Enhanced learning and memory of normal young rats by repeated oral administration of Krill Phosphatidylserine

Abstract

Objective

Phosphatidylserine, a major acidic phospholipid in the brain, has been studied extensively in regard to its actions on brain functions. The present study examined the effects of Krill phosphatidylserine (Krill-PS) on the learning and memory function and the neural activity in the normal young rats.

Methods

The rats were administered saline or Krill-PS (Krill-PS 50, 100 mg/kg, per oral) daily for 30 days. The cognitive improvement effect of Krill-PS on the normal young rats was investigated by assessing the Morris water maze (MWM) test and by insulin-like growth factor (IGF) and brain-derived neurotrophic factor (BDNF) immunohistochemistry. A positron emission tomography (PET) scan was also performed.

Results

Treatment with Krill-PS (100 mg/kg) produced a significant improvement of the escape latency to find the platform in the MWM at the 3rd day compared to that of the normal group. In the retention test, the Krill-PS100 group showed markedly increased time spent, distance, and crossing number around the platform compared to that of the normal group. Consistent with the behavioral data, the Krill-PS 100 group was significantly enhanced the BDNF and IGF immuno-positive neurons in the hippocampal CA1. In the PET analysis, the glucose uptake of the Krill-PS-treated groups was increased in the frontal lobe and hippocampus.

These results suggest that repeated Krill-PS treatment may be useful for improving the cognitive function via regulation of neuronal growth factor activity.

Keywords:

• Brain-derived neurotrophic factor (BDNF)
• Insulin-like growth factor (IGF)
• Krill phosphatidylserine (Krill-PS)
• Morris water maze
• Positron emission tomography (PET)

Acknowledgements

This research was supported by a grant from the Korea Healthcare Technology R& D Project, Ministry for Health, Welfare & Family Affairs (grant no. A091037), Republic of Korea and the Original Technology Research Program for Brain Science through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology (2011-0030091).