Increased proportion of high-affinity dopamine D2 receptors in rats with excitotoxic damage of the entorhinal cortex, an animal model of schizophrenia

Excitotoxic lesions of the left entorhinal cortex (EC) cause dopamine supersensitivity. In order to determine if these lesions selectively alter the high-affinity state of dopamine D2 receptors (D2High), these high-affinity states were measured by competition between dopamine and [3H]domperidone in striata from lesioned rats and sham-operated animals. The proportion of D2High sites was significantly elevated by 200% in the EC-lesioned rats while that of the D1High sites, measured by dopamine/[3H]SCH23390 competition, was unaltered. These results provide a biochemical basis for behavioral supersensitivity in rats with EC lesions.