Ergot drugs and central monoaminergic mechanisms: a histochemical, biochemical and behavioral analysis

The effects of ergot drugs on central monoaminergic mechanisms, particularly dopaminergic mechanisms, have been investigated in histochemical, biochemical and behavioral studies. It is concluded that the behavioral effects and the antiparkinsonian properties of ergot drugs can to a large extent be explained by the hypothesis that ergot drugs act at various dopamine receptor sites in the brain as partial agonists, the ratio of agonist-antagonist activity varying from one dopamine receptor population to another.