Determining of Operating Condition for the Open Field Test under Nonclinical Fertility Study

抄録

Open field test is a test for observing behavioral movement in detail and it is also a test for detecting chronological change of behavior, when an animal is put in a strange environment. The author and his colleague have established a standardized method including the determination of operating conditions, the analysis of data, and evaluation of the results based on the basal data that we have accumulated. In the present report, we have mentioned a process which we have established as valid up to the present. Namely, it involves one 3-minute trial at age 35 days. As the result of a large number of subjects which received the test under these operating condition, the physiological normal range in the ambulation values was 27.1 to 97.7 (times/trial) for the male and 42.0 to 105.5 (times/trial) for the female, and that in the rearing values was 2.6 to 30.6 for the male and 5.6 to 33.6 for the female. Thus there are sexual differences. Besides, variation due to estrous cycle is confirmed in the female. However, the coefficient of variance in females' group is always lower than males' in the ambulation and the rearing scores. It is interesting to note that variation in the females is lower than that in the males even if estrous variance was included. Consequently, when we compare the difference of mean score, it could be possible to neglect an effect caused by estrous differences. We are now utilizing this information to find abnormal animals or to evaluate the results in the nonclinical fertility study.