GM1-ganglioside suppresses septodentate sprouting and enhances recovery from entorhinal cortex lesions on DRL performance and locomotor behavior in rats

Administration of gangliosides accelerates recovery of function after entor hinal cortex lesions on open field activity and learned spatial alternation tasks. In the present study, we examined whether GM1 ganglioside might enh ance recovery from bilateral entorhinal cortex lesions on a differential re inforcement of low-rate responding task with a 20 sec delay (DRL-20) as wel l as on open field activity. Optical densitometry measurements were taken t o assess sprouting by the acetylcholinesterase-containing septodentate path way. Eighteen rats were assigned to sham/GM1, lesion/GM1, or lesion/saline conditions. After preoperative training and testing, the rats received surg ery and were then tested postoperatively for thirty days. GM1 injections (2 0 mg/kg) were given beginning the day before surgery through day 5 postsurg ery and then on alternating days. Relative to the lesion/saline group, rats in the lesion/GM1 group showed enhanced recovery on the DRL-20 and the ope n field tasks. The lesion/GM1 group had significantly less septodentate spr outing than the lesion group treated with saline. GM1 treatment may be faci litating recovery from bilateral entorhinal lesions by reducing the trauma of injury and denervation, reducing heterologous sprouting, or both.