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Foraging enrichment modulates open field response to monosodium glutamate in mice.

Onaolapo OJ, Onaolapo AY, Akanmu MA, Olayiwola G - Ann Neurosci (2015)

Bottom Line: Subchronic administration without enrichment was associated with increased locomotor activity and reduction in grooming, rearing activity however still showed a biphasic response.Addition of enrichment with acute administration resulted in sustained reduction in locomotor and rearing activities with a biphasic grooming response.Behavioural response to varying doses of MSG as observed in the open field is affected by modifications such as foraging enrichment, which can reverse or dampen the central effects seen irrespective of duration of administration.

View Article: PubMed Central - PubMed

Affiliation: Department of Pharmacology, Faculty of Basic Medical Sciences, College of Health Sciences, Ladoke Akintola University of Technology, Oshogbo, Osun State, Nigeria ; Department of Pharmacology, Faculty of Pharmacy, Obafemi Awolowo University, Ile- Ife, Osun State, Nigeria.

ABSTRACT

Background: Environmental enrichment can enhance expression of species-specific behaviour. While foraging enrichment is encouraged in laboratory animals, its impact on novelty induced behaviour remain largely unknown.

Purpose: Here, we studied behavioural response of mice to acute and subchronic oral monosodium glutamate (MSG) in an open field with /without foraging enrichment.

Methods: Adult male mice, assigned to five groups were administered vehicle (distilled water), or one of four selected doses of MSG (10, 20, 40 and 80 mg/kg) for 21 days. Open field novelty induced behaviours i.e. horizontal locomotion, rearing and grooming were assessed after the first and last doses of MSG. Results were analysed using MANOVA followed by Tukey HSD multiple comparison test and expressed as mean ± S.E.M.

Results: Following acute MSG administration without enrichment, locomotor activity reduced, grooming increased, while rearing activity reduced at lower doses and increased at higher doses. Subchronic administration without enrichment was associated with increased locomotor activity and reduction in grooming, rearing activity however still showed a biphasic response. Addition of enrichment with acute administration resulted in sustained reduction in locomotor and rearing activities with a biphasic grooming response. Subchronically, there was reduction in horizontal locomotion, biphasic rearing response and sustained increase in grooming activity.

Conclusion: Behavioural response to varying doses of MSG as observed in the open field is affected by modifications such as foraging enrichment, which can reverse or dampen the central effects seen irrespective of duration of administration.

No MeSH data available.


Effect of Monosodium glutamate on rearing activity in enriched and non enriched mice. Each bar represents Mean ± S.E.M, *p<0.05 compared to vehicle. n = 6; VEH: Vehicle.
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fig_2: Effect of Monosodium glutamate on rearing activity in enriched and non enriched mice. Each bar represents Mean ± S.E.M, *p<0.05 compared to vehicle. n = 6; VEH: Vehicle.

Mentions: Figure 2 compares the rearing response of mice following acute and subchronic administration of varying doses of MSG with or without enrichment respectively to corresponding vehicle (distilled water). Following acute administration without enrichment, rearing activity decreased at 10 (F = 3.69, p = 0.004) and 20 (F = 0.47, p = 0.648) mg/kg of MSG and increased at 40 (F = 2.20, p = 0.053) and 80 (F = 2.29, p = 0.045) mg/kg though, significant effects occurred only at 10 and 80 mg/kg, with introduction of enrichment, rearing activity reduced at all doses of MSG, {10 (F = 0.29, p = 0.777), 20 (F = 11.52, p = 0.001), 40 (F = 1.62, p = 0.137) and 80 (F = 3.66,p = 0.004)}, with significant effects at 20 and 80. Following subchronic administration of MSG without enrichment, rearing activity decreased significantly at 10 (F = 7.96, p = 0.001); 20 (F = 9.82,p = 0.001) and 80 (F = 5.80, p = 0.001) mg/kg MSG, with enrichment introduced, increased significantly at 20 (F = 6.30, p = 0.001) mg/kg, at 10 and 40 mg/kg a reduction in rearing occurred while at 80 mg/kg an increase is seen although this effect was only visual.


Foraging enrichment modulates open field response to monosodium glutamate in mice.

Onaolapo OJ, Onaolapo AY, Akanmu MA, Olayiwola G - Ann Neurosci (2015)

Effect of Monosodium glutamate on rearing activity in enriched and non enriched mice. Each bar represents Mean ± S.E.M, *p<0.05 compared to vehicle. n = 6; VEH: Vehicle.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4481551&req=5

fig_2: Effect of Monosodium glutamate on rearing activity in enriched and non enriched mice. Each bar represents Mean ± S.E.M, *p<0.05 compared to vehicle. n = 6; VEH: Vehicle.
Mentions: Figure 2 compares the rearing response of mice following acute and subchronic administration of varying doses of MSG with or without enrichment respectively to corresponding vehicle (distilled water). Following acute administration without enrichment, rearing activity decreased at 10 (F = 3.69, p = 0.004) and 20 (F = 0.47, p = 0.648) mg/kg of MSG and increased at 40 (F = 2.20, p = 0.053) and 80 (F = 2.29, p = 0.045) mg/kg though, significant effects occurred only at 10 and 80 mg/kg, with introduction of enrichment, rearing activity reduced at all doses of MSG, {10 (F = 0.29, p = 0.777), 20 (F = 11.52, p = 0.001), 40 (F = 1.62, p = 0.137) and 80 (F = 3.66,p = 0.004)}, with significant effects at 20 and 80. Following subchronic administration of MSG without enrichment, rearing activity decreased significantly at 10 (F = 7.96, p = 0.001); 20 (F = 9.82,p = 0.001) and 80 (F = 5.80, p = 0.001) mg/kg MSG, with enrichment introduced, increased significantly at 20 (F = 6.30, p = 0.001) mg/kg, at 10 and 40 mg/kg a reduction in rearing occurred while at 80 mg/kg an increase is seen although this effect was only visual.

Bottom Line: Subchronic administration without enrichment was associated with increased locomotor activity and reduction in grooming, rearing activity however still showed a biphasic response.Addition of enrichment with acute administration resulted in sustained reduction in locomotor and rearing activities with a biphasic grooming response.Behavioural response to varying doses of MSG as observed in the open field is affected by modifications such as foraging enrichment, which can reverse or dampen the central effects seen irrespective of duration of administration.

View Article: PubMed Central - PubMed

Affiliation: Department of Pharmacology, Faculty of Basic Medical Sciences, College of Health Sciences, Ladoke Akintola University of Technology, Oshogbo, Osun State, Nigeria ; Department of Pharmacology, Faculty of Pharmacy, Obafemi Awolowo University, Ile- Ife, Osun State, Nigeria.

ABSTRACT

Background: Environmental enrichment can enhance expression of species-specific behaviour. While foraging enrichment is encouraged in laboratory animals, its impact on novelty induced behaviour remain largely unknown.

Purpose: Here, we studied behavioural response of mice to acute and subchronic oral monosodium glutamate (MSG) in an open field with /without foraging enrichment.

Methods: Adult male mice, assigned to five groups were administered vehicle (distilled water), or one of four selected doses of MSG (10, 20, 40 and 80 mg/kg) for 21 days. Open field novelty induced behaviours i.e. horizontal locomotion, rearing and grooming were assessed after the first and last doses of MSG. Results were analysed using MANOVA followed by Tukey HSD multiple comparison test and expressed as mean ± S.E.M.

Results: Following acute MSG administration without enrichment, locomotor activity reduced, grooming increased, while rearing activity reduced at lower doses and increased at higher doses. Subchronic administration without enrichment was associated with increased locomotor activity and reduction in grooming, rearing activity however still showed a biphasic response. Addition of enrichment with acute administration resulted in sustained reduction in locomotor and rearing activities with a biphasic grooming response. Subchronically, there was reduction in horizontal locomotion, biphasic rearing response and sustained increase in grooming activity.

Conclusion: Behavioural response to varying doses of MSG as observed in the open field is affected by modifications such as foraging enrichment, which can reverse or dampen the central effects seen irrespective of duration of administration.

No MeSH data available.