Articles: neuropathic-pain.
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Transl Perioper Pain Med · Jan 2020
Long noncoding RNA H19 in the injured dorsal root ganglion contributes to peripheral nerve injury-induced pain hypersensitivity.
Peripheral nerve injury-induced changes in gene transcription and translation in the dorsal root ganglion (DRG) play a critical role in the development and maintenance of neuropathic pain. Long noncoding RNAs (lncRNAs) regulate gene expression. Here, we report that peripheral nerve injury caused by ligation of the fourth spinal nerve (SNL) led to a time-dependent increase in the expression in H19, an lncRNA, in the injured DRG. ⋯ DRG microinjection of neither siRNA affected locomotor activity and acute basal responses to mechanical and thermal stimuli. Our findings suggest that H19 participates in the peripheral mechanism underlying the development and maintenance of neuropathic pain. H19 may be a potential target for treatment of this disorder.
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Journal of pain research · Jan 2020
Usefulness of a Double-Blind Placebo-Controlled Response Test to Demonstrate Rapid Onset Analgesia with Phenytoin 10% Cream in Polyneuropathy.
Topical analgesics are an upcoming treatment option for neuropathic pain. In this observational study, we performed a double-blind placebo-controlled response test (DOBRET) in patients with polyneuropathy to determine the personalized analgesic effect of phenytoin 10% cream. ⋯ A DOBRET is easy to perform, quickly identifies an analgesic effect in responders and could be a useful tool to personalize neuropathic pain treatment with topical formulations.
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The central medial nucleus (CM), a prominent cell group of the intralaminar nuclei (ILN) of the thalamus, and the ventrolateral periaqueductal gray matter (vlPAG) are two major components of the medial pain system. Whether vlPAG and CM are input sources of nociceptive information to the basolateral amygdala (BLA) and whether they are involved in neuropathic pain regulation remain unclear. Clarifying the hierarchical organization of these subcortical nuclei (vlPAG, CM, and BLA) can enhance our understanding on the neural circuits for pain regulation. ⋯ Morphological studies revealed that: (1) the CM received afferents from vlPAG and sent efferents to BLA, indicating that an indirect vlPAG-CM-BLA pathway exists; (2) such CM-BLA projections were primarily excitatory glutamatergic neurons as revealed by fluorescence in situ hybridization; (3) the fibers originated from the CM-formed close contacts with both excitatory and inhibitory neurons in the BLA; and (4) BLA-projecting CM neurons expressed Fos induced by SNI and formed close contacts with fibers from vlPAG, suggesting that the vlPAG-CM-BLA indirect pathway was activated in neuropathic pain conditions. Finally, the vlPAG-CM-BLA indirect pathway was further confirmed using anterograde and monosynaptic virus tracing investigation. In summary, our present results provide behavioral and morphological evidence that the indirect vlPAG-CM-BLA pathway might be a novel pain pathway involved in neuropathic pain regulation.
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To compare the characteristics of neuropathic pain in neuromyelitis optica spectrum disorder (NMOSD) and multiple sclerosis (MS). ⋯ The severity of neuropathic pain and the pain-related interference in daily life were greater in NMOSD patients than in MS patients. Individualized analgesic management should be considered based on a comprehensive understanding of neuropathic pain in these patients.
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Physical exercise has been established as a low-cost, safe, and effective way to manage chronic pain, but exact mechanisms underlying such exercise-induced hypoalgesia (EIH) are not fully understood. Since a growing body of evidence implicated the amygdala (Amyg) as a critical node in emotional affective aspects of chronic pain, we hypothesized that the Amyg may play important roles to produce EIH effects. Here, using partial sciatic nerve ligation (PSL) model mice, we investigated the effects of voluntary running (VR) on the basal amygdala (BA) and the central nuclei of amygdala (CeA). ⋯ In addition, a tracer experiment demonstrated a marked increase in activated Glu neurons in the medBA projecting into the nucleus accumbens lateral shell in runner mice. Thus, our results suggest that VR may not only produce suppression of the negative emotion such as fear and anxiety closely related with pain chronification, but also promote pleasant emotion and hypoalgesia. Therefore, we conclude that EIH effects may be produced, at least in part, via such plastic changes in the Amyg.