Neuroscience letters
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Neuroscience letters · Feb 2004
Randomized Controlled Trial Clinical TrialRepetitive transcranial magnetic stimulation of the motor cortex attenuates pain perception in complex regional pain syndrome type I.
In complex regional pain syndrome (CRPS) many clinical symptoms suggest involvement of the central nervous system. Neuropathic pain as the leading symptom is often resistant to therapy. In the present study we investigated the analgesic efficiency of repetitive transcranial magnetic simulation (rTMS) applied to the motor cortex contralateral to the CRPS-affected side. ⋯ Pain re-intensified increasingly 45 min after rTMS. In contrast, sham rTMS did not alter pain perception. These findings provide evidence that in CRPS I pain perception can be modulated by repetitive motor cortex stimulation.
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Neuroscience letters · Feb 2004
Peri-sciatic administration of indomethacin early after nerve injury can attenuate the development of tactile allodynia in a rat model of L5 single spinal nerve injury.
To clarify the role of cyclooxygenase in the peripheral nerve on the development of neuropathic pain, we investigated the effects of peri-sciatic administration of indomethacin on the development of allodynia in a model of L5 single spinal nerve injury. Peri-sciatic administration of indomethacin (1 mg/kg) was performed 3, 24, or 72 h after nerve injury (n=6/each). ⋯ However, such efficacy was no longer apparent when indomethacin was administered 72 h after nerve injury. These results suggest that peri-sciatic administration of indomethacin early (less than 24 h) after nerve injury can attenuate the development of allodynia.
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Neuroscience letters · Jan 2004
Differential expression of tetrodotoxin-resistant sodium channels Nav1.8 and Nav1.9 in normal and inflamed rats.
In an attempt to understand mechanisms underlying peripheral sensitization of primary afferent fibers, we investigated the presence of the tetrodotoxin-resistant Na+ channel subunits Nav1.8 (SNS) and Nav1.9 (SNS2) on axons in digital nerves of normal and inflamed rat hindpaws. In normal animals, 14.3% of the unmyelinated and 10.7% of the myelinated axons labeled for the Nav1.8 subunit. ⋯ These data indicate that Nav1.8 and Nav1.9 subunits are transported to the periphery in normal animals and are differentially regulated during inflammation. The massive increase in Nav1.8 expression in myelinated axons suggests that these may contribute to peripheral sensitization and inflammatory hyperalgesia.
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Neuroscience letters · Jan 2004
Increased phosphorylated-mu-opioid receptor immunoreactivity in the mouse spinal cord following sciatic nerve ligation.
The present study was designed to determine whether a state of neuropathic pain induced by sciatic nerve ligation could alter phosphorylated-mu-opioid receptor-like immunoreactivity in the superficial dorsal horn of the mouse spinal cord. Mice with sciatic nerve ligation exhibited a significant suppression of the morphine-induced antinociception. Under this condition, phosphorylated-mu-opioid receptor-like immunoreactivity was clearly increased on the ipsilateral side in the superficial laminae of the L5 lumbar spinal dorsal horn in nerve-ligated mice. These findings suggest that the phosphorylation of the mu-opioid receptor in the spinal cord under a neuropathic pain-like state may, at least in part, contribute to the reduction in the antinociceptive effect produced by morphine in the mouse.
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Neuroscience letters · Dec 2003
Comparative StudyMagnetoencephalography detection of early syntactic processing in humans: comparison between L1 speakers and L2 learners of English.
In previous brain imaging studies of human syntax processing, only phrase structure (grammatical category) violations have been shown to elicit a very early (approximately 140 ms) neural response. This has led to interpretations about the nature of phrase structure encoding in the brain, particularly its relationship to early automatic brain processes. ⋯ A prominent syntactic magnetic field component, peaking at around 150 ms post-onset (labeled 'SF-M150'), was observed in both hemispheres of only the L1 speakers in response to within-phrase violations but not across-phrase violations. The results provide evidence that L1 speakers possess the ability for automated detection of non-phrase-structure violations, particularly within-phrase violations, and that L2 learners may not have sufficient neural representation available for an early automated response to the target violations.