The stimulating effect of ganglioside injections on the recovery of choline acetyltransferase and acetylcholinesterase activities in the hippocampus of the rat after septal lesions.

The effect of intramuscular administration of a mixture of gangliosides (21% GM1, 39.7% GD1a, 16% GD1b, 19% GT1) in a daily of 50 mg per kg upon the time course of changes in hippocampal acetylcholinesterase and choline acetyltransferase activities after extensive medioventral septal lesions in the rat was checked on days 3, 5, 18 and 50 after the operation. Following the early decrease in the enzyme activities to about 25% of control due to degeneration, a gradual recovery up to about 50% of control activity at the 50th day was found. When gangliosides were administered, the recovery in the activity of both enzyme was more pronounced. The ratio of the enzyme activities from the animals injected with gangliosides to that from uninjected animals was 1.45 and 1.48 on the 18th day and 1.62 and 1.50 on the 50th day after the operation, for choline acetyltransferase and acetylcholinesterase activity, respectively. Since no significant effect of ganglioside injection was seen at early post-operative times i.e. on days 3 and 5, the effects seen on days 18 and 50 seem to be specifically due to facilitation of the recovery processes and not to retardation of the degeneration processes. Assuming that the spontaneous recovery of cholinergic enzyme activity reflects reinnervation of the hippocampus through collateral sprouting gangliosides would seen to facilitate the regrowth of new cholinergic nerve terminals.