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Updated: Apr 22, 2026
Using Chronic Social Stress to Model Postpartum Depression in Lactating Rodents
Published on: June 10, 2013
Neonatal stress-induced affective changes in adolescent Wistar rats: early signs of schizophrenia-like behavior
Carlos Eduardo Neves Girardi1, Natália Cristina Zanta1, Deborah Suchecki1
1Department of Psychobiology - Escola Paulista de Medicina, Universidade Federal de São Paulo São Paulo, SP, Brazil.
Insights
Early life stress in rats, specifically maternal deprivation (MD), can lead to long-term behavioral changes and heightened stress responses, suggesting its utility in modeling psychiatric disorders like schizophrenia.
Area of Science:
- Neuroscience
- Psychiatry
- Animal Models
Background:
- Psychiatric disorders are complex, influenced by genetics, environment, and stress.
- The neurodevelopmental hypothesis of schizophrenia links perinatal insults to increased vulnerability.
- Maternal deprivation (MD) in neonatal rats models schizophrenia by affecting stress responses.
Purpose of the Study:
- To investigate the long-term emotional consequences of early life stress (maternal deprivation) in rats.
- To determine if maternal presence influences the effects of early life stress.
- To assess the impact of stress challenges on behavior and corticosterone levels.
Main Methods:
- Neonatal rats were subjected to maternal deprivation (22 hours) or not.
- Pups and adolescents underwent stress challenges (saline injection).
- Behavioral tests (open field, elevated plus maze, social investigation, negative contrast sucrose test) and corticosterone levels were measured.
Main Results:
- Maternally deprived rats showed higher corticosterone levels, especially when stressed.
- Social investigation was impaired only in maternally deprived rats.
- Stress challenge increased anxiety-like behavior and impaired sucrose consumption, independent of MD.
- Reduced exploration in the open field was observed in maternally deprived rats and stressed controls.
Conclusions:
- Early life stress, modeled by maternal deprivation, induces lasting emotional and neuroendocrine changes.
- Stressful stimuli alone can elicit differential emotional consequences, independent of early life stress.
- The maternal deprivation paradigm is a valuable model for studying early signs of psychiatric dysfunction, including schizophrenia.
Abstract:
Psychiatric disorders are multifactorial diseases with etiology that may involve genetic factors, early life environment and stressful life events. The neurodevelopmental hypothesis of schizophrenia is based on a wealth of data on increased vulnerability in individuals exposed to insults during the perinatal period. Maternal deprivation (MD) disinhibits the adrenocortical response to stress in neonatal rats and has been used as an animal model of schizophrenia. To test if long-term affective consequences of early life stress were influenced by maternal presence, we submitted 10-day old rats, either deprived (for 22 h) or not from their dams, to a stress challenge (i.p. saline injection). Corticosterone plasma levels were measured 2 h after the challenge, whereas another subgroup was assessed for behavior in the open field, elevated plus maze (EPM), social investigation and the negative contrast sucrose consumption test in adolescence (postnatal day 45). Maternally deprived rats exhibited increased plasma corticosterone (CORT) levels which were higher in maternally deprived and stress challenged pups. Social investigation was impaired in maternally deprived rats only, while saline injection, independently of MD, was associated with increased anxiety-like behavior in the EPM and an impaired intake decrement in the negative sucrose contrast. In the open field, center exploration was reduced in all maternally-deprived adolescents and in control rats challenged with saline injection. The most striking finding was that exposure to a stressful stimulus per se, regardless of MD, was linked to differential emotional consequences. We therefore propose that besides being a well-known and validated model of schizophrenia in adult rats, the MD paradigm could be extended to model early signs of psychiatric dysfunction, and would particularly be a useful tool to detect early signs that resemble schizophrenia.
