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Journal: European journal of pain (London, England)


Current arthritis treatments often have side-effects attributable to active compounds as well as route of administration. Cannabidiol (CBD) attenuates inflammation and pain without side-effects, but CBD is hydrophobic and has poor oral bioavailability. Topical drug application avoids gastrointestinal administration, first pass metabolism, providing more constant plasma levels.

Concepts: Pharmacology, Antibiotic, Medicinal chemistry, Topical, Route of administration, Pharmacokinetics, Biopharmaceutics Classification System, Bioavailability


To better manage post-surgical pain, standardized analgesic protocols allow for rescue analgesia (RA). This study seeks to determine which pre- and post-surgical clinical and patient-related factors, in addition to post-surgical pain, may influence health care professional decisions on RA administration.

Concepts: Health care, Health care provider, Medicine, Healthcare, Epidemiology, Clinical trial, Opioid, Pain


Opioids are commonly prescribed in primary care and can offer pain relief but may also have adverse effects. Little is known about the characteristics of people likely to receive an opioid prescription in primary care. The aim is to identify what factors are associated with primary care prescribing of high-strength analgesics in a community sample of older people with joint pain.

Concepts: Anesthesia, Opioid, Pain, Morphine, Buprenorphine, Hydrocodone


The aim of the study was to investigate if different frequencies, loads and trunk postures of occupational lifting and carrying increases the risk of sub-chronic (1-30 days last 12 months) low back pain (LBP) to become persistent (>30 days last 12 months) among female health care workers.

Concepts: Health care, Low back pain, Back pain


The role of extracellular signal-regulated kinases (ERKs) in nociception has been explored in the last years. While in spinal cord their activation is frequently correlated with pain or acute noxious stimuli, supraspinally, this association is not so evident and remains unclear. This study aims to evaluate ERK1/2 activation in the spinal cord and brainstem nuclei upon neuropathy and/or an additional mechanical stimulus.

Concepts: Signal transduction, Enzyme, Rheumatoid arthritis, Toxicology, Pain, Extracellular signal-regulated kinases, Peripheral neuropathy


BACKGROUND: Animal studies have shown that two repeated intramuscular injections of acidic saline induce mechanical allodynia that lasts for 4 weeks with spread to the contralateral side. In this study, we tested the hypothesis that two repeated intramuscular infusions of acidic saline into the human masseter muscle is associated with pain, mechanical allodynia and release of algesic substances. Eighteen healthy volunteers participated. On day 1, 2.5 mL of acidic saline (pH 3.3) was infused into one of the masseter muscles and isotonic saline (pH 6.0) into the other (randomized and single-blind). Two days later, intramuscular microdialysis was performed to sample serotonin, glutamate, pyruvate, lactate and glucose, during which the saline infusions were repeated. Pain and pressure pain thresholds (PPTs) were recorded before and after infusions on both days. RESULTS: Pain intensity induced by the infusions was higher after acidic than that after isotonic saline (p < 0.05). PPTs were decreased on both sides after microdialysis compared with baseline day 1 (p's < 0.05), but there were no differences in PPTs between sides at any time point. The levels of serotonin, glutamate, pyruvate, lactate or glucose did not change significantly during microdialysis. CONCLUSION: Infusion of acidic saline caused low levels of muscle pain, but no mechanical allodynia and no increased release of algesic substances. The value of this model appears modest, but future studies could be performed with larger sample size and higher flow rate before definite conclusions about the validity of the model for craniofacial myalgia can be drawn.

Concepts: Sample size, Muscle, Lactic acid, Peripheral neuropathy, Infusion, Hypokalemia, Myalgia, Masseter muscle


Whether fibromyalgia syndrome (FMS) can be classified as a somatoform disorder is under debate.

Concepts: Syndromes, Medically unexplained physical symptoms


BACKGROUND: Neuropathic pain is severely debilitating and resistant to pharmacological approaches; therefore, the study of therapies to complement its treatment is especially relevant. In a case report study, light-emitting diode therapy (LEDT) has shown analgesic activity as well as reduced the expression of pro-inflammatory cytokines in a rabbit osteoarthritis model and in calcaneal tendinitis in rats. Although LEDT stimulated morphofunctional recovery after nerve injury in rats, its effect against neuropathic pain has not been tested. METHODS: To that purpose, mice under anaesthesia were subjected to the sciatic nerve crush (SNC) model. On the seventh post-operative day, after determining analgesic dose (energy density in joules), LEDT (950 nm, 80 mW/cm(2) , 2.5 J/cm(2) ) was irradiated, daily for a period of 15 days, on the skin over the crush site. RESULTS: Compared with the SNC group, LEDT reduced mechanical hypersensitivity but not cold hypersensitivity which is induced by SNC, decreased spinal cord and sciatic nerve levels of tumour necrosis factor alpha (TNF-α) but did not alter interleukin (IL)-1β and IL-10 levels, and finally, failed to accelerate motor functional recovery and morphological nerve regeneration. CONCLUSION: Taken together, these data provide first-hand evidence of LEDT effectiveness against neuropathic pain induced by SNC, with corresponding decrease of pro-inflammatory cytokine levels, both in the sciatic nerve and in the spinal cord, although at a small analgesic dose, LEDT failed to accelerate nerve regeneration.

Concepts: Immune system, Cytokine, Energy, Rheumatoid arthritis, Opioid, Pain, Ketamine, Dextromethorphan


GABA disinhibition within the spinal dorsal horn has been implicated in pain hypersensitivity on injury in different neuropathic models. However, GABA alteration has been explored in only one study on trigeminal neuropathic pain.

Concepts: Nervous system, Neuron, Cerebellum, Neurons


The link between humor and sense of humor with pain has been a topic of research for decades. The purpose of the present article is to review the different studies that have been conducted to date on the association between humor and sense of humor with pain.