Effects of GM1 ganglioside treatment on dopamine innervation of the striatum of MPTP-treated mice.

GM1 ganglioside has been shown to stimulate repair of the nigrostriatal dopamine system after injury. This has been particularly evident in the mouse MPTP model of Parkinsonism. Systemic administration of GM1 has been shown to increase striatal dopamine levels and lead to increased density of substantia nigra pars compacta neurons after MPTP administration versus mice treated with MPTP and saline. The purpose of the present study was to assess regional changes in dopaminergic innervation of the striatum of mice treated with MPTP then GM1. Studies consisted of [3H] mazindol binding of dopamine uptake sites, postmortem striatal tissue dopamine levels, and peak dopamine release in response to KCl stimulation measured in vivo. Results showed that measures of dopamine innervation were significantly increased in most striatal areas in MPTP+GM1-treated mice compared to MPTP+saline-treated controls. The results indicate that GM1 treatment increases measures of dopaminergic innervation after an MPTP lesion, possibly through sprouting of new terminals or increased dopamine production and release from remaining terminals.