Environmental enrichment reduces brain excitability in adult rats overnourished during lactation

Abstract

Objective: This study aimed to analyze whether exposure to environmental enrichment (EE) during the juvenile phase of life interferes with the electrical activity of the adult rat brain. In addition, the present research also investigated whether this putative effect on brain electrical activity could be affected by prior overnutrition during lactation. Electrophysiology was measured through cortical spreading depression (CSD), a phenomenon related to brain excitability. Methods: Wistar rats were suckled in litters of either nine or three pups, forming the nourished (N) or overnourished (ON) groups, respectively. At 36 days old, half of the animals from each nutritional condition were exposed to EE. The other half was kept in the standard environment (SE). At 90-120 days of life, each animal was anesthetized for CSD recordings. Results: Overnutrition during lactation caused increases (p < 0.05) in body and brain weights. The EE decelerated CSD propagation velocity regardless of nutritional state during lactation (p < 0.001). The CSD deceleration in the N-EE group was 23.8% and in the ON-EE group was 15% in comparison with the N-SE and ON-SE groups, respectively. Conclusion: Our data demonstrated that EE exposure in the juvenile phase of the rat's life reduced brain excitability, and this effect was observed even if animals were overnourished during lactation. An EE could be considered an adjuvant therapeutic resource to modulate brain excitability.

Environmental Enrichment Reduces Cortical Excitability In Rats Submitted To Status Epilepticus In The Pilocarpine Model: An Evaluation From Cortical Spreading Depression

“…It's possible to observe that both environmental enrichment and pilocarpine, alone, were able to reduce the speed of the spread of CSD. These findings are corroborated by the literature 4,12,13 . However, the causes for this reduction are distinct.…”

“…It has been reported that EE increases brain plasticity, improves the metabolism of the nervous system, as well as cognitive and behavioral parameters 1,2,3 . Recent research from our laboratory has shown that environmental enrichment reduces the propagation of cortical spreading depression (CSD) 4 .…”