Alteration of catecholamine uptake in cerebral cortex from rats fed a saturated fat diet

The transport of [³H]norepinephrine into chopped cerebral cortex of neonates was changed by feeding pregnant rats with semisynthetic diets enriched in saturated fat (coconut oil) as compared to polyunsaturated fat (sunflower oil). There was a significant decrease in the uptake of norepinephrine in neonates from dams fed coconut oil compared to neonatal pups from animals fed sunflower oil. Differences were observed on days 7, 11, 24, and 37 but not in adults which had been maintained on the diet since birth. Kinetic analysis of norepinephrine uptake on day 7 neonates demonstrated a 5-fold increase in K_m and a 2-fold increas in V_max for the coconut oil fed group as compared to control or the sunflower oil fed rats. [³H]Dopamine uptake kinetics revealed no significant difference in day 7 neonates but a doubling of the K_m and V_max in day 37 rats and in adults fed coconut oil. Lipid analysis of cerebral cortex synaptosome membrane fractions revealed significant differences in the fatty acyl composition of the phospholipid. The results indicate that the norepinephrine and dopamine transport systems can be differentially affected by dietary lipid composition in the developing rat. It is suggested that the changes may be due to alterations in membranes fluidity in the local environment of the transport system.