Articles: hyperalgesia.
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J. Gastroenterol. Hepatol. · Apr 2011
Randomized Controlled Trial Comparative StudyVisceral sensation and irritable bowel syndrome; with special reference to comparison with functional abdominal pain syndrome.
Stress-induced visceral hypersensitivity may play an important role in the pathogenesis of irritable bowel syndrome (IBS) but not in functional abdominal pain syndrome (FAPS). We examined rectal sensation in those patients. ⋯ RRD-induced rectal hypersensitivity seems to be reliable marker for IBS, and CRF may contribute to this response. FAPS patients may have hyposensitivity to non-noxious physiological distention, suggesting FAPS has different pathogenesis from IBS.
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Curr Pain Headache Rep · Apr 2011
ReviewOpioid-induced hyperalgesia: clinically relevant or extraneous research phenomenon?
Opioids have become the unequivocal therapy of choice in treating many varieties of chronic pain. With the increased prescription of opioids, some unintended consequences have occurred. After prolonged opioid exposure, opioid-induced hyperalgesia (OIH), the paradoxical effect that opioid therapy may in fact enhance or aggravate preexisting pain, may occur. ⋯ However, not all evidence supports the clinical importance of OIH, and some question whether the phenomenon exists at all. Here, we present a nonexhaustive, brief review of the recent literature. OIH will be reviewed in terms of preclinical and clinical evidence for and against its existence; recommendations for clinical evaluation and intervention also will be discussed.
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J. Chem. Neuroanat. · Apr 2011
Evidence for cellular injury in the midbrain of rats following chronic constriction injury of the sciatic nerve.
Complex behavioural disabilities, as well as pain, characterise neuropathic pain conditions for which clinical treatment is sought. In rats, chronic constriction injury (CCI) of the sciatic nerve evokes, allodynia and hyperalgesia as well as three distinct patterns of disability, characterised by changes in social and sleep-wake behaviours: (i) Pain & Disability; (ii) Pain & Transient Disability and (iii) Pain alone. Importantly, the degree of allodynia and hyperalgesia is identical for each of these groups. ⋯ The anatomical location of TUNEL and cleaved-caspase-3 immunoreactive profiles in the midbrain was also identified. Rats with Pain & Disability showed: (i) pro-apoptotic ratios of Bax:Bcl-2 mRNAs; (ii) decreased HSP60 mRNA; (iii) increased iNOS and MEK2 mRNAs; (iv) TUNEL-positive profiles in the lateral and ventrolateral PAG; and (v) caspase-3 immunoreactive neurons in the mesencephalic nucleus of the trigeminal nerve. Cell death in these specific midbrain regions may underlie the disabilities characterising this subgroup of nerve-injured rats.
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Pharmacol. Biochem. Behav. · Apr 2011
Granulocyte-colony stimulating factor (G-CSF) induces mechanical hyperalgesia via spinal activation of MAP kinases and PI3K in mice.
Granulocyte-colony stimulating factor (G-CSF) is a current pharmacological approach to increase peripheral neutrophil counts after anti-tumor therapies. Pain is most relevant side effect of G-CSF in healthy volunteers and cancer patients. Therefore, the mechanisms of G-CSF-induced hyperalgesia were investigated focusing on the role of spinal mitogen-activated protein (MAP) kinases ERK (extracellular signal-regulated kinase), JNK (Jun N-terminal Kinase) and p38, and PI(3)K (phosphatidylinositol 3-kinase). ⋯ Furthermore, G-CSF-induced hyperalgesia was inhibited in a dose-dependent manner by intrathecal pre-treatment with ERK (PD98059), JNK (SB600125), p38 (SB202190) or PI(3)K (wortmanin) inhibitors. The co-treatment with MAP kinase and PI(3)K inhibitors, at doses that were ineffective as single treatment, significantly inhibited G-CSF-induced hyperalgesia. Concluding, in addition to systemic opioids, peripheral opioids as well as spinal treatment with MAP kinases and PI(3)K inhibitors also reduce G-CSF-induced pain.
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Biomedical research · Apr 2011
Proteomic analysis of rat brains in a model of neuropathic pain following exposure to electroconvulsive stimulation.
Some reports have shown that electroconvulsive shock therapy is effective for treating refractory neuropathic pain. However, its mechanism of action remains unknown. This study analyzes changes in protein expression in the brainstems of neuropathic pain model rats with or without electroconvulsive stimulation (ECS). ⋯ In conclusion, ECS improved thermal hypersensitivity in a rat CCI model. Proteomic analysis showed that altered expression levels of proteins in the brainstem of CCI model rats returned to close to control levels after ECS, including many proteins associated with pain. This trend suggests an association of ECS with improved hypersensitivity, and these results may help elucidate the mechanism of this effect.