Protective effects of ginseng total saponins on reward-directed operant conditioning in hindlimb suspension rats

Abstract

Objective: To explore the therapeutic effects of ginseng total saponins (GTSs) on cognitive impairments in astronauts caused by prolonged exposure to microgravity environment. Methods: Fifty specific pathogen-free (SPF) male Wistar rats were randomized into control, hindlimb suspension (HLS), Huperzine A (HLS-Hup A 0.1 mg/kg), low-dose GTSs (HLS-GTSs 100 mg/kg), and high-dose GTSs (HLS-GTSs 200 mg/kg) groups, based on the completion time of reward-directed conditioning tasks. Except for rats in the control group, the others were subjected to HLS and treated with drugs (day 20 – 58), received reflex test under the condition of rewarding, and underwent Nissl body staining and Western blot detection on hippocampal. Results: After modeling, rats in HLS group exhibited a reduction in the number of lever presses and an increase in the completion time of the reward-directed operant conditioning task Ⅰ (P 0.05). In the reward-directed operant conditioning task Ⅱ, the HLS group rats demonstrated a marked decrease in the number of lever presses (P 0.05). GTSs increased the expression levels of p-NR2B (P < 0.01). Conclusion: GTSs improved the learning and memory ability of complex operations by regulating the NR1/NR2B phosphorylation pathways in rats.

Keywords

• Ginseng total saponins
• Weightlessness simulation
• Learning and memory
• Reward-directed instrumental learning
• N-Methyl-D-aspartic acid receptors