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High corticosterone levels in prenatally stressed rats predict persistent paradoxical sleep alterations
Insights
Prenatal stress in rats causes long-term sleep disturbances and elevated corticosterone, mirroring changes seen in human depression. These findings suggest prenatal stress may be a valuable animal model for studying depression and its effects on sleep.
Area of Science:
- Neuroscience
- Psychiatry
- Animal Models
Background:
- Prenatal stress induces lasting behavioral and hormonal changes in rodents.
- These changes resemble symptoms observed in human depression, including anxiety and altered stress responses.
- Sleep disturbances and hypercortisolemia are common in depressed individuals.
Purpose of the Study:
- To investigate sleep-wake parameters in adult rats exposed to prenatal stress.
- To examine the relationship between sleep alterations and corticosterone levels in these rats.
- To assess the utility of prenatal stress as an animal model for depression.
Main Methods:
- Comparison of sleep-wake patterns between control and prenatally stressed adult rats.
- Measurement of plasma corticosterone levels at baseline and after acute stress.
- Analysis of correlations between sleep parameters and corticosterone levels.
Main Results:
- Prenatally stressed rats exhibited increased paradoxical sleep, sleep fragmentation, and altered slow-wave sleep.
- These sleep changes were positively correlated with baseline and stress-induced corticosterone levels.
- Sleep alterations persisted even after recovery from acute stress.
Conclusions:
- Prenatal stress leads to persistent, long-term sleep-wake disturbances in rats.
- Elevated corticosterone levels are associated with these sleep alterations.
- The study supports the use of prenatal stress as a relevant animal model for depression research.
Abstract:
Prenatal stress predisposes rats to long-lasting disturbances that persist throughout adulthood (e.g., high anxiety, dysfunction of the hypothalamo-pituitary-adrenal axis, and abnormal circadian timing). These disturbances parallel to a large extent those found in depressed patients, in which hypercortisolemia and sleep alterations may be related to stress-inducing events. We studied sleep-wake parameters in control and prenatally stressed adult rats (3-4 months old) and examined possible relationships with their corticosterone levels (determined at 2 months of age). Under baseline conditions, prenatally stressed rats showed increased amounts of paradoxical sleep, positively correlated to plasma corticosterone levels. Other changes include increased sleep fragmentation, total light slow-wave sleep time, and a slight decrease in the percentage of deep slow-wave sleep relative to total sleep time. During recovery sleep from acute restraint stress, all sleep changes persisted and were correlated with stress-induced corticosterone secretion. High corticosterone levels under baseline conditions as well as an acute stress challenge may thus predict long-term sleep-wake alterations in rats. Taken together with other behavioral and hormonal abnormalities in prenatally stressed animals, the pronounced changes in sleep-wake parameters that are similar to those found in depressed patients suggest that prenatal stress may be a useful animal model of depression.