Interaction Between Opiate Subtype and Alpha-2 Adrenergic Agonists in Suppression of Noxiously Evoked Activity of WDR Neurons in the Spinal Dorsal Horn

1991 ◽  
Vol 74 (4) ◽  
pp. 737-743 ◽  
Author(s):  
Keiichi Omote ◽  
Luke M. Kitahata ◽  
J. G. Collins ◽  
Keio Nakatani ◽  
Itsuo Nakagawa
Keyword(s):  
Dorsal Horn ◽  
Spinal Dorsal Horn ◽  
Adrenergic Agonists ◽  
Spinal Dorsal ◽  
Evoked Activity ◽  
Wdr Neurons

Changes in Properties of Spinal Dorsal Horn Neurons and Their Sensitivity to Morphine after Spinal Cord Injury in the Rat

2005 ◽  
Vol 102 (1) ◽  
pp. 152-164 ◽  
Author(s):  
Jungang Wang ◽  
Mikito Kawamata ◽  
Akiyoshi Namiki
Keyword(s):  
Spinal Cord ◽  
Spontaneous Activity ◽  
Dorsal Horn ◽  
Spinal Dorsal Horn ◽  
High Threshold ◽  
Dorsal Horn Neurons ◽  
Spinal Dorsal ◽  
Cord Injury ◽  
Spinal Dorsal Horn Neurons ◽  
Wdr Neurons

Background To gain a better understanding of spinal cord injury (SCI)-induced central neuropathic pain, the authors investigated changes in properties of spinal dorsal horn neurons located rostrally and caudally to the lesion and their sensitivity to morphine in rats after SCI. Methods The right spinal cord of Sprague-Dawley rats was hemisected at the level of L2. At 10 to 14 days after the SCI, when mechanical hyperalgesia/allodynia had fully developed, spontaneous activity and evoked responses to mechanical stimuli of wide-dynamic-range (WDR) and high-threshold neurons rostral and caudal to the lesion were recorded. Effects of cumulative doses of systemic (0.1-3 mg/kg) and spinal (0.1-5 microg) administration of morphine on spontaneous activity and evoked responses to the stimuli of the neurons were evaluated. Results Spontaneous activity significantly increased in WDR neurons both rostral and caudal to the SCI site, but high-frequency background discharges with burst patterns were only observed in neurons rostral to the SCI site. Significant increases in responses to the mechanical stimuli were seen both in WDR and high-threshold neurons located both rostrally and caudally to the lesion. The responses to nonnoxious and noxious stimuli were significantly greater in caudal WDR neurons than in rostral WDR neurons. In contrast, the responses to pinch stimuli were significantly higher in rostral high-threshold neurons than those in caudal high-threshold neurons. Systemically administered morphine had a greater effect on responses to nonnoxious and noxious stimuli of rostral WDR neurons than those of caudal WDR neurons. Spinally administered morphine significantly suppressed responses of WDR neurons in SCI animals to nonnoxious stimuli compared with those in sham-operated control animals. Conclusions The findings suggest that changes in properties of spinal dorsal horn neurons after SCI are caused by different mechanisms, depending on the classification of the neurons and their segmental locations.

Analysis of Interspike Interval of Dorsal Horn Neurons Evoked by Different Needle Manipulations at St36

2014 ◽  
Vol 32 (1) ◽  
pp. 43-50 ◽  
Author(s):  
Tao Zhou ◽  
Jiang Wang ◽  
Chun-Xiao Han ◽  
Ishida Torao ◽  
Yi Guo
Keyword(s):  
Firing Rate ◽  
Dorsal Horn ◽  
Neural Coding ◽  
Spinal Dorsal Horn ◽  
Interspike Interval ◽  
Dynamic Range ◽  
Stimulus Frequency ◽  
Electrical Signals ◽  
Spinal Dorsal ◽  
Wdr Neurons

Objectives Previous research has suggested that different manual acupuncture (MA) manipulations may have different physiological effects. Recent studies have demonstrated that neural electrical signals are generated or changed when acupuncture is administered. In order to explore the effects of different MA manipulations on the neural system, an experiment was designed to record the discharges of wide dynamic range (WDR) neurons in the spinal dorsal horn evoked by MA at different frequencies (0.5, 1, 2 and 3 Hz) at ST36. Methods Microelectrode extracellular recordings were used to record the discharges of WDR neurons evoked by different MA manipulations. Approximate firing rate and coefficient of variation of interspike interval (ISI) were used to extract the characteristic parameters of the neural electrical signals after spike sorting, and the neural coding of the evoked discharges by different MA manipulations was obtained. Results Our results indicated that the neuronal firing rate and time sequences of ISI showed distinct clustering properties for different MA manipulations, which could distinguish them effectively. Conclusions The combination of firing rate and ISI codes carries information about the acupuncture stimulus frequency. Different MA manipulations appear to change the neural coding of electrical signals in the spinal dorsal horn through WDR neurons.

Effect of Chronic Inflammation on Dorsal Horn Nociceptive Neurons in Aged Rats

2005 ◽  
Vol 93 (6) ◽  
pp. 3594-3604 ◽  
Author(s):  
Junichi Kitagawa ◽  
Kenro Kanda ◽  
Miho Sugiura ◽  
Yoshiyuki Tsuboi ◽  
Akiko Ogawa ◽  
...  
Keyword(s):  
Dorsal Horn ◽  
Mechanical Stimulation ◽  
Spinal Dorsal Horn ◽  
Inflammatory Responses ◽  
Aged Rats ◽  
Adult Rats ◽  
Nociceptive Neurons ◽  
Spinal Dorsal ◽  
Noxious Mechanical Stimulation ◽  
Wdr Neurons

To elucidate the effect of chronic inflammation on spinal nociceptive neurons in the elderly, we compared nocifensive behavior, peripheral inflammatory responses, and spinal dorsal horn neuronal activities between the aged (29–34 mo) and adult (7–12 mo) male rats after injection of complete Freund's adjuvant (CFA) into the hind paw. Aged rats exhibited a significantly lower mechanical paw withdrawal threshold before inflammation. However, after CFA injection mechanical allodynia developed in both adult and aged rats after CFA injection. The changes of foot temperature and thickness after CFA injection were greater and lasted longer in aged than in adult rats. Sets of 124 wide dynamic range (WDR) neurons (aged: 59, adult: 65) and 26 nociceptive specific (NS) neurons (aged: 13, adult: 13) were recorded from the lumber spinal dorsal horn. NS neurons from the inflamed adult rats showed significantly higher responses to noxious mechanical stimulation than those in aged rats, whereas WDR neurons from inflamed adult and aged rats were similar. Background activity of WDR neurons from the adult rats increased after CFA, whereas WDR neurons of aged rats and NS neurons from either group were not. The afterdischarge followed by noxious mechanical stimulation was significantly greater for WDR neurons in both adult and aged rats, whereas no significant differences were observed in NS neurons. Two days after CFA injection, Fos expression increased similarly in aged and adult rats. Thus the aged rats showed enhanced peripheral inflammatory responses to CFA injection with only a slight change in dorsal horn neuronal activity. Together with our previous finding that nociceptive neurons in aged rats exhibit hyperexcitability, these results suggest that the dorsal horn nociceptive system becomes sensitized with advancing age and its excitability cannot be further increased by inflammation.

Effects of microinjection of OFQ into PAG on spinal dorsal horn WDR neurons in rats

2001 ◽  
Vol 888 (1) ◽  
pp. 167-171 ◽  
Author(s):  
Zhi-Lan Yang ◽  
Yu-Qiu Zhang ◽  
Gen-Cheng Wu
Keyword(s):  
Dorsal Horn ◽  
Spinal Dorsal Horn ◽  
Spinal Dorsal ◽  
Wdr Neurons

scholarly journals Calcitonin gene-related peptide regulates spinal microglial activation through the histone H3 lysine 27 trimethylation via enhancer of zeste homolog-2 in rats with neuropathic pain

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Qi An ◽  
Chenyan Sun ◽  
Ruidi Li ◽  
Shuhui Chen ◽  
Xinpei Gu ◽  
...  
Keyword(s):  
Neuropathic Pain ◽  
Dorsal Horn ◽  
Nerve Injury ◽  
Spinal Dorsal Horn ◽  
Microglial Activation ◽  
Microglial Cells ◽  
Gene Promoters ◽  
Spinal Dorsal ◽  
Related Peptide ◽  
Calcitonin Gene

Abstract Background Calcitonin gene-related peptide (CGRP) as a mediator of microglial activation at the transcriptional level may facilitate nociceptive signaling. Trimethylation of H3 lysine 27 (H3K27me3) by enhancer of zeste homolog 2 (EZH2) is an epigenetic mark that regulates inflammatory-related gene expression after peripheral nerve injury. In this study, we explored the relationship between CGRP and H3K27me3 in microglial activation after nerve injury, and elucidated the underlying mechanisms in the pathogenesis of chronic neuropathic pain. Methods Microglial cells (BV2) were treated with CGRP and differentially enrichments of H3K27me3 on gene promoters were examined using ChIP-seq. A chronic constriction injury (CCI) rat model was used to evaluate the role of CGRP on microglial activation and EZH2/H3K27me3 signaling in CCI-induced neuropathic pain. Results Overexpressions of EZH2 and H3K27me3 were confirmed in spinal microglia of CCI rats by immunofluorescence. CGRP treatment induced the increased of H3K27me3 expression in the spinal dorsal horn and cultured microglial cells (BV2) through EZH2. ChIP-seq data indicated that CGRP significantly altered H3K27me3 enrichments on gene promoters in microglia following CGRP treatment, including 173 gaining H3K27me3 and 75 losing this mark, which mostly enriched in regulation of cell growth, phagosome, and inflammation. qRT-PCR verified expressions of representative candidate genes (TRAF3IP2, BCL2L11, ITGAM, DAB2, NLRP12, WNT3, ADAM10) and real-time cell analysis (RTCA) verified microglial proliferation. Additionally, CGRP treatment and CCI increased expressions of ITGAM, ADAM10, MCP-1, and CX3CR1, key mediators of microglial activation in spinal dorsal horn and cultured microglial cells. Such increased effects induced by CCI were suppressed by CGRP antagonist and EZH2 inhibitor, which were concurrently associated with the attenuated mechanical and thermal hyperalgesia in CCI rats. Conclusion Our findings highly indicate that CGRP is implicated in the genesis of neuropathic pain through regulating microglial activation via EZH2-mediated H3K27me3 in the spinal dorsal horn.

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