The effect of CDP-choline on learning and memory parameters in sleep deprivated rats

In this study, the effects of various doses of cytidine diphosphocholine (CDP-choline) on the well known negative effects of Rapid Eye Movements (REM) sleep deprivation on learning and memory were investigated. Male Wistar albino rats (n=72, 200-300 g, 8-12 weeks old) were randomized to 12 groups and placed in appropriate cages. Sleep deprivation or environmental control was induced by placing rats on a platform with 6.5 cm or 13 cm diameter, respectively, for 4 days according to "Flower pot" method. Learning parameters were tested for 4 consecutive days (trial phase) and on the 5th day (probe phase) memory parameters were tested in Morris Water Maze. 30 minutes before the Morris water maze experiments saline or 100 µmol/kg, 300 µmol/kg, 600 µmol/kg doses of CDP-choline were administered intraperitoneally. After behavioral tests rats were decapitated and then phosphorylated cyclic adenosine monophosphate response element binding (pCREB), total Ca2+/calmodulin-dependent protein kinase II (tCaMKII) and β-tubulin proteins were analyzed in hippocampus homogenates using Western-blot technique. In our study, we observed that selective REM sleep deprivation had no effect on learning parameters but may impaire memory parameters. We determined that CDP-choline can reduce the impairment in memory parameters. It has been observed that the model used to generate sleep deprivation may cause stress therefore affects the learning and memory parameters and CDP-choline may have positive effects on stress. Western blot analyzes revealed that, the ratio of total CaMKII was unchanged while the rate of pCREB was decreased as a result of sleep deprivation. Key Words: REM sleep deprivation, Morris water maze, learning, memory, CDP-choline