Chronic Administration of 1-Methyl-4-Phenyl-1,2,3,6- Tetrahydropyridine to Marmosets

It is well established that the administration of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) to human beings or to non-human primates brings about a parkinsonian syndrome which closely resembles idiopathic Parkinson’s disease (Snyder and D’Amato, 1986). With few noticeable exceptions (Langston and Ballard 1983), the human cases of accidental exposure to MPTP were caused by acute administration of this toxin (i.e., a single or few repeated injections; Langston, 1987). Similarly, in order to obtain experimental animals which are clinically affected, monkeys are usually injected with repeated doses of MPTP over 2 to 5 days. Regimen varies according to the species. In marmosets, 4–5 daily injections of 1–4 mg/kg/day i.p. are effective so as to obtain animals which are obviously parkinsonian, but who can maintain themselves (Jenner et al., 1984). The resemblance of MPTP-induced parkinsonism to Parkinson’s disease is still an unsolved issue (Albanese 1989). Recently, Kish et al. (1988) found that, in patients affected by Parkinson’s disease, dopamine loss is more severe in the putamen than in the caudate nucleus, while in monkeys poisoned acutely with MPTP dopamine loss is higher in the caudate nucleus than in the putamen.