Articles: neuralgia.
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The aim of the present study was to investigate efficacy of continuous epidural block for prevent postherpetic neuralgia (PHN) progression in cases of acute herpes zoster with severe pain and also to identify predictive factors for PHN in such conditions. We retrospectively analyzed the clinical data of patients with herpes zoster who underwent continuous epidural block between March 2013 and October 2015. Time points were set as 1 month, 3 months, and 6 months after zoster onset. ⋯ The incidence of PHN is higher in zoster patients with severe pain that requires continuous epidural block compared to incidence in the general population. Advanced age and severe initial pain intensity were predictive factors of PHN development. Prolonged catheterization resulting from weak response to treatment strongly suggested progression to PHN.
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Clinical studies have reported that pan-cannabinoid receptor agonists may have efficacy in neuropathic pain states and that this might be enhanced by co-administration with opioids. While cannabinoid-opioid analgesic synergy has been demonstrated in animal models of acute pain, it has not been examined in neuropathic pain models. We examined the effect of combination treatment with cannabinoid and opioid receptor agonists on allodynia and side effects in a nerve injury-induced neuropathic pain model. ⋯ These findings indicate that administration of a combination of a non-selective opioid and cannabinoid receptor agonist synergistically reduces nerve injury-induced allodynia, while producing side effects in an additive manner. This suggests that this combination treatment has an improved anti-allodynic potency and therapeutic index in a neuropathic pain model.
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Molecular neurobiology · Aug 2016
Interleukin-17A Acts to Maintain Neuropathic Pain Through Activation of CaMKII/CREB Signaling in Spinal Neurons.
Immunity and neuroinflammation play major roles in neuropathic pain. Spinal interleukin (IL)-17A, as a mediator connecting innate and adaptive immunity, has been shown to be an important cytokine in neuroinflammation and acute neuropathic pain. However, the effects and underlying mechanisms of spinal IL-17A in the maintenance of neuropathic pain remain unknown. ⋯ Furthermore, we showed that blocking CaMKII with KN93 significantly reduced SNL- or rIL-17A-induced hyperalgesia and p-CREB expression. Our in vitro data showed that KN93 also significantly inhibited rIL-17A-induced CREB activation in primary cultured spinal neurons. Taken together, our study indicates that astrocytic IL-17A plays important roles in the maintenance of neuropathic pain through CaMKII/CREB signaling pathway in spinal cord, and thus targeting IL-17A may offer an attractive strategy for the treatment of chronic persistent neuropathic pain.
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Anesthesia and analgesia · Aug 2016
Amitriptyline, but Not Pregabalin, Reverses the Attenuation of Noxious Stimulus-Induced Analgesia After Nerve Injury in Rats.
Noxious stimulus-induced analgesia (NSIA) is a type of conditioned pain modulation in rats that has been used to assess endogenous pain control systems. The descending noradrenergic system is involved in NSIA, and nerve injury induces plastic changes of descending noradrenergic neurons. Thus, we hypothesized that nerve injury would affect NSIA strength and that amitriptyline and pregabalin, which often are used for treating neuropathic pain, might further modulate NSIA through effects on the descending noradrenergic system. ⋯ These data suggest that endogenous analgesia in neuropathic pain states is strongly decreased from a certain time after nerve injury and that amitriptyline reverses the attenuation of endogenous analgesia through effects on the descending noradrenergic system.