European journal of pain : EJP
-
Randomized Controlled Trial
Effects of transcranial direct current stimulation on pain perception and working memory.
Previous studies have shown that non-invasive stimulation of the dorsolateral prefrontal cortex (DLPFC) could modulate experimentally induced pain and working memory (WM) in healthy subjects. However, the two aspects have never been assessed concomitantly. The present study was set up to investigate the effects of transcranial direct current stimulation (tDCS) of the DLPFC on thermal pain and WM in the same population of healthy volunteers. ⋯ The present data show an involvement of the DLPFC in the processing of pain and WM. There was no correlation between these findings, suggesting that the analgesic effects of cortical stimulation are not associated with cognitive processing. However, this conclusion is difficult to affirm because of some limitations of the study regarding the parameters of stimulation or a ceiling effect of the 2-back task for instance.
-
The analgesic properties and mechanisms of loperamide hydrochloride, a peripherally acting opioid receptor agonist, in neuropathic pain warrant further investigation. ⋯ These findings suggest that both systemic and local administration of loperamide induce an opioid receptor-dependent inhibition of heat and mechanical hyperalgesia in nerve-injured rats, but that local paw administration of loperamide also induces thermal and mechanical antinociception.
-
To clarify the mechanism of tenderness after bone injury, we investigated changes in the withdrawal threshold to mechanical stimuli, nerve distribution and nerve growth factor (NGF)-expression in a rat model of bone injury without immobilization for bone injury healing. Rats were divided into three groups as follows: (1) rats incised in the skin and periosteum, followed by drilling a hole in the tibia [bone lesion group (BLG)]; (2) those incised in the skin and periosteum without bone drilling [periosteum lesion group (PLG)]; and (3) those incised in the skin [skin lesion group (SLG)]. Mechanical hyperalgesia continued for 28 days at a lesion in the BLG, 21 days in PLG and 5 days in SLG after treatments, respectively. ⋯ Anti-NGF and trk inhibitor K252a inhibited hyperalgesia in the different time course. This study shows that localized tenderness coincides with the bone healing and involves NGF expression and nerve sprouting after bone injury. The findings present underlying mechanisms and provide pathophysiological relevance of local tenderness to determination of bone fracture and its healing.
-
Randomized Controlled Trial Multicenter Study Comparative Study
Randomized controlled trial of the combined monoaminergic and opioid investigational compound GRT9906 in painful polyneuropathy.
GRT9906 is an investigational novel compound with μ-opioid receptor agonism and inhibition of noradrenalin/serotonin re-uptake. In this randomized, double-blind, placebo-controlled, three-way cross-over trial in painful polyneuropathy, the efficacy and safety of GRT9906 was assessed and compared with tramadol. During 4-week treatment periods, daily oral doses of either GRT9906 120-240 mg, or placebo, or tramadol 200-400 mg were given. ⋯ The most frequently reported adverse events were nausea, fatigue, constipation and sleep disorder for GRT9906 and tramadol. Four patients dropped out due to adverse events during both GRT9906 and tramadol treatment and two dropped out during placebo treatment. In conclusion, in painful polyneuropathy, GRT9906 demonstrated analgesic efficacy with a magnitude of effect comparable with tramadol and was well tolerated.
-
Randomized Controlled Trial
Preoperative administration of etoricoxib in patients undergoing hip replacement causes inhibition of inflammatory mediators and pain relief.
Administering cyclooxygenase-2 inhibitors preoperatively appears attractive since these drugs reduce post-operative pain, but do not increase the risk of post-operative bleeds, asthmatic attacks and stress-related gastrointestinal ulcers. In a former investigation, we could show that post-operative administration of etoricoxib reduces prostaglandin production in wound fluid, but the onset of action is variable due to delayed post-operative absorption. ⋯ Administration of etoricoxib 2 h before surgery allows for an effective drug concentration in critical tissues, a reduction of the production of pro-inflammatory mediators and for better pain relief.