Evidence that thioridazine enhances amphetamine-induced stereotypy via anticholinergic activity.

The hypothesis that the anticholinergic properties of thioridazine can account for its ability to enhance amphetamine-induced stereotyped behaviors was tested. In one experiment, scopolamine-induced repetitive head movements were shown to be potentiated by thioridazine. In another experiment, subthreshold doses of scopolamine and thioridazine interacted to potentiate amphetamine-induced repetitive head movements. The data suggest that thioridazine, in addition to its neuroleptic activity, has significant anticholinergic effects in vivo and these effects may account for its potentiation of amphetamine-induced stereotypy.