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Effects of early protein malnutrition and repeated testing upon locomotor and exploratory behaviors in the elevated
S S Almeida1, R A Garcia, L M de Oliveira
1Laboratory of Psychobiology, FFCLRP, University of São Paulo, Ribeirão Preto, Brazil.
Insights
Repeated testing in the elevated plus-maze increased anxiety in rats. Malnourished rats exhibited higher exploration and impulsiveness compared to controls, indicating the maze
Area of Science:
- Neuroscience
- Behavioral Science
- Nutritional Science
Background:
- Early life malnutrition can have lasting effects on brain development and behavior.
- The elevated plus-maze is a standard tool for assessing anxiety-like behaviors in rodents.
- Understanding the impact of repeated testing is crucial for reliable behavioral assessments.
Purpose of the Study:
- To investigate the effects of repeated elevated plus-maze testing on locomotor and exploratory behaviors.
- To assess anxiety levels in malnourished rats compared to controls.
- To evaluate the utility of the elevated plus-maze for studying early protein malnutrition.
Main Methods:
- Pup malnutrition induced using a 6% protein diet during lactation (0-21 days).
- Animals recovered on standard chow until 70 days of age.
- Repeated exposure (6 days) to the elevated plus-maze for 5 minutes per session.
Main Results:
- Repeated testing decreased open arm entries, time in open arms, and central platform time, suggesting increased anxiety.
- Malnourished rats showed increased rearing and attempts to enter open arms, indicating higher exploration/impulsiveness.
- No significant changes in total arm entries or attempts to enter open arms with repeated testing.
Conclusions:
- Repeated elevated plus-maze testing can induce anxiety-like behaviors in rats.
- Early protein malnutrition leads to increased exploratory and/or impulsive behaviors.
- The elevated plus-maze is a valuable model for studying behavioral consequences of early malnutrition.
Abstract:
An elevated plus-maze was used to investigate the effects of repeated testing on the locomotor and exploratory behaviors of malnourished rats. Pup malnutrition was induced during the lactation period (0 to 21 days of age) by feeding the dams a protein-deficient diet (6% protein) and the animals were allowed to recover from weaning to 70 days of age by eating a commercial lab chow diet. Control animals were suckled by dams receiving a normal protein diet (16% protein) during the lactation period and were fed a commercial lab chow diet after weaning. At 70 days, malnourished and control animals were placed on the central platform of the elevated plus-maze facing an enclosed arm and allowed to explore for 5 min. This procedure was repeated at 24-h intervals for 6 days. The repeated testing in the elevated plus-maze did not change the total number of arm entries and attempts to enter open arms, but decreased the percentage of open arm entries, time spent in open arms, and total time spent on the central platform. These data suggest an increase in anxiety with repeated testing in the elevated plus-maze. In addition, the malnourished animals showed a larger number of both rearings and attempts to enter the open arms, suggesting a high level of exploration and/or high impulsiveness of these animals as compared to control. The elevated plus-maze proved to be a useful animal model to evaluate exploratory behaviors in early protein malnourished animals.