BACKGROUND Thalidomide has been recognized as having an anti-allodynic effect against neuropathic pain induced by spinal nerve ligation. Its clinical beneficial effects are mainly derived from its immune-modulating property, which is known to influence the analgesic action of morphine. The possible characteristics of systemic interactions between thalidomide and morphine in the context of spina...

Ligation and transection of the L5 spinal nerve in the rat lead to behavioral signs of pain and hyperalgesia. Discharge of injured nociceptors has been presumed to play a role in generating the pain. However, A fibers, but not C fibers, in the injured L5 spinal nerve have been shown to develop spontaneous activity. Moreover, an L5 dorsal root rhizotomy does not reverse this pain behavior, sugge...

Nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF) are two major members of the neurotrophin family. Using immunohistochemistry and in situ hybridization histochemistry, we examined the effect of L5 spinal nerve ligation (SPNL), a neuropathic pain model, on the expression of BDNF in the uninjured L4 dorsal root ganglion (DRG). After L5 SPNL, both immunoreactivity for BDNF an...

Introduction: Glycogen Synthase Kinase-3β (GSK-3β) participates in several signaling pathways and plays a crucial role in neurodegenerative diseases, inflammation, and neuropathic pain. The ratio of phosphorylated GSK-3β over total GSK-3β (p-GSK-3β/t-GSK-3β) is reduced following nerve injury. Apoptosis is a hallmark of many neuronal dysfunctions in the context of neuropathic pain. Thus, this st...

introduction: several studies have reported the involvement of age-related changes in the development of neuropathic pain behaviors. however, limited data are available on the role of age in establishing and maintaining chronic neuropathic pain after peripheral nerve injury. methods: in the present study, we examined age-related neuropathic behavior among rats in 4 age groups: pups (4 weeks old...

BACKGROUND Morphine produces powerful analgesic effects against acute pain, but it is not effective against neuropathic pain, and the mechanisms underlying this reduced efficacy remain unclear. Here, the authors compared the efficacy of systemic morphine between normal rats and rats with peripheral nerve injury, with a specific focus on descending serotonergic mechanisms. METHODS After L5 spi...

BACKGROUND Intrathecal adenosine is antinociceptive under conditions of central sensitization, but not in response to acute stimuli in normals. The reasons for this selective circumstance of action remain unclear, but some evidence links adenosine's antinociceptive effects to release of norepinephrine by terminals in the spinal cord. The purpose of this study was to test whether spinal adenosin...

An rodent animal model of pain offers a powerful tool in order to understand the mechanism involved in peripheral nerve injury for preclinical study of pain. A battery of neuropathic pain models has been developed to simulate the clinical pain conditions with diverse etiology. This article reviews some of the most widely used or promising new models for chronic pain. Partial spinal ligation, ch...

The medial part of the L4 and 5 dorsal horn in adult rats is dominated by afferents from the toes and foot. After transection of the sciatic and saphenous nerves, virtually all cells in this region are left without any peripheral receptive field. Beginning 4 to 5 days after nerve section, however, many peripherally deafferented cells take on a novel receptive field on the thigh, lower back, or ...

BACKGROUND The degree to which intrathecally administered morphine can alleviate hypersensitivity in animals after peripheral nerve injury is controversial, and the mechanisms by which morphine works in these circumstances are uncertain. In normal animals, morphine induces adenosine release, and in vitro data suggest that this link is disrupted after peripheral nerve injury. Therefore, using a ...