The effect of GM1 ganglioside on cholinergic and serotoninergic systems in the rat hippocampus following partial denervation is dependent on the degree of fiber degeneration.

The partial lesion paradigm of the dorsal hippocampal afferents in the rat was used as a model to study the effect of GM1 ganglioside treatment on recovery of neurotransmitter markers of the cholinergic and serotoninergic activity in various hippocampal regions. It was found that the enhancement of recovery of acetylcholinesterase, choline acetyltransferase and serotonin uptake by GM1 treatment (30 mg/kg i.m., daily), as studied on the 6th and 21st postlesion day, was dependent on the degree of fiber degeneration. The results may be interpreted in terms of the relationship between the action of GM1 and that of neuronotrophic factors whose release also depends on the extent of the fiber degeneration. These data indicate that GM1 elicits the recovery of biochemical parameters, or fails to, depending on the specificity of the trauma. The result may explain why, after certain brain lesions, GM1 does not promote functional recovery.