Neuroscience letters
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Neuroscience letters · Sep 2004
Comparative StudyGabapentin relieves mechanical, warm and cold allodynia in a rat model of peripheral neuropathy.
Although recent studies demonstrated the relieving effect of gabapentin on neuropathic pain, the effect has not been sufficiently examined. In the present study, we investigated the effect of gabapentin on mechanical, warm and cold allodynia in a rat model of peripheral neuropathy. ⋯ Intraperitoneal injection of gabapentin (30, 100, 300 mg/kg) significantly alleviated mechanical, warm and cold allodynia in a dose-dependent manner. Our results suggest that gabapentin is an effective agent against mechanical, warm and cold allodynia in a rat model of peripheral neuropathy.
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Neuroscience letters · Sep 2004
Comparative StudyKetamine potentiates the effect of electroacupuncture on mechanical allodynia in a rat model of neuropathic pain.
Mu-opioid agonists and N-methyl-d-aspartate (NMDA) receptor antagonists have been shown to attenuate mechanical allodynia in neuropathic pain models. We have previously reported that 2Hz electroacupuncture (EA) produced analgesia via releasing endogenous opioid peptides (i.e. beta-endorphin and endomorphin) and the activated micro-opioid receptors. ⋯ The results are as follows: (1) EA itself or i.p. injection of ketamine reduced mechanical allodynia (i.e. increase in withdrawal threshold). (2) Although injection of ketamine at a low dose (1.0mg/kg) alone did not influence mechanical withdrawal threshold, combination of ketamine at this dose with EA produced more potent anti-allodynic effect than that induced by EA alone. (3) The anti-allodynic effect of EA combined with ketamine could be reversed by i.p. injection of naloxone (2.0 mg/kg). These results suggested that ketamine potentiate the anti-allodynic of EA in rats with spinal nerve ligation, and endogenous opioid system is likely to be involved in this process.
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Neuroscience letters · Sep 2004
Comparative StudyChanges to cold detection and pain thresholds following low and high frequency transcranial magnetic stimulation of the motor cortex.
There is some evidence that repetitive transcranial magnetic stimulation (rTMS) can alleviate the experience of chronic pain. The mechanisms by which rTMS may induce pain relief, however, are unknown. The present study examined whether a session of rTMS would produce sensory threshold changes in healthy individuals. ⋯ While cold detection threshold was significantly lowered by both rTMS rates, only high frequency rTMS produced a significant change in cold pain threshold. In contrast, sham rTMS did not alter thresholds for cold stimuli. These findings provide evidence that sensory thresholds can be influenced by repetitive transcranial magnetic stimulation.
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Neuroscience letters · Sep 2004
Cannabinoids blocks tactile allodynia in diabetic mice without attenuation of its antinociceptive effect.
Diabetic neuropathic pain is one of the most commonly encountered neuropathic pain syndromes. However, the treatment of diabetic neuropathic pain is challenging because of partial effectiveness of currently available pain relievers. It is well known that diabetic animals are less sensitive to the analgesic effect of morphine, and opioids are found to be ineffective in the treatment of diabetic neuropathic pain. ⋯ WIN 55, 212-2-induced antinociception were found to be similar in diabetic mice when compared to controls suggesting efficacy of cannabinoid antinociception was not diminished in diabetic mice. WIN 55, 212-2 also produced a dose-dependent antiallodynic effect in diabetic mice. This study suggests that cannabinoids have a potential beneficial effect on experimental diabetic neuropathic pain.
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Neuroscience letters · Sep 2004
Development of neuropathic pain is affected by bedding texture in two models of peripheral nerve injury in rats.
It has long been known that there are numerous genetic and environmental factors that affect the in vivo research of neuropathic pain. In this letter, we describe the impact that bedding material can have on the development of neuropathic pain behaviors in rodents. ⋯ Rats housed on coarse sawdust presented with a much-reduced response to a pinprick and acetone test compared to counterparts housed on fine sawdust. It is therefore concluded that the development of specific stimulus modalities of neuropathic pain behavior following peripheral nerve injury can be influenced in part by environmental factors, in this case bedding texture.