[Application of the common marmoset to pharmacological studies]

Application of the common marmoset to pharmacological studies was reviewed, especially employment of the animal as a model of Parkinson's disease were presented. The common marmoset is one of the New World monkeys with a body weight of 300-350 g. It is small enough to be easily handled and to be kept as a group in a room. In the fields of pharmacology, it has been used in studies of plasma renin activity inhibitors, lipoprotein, memory/learning, obstetrics, transplantation, toxicology, anxiolytic agents and virology/immunology. We showed that the common marmoset was a useful animal for studies on Parkinson's disease, dopamine metabolism by microdialysis and nausea/vomiting. The common marmoset was sensitive to 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) and developed permanent parkinsonism after MPTP injection. MPTP-treated common marmosets showed tremor and akinesia, and it remarkably responded to antiparkinsonian agents. A dopamine D1 agonist, which caused stereotyped behavior in rats, did not reverse parkinsonism in humans. We showed this agent did not have any antiparkinsonian effects on MPTP-treated common marmosets. MAO has subtypes, A and B, that have differences of distribution in different species. MAO type B inhibitors were applied for the treatment of Parkinson's disease. MAO subtype B inhibitors do not cause any change in behavior or extracellular concentration of dopamine or its metabolites in rodents. In MPTP-treated common marmosets, however, administration of a MAO type B inhibitor increased the antiparkinsonian effects of levodopa and decreased dopamine metabolites. The common marmoset is a suitable animal for the study of MAO type B inhibitors.