Effect of monosialoganglioside (GM1) on transected monoaminergic pathways

The effects of exogenous monosialogangliosides (GM1) on transected monoaminergic cerebral cortical pathways were investigated in mice. Norepinephrine (NE), 5-hydroxytryptamine (5-HT), and 5-hydroxyindole-3-acetic acid (5-HIAA) contents were determined in cerebral cortex rostral and caudal to unilateral coronal transection sites. The transmitter contents were expressed as a ratio of those in the unlesioned contralateral cortex. In the caudal cortex, NE ratios fell to 70% within a week after transection and decreased further to 35-40% by 4 weeks. Treatment with exogenous GM1 for 2 weeks starting shortly after the lesion increased NE concentrations in the caudal cortex to 47.4-55.0% at 4 weeks, significantly greater than control animals (p less than 0.01, Mann-Whitney U-test). GM1 treatment for 2 and 4 weeks, starting 2 weeks after the lesion, yielded similar results. The 5-HT and 5-HIAA ratios in the caudal cortex also rose significantly after GM1 treatment. Thus, GM1 increased monoaminergic levels nonspecifically in the cortex caudal to the cortical lesion. The treatment effect did not depend on the timing or duration of treatment. These results indicate that exogenous GM1 treatment has a nonspecific restorative effect on the central nervous system after axonal lesions.