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Behavior ontogeny in the elevated plus-maze: prenatal stress effects
Celio Estanislau1, Silvio Morato
1Faculdade de Filosofia Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Av. Bandeirantes, 3900, 14040-901 Ribeirão Preto-SP, Brazil.
Insights
Prenatal stress increases anxiety in adult offspring, but effects vary with age. Anxiogenic effects in the elevated plus-maze appear in adulthood, with a transient anxiolytic-like effect in adolescence.
Area of Science:
- Neuroscience
- Developmental Psychology
- Behavioral Pharmacology
Background:
- Prenatal stress is a key factor in psychopathology development.
- Stress during pregnancy can lead to heightened anxiety in offspring.
- The developmental trajectory of prenatal stress effects on anxiety is not well understood.
Purpose of the Study:
- To investigate the developmental impact of prenatal stress on anxiety-like behaviors.
- To determine how prenatal stress interacts with anxiety across different life stages in rats.
- To analyze behavioral changes in prenatally stressed rats using the elevated plus-maze.
Main Methods:
- Pregnant rats were exposed to uncontrollable foot shocks or left undisturbed.
- Offspring (male and female) were tested in the elevated plus-maze at 30, 45, and 60 days of age.
- Behavioral measures included arm entries, time spent in arms, and naturalistic behaviors.
Main Results:
- Prenatally stressed rats showed reduced anxiety-like behavior (decreased open arm entries/time) only at 60 days old.
- A transient anxiolytic-like effect (increased risk-taking) was observed in 45-day-old males.
- Prenatally stressed rats were heavier at younger ages, but this difference vanished in adulthood.
Conclusions:
- Anxiogenic effects of prenatal stress manifest in early adulthood, not before.
- Prenatal stress can induce age-dependent behavioral changes, including transient anxiolytic-like effects.
- These findings highlight the complex, time-sensitive impact of prenatal stress on offspring anxiety.
Abstract:
Prenatal stress is a putative model for studying some psychopathological disorders. Indeed, submitting pregnant animals to stress leads to enhanced anxiety in the adult offspring. However, little is known about how prenatal stress effects interacts with anxiety throughout development. To study this issue, prenatally stressed rats were tested in the elevated plus-maze at different ages. During pregnancy female rats were submitted to uncontrollable electric foot shock sessions every other day or kept undisturbed (controls). After delivery, litters from control and stressed dams were left undisturbed from the 3rd to the 14th postnatal days. Male and female rats were tested in the elevated plus-maze at the ages of 30, 45 or 60 days. The following measures were taken in the elevated plus-maze: number of entries and time spent in the arms (or their extremities) and frequency and time spent in naturalistic behaviors (stretching, rearing, end exploring, grooming and head dipping). Decreases in the percentage of entries into and in the time spent (only females) in the open arms were shown by 60-day-old prenatally stressed rats, but not by 30- and 45-day old. Increased open arm ends exploration was shown by 45-day-old prenatally stressed males. Rearing behavior was found to increase with age, a phenomenon more pronounced in females. Additionally, at the younger ages prenatally stressed rats were heavier than controls, an effect which disappeared at young adulthood. In conclusion, anxiogenic prenatal stress effects in the elevated plus-maze could only be detected at early adulthood, not before. Nonetheless, at late adolescence (45 days of age) prenatal stress leaded to an anxiolytic-like effect which can be interpreted as increased risk-taking behavior.
