Effects of dietary vegetable oils on behavior and drug responses in mice

Previously, we noted significant differences in the behavioral patterns of mice fed safflower oil with a very low alpha-linolenate/linoleate ratio and perilla oil with a high alpha-linolenate/linoleate ratio from mothers to offsprings. In this report, we compared the behavior and drug responses in mice fed diets containing six different vegetable oils-corn, rapeseed, soybean, safflower, perilla and a mixture of perilla and safflower oils- for a relatively short period: 8 months after weaning. Soybean oil is a component of most conventional diets and was used as a control. The alpha-linolenate/linoleate ratios of the oils appeared to affect the locomotor activities in a wheel cage: the activity decreased in the order of safflower, the mixture (1:1) and the perilla oil groups. However, the rapeseed oil group exhibited much higher locomotor activity than that expected from the alpha-linolenate/linoleate ratio. Additionally, the rapeseed oil group exhibited unusual behavior patterns, including higher ambulation and rearing activities, faster acquisition of the water maze task and slower habituation behavior as compared with the control group. Susceptibility to pentobarbital anesthesia tended to be higher in the rapeseed oil group. The differences in the alpha-linolenate/linoleate ratios of these oils alone do not account for the observed differences in the behavioral patterns among the six dietary groups. Although we cannot exclude the possibility that the observed behavioral anomaly is due to the unique fatty acid composition of rapeseed oil, we speculate that a factor(s) other than fatty acids in rapeseed oil affected nervous system functions.