Promoting effects of collapsin-response mediator protein 2 on memory formation in rats

Abstract

The article concerns the study of the effect of collapsin-response mediator protein 2 (CRMP2) on long-term memory formation in male and female Wistar rats. In the 1^st experimental series, male rats were subjected to audiogenic stress, and only stress-resistant male rats were chosen for the following experiments. The animals were culled into 2 groups: 1) the control group, and 2) the experimental group. The rats of the experimental group were trained in the shuttle box for 6 days by presenting sound followed by electric shock to the paws, while the control animals were exposed to these stimuli in occasional order. After reaching 80% of correct trials, all animals were sacrificed, the hippocampus and the left parietal cortex were removed from the brain, and CRMP2 levels were evaluated by an indirect ELISA test. Significant upregulation of CRMP2 was revealed in the left parietal cortex of the experimental animals, while in the hippocampus, no changes were observed. In the 2^nd experimental series, the food-deprived female rats in pairs were put into a dominant behavior box for 5 min, for 5 successive days. Based on the duration of the timeframe spent at the feeder, the dominant and submissive rats were identified. In the 3^rd experimental series, the dominant and submissive animals were placed one-by-one into the container with fresh water for 5 min and the total duration of passive swimming was recorded. The passive swimming time of the submissive rats was 2.5 times higher than that of the dominant specimens. In the 4^th experimental series, the animals of both groups were trained in a shuttle box for 6 successive days, and the submissive animals demonstrated higher scores on correct trials compared to the dominant specimens. In the 5^th experimental series, the levels of CRMP2 in the amygdala, hippocampus, and left parietal cortex of the brains of the submissive and dominant rats were evaluated by an indirect ELISA test. The results showed higher levels of CRMP2 in the brain structures of the submissive rats relative to the dominant specimens. The conclusion regarding the promoting effect of CRMP2 upregulation in the brain structures on memory formation is made.