BACKGROUND Activation of NMDA receptors play an important role in the development of remifentanil-induced hyperalgesia. We hypothesized that in addition to ketamine, intrathecal MgSO4 could also relieve thermal and mechanical hyperalgesia in rats. METHODS Initially, 24 Sprague-Dawley rats were divided into control group, remifentanil group, surgical incision group and remifentanil combined wi...

primarily opioidergic and adenosine mechanisms are considered to be involved in the antinociceptive effects of antidepressants. this study was designed to determine the efficacy of acute venlafaxine administration in alleviating symptoms of neuropathic pain and the role of endogenous adenosine and opioid systems in this effect of venlafaxine. we have evaluated the effect of caffeine, a non-sele...

In a rat model of morphine tolerance, we examined the hypotheses that thermal hyperalgesia to radiant heat develops in association with the development of morphine tolerance and that both the development and expression of thermal hyperalgesia in morphine-tolerant rats are mediated by central NMDA and non-NMDA receptors and subsequent protein kinase C (PKC) activation. Tolerance to the analgesic...

Neuropathic pain after nerve injury is severe and intractable, and current drugs and nondrug therapies offer substantial pain relief to no more than half of affected patients. The present study investigated the analgesic roles of the B vitamins thiamine (B1), pyridoxine (B6) and cyanocobalamin (B12) in rats with neuropathic pain caused by spinal ganglia compression (CCD) or loose ligation of th...

Thermal hyperalgesia is the heightened sensitivity to heat and occurs during inflammation. NGF-induced thermal hyperalgesia is neutrophil-dependent (Foster et al., 2003). This group previously found that the TRPV1 receptor mediates a bilateral thermal hyperalgesia in TNFα-induced inflammation (Russell et al., 2005), but it is not yet known how TNFα mediates the response. The aim of this study w...

Opioid peptides have been proven effective in reducing the sign of hyperalgesia associated with inflammation. Electroacupuncture (EA) produces antinociception via release of endogenous opioid peptides in normal rats. Moreover, intrathecal injection of dynorphin has antinociceptive effect in rats. The present study was designed to examine whether EA has effect on the thermal and mechanical hyper...

INTRODUCTION Development of secondary hyperalgesia following a cutaneous injury is a centrally mediated, robust phenomenon. The pathophysiological role of endogenous opioid signalling to the development of hyperalgesia is unclear. Recent animal studies, carried out after the resolution of inflammatory pain, have demonstrated reinstatement of tactile hypersensitivity following administration of ...

Introduction: Peripheral nerve injury leads to neuropathic pain syndromes and different sensation like allodynia and hyperalgesia. Different animal models of neuropathic pain are used to study the neuropathic pain mechanisms. The present study was performed on two models, (SNI). The purpose of this study was comparing the behavioral responses of yhese two models and the role of saphenous and...

To study the neuropathic pain mechanism, various behavioral responses of animals in to different neuropathic models were considered. Adult male Sprague-Dawley rats weighing 230-280 g were used. Anesthesia was initially induced with pentobarbital I.P. (50 mg/kg). These models included (1): chronic constriction injury (CCI) by loose ligation of the sciatic nerve (2) Spared nerve injury (SNI) by a...