Electroacupuncture alleviates affective pain in an inflammatory pain rat model

Meng, Xianze; Li, Aihui; Xin, Jiajia; Berman, Brian M.; Lao, Lixing; Tan, Ming; Ren, Ke; Zhang, Rui-Xin

doi:10.1016/j.ejpain.2011.07.002

Cited by 31 publications

(28 citation statements)

References 34 publications

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“…2A, all rats spent about 5 min in the pain-paired chambers during the 10 min pre-conditioning test, demonstrating no preference for either. This result is similar to that of our previous report (Zhang Y et al, 2012). Rats receiving CFA and i.p.…”

Section: Resultssupporting

confidence: 93%

DAMGO in the central amygdala alleviates the affective dimension of pain in a rat model of inflammatory hyperalgesia

Zhang

et al. 2013

Neuroscience

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Pain has sensory-discriminative and emotional-affective dimensions. Recent studies show that the affective component can be assessed with a conditioned place avoidance (CPA) test. We hypothesized that systemic morphine before a post-conditioning test would more potently attenuate the affective aspect compared to the sensory component and that DAMGO, a μ-selective opioid receptor agonist, injected into the central nucleus of the amygdala (CeA) would reduce established CPA. A rat model of inflammatory pain, produced by a complete Freund adjuvant (CFA) injection into the hind paw, was combined with a CPA test. Three experiments were performed on adult male Sprague-Dawley rats. Systemic morphine (0.5 or 1.0 mg/kg) in Experiment 1, intrathecal (i.t.) morphine (2.5 μg/rat) in Experiment 2, and intra-CeA DAMGO (7.7-15.4 ng/0.4μl) in Experiment 3 were given to CFA-injected rats (n=6-8/group) prior to a post-conditioning test. Saline-injected rats were used as control. Time spent in a pain-paired compartment was recorded twice, before conditioning and after a post-conditioning test. Paw withdrawal latency (PWL) to a noxious thermal stimulus was measured before experiment at day −1 and after the post-conditioning test; hyperalgesia was defined as a decrease in PWL. The data showed that CFA-injected rats had significantly negative CPA compared to those of saline-injected rats (P<0.05). Low dosage systemic morphine significantly (P<0.05) reduced CFA-induced CPA but had no effect on PWL. I.t. morphine did not inhibit the display of CPA but significantly increased PWL, suppressing hyperalgesia (P<0.05). Intra-CeA DAMGO significantly inhibited the display of CPA compared to saline (P<0.05) but had no effect on PWL. The data demonstrates that morphine attenuates the affective component more powerfully than it does the sensory and suggests that the sensory and the emotional-affective dimensions are underpinned by different mechanisms.

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Section: Resultssupporting

confidence: 93%

DAMGO in the central amygdala alleviates the affective dimension of pain in a rat model of inflammatory hyperalgesia

Zhang

et al. 2013

Neuroscience

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“…A CFA inflammatory pain rat model was combined with a conditioned place avoidance test to determine whether electroacupuncture inhibits pain-induced affective response. 122 During preconditioning, rats spent similar amounts of time in two compartments, indicating no aversion to either. After conditioning, rats that received sham electroacupuncture spent less time in a pain-paired compartment, demonstrating place aversion to that compartment.…”

Section: Inflammatory Pain Animal Modelsmentioning

confidence: 95%

“…By contrast, electroacupuncture-treated rats showed no aversion to the pain-paired compartment, demonstrating that electroacupuncture inhibited the CFA-produced affective response. 122 Saline-injected rats showed neither preference nor aversion to electroacupuncture- or sham electroacupuncture-paired chambers; this shows that the electroacupuncture treatment did not produce reward or aversion (fig. 4).…”

Section: Inflammatory Pain Animal Modelsmentioning

confidence: 98%

Mechanisms of Acupuncture–Electroacupuncture on Persistent Pain

Zhang

Lao

Ren³

et al. 2014

Anesthesiology

648

465

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In the last decade, preclinical investigations of electroacupuncture mechanisms on persistent tissue-injury (inflammatory), nerve-injury (neuropathic), cancer, and visceral pain have increased. These studies show that electroacupuncture activates the nervous system differently in health than in pain conditions, alleviates both sensory and affective inflammatory pain, and inhibits inflammatory and neuropathic pain more effectively at 2–10 Hz than at 100 Hz. Electroacupuncture blocks pain by activating a variety of bioactive chemicals through peripheral, spinal, and supraspinal mechanisms. These include opioids, which desensitize peripheral nociceptors and reduce pro-inflammatory cytokines peripherally and in the spinal cord, and serotonin and norepinephrine, which decrease spinal n-methyl-d-aspartate receptor subunit GluN1 phosphorylation. Additional studies suggest that electroacupuncture, when combined with low dosages of conventional analgesics, provides effective pain management that can forestall the side effects of often-debilitating pharmaceuticals.

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“…To explore the effective therapy and the potential mechanisms of pain memory, affective-motivational and evaluative-cognitive pain have increasingly gained researchers' attentions [2, 3, 26, 28, 33]. EA, an effective pain treatment that is considered to be a mind-body therapy, has a wide range of data supporting its analgesic role and capacity to regulate mood disorder and memory [2, 23, 34, 35]. In our previous studies, we have found that the retrieval of pain memory can be alleviated by pretreatment with EA, which is partially attributed to the downregulated expression of p-CREB [21].…”

Section: Discussionmentioning

confidence: 99%

“…Pain memory is one of the pivotal pathogeneses of chronic pain, which is involved in sensory-discriminative, emotional affective, and cognitive evaluative pain [1, 2]. It is a nociceptive pain characterized by hyperalgesia and allodynia, resulting in formation of memories and negative emotions of pain in the brain [3–6].…”

Section: Introductionmentioning

confidence: 99%

Inhibition of the cAMP/PKA/CREB Pathway Contributes to the Analgesic Effects of Electroacupuncture in the Anterior Cingulate Cortex in a Rat Pain Memory Model

et al. 2016

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Pain memory is considered as endopathic factor underlying stubborn chronic pain. Our previous study demonstrated that electroacupuncture (EA) can alleviate retrieval of pain memory. This study was designed to observe the different effects between EA and indomethacin (a kind of nonsteroid anti-inflammatory drugs, NSAIDs) in a rat pain memory model. To explore the critical role of protein kinase A (PKA) in pain memory, a PKA inhibitor was microinjected into anterior cingulate cortex (ACC) in model rats. We further investigated the roles of the cyclic adenosine monophosphate (cAMP), PKA, cAMP response element-binding protein (CREB), and cAMP/PKA/CREB pathway in pain memory to explore the potential molecular mechanism. The results showed that EA alleviates the retrieval of pain memory while indomethacin failed. Intra-ACC microinjection of a PKA inhibitor blocked the occurrence of pain memory. EA reduced the activation of cAMP, PKA, and CREB and the coexpression levels of cAMP/PKA and PKA/CREB in the ACC of pain memory model rats, but indomethacin failed. The present findings identified a critical role of PKA in ACC in retrieval of pain memory. We propose that the proper mechanism of EA on pain memory is possibly due to the partial inhibition of cAMP/PKA/CREB signaling pathway by EA.

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Electroacupuncture alleviates affective pain in an inflammatory pain rat model

Cited by 31 publications

References 34 publications

DAMGO in the central amygdala alleviates the affective dimension of pain in a rat model of inflammatory hyperalgesia

DAMGO in the central amygdala alleviates the affective dimension of pain in a rat model of inflammatory hyperalgesia

Mechanisms of Acupuncture–Electroacupuncture on Persistent Pain

Inhibition of the cAMP/PKA/CREB Pathway Contributes to the Analgesic Effects of Electroacupuncture in the Anterior Cingulate Cortex in a Rat Pain Memory Model

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