Interaction of atropine-like drugs with dopamine-containing neurones in rat brain.

1. A variety of atropine-like drugs effective in the treatment of drug-induced extrapyramidal syndromes have been investigated with regard to their interaction with dopamine-containing neurones in rat brain.2. Under some conditions benztropine, trihexyphenidyl, atropine and ethopropazine significantly antagonized the chlorpromazine-induced increase in subcortical concentrations of homovanillic acid.3. Most of the atropine-like drugs investigated also decreased the turnover of dopamine in the subcortex as measured by following the disappearance of dopamine after administration of alpha-methyl-p-tyrosine.4. These findings are suggestive that an imbalance between a dopaminergic and cholinergic system might be closely linked to the pathogenesis of extra-pyramidal movement disorders.