Int J Oral Biol.  2018 Dec;43(4):209-216. 10.11620/IJOB.2018.43.4.209.

Pre- and Postsynaptic Actions of Reactive Oxygen Species and Nitrogen Species in Spinal Substantia Gelatinosa Neurons

• Park A
• Chun SW

• KMID: 2437338
• DOI: http://doi.org/10.11620/IJOB.2018.43.4.209

Abstract

Reactive oxygen species (ROS) and nitrogen species (RNS) are involved in cellular signaling processes as a cause of oxidative stress. According to recent studies, ROS and RNS are important signaling molecules involved in pain transmission through spinal mechanisms. In this study, a patch clamp recording was used in spinal slices of rats to investigate the action mechanisms of O₂˙⁻ and NO on the excitability of substantia gelatinosa (SG) neuron. The application of xanthine and xanthine oxidase (X/XO) compound, a ROS donor, induced inward currents and increased the frequency of spontaneous excitatory postsynaptic currents (sEPSC) in slice preparation. The application of S-nitroso-N-acetyl-DLpenicillamine (SNAP), a RNS donor, also induced inward currents and increased the frequency of sEPSC. In a single cell preparation, X/XO and SNAP had no effect on the inward currents, revealing the involvement of presynaptic action. X/XO and SNAP induced a membrane depolarization in current clamp conditions which was significantly decreased by the addition of thapsigargin to an external calcium free solution for blocking synaptic transmission. Furthermore, X/XO and SNAP increased the frequency of action potentials evoked by depolarizing current pulses, suggesting the involvement of postsynaptic action. According to these results, it was estblished that elevated ROS and RNS in the spinal cord can sensitize the dorsal horn neurons via pre- and postsynaptic mechanisms. Therefore, ROS and RNS play similar roles in the regulation of the membrane excitability of SG neurons.

Keyword

substantia gelatinosa neuron; superoxide; nitric oxide; pain; patch clamp

MeSH Terms

Action Potentials
Animals
Calcium
Excitatory Postsynaptic Potentials
Humans
Membranes
Neurons*
Nitric Oxide
Nitrogen*
Oxidative Stress
Posterior Horn Cells
Rats
Reactive Oxygen Species*
Spinal Cord
Substantia Gelatinosa*
Superoxides
Synaptic Transmission
Thapsigargin
Tissue Donors
Xanthine
Xanthine Oxidase
Calcium
Nitric Oxide
Nitrogen
Reactive Oxygen Species
Superoxides
Thapsigargin
Xanthine
Xanthine Oxidase