Abstract

Social Buffering Prevents Stress-Induced Decreases in Dendritic Length, Branching in Dentate Granule Cells and Hippocampus-Related Memory Performance

Author(s): Wen-Yu Tzeng, Tung-Yi Huang, Chianfang G Cherng, San-Nan Yang, Lung Yu

Abstract

Objectives: A robust stressor regimen may cause a rapid decrease in BDNF level in the dentate gyrus (DG) while social buffering appears to prevent such decrease. Local BDNF levels and downstream phosphorylation of ERK and CREB play a critical role in mediating morphological and synaptic plasticity in DG. Thus, this study was undertaken to assess whether an acute stressor regimen may render morphological changes and whether the social buffering may prevent such changes in the existing DG granule cells. Moreover, we attempted to assess whether the stressor regimen and social buffering may also affect local ERK and CREB phosphorylation and the hippocampus-related memory.

Methods: Six hours after the conclusion of the stressor regimen, morphological indices of the granule cell in DG were obtained in Balb/C mice experiencing no stressor, the stressor regimen alone or in a group.

Results: The stressor caused significant decreases in the total length of dendrites, number of dendritic branches, and the size of the dendritic field in granule cells, while the social buffering prevented all these changes. Likewise, the stressor caused decreases in local ERK phosphorylation and object location performance, while the social buffering prevented such decreases of ERK phosphorylation and deteriorated memory performance.

Conclusion: These results, taken together, suggest that stress and social buffering may rapidly affect the existing DG granule cell morphology and hippocampus-related memory performance by modulating local ERK phosphorylation.