Dietary n-3 fatty acid restriction during gestation in rats: neuronal cell body and growth-cone fatty acids.
Growth cones are membrane-rich structures found at the distal end of growing axons and are the predecessors of the synaptic membranes of nerve endings. This study examined whether n-3 fatty acid restriction during gestation in rats alters the composition of growth cone and neuronal cell body membrane fatty acids in newborns. Female rats were fed a standard control diet containing soy oil (8% of fatty acids as 18:3n-3 by wt) or a semisynthetic n-3 fatty acid-deficient diet with safflower oil (0.3% of fatty acids as 18:3n-3 by wt) throughout normal pregnancy. Experiments were conducted on postnatal day 2 to minimize the potential for contamination from synaptic membranes and glial cells. Dietary n-3 fatty acid restriction resulted in lower docosahexaenoic acid (DHA) concentrations and a corresponding higher docosapentaenoic acid concentration in neuronal growth cones, but had no effects on neuronal cell body fatty acid concentrations. These studies suggest that accretion of DHA in growth cones, but not neuronal cell bodies, is affected by n-3 fatty acid restriction during gestation. Differences in other fatty acids or components between the semisynthetic and the standard diet, however, could have been involved in the effects on growth-cone DHA content. The results also provide evidence to suggest that the addition of new membrane fatty acids to neurons during development occurs along the shaft of the axon or at the growth cone, rather than originating at the cell body.
Auestad
N
N
Department of Paediatrics, University of British Columbia, Vancouver, Canada.
Innis
S M
SM
D000818:Animals; D000831:Animals, Newborn; D001923:Brain Chemistry; D002849:Chromatography, Gas; D018752:Diet, Fat-Restricted / Q000009:adverse effects*; D004281:Docosahexaenoic Acids / Q000032:analysis; D015525:Fatty Acids, Omega-3 / Q000502:physiology*; D005260:Female; D020439:Growth Cones / Q000737:chemistry*; D009474:Neurons / Q000737:chemistry*; D011247:Pregnancy; D051381:Rats; D017208:Rats, Wistar; D017962:alpha-Linolenic Acid / Q000172:deficiency*
D015525:Fatty Acids, Omega-3; D017962:alpha-Linolenic Acid; D004281:Docosahexaenoic Acids