Maternal dietary loads of α-tocopherol differentially influence fear conditioning and spatial learning in adult offspring

Physiol Behav. 2011 Oct 24;104(5):809-15. doi: 10.1016/j.physbeh.2011.07.026. Epub 2011 Aug 4.

Abstract

α-Tocopherol, the main component of vitamin E, is well known to be a radical scavenger, so an increased intake of vitamin E is recommended in complicated pregnancy, to prevent possible fetus damage by free radical. In a previous work, we found that maternal α-tocopherol supplementation affects PKC-mediated cellular signaling and hippocampal synaptic plasticity in developing brain; the latter effect persists in adulthood. Here, adult rats maternally exposed to supranutritional doses of α-tocopherol were evaluated for Contextual Fear Conditioning and spatial learning in Morris Water Maze, two different hippocampus-dependent learning tasks. Moreover, anxiety, spontaneous activity, and explorative drive were also evaluated as factors potentially affecting learning performance. Treated rats showed a different behavior with respect to controls: performance in Contextual Fear Conditioning was improved, while spatial learning tested in Morris Water Maze, was impaired. The improvement of fear response was not ascribable to differences in anxiety level and/or spontaneous activity; thus it appears to be a specific effect of α-tocopherol overloading during brain development. On the contrary, the impaired performance in Morris Water Maze exhibited by treated rats can be in part explained by their enhanced explorative drive. Although extrapolation from rats to humans is difficult, a caveat in assuming supranutritional doses of vitamin E in pregnancy arises from this study.

MeSH terms

  • Adult Children*
  • Analysis of Variance
  • Animals
  • Antioxidants / administration & dosage*
  • Conditioning, Psychological / drug effects*
  • Dark Adaptation / drug effects
  • Dark Adaptation / physiology
  • Exploratory Behavior / drug effects
  • Fear*
  • Female
  • Freezing Reaction, Cataleptic / drug effects
  • Freezing Reaction, Cataleptic / physiology
  • Hippocampus / drug effects
  • Hippocampus / physiology
  • Maternal-Fetal Exchange
  • Maze Learning / drug effects
  • Maze Learning / physiology
  • Pregnancy
  • Rats
  • Rats, Sprague-Dawley
  • Time Factors
  • alpha-Tocopherol / administration & dosage*
  • alpha-Tocopherol / metabolism

Substances

  • Antioxidants
  • alpha-Tocopherol