Articles: hyperalgesia.
-
Spinal cord injury (SCI) is a common type of injury, and about half of patients affected by SCI will suffer from neuropathic pain within a year after injury. However, the treatment effect of neuropathic pain is far from satisfactory. Our study attempted to reveal whether salvianolic acid B (SalB) could relieve the neuropathic pain caused by SCI in mice by inhibiting the Toll-like receptor 4 (TLR4)/Myeloid differentiation factor 88 (MyD88) pathway. ⋯ SalB reduced the release of tumor necrosis factor-α and substance P by inhibiting the TLR4/MyD88 pathway in the SCI mouse model. This not only resulted in lower pain, but also contributed to long-term relief of mechanical hyperalgesia.
-
Previous studies have shown that α7 nicotinic acetylcholine receptor (nAChR) has a critical role in the regulation of pain sensitivity and neuroinflammation. However, pharmacological effects of α7 nAChR activation in the hippocampus on neuroinflammatory mechanisms associated with allodynia and hyperalgesia remain unknown. We have determined the effects of 3a,4,5,9b-tetrahydro-4-(1-naphthalenyl)-3H-cyclopentan[c]quinoline-8-sulfonamide (TQS), an α7 nAChR positive allosteric modulator, on lipopolysaccharide (LPS)-induced allodynia and hyperalgesia in mice. We also evaluated the effects of TQS on immunoreactivity of microglial marker ionized-calcium binding adaptor molecule 1 (Iba-1), phospho-nuclear factor-κB (p-NF-κB p65), tumor necrosis factor-alpha (TNF-α), and norepinephrine (NE) level. ⋯ Taken together, our results suggest that TQS prevented LPS-induced allodynia and hyperalgesia, upregulation of TNF-α expression and NE level reduction involving microglial α7 nAChR in part in the hippocampus. Therefore, these findings highlight the important effects of α7 nAChR allosteric modulator against symptoms of inflammatory pain.
-
Randomized Controlled Trial
Short-Term Effects of 10% Lidocaine Ointment on Allodynia in Cancer Pain: A Randomized, Double-Blind, Placebo-Controlled, Crossover Study.
Background: There is currently no established therapy for allodynia, which is a type of neuropathic pain. However, high concentrations of topical anesthetics can anesthetize the skin and increase the sensory threshold to tactile stimulation. Objective: We aimed to evaluate the short-term effects and safety of 10% lidocaine ointment for treating allodynia in cancer pain. Design: This was a randomized double-blind crossover study comparing the efficacies of 10% lidocaine ointment and placebo ointment for the treatment of static allodynia and spontaneous pain within 24 hours after ointment application, using a numerical rating scale (NRS). Setting/Subjects: The subjects were 25 cancer patients with current pain rating of ≥4 on NRS of static allodynia in cancer pain. Results: The NRS scores for static allodynia were significantly lower in the lidocaine group than in the placebo group at two to eight hours after initial ointment application. ⋯ There was no interaction between time and group in terms of NRS values for spontaneous pain (p = 0.835), but a significant main effect of group was found, with NRS scores being significantly lower in the lidocaine group than in the placebo group (p = 0.027). There were no adverse events associated with lidocaine use. Conclusions: Lidocaine ointment 10% can alleviate allodynia for two to eight hours after application.
-
Exercise is considered an important component of effective chronic pain management and it is well-established that long-term exercise training provides pain relief. In healthy, pain-free populations, a single bout of aerobic or resistance exercise typically leads to exercise-induced hypoalgesia (EIH), a generalized reduction in pain and pain sensitivity that occurs during exercise and for some time afterward. In contrast, EIH is more variable in chronic pain populations and is more frequently impaired; with pain and pain sensitivity decreasing, remaining unchanged or, in some cases, even increasing in response to exercise. ⋯ The clinical implications of impaired EIH are discussed and recommendations are made for future research, including further exploration of individual differences in EIH, the relationship between exercise dose and EIH, the efficacy of combined treatments and the use of alternative measures to quantify EIH. PERSPECTIVE: This article provides a contemporary review of the acute effects of exercise on pain and pain sensitivity, including in people with chronic pain conditions. Existing findings are critically reviewed, clinical implications are discussed, and recommendations are offered for future research.
-
We report the development and characterization of a novel, injury-free rat model in which nociceptive sensitization after red light is observed in multiple body areas reminiscent of widespread pain in functional pain syndromes. Rats were exposed to red light-emitting diodes (RLED) (LEDs, 660 nm) at an intensity of 50 Lux for 8 hours daily for 5 days resulting in time- and dose-dependent thermal hyperalgesia and mechanical allodynia in both male and female rats. Females showed an earlier onset of mechanical allodynia than males. ⋯ PERSPECTIVE: This study demonstrates the effect of light exposure on nociceptive thresholds. These biological effects of red LED add evidence to the emerging understanding of the biological effects of light of different colors in animals and humans. Understanding the underlying biology of red light-induced widespread pain may offer insights into functional pain states.