scholarly journals Reactive Oxygen Species Donors Increase the Responsiveness of Dorsal Horn Neurons and Induce Mechanical Hyperalgesia in Rats

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Hee Young Kim ◽  
Inhyung Lee ◽  
Sang Woo Chun ◽  
Hee Kee Kim
Keyword(s):  
Reactive Oxygen Species ◽  
Spinal Cord ◽  
Dorsal Horn ◽  
Dynamic Range ◽  
Intrathecal Injection ◽  
Reactive Oxygen ◽  
Substantia Gelatinosa ◽  
Oxygen Species ◽  
Mechanical Stimuli ◽  
Dorsal Horn Neurons

Our previous studies suggest that reactive oxygen species (ROS) scavengers have analgesic effect on neuropathic pain through spinal mechanisms in the rat. The studies suggest that superoxide in spinal cord is one of important mediators of persistent pain. To test the hypothesis that increase of superoxide-derived intermediates leads to central sensitization and pain, the effects of an intrathecal injection of chemical ROS donors releasing eitherOH∙,OCl-, or H2O2were examined on pain behaviors. Following treatment witht-BOOH (OH∙donor), dorsal horn neuron responses to mechanical stimuli in normal rats and the changes of neuronal excitability were explored on substantia gelatinosa (SG) neurons using whole-cell patch clamping recordings. Intrathecal administration oft-BOOH or NaOCl (OCl-donor), but not H2O2, significantly decreased mechanical thresholds of hind paws. The responses of wide dynamic range neurons to mechanical stimuli increased after a local application oft-BOOH. Thet-BOOH increased the frequency and the amplitude of excitatory postsynaptic potentials, depolarized membrane potential in SG neurons, and increased the frequency of action potentials evoked by depolarizing current pulses. These results suggest that elevated ROS, especiallyOH∙, in the spinal cord sensitized dorsal horn neurons and produced hyperalgesia in normal rats.

scholarly journals Electrophysiological Changes in Adult Rat Dorsal Horn Neurons After Neonatal Peripheral Inflammation

2003 ◽  
Vol 90 (1) ◽  
pp. 73-80 ◽  
Author(s):  
Yuan Bo Peng ◽  
Qing Dong Ling ◽  
M. A. Ruda ◽  
Daniel R. Kenshalo
Keyword(s):  
Spinal Cord ◽  
Receptive Field ◽  
Dorsal Horn ◽  
Dynamic Range ◽  
High Threshold ◽  
Peripheral Inflammation ◽  
Mechanical Stimuli ◽  
Neonatal Rats ◽  
Adult Rats ◽  
Dorsal Horn Neurons

Neonatal peripheral inflammation has been shown to produce profound anatomical changes in the dorsal horn of adult rats. In this study, we explored whether parallel physiological changes exist. Neonatal rats were injected with complete Freund's adjuvant (CFA) into the left hind paw. At 8–10 wk of age, single dorsal horn neurons were recorded in response to graded intensities of mechanical stimuli delivered to the receptive field. In addition, cord dorsum potentials, produced by electrical stimuli delivered to the left sciatic nerve at 2.5× threshold, were recorded bilaterally from L2 to S3. There were significant increases in background activity and responses to brush and pinch in neonatal rats that were treated with CFA, as compared with control rats. Further analysis showed similar significant changes when dorsal horn neurons were categorized into wide dynamic range (WDR), high-threshold (HT), and low-threshold (LT) groups. The receptive field was significantly larger in neonatally treated rats as compared with control rats. Additionally, there was a significant increase in the response to a 49°C heat stimulus in neonatally treated rats as compared with control rats. There was also a trend for the amplitudes of N1, N2, and P waves of the cord dorsum potential to increase and latencies to decrease in neonatally treated rats, but no significant differences were detected between different levels of the spinal cord (L2 to S3). These data further support the notion that anatomical and physiological plasticity changes occurred in the spinal cord following early neonatal CFA treatment.

scholarly journals The role of reactive oxygen species in capsaicin-induced mechanical hyperalgesia and in the activities of dorsal horn neurons

Pain ◽  
2007 ◽  
Vol 133 (1) ◽  
pp. 9-17 ◽  
Author(s):  
Inhyung Lee ◽  
Hee Kee Kim ◽  
Jae Hyo Kim ◽  
Kyungsoon Chung ◽  
Jin Mo Chung
Keyword(s):  
Reactive Oxygen Species ◽  
Dorsal Horn ◽  
Reactive Oxygen ◽  
Mechanical Hyperalgesia ◽  
Oxygen Species ◽  
Dorsal Horn Neurons

Role of reactive oxygen species and spinal cord apoptotic genes in the development of neuropathic pain

2007 ◽  
Vol 55 (2) ◽  
pp. 158-166 ◽  
Author(s):  
D SINISCALCO ◽  
C FUCCIO ◽  
C GIORDANO ◽  
F FERRARACCIO ◽  
E PALAZZO ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Spinal Cord ◽  
Neuropathic Pain ◽  
Reactive Oxygen ◽  
Oxygen Species ◽  
Apoptotic Genes

scholarly journals An automated online instrument to quantify aerosol-bound reactive oxygen species (ROS) for ambient measurement and health-relevant aerosol studies

2016 ◽  
Vol 9 (10) ◽  
pp. 4891-4900 ◽  
Author(s):  
Francis P. H. Wragg ◽  
Stephen J. Fuller ◽  
Ray Freshwater ◽  
David C. Green ◽  
Frank J. Kelly ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Dynamic Range ◽  
Measurement Techniques ◽  
Reactive Oxygen ◽  
Fast Response ◽  
Urban Site ◽  
Aerosol Sampling ◽  
Oxygen Species ◽  
Toxicological Studies ◽  
New Instrument

Abstract. The adverse health effects associated with ambient aerosol particles have been well documented, but it is still unclear which aerosol properties are most important for their negative health impact. Some studies suggest the oxidative effects of particle-bound reactive oxygen species (ROS) are potential major contributors to the toxicity of particles. Traditional ROS measurement techniques are labour-intensive, give poor temporal resolution and generally have significant delays between aerosol sampling and ROS analysis. However, many oxidising particle components are reactive and thus potentially short-lived. Thus, a technique to quantify particle-bound ROS online would be beneficial to quantify also the short-lived ROS components. We introduce a new portable instrument to allow online, continuous measurement of particle-bound ROS using a chemical assay of 2′7′-dichlorofluorescein (DCFH) with horseradish peroxidase (HRP), via fluorescence spectroscopy. All components of the new instrument are attached to a containing shell, resulting in a compact system capable of automated continuous field deployment over many hours or days. From laboratory measurements, the instrument was found to have a detection limit of ∼  4 nmol [H2O2] equivalents per cubic metre (m3) air, a dynamic range up to at least ∼  2000 nmol [H2O2] equivalents per m3 air and a time resolution of ≤  12 min. The instrument allows for ∼  16 h automated measurement if unattended and shows a fast response to changes in concentrations of laboratory-generated oxidised organic aerosol. The instrument was deployed at an urban site in London, and particulate ROS levels of up to 24 nmol [H2O2] equivalents per m3 air were detected with PM2.5 concentrations up to 28 µg m−3. The new and portable Online Particle-bound ROS Instrument (OPROSI) allows fast-response quantification; this is important due to the potentially short-lived nature of particle-bound ROS as well as fast-changing atmospheric conditions, especially in urban environments. The instrument design allows for automated operation and extended field operation with twice-daily presence of an operator. As well as having sensitivity suitable for ambient level measurement, the instrument is also suitable at concentrations such as those required for laboratory and chamber toxicological studies.

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