Prenatal stressors in rodents: Effects on behavior

Abstract

The current review focuses on studies in rodents published since 2008 and explores possible reasons for any differences they report in the effects of gestational stress on various types of behavior in the offspring. An abundance of experimental data shows that different maternal stressors in rodents can replicate some of the abnormalities in offspring behavior observed in humans. These include, anxiety, in juvenile and adult rats and mice, assessed in the elevated plus maze and open field tests and depression, detected in the forced swim and sucrose-preference tests. Deficits were reported in social interaction that is suggestive of pathology associated with schizophrenia, and in spatial learning and memory in adult rats in the Morris water maze test, but in most studies only males were tested. There were too few studies on the novel object recognition test at different inter-trial intervals to enable a conclusion about the effect of prenatal stress and whether any deficits are more prevalent in males. Among hippocampal glutamate receptors, NR2B was the only subtype consistently reduced in association with learning deficits. However, like in humans with schizophrenia and depression, prenatal stress lowered hippocampal levels of BDNF, which were closely correlated with decreases in hippocampal long-term potentiation. In mice, down-regulation of BDNF appeared to occur through the action of gene-methylating enzymes that are already increased above controls in prenatally-stressed neonates. In conclusion, the data obtained so far from experiments in rodents lend support to a physiological basis for the neurodevelopmental hypothesis of schizophrenia and depression.

Juvenile stress causes reduced locomotor behavior and dendritic spine density in the prefrontal cortex and basolateral amygdala in Sprague–Dawley rats

“…Little relevance has been given to the stress during the stage before puberty. This stage is considered by several reports as juvenile (Argue & McCarty, ; Burke, McCormick, Pellis, & Lukkes, ; Horovitz et al, ; Schmitt et al, ; Weinstock, ) and it is also considered the social play behavior stage in rats (for review see Argue & McCarty, ). Interestingly, our data show that juvenile stress results in a reduced locomotor activity in a novel environment before and after puberty; together there are changes in dendritic morphology of the limbic cortical regions.…”

Effects of prenatal stress on anxiety‐ and depressive‐like behaviours are sex‐specific in prepubertal rats

“…The sex‐specific effects induced by prenatal stress on anxiety‐ and depressive‐like behaviours is lost in adult rats . The amygdala is the main brain area that regulates mood and plays a major role in the development of anxiety‐ and depressive‐like behaviours .…”

The association between perinatal hypoxia exposure and externalizing symptoms and children’s decision making in conditions of uncertainty is moderated by DRD2 genotype

“…The observed increase in conservative decision making is consistent with the neuronal effects of cortisol release in response to hypoxic stress. Prenatal cortisol exposure has been shown to contribute to a decrease in tolerance for uncertainty, driving individuals toward more cautious and conservative behavior (Weinstock, 2017), likely through an increase in D2 receptor expression (Rodrigues et al, 2012). The possibility that hypoxia has differential effects on brain development as a function of genotype is consistent with research indicating that D2 receptors contribute to the cellular response to acute hypoxic events.…”

“…In the context of low-grade hypoxic exposure, it is possible that cortisol release will reduce the extent of neuronal damage, while still altering the sensitivity of the developing dopamine system (Gatzke-Kopp, 2011). Prenatal chronic stress exposure has been shown to lead to more conservative behavioral phenotypes in rodents (Weinstock, 2017), and this effect appears to be associated with a significant and selective upregulation of D2 receptors (Rodrigues et al, 2012). If stress exposure induces D2 receptor expression, A1- individuals may show a greater tendency toward conservative decision making in response to hypoxia exposure due to their ability to produce more efficient receptors.…”