Effects of Dietary n-3 Fatty Acid Deficiency on Morris Water-Maze Performance and Amphetamine-Induced Conditioned Place Preference in Rats.

In these studies we examined whether dietary n-3 fatty acid (FA) deficiency in adult male rats was associated with effects on performance in the Morris water-maze and with the development of a conditioned place preference to low (0.5 mg/kg) and high (2.0 mg/kg) doses of amphetamine. The male rats used in these studies had been raised for two generations on n-3 deficient diets, which produced an n-6: n-3 FA ratio in brain lipids three times that of animals fed an n-3 adequate diet. Although the two groups did not differ on learning the position of the hidden platform in the Morris water-maze, the n-3 deficient rats did show deficits on a subsequent working memory version of this task, and swam longer distances to reach a visible platform. There were no differences between the groups on the development of a conditioned place preference although, during the initial conditioning cycle, the increase in activity in response to the high dose of amphetamine was apparent only in the n-3 deficient group. These findings provide preliminary support for effects of n-3 FA deficiency on working memory, but not on motivational processes as measured by response to a drug reward.