Electroacupuncture analgesia with different frequencies is mediated via different opioid pathways in acute visceral hyperalgesia rats

Qi, Debo; Wu, Shuqin; Zhang, Yuhua; Li, Weimin

doi:10.1016/j.lfs.2016.06.025

Cited by 32 publications

(41 citation statements)

References 40 publications

(46 reference statements)

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“…The analytic period was 40 seconds (20 seconds during and 20 seconds after each CRD). The net value for each CRD was calculated by subtracting the AUC of the baseline (40 seconds interval) before each CRD …”

Section: Methodsmentioning

confidence: 99%

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Activation of cannabinoid 2 receptor relieves colonic hypermotility in a rat model of irritable bowel syndrome

Lin

Chen

Xiao

et al. 2019

Neurogastroenterology Motil

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Background Irritable bowel syndrome (IBS) is a common disease with intestinal dysmotility, whose mechanism remains elusive. The endocannabinoid system is emerging as an important modulator of gastrointestinal (GI) motility in multiple diseases, but its involvement in IBS is unknown. We aimed to determine whether cannabinoid 2 (CB2) receptor modulates intestinal motility associated with stress‐induced IBS. Methods A rat IBS model was established by chronic water avoidance stress (WAS). Colonic pathological alterations were detected histologically and intestinal motility was assessed by intestinal transit time (ITT) and fecal water content (FWC). Visceral sensitivity was determined by visceromotor response (VMR) to colorectal distension (CRD). Real‐time PCR, western blot, and immunostaining were performed to identify colonic CB2 receptor expression. Colonic muscle strip contractility was studied by isometric transducers and nitric oxide (NO) was detected by the Griess test. The effects of AM1241, a selective agonist of CB2 receptors, on colonic motility were examined. Key Results After 10 days of WAS exposure, ITT was decreased and FWC elevated while VMR magnitude in response to CRD was significantly enhanced. Colon CB2 protein and mRNA levels increased and density of CB2‐positive macrophages in the mucosa and enteric neurons in the myenteric plexus was higher than in controls. Pharmacological enhancement of CB2 activity by AM1241 relieved colonic hypermotility in WAS rats in a concentration‐dependent manner via inhibition of p38 phosphorylation and elevation of NO production. Conclusion CB2 receptor may exert an important inhibitory effect in stress‐induced colonic hypermotility by modulating NO synthesis through p38 mitogen‐activated protein kinase signaling. AM1241 could be used as a potential drug to treat disorders with colonic hypermotility.

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Section: Methodsmentioning

confidence: 99%

“…The net value for each CRD was calculated by subtracting the AUC of the baseline (40 seconds interval) before each CRD. 16…”

Section: Electromyogram Measurementsmentioning

confidence: 99%

Activation of cannabinoid 2 receptor relieves colonic hypermotility in a rat model of irritable bowel syndrome

Lin

Chen

Xiao

et al. 2019

Neurogastroenterology Motil

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“…The net value for each CRD was calculated by subtracting the AUC of the baseline (40 seconds interval) before each CRD. 21 …”

Section: Methodsmentioning

confidence: 99%

Upregulation of the high-affinity choline transporter in colon relieves stress-induced hyperalgesia

Lin¹,

Yu²

2018

JPR

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BackgroundIrritable bowel syndrome (IBS) is a common disease with hyperalgesia, the mechanisms of which remain elusive. The cholinergic system is known to be involved in pain inhibitory pathways in multiple diseases, and its involvement in IBS is unknown.ObjectiveWe aimed to determine whether high-affinity choline transporter CHT1, a major determinant of the cholinergic signaling capacity, is involved in regulating intestinal sensations associated with stress-induced visceral pain.Materials and methodsAn IBS rat model was established by chronic water avoidance stress (WAS). Colonic pathologic alterations were detected by H&E staining. Visceral sensations were determined by scoring the abdominal withdrawal reflex (AWR) and visceromotor response (VMR) magnitude of the electromyogram in response to colorectal distension (CRD). Abdominal mechanical hyperalgesia was assessed by counting the number of withdrawal events evoked by applying von Frey filaments. Real-time PCR, Western blot, and immunostaining were performed to identify CHT1 expression in the colon. Acetylcholine (ACh) secretion was determined by ELISA. Effects of MKC-231, a choline uptake enhancer, on visceral pain were examined.ResultsAfter 10 days of WAS exposure, AWR score and VMR magnitude in response to CRD were significantly enhanced and the number of withdrawal events was elevated. Protein and mRNA levels of CHT1 were considerably increased in the colon after WAS. CHT1 upregulation in the WAS-exposed group was largely abolished by ammonium pyrrolidinedithiocarbamate. The density of CHT1-positive intramuscular cells and enteric neurons in the myenteric plexus was enhanced in WAS-exposed rats. Pharmacologic enhancement of CHT1 activity by MKC-231 gavage could relieve the visceral pain of WAS rats by upregulating CHT1 protein expression and enhancing ACh production.ConclusionCHT1 may exert an antinociceptive effect in stress-induced visceral pain by modulating ACh synthesis through nuclear factor kappa B signaling. MKC-231 could be used as a potential drug to treat disorders with hyperalgesia.

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“…Behavioral changes in response to colorectal distension (CRD) were assessed by abdominal withdrawal reflex (AWR) as per previous studies. 30 AWR in response to graded CRD stimulation was observed and recorded by a blind observer. Each graded CRD was repeated thrice, and the mean of these scores was used for further analysis.…”

Section: Colorectal Distension Testmentioning

confidence: 99%

Metformin prevents colonic barrier dysfunction by inhibiting mast cell activation in maternal separation‐induced IBS‐like rats

Yang

Yao

et al. 2019

Neurogastroenterology Motil

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Background Intestinal barrier dysfunction is a key etiologic factor of irritable bowel syndrome (IBS). Metformin improves intestinal barrier function, although the underlying mechanism has yet to be fully explained. This study evaluates the protective effect of metformin on colonic barrier integrity and explores the underlying cellular mechanisms. Methods IBS‐like rats were induced by maternal separation. Metformin was administered daily by gavage at 08:30, and rat pups were then separated from their mother. Visceral hyperalgesia and depression‐like behaviors were evaluated by colorectal distension, sucrose preference tests, and forced swimming tests. Intestinal integrity was analyzed using sugar probes and transmission electron microscopy. Inflammatory factors and the levels of corticotropin‐releasing factor were assessed by PCR and ELISA. The number of mast cells was evaluated by toluidine blue staining. Protein expression and localization were determined using Western blot and immunochemistry. Key Results Metformin pretreatment (a) reduced visceral hypersensitivity to colorectal distension, immobility time and enhanced sucrose consumption; (b) decreased urine lactulose/mannitol ratio and sucralose output; (c) inhibited the dilation of tight junction and prevented claudin‐4 translocation; (d) inhibited mast cell activation and downregulated the expression of IL‐6, IL‐18, tryptase, PAR‐2, and ERK activation; (e) inhibited claudin‐4 phosphorylation at serine sites and interactions between clau‐4 and ZO‐1. Conclusions & Inferences Metformin may block mast cell activation to reduce PAR‐2 expression and subsequently inhibit ERK activation and clau‐4 phosphorylation at serine sites to normalize the interaction of clau‐4 and ZO‐1 and clau‐4 distribution. Metformin may be clinically beneficial for patients with IBS or IBS‐like symptoms.

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Electroacupuncture analgesia with different frequencies is mediated via different opioid pathways in acute visceral hyperalgesia rats

Cited by 32 publications

References 40 publications

Activation of cannabinoid 2 receptor relieves colonic hypermotility in a rat model of irritable bowel syndrome

Activation of cannabinoid 2 receptor relieves colonic hypermotility in a rat model of irritable bowel syndrome

Upregulation of the high-affinity choline transporter in colon relieves stress-induced hyperalgesia

Metformin prevents colonic barrier dysfunction by inhibiting mast cell activation in maternal separation‐induced IBS‐like rats

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