regions (the medial prefrontal cortex, anterior cingulate cortex, caudate-putamen, accumbens nucleus, and lateral amygdala), 14 and 28 days after quinolinic acid or sham lesions of the left entorhinal cortex in rats. Concentrations of 3,4-dihydroxyphenylacetic acid (DOPAC) on day 14 in the medial prefrontal cortex, accumbens nucleus, and lateral amygdala of the entorhinal cortex lesioned animals were significantly decreased compared with the controls, but they returned to control levels on day 28. The concentration of DA in the lateral amygdala and spontaneous locomotion to a novel environment were significantly increased on day 28 after the lesion. These results suggest that entorhinal cortex lesions alter mesolimbic dopamine metabolism, particularly in the amygdala.