Explorative strategies in the open field (OF), elevated plus maze (EPM) and multivariate concentric square field^TM (MCSF) in adolescent male Wistar rats

Abstract:

Mental disorders, like anxiety and depression, are a major health problem and can appear early in life. Developing new compounds for anxiety and other mental disorders is desirable and requires good animal models. Two widely used tests to evaluate fear and anxious behavior in rodents are the open field (OF) and elevated plus maze (EPM) tests. The models are simple and it has been argued that different environments give different behavior profiles and measure different kind of behavior. The multivariate concentric square field^TM (MCSF) is a new test that gives the rodent opportunity to visit different environments and to evaluate more parameters in one test. Validation of the tests is mainly done with adult animals. The aim with this study is to study adolescent rat behavior in the OF, OF with start box, EPM and MCSF tests and to see if there is any difference in running trials in the morning or in the afternoon. A total of 48 adolescent male Wistar rats were divided into 12 rats per group. The groups were OF and MCSF, OF with start box and MCSF, EPM and MCSF, and repeated testing in MCSF. Each session was 20 minutes and there was one week between the two tests. Three rats where run in the morning and three in the afternoon. Statistical analysis did show significant difference in some parameters in the comparison between running trials in the morning or in the afternoon. Repeated testing in the MCSF yielded differences in trial two compared to trial one. No significant difference was found in the trend analysis. The results show individual differences and with larger groups results may have been more liable. In this study some differences were found between morning and afternoon groups. Lots of data have been generated and there are many opportunities to use the same data for additional analyses.