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Published on: February 18, 2016
Effects of postnatal cocaine exposure and environmental enrichment on rat behavior in a forced swim test
Ana Magalhães1, Teresa Summavielle, Maria Amélia Tavares
1Neurobehavior Unit, Institute for Molecular and Cellular Biology, University of Porto, Porto, Portugal. anam@ibmc.up.pt
Insights
Environmental enrichment can mitigate negative behavioral effects of early-life cocaine exposure in rats. Enriched environments promote more active coping strategies in young rats facing stress.
Area of Science:
- Neuroscience
- Behavioral Science
- Developmental Toxicology
Background:
- Early-life exposure to drugs of abuse can have lasting impacts on behavior.
- Environmental factors play a crucial role in neurodevelopment and behavioral outcomes.
Purpose of the Study:
- To investigate the impact of environmental enrichment on behavioral responses in rats exposed to cocaine during early development.
- To assess how environmental enrichment influences coping strategies in a stress test following early-life cocaine exposure.
Main Methods:
- Wistar rats were exposed to cocaine or saline from postnatal days 1-27.
- Rats were housed in either standard or enriched environments.
- Behavioral analysis was conducted using a forced swim test on postnatal days 26-27, measuring categories like swimming, struggling, diving, and immobility.
Main Results:
- Postnatal cocaine exposure in a standard environment led to decreased fast swimming and increased immobility.
- Environmental enrichment alone increased active behaviors (fast swim, slow swim, diving) and decreased immobility.
- Environmental enrichment counteracted some negative effects of cocaine, increasing fast swim and struggling while reducing immobility compared to cocaine-exposed rats in standard environments.
Conclusions:
- Early-life cocaine exposure impairs coping mechanisms in stressful situations.
- Environmental enrichment appears to facilitate more active and adaptive behavioral strategies in young rats, mitigating some adverse effects of prenatal cocaine exposure.
Abstract:
This study examined the effects of environmental enrichment on rats exposed to cocaine during the first month of life, in several categories of behavior observed in a forced swim test. Wistar rats were divided in four groups. The first included pups that were subjected to injections of cocaine hydrochloride (15 mg/kg body weight/day, subcutaneously, in two daily doses, from postnatal days 1 to 27) and reared in an enriched environment (CocEE); the second, pups that were subjected to injections of cocaine (as previously described) and reared in a standard environment (CocSE); the third, pups that were subjected to saline injections and reared in an enriched environment (SalEE); the fourth, pups that were subjected to saline injections and reared in a standard environment (SalSE). On postnatal days 26 and 27, rats were tested in a swimming pool in two 5-min sessions. The categories of behavior studied in this work were: fast swim, slow swim, struggling, diving, and immobility. Results showed that postnatal cocaine exposure decreased the time spent on fast swim during the two sessions and increased the immobility behavior during the second session in CocSE pups compared with SalSE pups. SalEE pups increased the time spent in fast swim, slow swim, and diving, and decreased the time spent in struggling and immobility during the two sessions compared with SalSE pups. CocEE animals spent more time in fast swim and struggling and less the time in immobility compared with CocSE pups. The present results suggest that postnatal cocaine exposure affects the ability of these animals to cope with stressful situations, and that environmental enrichment seems to enable the rats to adopt a more active strategy, one that allows them to better cope with this particular stress situation.
