• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 1
  • Tagged with
  • 1
  • 1
  • 1
  • 1
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Modulation of N-Methyl-D-Asparate Receptor by Transient Receptor Potential Melastatin Type-2 Regulates Neuronal Vulnerability to Ischemic Cell Death

Alim, Ishraq 16 July 2014 (has links)
Neuronal vulnerability to ischemia is dependent on the balance between pro-survival and pro-death cellular signaling. In the latter, it is increasingly appreciated that toxic Ca2+ influx can occur not only via postsynaptic glutamate receptors, but also through other cation conductances. One such conductance, the Transient receptor potential melastatin type-2 (TRPM2) channel, is a non-specific cation channel having similar homology to TRPM7, a conductance reported to play a key role in anoxic neuronal death. The role of TRPM2 conductances in ischemic Ca2+ influx has been difficult to study due to the lack of specific modulators. Here we used TRPM2-null mice (TRPM2(-/-)) to study how TRPM2 may modulate neuronal vulnerability to ischemia. TRPM2(-/-) mice subjected to transient middle cerebral artery occlusion (tMCAO) exhibited smaller infarcts when compared to wild-type (WT) animals, suggesting the absence of TRPM2 to be protective. Surprisingly, field potentials (fEPSPs) recorded during oxidative stress in brain slices taken from TRPM2(-/-) mice revealed increased excitability, a phenomenon normally associated with ischemic vulnerability, whereas WT fEPSPs were unaffected. The upregulation in fEPSP in TRPM2(-/-) neurons was blocked selectively by an NR2A antagonist. This oxidative stress-induced increase in excitability of TRPM2(-/-) fEPSPs depended on the upregulation and downregulation of NR2A and NR2B-containing NMDARs, respectively, and augmented pro-survival signaling via Akt and ERK pathways culminating in the inhibition of the proapoptotic factor, GSK3β. Cultured hippocampal neurons from TRPM2(-/-) animals subjected to oxygen glucose deprivation had a reduction in cell death in comparison to WT neurons, demonstrating that absence of TRPM2 is protective at the neuronal level in vitro. Our results suggest that TRPM2 plays a role in downregulating pro-survival signals in central neurons and that TRPM2 channels may comprise a therapeutic target for preventing ischemic damage.

Page generated in 0.0162 seconds