Effect of dietary lipid on locomotor activity and response to psychomotor stimulants.

Spontaneous locomotor activity was investigated in developing rats fed diets rich in either saturated fat (coconut oil) or polyunsaturated fat (sunflower oil). The locomotor activity response to amphetamine, methylphenidate, and atropine in the dietary groups was also measured. Rats from dams fed sunflower oil had a late developing (20 days of age) increase in basal locomotor activity when compared to rats from dams fed coconut oil and the standard laboratory diet. The locomotor activity response to d-amphetamine administered IP to 30-day-old animals was potentiated in rats exposed to coconut oil compared to the other two groups. A dose-response analysis of the effect of methylphenidate revealed no differences among the dietary groups. A low dose of atropine (2 mg/kg) decreased 1 h locomotor activity 40% below basal level in rats fed sunflower oil but increased locomotor activity 90% over basal activity in rats fed coconut oil. These results indicate that dietary lipid can have a marked effect on basal locomotor activity as well as on the response to stimulant drugs.