The effect of SNK12 (CPLP) supplementation on mRNA levels of hippocampal neurotrophic factors and gamma aminobutyric acid receptors (GABA) was tested. In Experiment 1, stress-free, unsupplemented and CPLP (4 × 10 cells/head)-supplemented male C57BL/6J (B6) mice were the experimental animals. In Experiment 2, (male, B6) mice [negative control; unsupplemented, sub-chronic mild social defeat stress (sCSDS)-induced; and CPLP-supplemented, sCSDS-induced] were exposed to mice (adult male Slc:ICR). mRNA levels of neurotrophic factors and GABA in hippocampal samples of these mice were analyzed. In CPLP-supplemented mice of both experiments, mRNA levels of , and GABA were upregulated. Moreover, a tendency toward the improvement of habituation ability (Experiment 1) and behavior (Experiment 2) was observed in mice, which may be associated with upregulated neurotrophic factors and GABA. We demonstrated that oral supplementation of CPLP to stress-free and stress-induced mice upregulated mRNA levels of hippocampal neurotrophic factors and GABA.