Articles: neuralgia.
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Comparative Study
The multiplicity of spinal AA-5-HT anti-nociceptive action in a rat model of neuropathic pain.
There is considerable evidence to support the role of anandamide (AEA), an endogenous ligand of cannabinoid receptors, in neuropathic pain modulation. AEA also produces effects mediated by other biological targets, of which the transient receptor potential vanilloid type 1 (TRPV1) has been the most investigated. Both, inhibition of AEA breakdown by fatty acid amide hydrolase (FAAH) and blockage of TRPV1 have been shown to produce anti-nociceptive effects. ⋯ Moreover AA-5-HT (500nM) elevated AEA and palmitoylethanolamide (PEA) levels. Among the possible targets of these mediators, only the mRNA levels of CB2, GPR18 and GPR55, which are believed to be novel cannabinoid receptors, were upregulated in the spinal cord and/or DRG of CCI rats. It was previously reported that AA-5-HT acts in CB1 and TRPV1-dependent manner after systemic administration, but here for the first time we show that AA-5-HT action at the spinal level involves CB2, with potential contributions from GRP18 and/or GPR55 receptors.
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Both early life stress and neuropathic pain induce morphological and functional abnormalities of the nervous system that are associated with emotional regulation. In our previous study, early life stress enhanced nerve injury-induced hyperalgesia in adult male and female mice. In the present study, using phosphorylated extracellular signal-regulated kinase (p-ERK) as a marker of neuronal activation, we examined the effect of early life stress on neuronal function following partial sciatic nerve ligation (PSL). ⋯ The present data suggest that early life stress sex-dependently and site-specifically increases neuronal activity in the brain. In addition, increased neuronal activity in multiplebrain regions of mice subjected to early life stress may enhance hyperalgesia after nerve injury. WHAT DOES THIS STUDY ADD?: Maternal separation and social isolation (MSSI) increased p-ERK in the paraventricular nucleus (PVN) and amygdala of male mice. MSSI increased p-ERK in the medial prefrontal cortex and nucleus accumbens of female mice. Neuropathic pain increased p-ERK in the PVN and amygdala of female MSSI mice.
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Observational Study
Paravertebral block for management of acute postoperative pain and intercostobrachial neuralgia in major breast surgery.
Several locoregional techniques have been described for the management of acute and chronic pain after breast surgery. The optimal technique should be easy to perform, reproducible, with little discomfort to the patient, little complications, allowing good control of acute pain and a decreased incidence of chronic pain, namely intercostobrachial neuralgia for being the most frequent entity. ⋯ Single-injection paravertebral block allows proper control of acute pain with less intraoperative and postoperative consumption of opioids but apparently it cannot prevent pain chronicity. Further studies are needed to clarify the role of paravertebral block in pain chronicity in major breast surgery.
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Spontaneous pain is the most devastating positive symptom in neuropathic pain patients. Recent data show a direct relationship between spontaneous discharges in C-fibres and spontaneous pain in neuropathic patients. Unfortunately, to date there is a lack of experimental animal models for drug testing. ⋯ Partial damage to a peripheral nerve may increase the incidence of spontaneous activity in C-fibres. Retigabine reduced spontaneous activity but not stimulus-evoked activity, suggesting an important role for ion channels in the control of spontaneous pain and demonstrating the utility of the model for the testing of compounds in clinically relevant variables. WHAT DOES THIS STUDY ADD?: Our in vitro experimental model of peripheral neuropathy allows for pharmacological characterization of spontaneously active fibres. Using this model, we show that retigabine inhibits aberrant spontaneous discharges without altering physiological responses in primary afferents.
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BMJ Support Palliat Care · Sep 2016
Pharmacovigilance in hospice/palliative care: net effect of pregabalin for neuropathic pain.
Real-world effectiveness of many medications has been poorly researched, including in hospice/palliative care. Directly extrapolating findings from other clinical settings may not yield robust clinical advice. Pharmacovigilance studies provide an opportunity to understand better the net impact of medications. The study aimed to examine immediate and short-term benefits and harms of pregabalin in routine practice for neuropathic pain in hospice/palliative care. ⋯ Pregabalin delivered benefit to many patients, with 4 of 10 experiencing pain reductions by 21 days. Harms, occurring in 1 in 3 patients, may be difficult to detect in clinical practice, as they mostly involve worsening of symptoms prevalent at baseline.