Role of TRPM2 cation channels in dorsal root ganglion of rats after experimental spinal cord injury



Introduction: We sought to determine the contribution of oxidative stress–dependent activation of TRPM2 and L-type voltage-gated Ca2+ channels (VGCC) in dorsal root ganglion (DRG) neurons of rats after spinal cord injury (SCI). Methods: The rats were divided into 4 groups: control; sham control; SCI; and SCI+nimodipine groups. The neurons of the SCI groups were also incubated with non-specific TRPM2 channel blockers, 2-aminoethoxydiphenylborate (2-APB) and N-(p-amylcinnamoyl)anthranilic acid (ACA), before H2O2 stimulation. Results:The [Ca2+]i concentrations were higher in the SCI group than in the control groups, although their concentrations were decreased by nimodipine and 2-APB. The H2O2-induced TRPM2 current densities in patch-clamp experiments were decreased by ACA and 2-APB incubation. In the nimodipine group, the TRPM2 channels of neurons were not activated by H2O2 or cumene hydroperoxide. Conclusions: Increased Ca2+ influx and currents in DRG neurons after spinal injury indicated TRPM2 and voltage-gated Ca2+ channel activation. Muscle Nerve 48: 945–950, 2013