Stereotypy, locomotor and cataleptic effects produced by drugs influencing dopaminergic systems in a mutant strain of Wistar rats: a genuine model of basal ganglia dysfunction?

The mutant strain of Wistar rats carrying an autosomal recessive gene defect is characterized by a sequence of progressively developing behavioural alterations including hyperexcitability, tremor, olfactory and gustatory automatisms, bradykinesia, ataxia, rigidity, paresis and cachexia. The stereotypy and locomotor responses to increasing doses of apomorphine hydrochloride and D-amphetamine sulphate, and the catalepsy response to increasing doses of haloperidol were studied in mutant rats at the age of 6-7 weeks. In the mutants, both the stereotypy and locomotor responses to amphetamine were enhanced, while stereotypy and locomotor effects induced by apomorphine were unaltered. The cataleptic response to haloperidol was significantly diminished compared to controls. These findings indicate a derangement in the function of basal ganglia in the mutants.