Articles: neuralgia.
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Anesthesia and analgesia · Jun 2018
Sex Difference of Angiotensin IV-, LVV-Hemorphin 7-, and Oxytocin-Induced Antiallodynia at the Spinal Level in Mice With Neuropathic Pain.
We demonstrated previously that angiotensin IV (Ang IV) and LVV-hemorphin 7 (LVV-H7) act through the blockade of insulin-regulated aminopeptidase to decrease oxytocin degradation, thereby causing antihyperalgesia at the spinal level in rats. We determined that intrathecal oxytocin can induce significant antihyperalgesia in male rats with inflammation but not in female rats. Thus, we speculate that Ang IV, LVV-H7, and oxytocin can induce antiallodynia, which could be of great therapeutic potential. Because the antihyperalgesia by using these peptides was with sex difference, their possible antiallodynia was examined in male and female mice for comparison. We investigated whether Ang IV, LVV-H7, and oxytocin produce antiallodynia at the spinal level in mice and whether this antiallodynia differs between the sexes. ⋯ Intrathecal Ang IV, LVV-H7, and oxytocin can all cause significant antiallodynia in male mice. The Ang IV-, LVV-H7-, and oxytocin-induced antiallodynia effects differed between the sexes at the spinal level in mice.
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Current medical science · Jun 2018
Effects of Repetitive Transcranial Magnetic Stimulation on Astrocytes Proliferation and nNOS Expression in Neuropathic Pain Rats.
This study investigated the effects of different frequencies of repetitive transcranial magnetic stimulation (rTMS) on chronic neuropathic pain in rats. The behavior of rats with experimental chronic neuropathic pain was observed, and the expression of neuronal nitric oxide synthase (nNOS) in the ipsilateral dorsal root ganglions (DRGs) and the activation and proliferation of astrocytes in the ipsilateral spinal dorsal horn were detected. Thirty-two male Sprague-Dawley rats were randomly divided into four groups: sham-operated group, sham-rTMS group, 1 Hz group and 20 Hz group (8 rats in each group). ⋯ After rTMS treatment, the expression of GFAP and the co-localization with BrdU decreased in the 20 Hz group as compared with the sham-rTMS group and the 1 Hz group (P<0.05). In addition, the alleviation degree of spontaneous pain and brush-evoked pain in the 20 Hz group was negatively correlated with the expression of nNOS in ipsilateral DRGs and the number of GFAP/BrdU co-labelled astrocytes in L4-6 spinal dorsal horn ipsilateral to the neuropathic pain (P<0.05). It was suggested that high-frequency rTMS may relieve neuropathic pain through down-regulating the overexpression of nNOS in ipsilateral DRGs and inhibiting the activity and proliferation of astrocytes in L4-6 spinal dorsal horn ipsilateral to the neuropathic pain.
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Depression and anxiety are frequent in patients with chronic diseases such as diabetic neuropathic pain. The pain seems to be more severe in patients in whom depressive findings accompanied pain symptoms. Pregabalin was reported to have positive effects on anxiety and depression. This brings out the question, whether the pain relief effect of pregabalin is due to its analgesic effect or to its effects on mood? The aim of this study is to find out whether the positive effect of pregabalin in patients with diabetic neuropathic pain is limited to its effect on pain. Thus the question - do patients suffer from less pain or do they less care about pain? - should be answered. ⋯ This results suggests that the reduced pain in pregabalin treatment should be independent from its effects on depression and anxiety.
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Neuroscience letters · May 2018
Microencapsulated Schwann cell transplantation inhibits P2X2/3 receptors overexpression in a sciatic nerve injury rat model with neuropathic pain.
Transplantation of Schwann cells (SCs) can promote axonal regeneration and formation of the myelin sheath, reduce inflammation, and promote repair to the damaged nerve. Our previous studies have shown that transplantation of free or micro-encapsulated olfactory ensheathing cells can relieve neuropathic pain. There are no related reports regarding whether the transplantation of micro-encapsulated SCs can alleviate neuropathic pain mediated by P2X2/3 receptors. ⋯ Co-expression of P2X2/3 receptors with other markers in neurons in the L4-5 dorsal root ganglia (DRG) were assessed using double-label immunofluorescence 14 days after surgery. We determined P2X2/3 mRNA expression and protein level changes in the DRG using quantitative real-time polymerase change reaction technology and Western blotting analysis. We have investigated that the transplantation of micro-encapsulated SCs can alleviate pathological pain caused by P2X2/3 receptor stimulation and explored new methods for the prevention and treatment of neuropathic pain.
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Postsynaptic density-95 (PSD-95) is a synaptic scaffolding protein that plays a crucial role in the development of neuropathic pain. However, the underlying mechanism remains unclear. To address the role of PSD-95 in N-methyl-D-aspartate receptor subtype 2B (NR2B) -mediated chronic pain, we investigated the relationship between PSD-95 activation and NR2B function in the spinal cord, by using a rat model of sciatic nerve chronic constriction injury (CCI). ⋯ Moreover, repeated treatment with Ro 25-6981 markedly attenuated the thermal hypersensitivity, and inhibited the CCI-induced upregulation of PSD-95 in the spinal dorsal horn. Furthermore, intrathecal injection of the PSD-95 inhibitor strikingly reversed the thermal and mechanical hyperalgesia. Our results suggest that blocking of NR2B signaling in the spinal cord could be used as a therapeutic candidate for treating neuropathic pain.