Electromagnetic radiation (Wi-Fi) and epilepsy induce calcium entry and apoptosis through activation of TRPV1 channel in hippocampus and dorsal root ganglion of rats

Metab Brain Dis. 2014 Sep;29(3):787-99. doi: 10.1007/s11011-014-9549-9. Epub 2014 May 3.

Abstract

Incidence rates of epilepsy and use of Wi-Fi worldwide have been increasing. TRPV1 is a Ca(2+) permeable and non-selective channel, gated by noxious heat, oxidative stress and capsaicin (CAP). The hyperthermia and oxidant effects of Wi-Fi may induce apoptosis and Ca(2+) entry through activation of TRPV1 channel in epilepsy. Therefore, we tested the effects of Wi-Fi (2.45 GHz) exposure on Ca(2+) influx, oxidative stress and apoptosis through TRPV1 channel in the murine dorsal root ganglion (DRG) and hippocampus of pentylentetrazol (PTZ)-induced epileptic rats. Rats in the present study were divided into two groups as controls and PTZ. The PTZ groups were divided into two subgroups namely PTZ + Wi-Fi and PTZ + Wi-Fi + capsazepine (CPZ). The hippocampal and DRG neurons were freshly isolated from the rats. The DRG and hippocampus in PTZ + Wi-Fi and PTZ + Wi-Fi + CPZ groups were exposed to Wi-Fi for 1 hour before CAP stimulation. The cytosolic free Ca(2+), reactive oxygen species production, apoptosis, mitochondrial membrane depolarization, caspase-3 and -9 values in hippocampus were higher in the PTZ group than in the control although cell viability values decreased. The Wi-Fi exposure induced additional effects on the cytosolic Ca(2+) increase. However, pretreatment of the neurons with CPZ, results in a protection against epilepsy-induced Ca(2+) influx, apoptosis and oxidative damages. In results of whole cell patch-clamp experiments, treatment of DRG with Ca(2+) channel antagonists [thapsigargin, verapamil + diltiazem, 2-APB, MK-801] indicated that Wi-Fi exposure induced Ca(2+) influx via the TRPV1 channels. In conclusion, epilepsy and Wi-Fi in our experimental model is involved in Ca(2+) influx and oxidative stress-induced hippocampal and DRG death through activation of TRPV1 channels, and negative modulation of this channel activity by CPZ pretreatment may account for the neuroprotective activity against oxidative stress.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Apoptosis / drug effects
  • Apoptosis / radiation effects*
  • Calcium / metabolism*
  • Capsaicin / analogs & derivatives
  • Capsaicin / pharmacology
  • Caspase 3 / metabolism
  • Electromagnetic Radiation*
  • Epilepsy / metabolism*
  • Ganglia, Spinal / drug effects
  • Ganglia, Spinal / metabolism
  • Ganglia, Spinal / radiation effects*
  • Hippocampus / drug effects
  • Hippocampus / metabolism
  • Hippocampus / radiation effects*
  • Male
  • Neurons / drug effects
  • Neurons / metabolism
  • Neurons / radiation effects
  • Oxidative Stress / drug effects
  • Oxidative Stress / radiation effects
  • Rats
  • TRPV Cation Channels / metabolism*

Substances

  • TRPV Cation Channels
  • Trpv1 protein, rat
  • Caspase 3
  • capsazepine
  • Capsaicin
  • Calcium