Int J Oral Biol.  2014 Dec;39(4):229-236. 10.11620/IJOB.2014.39.4.229.

Reactive Oxygen Species and Nitrogen Species Differentially Regulate Neuronal Excitability in Rat Spinal Substantia Gelatinosa Neurons

• Lee HI
• Park AR
• Chun SW

• KMID: 2170792
• DOI: http://doi.org/10.11620/IJOB.2014.39.4.229

Abstract

Reactive oxygen species (ROS) and nitrogen species (RNS) are implicated in cellular signaling processes and as a cause of oxidative stress. Recent studies indicate that ROS and RNS are important signaling molecules involved in nociceptive transmission. Xanthine oxidase (XO) system is a well-known system for superoxide anions (O2(.-)) generation, and sodium nitroprusside (SNP) is a representative nitric oxide (NO) donor. Patch clamp recording in spinal slices was used to investigate the role of O2(.-) and NO on substantia gelatinosa (SG) neuronal excitability. Application of xanthine and xanthine oxidase (X/XO) compound induced membrane depolarization. Low concentration SNP (10 microM) induced depolarization of the membrane, whereas high concentration SNP (1 mM) evoked membrane hyperpolarization. These responses were significantly decreased by pretreatment with phenyl N-tert-butylnitrone (PBN; nonspecific ROS and RNS scavenger). Addition of thapsigargin to an external calcium free solution for blocking synaptic transmission, led to significantly decreased X/XO-induced responses. Additionally, X/XO and SNP-induced responses were unchanged in the presence of intracellular applied PBN, indicative of the involvement of presynaptic action. Inclusion of GDP-beta-S or suramin (G protein inhibitors) in the patch pipette decreased SNP-induced responses, whereas it failed to decrease X/XO-induced responses. Pretreatment with n-ethylmaleimide (NEM; thiol-alkylating agent) decreased the effects of SNP, suggesting that these responses were mediated by direct oxidation of channel protein, whereas X/XO-induced responses were unchanged. These data suggested that ROS and RNS play distinct roles in the regulation of the membrane excitability of SG neurons related to the pain transmission.

Keyword

ROS; RNS; O2(.-); NO; membrane excitability

MeSH Terms

Animals
Calcium
Ethylmaleimide
Humans
Membranes
Neurons*
Nitric Oxide
Nitrogen*
Nitroprusside
Oxidative Stress
Rats*
Reactive Oxygen Species*
Substantia Gelatinosa*
Superoxides
Suramin
Synaptic Transmission
Thapsigargin
Tissue Donors
Xanthine
Xanthine Oxidase
Calcium
Ethylmaleimide
Nitric Oxide
Nitrogen
Nitroprusside
Reactive Oxygen Species
Superoxides
Suramin
Thapsigargin
Xanthine
Xanthine Oxidase