scholarly journals Electroacupuncture Inhibits the Activation of p38MAPK in the Central Descending Facilitatory Pathway in Rats with Inflammatory Pain

2017 ◽  
Vol 2017 ◽  
pp. 1-10 ◽  
Author(s):  
Man-Li Hu ◽  
Fei-Yan Zhou ◽  
Jing-Jing Liu ◽  
Yi Ding ◽  
Ju-Ming Zhong ◽  
...  
Keyword(s):  
Inflammatory Pain ◽  
Spinal Cord Dorsal Horn ◽  
Rostral Ventromedial Medulla ◽  
Saline Injection ◽  
Paw Edema ◽  
Pain Model ◽  
Withdrawal Threshold ◽  
Ventromedial Medulla ◽  
Mitogen Activated Protein ◽  
Spinal Cord Dorsal

The mitogen-activated protein kinases (MAPKs), especially p38MAPK, play a pivotal role in chronic pain. Electroacupuncture (EA) relieves inflammatory pain underlying the descending pathway, that is, the periaqueductal gray (PAG), the rostral ventromedial medulla (RVM), and the spinal cord dorsal horn (SCDH). However, whether EA antagonizes inflammatory pain through regulation of p38MAPK in this descending facilitatory pathway is unclear. Complete Freund’s adjuvant (CFA) was injected into the hind paw of rats to establish inflammatory pain model. EA was administrated for 30 min at Zusanli and Kunlun acupoints at 0.5, 24.5, 48.5, and 72.5 h, respectively. The paw withdrawal threshold (PWT), paw edema, and Phosphor-p38MAPK-Immunoreactivity (p-p38MAPK-IR) cells were measured before (0 h) and at 1, 3, 5, 7, 25, and 73 h after CFA or saline injection. EA increased PWT at 1, 3, 25, and 73 h and inhibited paw edema at 25 and 73 h after CFA injection. Moreover, the increasing number of p-p38MAPK-IR cells which was induced by CFA was suppressed by EA stimulation in PAG and RVM at 3 and 5 h and in SCDH at 5, 7, 25, and 73 h. These results suggest that EA suppresses inflammation-induced hyperalgesia probably through inhibiting p38MAPK activation in the descending facilitatory pathway.

scholarly journals Electroacupuncture Stimulation Alleviates CFA-Induced Inflammatory Pain Via Suppressing P2X3 Expression

2019 ◽  
Vol 20 (13) ◽  
pp. 3248 ◽  
Author(s):  
Xuaner Xiang ◽  
Sisi Wang ◽  
Fangbing Shao ◽  
Junfan Fang ◽  
Yingling Xu ◽  
...  
Keyword(s):  
Inflammatory Pain ◽  
Analgesic Effect ◽  
Purinergic Receptor ◽  
Pathological Process ◽  
Spinal Cord Dorsal Horn ◽  
Chronic Inflammatory Pain ◽  
Withdrawal Threshold ◽  
Analgesic Effects ◽  
Spinal Cord Dorsal

Chronic inflammatory pain is one of the most common complaints that seriously affects patients’ quality of life. Previous studies have demonstrated that the analgesic effect of electroacupuncture (EA) stimulation on inflammatory pain is related to its frequency. In this study, we focused on whether the analgesic effects of EA are related to the period of stimulation. Purinergic receptor P2X3 (P2X3) is involved in the pathological process underlying chronic inflammatory pain and neuropathic pain. We hypothesized that 100 Hz EA stimulation alleviated Freund’s complete adjuvant (CFA) induced inflammatory pain via regulating P2X3 expression in the dorsal root ganglion (DRG) and/or spinal cord dorsal horn (SCDH). We also assumed that the analgesic effect of EA might be related to the period of stimulation. We found that both short-term (three day) and long-term (14 day) 100 Hz EA stimulation effectively increased the paw withdrawal threshold (PWT) and reversed the elevation of P2X3 in the DRG and SCDH of CFA rats. However, the analgesic effects of 100 Hz EA were not dependent on the period of stimulation. Moreover, P2X3 inhibition or activation may contribute to or attenuate the analgesic effects of 100 Hz EA on CFA-induced inflammatory pain. This result indicated that EA reduced pain hypersensitivity through P2X3 modulation.

scholarly journals The Role of the Periaqueductal Gray in the Modulation of Pain in Males and Females: Are the Anatomy and Physiology Really that Different?

2009 ◽  
Vol 2009 ◽  
pp. 1-12 ◽  
Author(s):  
Dayna R. Loyd ◽  
Anne Z. Murphy
Keyword(s):  
Spinal Cord ◽  
Periaqueductal Gray ◽  
Pain Modulation ◽  
Spinal Cord Dorsal Horn ◽  
Implicit Assumption ◽  
Anatomy And Physiology ◽  
Wide Range ◽  
Ventromedial Medulla ◽  
Spinal Cord Dorsal ◽  
The 1960S

Anatomical and physiological studies conducted in the 1960s identified the periaqueductal gray (PAG) and its descending projections to the rostral ventromedial medulla (RVM) and spinal cord dorsal horn, as a primary anatomical pathway mediating opioid-based analgesia. Since these initial studies, the PAG-RVM-spinal cord pathway has been characterized anatomically and physiologically in a wide range of vertebrate species. Remarkably, the majority of these studies were conducted exclusively in males with the implicit assumption that the anatomy and physiology of this circuit were the same in females; however, this is not the case. It is well established that morphine administration produces greater antinociception in males compared to females. Recent studies indicate that the PAG-RVM pathway contributes to the sexually dimorphic actions of morphine. This manuscript will review our anatomical, physiological, and behavioral data identifying sex differences in the PAG-RVM pathway, focusing on its role in pain modulation and morphine analgesia.

scholarly journals The Effect of Electroacupuncture on PKMzeta in the ACC in Regulating Anxiety-Like Behaviors in Rats Experiencing Chronic Inflammatory Pain

2017 ◽  
Vol 2017 ◽  
pp. 1-13 ◽  
Author(s):  
Junying Du ◽  
Junfan Fang ◽  
Cun Wen ◽  
Xiaomei Shao ◽  
Yi Liang ◽  
...  
Keyword(s):  
Chronic Pain ◽  
Protein Expression ◽  
Inflammatory Pain ◽  
Direct Evidence ◽  
Anterior Cingulate ◽  
Model Group ◽  
Pain Model ◽  
Chronic Inflammatory Pain ◽  
Withdrawal Threshold ◽  
Other Substances

Chronic inflammatory pain can induce emotional diseases. Electroacupuncture (EA) has effects on chronic pain and pain-related anxiety. Protein kinase Mzeta (PKMzeta) has been proposed to be essential for the maintenance of pain and may interact with GluR1 to maintain CNS plasticity in the anterior cingulate cortex (ACC). We hypothesized that the PKMzeta-GluR1 pathway in the ACC may be involved in anxiety-like behaviors of chronic inflammatory pain and that the mechanism of EA regulation of pain emotion may involve the PKMzeta pathway in the ACC. Our results showed that chronic inflammatory pain model decreased the paw withdrawal threshold (PWT) and increased anxiety-like behaviors. The protein expression of PKCzeta, p-PKCzeta (T560), PKMzeta, p-PKMzeta (T560), and GluR1 in the ACC of the model group were remarkably enhanced. EA increased PWT and alleviated anxiety-like behaviors. EA significantly inhibited the protein expression of p-PKMzeta (T560) in the ACC, and only a downward trend effect for other substances. Further, the microinjection of ZIP remarkably reversed PWT and anxiety-like behaviors. The present study provides direct evidence that the PKCzeta/PKMzeta-GluR1 pathway is related to pain and pain-induced anxiety-like behaviors. EA treatment both increases pain-related somatosensory behavior and decreases pain-induced anxiety-like behaviors by suppressing PKMzeta activity in the ACC.

(137) Cellular localization of inflammatory pain signaling in spinal cord dorsal horn

2008 ◽  
Vol 9 (4) ◽  
pp. 10
Author(s):  
A. Weyerbacher ◽  
C. Tamasdan ◽  
Q. Xu ◽  
H. Cheng ◽  
C. Inturrisi
Keyword(s):  
Spinal Cord ◽  
Dorsal Horn ◽  
Inflammatory Pain ◽  
Cellular Localization ◽  
Spinal Cord Dorsal Horn ◽  
Spinal Cord Dorsal

Dorsal striatum metabotropic glutamate receptor 8 affects nocifensive responses and rostral ventromedial medulla cell activity in neuropathic pain conditions

2014 ◽  
Vol 111 (11) ◽  
pp. 2196-2209 ◽  
Author(s):  
Francesca Rossi ◽  
Ida Marabese ◽  
Maria De Chiaro ◽  
Serena Boccella ◽  
Livio Luongo ◽  
...  
Keyword(s):  
Metabotropic Glutamate Receptor ◽  
Cell Activity ◽  
Dorsal Striatum ◽  
Rostral Ventromedial Medulla ◽  
Tail Flick ◽  
Metabotropic Glutamate ◽  
Withdrawal Threshold ◽  
Ventromedial Medulla ◽  
Stimulation Of

The present study investigated the role of metabotropic glutamate receptor subtype 8 (mGluR8) in the dorsal striatum (DS) in modulating thermonociception and rostral ventromedial medulla (RVM) ON and OFF cell activities in conditions of neuropathic pain induced by spared nerve injury (SNI) of the sciatic nerve in rats. The role of DS mGluR8 on mechanical allodynia was also investigated. Intra-DS ( S)-3,4-dicarboxyphenylglycine [( S)-3,4-DCPG], a selective mGluR8 agonist, did not modify the activity of the ON and OFF cells in sham-operated rats. In SNI rats, which showed a reduction of the mechanical withdrawal threshold, intra-DS microinjection of ( S)-3,4-DCPG inhibited the ongoing and tail flick-evoked activity of the ON cells while increasing the activity of the OFF cells. AZ12216052, a selective mGluR8 positive allosteric modulator (PAM), behaved like ( S)-3,4-DCPG in increasing tail flick latency and OFF cell activity and decreasing ON cell activity in SNI rats only but was less potent. VU0155041, a selective mGluR4 PAM, was ineffective in changing thermal nociception and ON and OFF cell activity in both sham-operated and SNI rats. ( S)-3,4-DCPG did not change mechanical withdrawal threshold in sham-operated rats but increased it in SNI rats. Furthermore, a decreased level of mGluR8 gene and immunoreactivity, expressed on GABAergic terminals, associated with a protein increase was found in the DS of SNI rats. These results suggest that stimulation of mGluR8 inhibits thermoceptive responses and mechanical allodynia. These effects were associated with inhibition of ON cells and stimulation of OFF cells within RVM.

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