Elsevier

Physiology & Behavior

Volume 142, 1 April 2015, Pages 155-160
Physiology & Behavior

Psychological or physical prenatal stress differentially affects cognition behaviors

https://doi.org/10.1016/j.physbeh.2015.02.016Get rights and content

Highlights

  • Prenatal stress effects on motor function is sex and stressor dependent.

  • Motor function was impaired in male and female offspring in a stressor-dependent manner.

  • Prenatal stress effects on cognitive function are sex and stressor dependent.

  • Anxiety-like behaviors are only altered in female offspring of the stressed mothers.

Abstract

Introduction

Prenatal stress is proposed as a major risk factor in the development of cognitive impairments in the offspring. The objective of the current study was to evaluate the effect of prenatal physical or psychological stress on the motor and cognitive functions of male and female offspring.

Methods

Adult female rats were stressed during their conception using a novel method to induced whether physical or psychological stress. Animal offspring were then kept until adulthood. Elevated plus maze (EPM) was used to evaluate their anxiety-like behavior. Rotarod and wire grip were used to evaluate muscle strength and balance function. Morris water maze (MWM) and passive avoidance (PA) learning and memory paradigm were used to evaluate the cognitive function of the offspring.

Results

Female offspring of both physical and psychological stress had an increased anxiety-like behavior in the EPM test in comparison to female control rats. Balance function was impaired in physical stressed female offspring in comparison to the control and male offspring. Muscle strength was reduced in physical male and female offspring. Both male and female offspring groups that underwent prenatal physical and psychological stress had an impaired spatial learning and memory. PA learning and memory were impaired in both male and female offspring except for the psychological stress female offspring in PA learning.

Conclusion

Results of our study revealed that prenatal physical or psychological stress have different effects on motor and cognitive functions of the offspring. Male and female offspring were differentially affected by prenatal stress. We suggest more studies to evaluate the role of sex hormones on the effects of prenatal physical or psychological stress on cognitive and motor functions of the offspring.

Introduction

Stress during pregnancy has been shown to be associated with cognitive impairments in adulthood of the children. Prenatal stress is considered as a risk factor for psychiatric disorders such as schizophrenia and autism [8], [9], [12]. Previous animal studies have demonstrated cognitive deficits similar to that observed in schizophrenic patients in the offspring of female exposed to different stressors [4], [10].

Glucocorticoids play a prominent role in the development of neural system during fetal period as it is shown that HPA axis is reprogrammed by the stressors during pregnancy [10], [20], [23]. Though the exact mechanisms are not fully understood, exposure to excessive stress hormones during the fetal period leads to the delayed development of the nervous system and inhibition of neurogenesis in different parts of the brain, which might provide an explanation for the cognitive deficits observed in the offspring [7], [14].

It is previously demonstrated that prenatal stress increases the anxiety-like behaviors and post-natal handling leads to low-anxiety in rats. Though studies have attempted to assess the anxiety-like behaviors and cognitive function of the prenatally stressed rats, there is still a lack of evidence for the effect of different prenatal stressors on the adolescent offspring cognitive functions [3], [10], [11], [12]. It is previously shown that different stressors have diverse effects on cognition and other function of the animals. Proposed mechanisms for these differences include the activation of different brain regions and involvement of different neurotransmitters and also the level of threat that each stressor evokes in the animals [9], [15]. Considering the importance of stressor type, it seems rational to evaluate the effect of prenatal physical or psychological stress on the cognitive function of the offspring to see whether any of them is more harmful than the other one or not.

Thus, the objective of the current study was to evaluate the effect of prenatal physical or psychological stressor on cognitive and motor functions of the adolescent male and female offspring. We evaluated the effect of prenatal physical or psychological stress on spatial and fear learning and memory and we also assessed motor and balance functions of the animals.

Section snippets

Methods and materials

Female rats with no experience of sexual activity were used in the current study. They were caged in the groups of four with free access to food and water. Animals were kept under standard conditions according to the guidelines provided by Kerman University of Medical Sciences, Kerman, Iran. Maximum effort was made to minimize pain and discomfort for the animals.

The effect of prenatal stress on mobility and anxiety-like behaviors

Data of the open field test revealed no significant difference among groups of study in both male and female offspring (p > 0.05) (data not shown).

Male offspring that were exposed to prenatal physical or psychological stress did not show any significant difference in elevated plus maze test in comparison to the control male rats (p > 0.05, ANOVA). Female offspring of the physical and psychological prenatal stress had a decreased number of entrances into the open arms in comparison to the control

Discussion

Results of the current study imply a role for the type of stressor applied prenatally and the role of sex hormones in response of the offspring prenatally exposed to different stressors. Female offspring had an increased anxiety-like behavior in comparison to their control groups. Balance and motor functions of the offspring were also impaired in female groups. Spatial and passive avoidance learning and memory were also altered in a sex and stressor-type dependent manner.

It was previously

Conclusion

The effects of prenatal exposure to physical or psychological stress on anxiety-like behaviors, motor function and learning and memory were evaluated in adolescent male and female offspring. Results of our study suggest a sex and stressor-dependent response to prenatal stress. We suggest further studies to elucidate the possible mechanisms involved to provide better preventive and treatment modalities for at risk populations.

Conflict of interest

The authors declare no conflict of interest. This study was performed by a grant from the Kerman Neuroscience Research Center [KNRC/93-35] for the MSc thesis of Samaneh Ghotbi.

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