Poster abstracts

Poster number 82 submitted by Kathryn Madalena

Restraint stress induces plasticity and regeneration in peripheral neurons

Kathryn M Madalena (Neuroscience), Akhil Dhamija, Ash Zawerton, Harrison Taylor, Jessica K Lerch (Neuroscience)

Abstract:
Restraint stress induces plasticity in the central nervous system (Vyas et al., 2002) and increases mechanical allodynia after spared nerve injury (Alexander et al., 2009). We have replicated the findings that acute stress (one hour, one time) increases mechanical allodynia. We expanded this investigation using chronic stress (two hours per day for two weeks) and found the exact opposite effect. Chronic stress ameliorated the increased allodynia. The evidence for changes in the nervous system led us to study the effects of restraint stress on growth in dorsal root ganglia (DRG) sensory neurons and regeneration in the sciatic nerve. We find that restraint stress, both acute and chronic, significantly increased neurite outgrowth in DRG neurons measured after 24 hours of growth in vitro. Regeneration in the sciatic nerve can be observed at 1-3 days post crush injury using the marker for regenerating axons SCG10 (Shin et al., 2014). One hour of restraint stress given immediately prior to crush injury increased regeneration in the sciatic nerve three days post injury compared to non-stressed injured mice. We conclude from these findings that restraint stress can induce growth in DRGs and regeneration in the sciatic nerve. We expect that the changes observed are mediated by a glucocorticoid/glucocorticoid receptor mechanism and are working to develop mice with a conditional deletion of the glucocorticoid receptor in sensory neurons.

References:
Alexander JK, DeVries AC, Kigerl KA, Dahlman JM, Popovich PG (2009) Stress exacerbates neuropathic pain via glucocorticoid and NMDA receptor activation. Brain Behav Immun 23:851–860

Shin JE, Geisler S, DiAntonio A (2014) Dynamic regulation of SCG10 in regenerating axons after injury. Exp Neurol 252:1–11

Vyas A, Mitra R, Shankaranarayana Rao BS, Chattarji S (2002) Chronic stress induces contrasting patterns of dendritic remodeling in hippocampal and amygdaloid neurons. J Neurosci 22:6810–6818.

Keywords: Glucocorticoids, Stress, Plasticity