Dopaminergic supersensitivity follows ferric chloride-induced limbic seizures

Injection of ferric chloride (FC) into the left amygdala of rats produced limbic seizures that lasted at least 3 weeks. In addition, FC-injected animals demonstrated motor impairment, decreased protesting vocalizations, and spontaneous stereotypies during a behavioral examination. An increase in apomorphine-induced stereotypies was also noted, and weekly administration of apomorphine for 3 weeks potentiated the increase in stereotypies produced by FC injection. These behavioral changes were associated with changes in postsynaptic dopamine D2 receptors. In animals injected only with FC, an increase in the [3H]-spiperone Bmax in the left nucleus accumbens and an increase in Kd in the right nucleus accumbens were noted. In FC-injected animals challenged weekly with apomorphine for 3 weeks, increases in the [3H]-spiperone Bmax in both amygdalae, the left nucleus accumbens, and the right nucleus caudatus and increases in Kd in the left amygdala and right nucleus accumbens were noted. Severance of the anterior commissure at the time of FC injection reversed most of these changes in behavior and dopamine receptor binding. Possible mechanisms for these changes are discussed, as well as the implications of these results for research on limbic dysfunction and psychopathology.