Low dose prenatal ethanol exposure induces anxiety-like behaviour and alters dendritic morphology in the basolateral amygdala of rat offspring

PLoS One. 2013;8(1):e54924. doi: 10.1371/journal.pone.0054924. Epub 2013 Jan 30.

Abstract

Prenatal exposure to high levels of alcohol is strongly associated with poor cognitive outcomes particularly in relation to learning and memory. It is also becoming more evident that anxiety disorders and anxiety-like behaviour can be associated with prenatal alcohol exposure. This study used a rat model to determine if prenatal exposure to a relatively small amount of alcohol would result in anxiety-like behaviour and to determine if this was associated with morphological changes in the basolateral amygdala. Pregnant Sprague Dawley rats were fed a liquid diet containing either no alcohol (Control) or 6% (vol/vol) ethanol (EtOH) throughout gestation. Male and Female offspring underwent behavioural testing at 8 months (Adult) or 15 months (Aged) of age. Rats were perfusion fixed and brains were collected at the end of behavioural testing for morphological analysis of pyramidal neuron number and dendritic morphology within the basolateral amygdala. EtOH exposed offspring displayed anxiety-like behaviour in the elevated plus maze, holeboard and emergence tests. Although sexually dimorphic behaviour was apparent, sex did not impact anxiety-like behaviour induced by prenatal alcohol exposure. This increase in anxiety - like behaviour could not be attributed to a change in pyramidal cell number within the BLA but rather was associated with an increase in dendritic spines along the apical dendrite which is indicative of an increase in synaptic connectivity and activity within these neurons. This study is the first to link increases in anxiety like behaviour to structural changes within the basolateral amygdala in a model of prenatal ethanol exposure. In addition, this study has shown that exposure to even a relatively small amount of alcohol during development leads to long term alterations in anxiety-like behaviour.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amygdala / drug effects*
  • Amygdala / pathology*
  • Amygdala / physiopathology
  • Animals
  • Anxiety / chemically induced*
  • Anxiety / pathology*
  • Anxiety / physiopathology
  • Behavior, Animal / drug effects*
  • Dendrites / drug effects
  • Dendrites / pathology*
  • Dose-Response Relationship, Drug
  • Ethanol
  • Female
  • Interpersonal Relations
  • Male
  • Maze Learning / drug effects
  • Mothers
  • Pregnancy
  • Prenatal Exposure Delayed Effects / pathology*
  • Prenatal Exposure Delayed Effects / physiopathology
  • Prenatal Exposure Delayed Effects / psychology
  • Rats
  • Rats, Sprague-Dawley

Substances

  • Ethanol

Grants and funding

This work was supported by a project grant from the National Health and Medical Research Council of Australia. KMM is supported by a NH&MRC Senior Research Fellowship and CC by an Australian post-graduate award. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.