GM1-Ganglioside Suppresses Septodentate Sprouting and Enhances Recovery from Entorhinal Cortex Lesions on DRL Perfomance and Locomotor Behavior in Rats

Administration of gangliosides accelerates recovery of function after entorhinal cortex lesions on open field activity and learned spatial alternation tasks. In the present study, we examined whether GM1 ganglioside might enhance recovery from bilateral entorhinal cortex lesions on a differential reinforcement of low-rate responding tak with a 20 sec delay (DRL-20) as well as on open field activity. Optical densitometry measurements were taken to assess sprouting by the acetylcholinesterase-containing septodentate pathway. Eighteen rats were assigned to sham/GM1, lesion/GM1, or lesion/saline conditions. After preoperative training and testing, the rats received surgery and were then tested post-operatively for thirty days. GM1 injections (20 mg/kg) were given beginning the day before surgery through day 5 postsurgery 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 open field tasks. The lesion/GM1 group had significantly less septodentate sprouting than the lesion group treated with saline. GM1 treatment may be facilitating recovery from bilateral entorhinal lesions by reducing the trauma of injury and denervation, reducing heterologous sprouting, or both.