Regulation mechanism of peptides derived from sea cucumber (Apostichopus japonicas) for modulation of learning and memory.

Peptides derived from the sea cucumber Apostichopus japonicas have immunomodulatory and antioxidant activities. Three dosage levels of peptide hydrolysates were fed to Institute of Cancer Research (ICR) mice. Standardized Y and Morris water mazes were used to determine the effects of A. japonicas peptides on learning and memory. All 3 mouse test groups showed reductions in the latency period (LP), the number of times that a mouse swam over the location of a platform (NCP), the ratio of the distance from a target quadrant to the total swimming distance (DTQ), and the time spent in the target quadrant (TTQ). Microarray analysis was then carried out and 308 genes were differentially expressed between groups, of which 235 were up and 73 were down regulated in the brains of test group animals, compared with control group animals. Expressions of genes identified in microarrays were then analyzed using qRT-PCR.