Neuroscience letters
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Neuroscience letters · Feb 2007
'Prior entry' for pain: attention speeds the perceptual processing of painful stimuli.
We investigated whether the perception of simultaneity for pairs of nociceptive and visual stimuli was dependent upon the focus of participants' attention to a particular sensory modality (either pain or vision). Two stimuli (one painful and the other visual) were presented randomly at different stimulus onset asynchronies (SOAs) using the method of constant stimuli. Participants made unspeeded verbal responses as to which stimulus they perceived as having been presented first, or else responded that the two stimuli were presented simultaneously. ⋯ The results showed that under conditions of divided attention, nociceptive stimuli had to be presented before visual stimuli in order for the two to be perceived as simultaneous. A comparison of the two focused attention conditions revealed that the painful stimulus was perceived as occurring earlier in time (relative to the visual stimulus) when attention was directed toward pain than when it was directed toward vision. These results provide the first empirical demonstration that attention can modulate the temporal perception of painful stimuli.
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Neuroscience letters · Feb 2007
Edaravone inhibits lipid peroxidation in neonatal hypoxic-ischemic rats: an in vivo microdialysis study.
The occurrence of hypoxia-ischemia (HI) during early fetal or neonatal stages of an individual leads to the damaging of immature neurons resulting in behavioral and psychological dysfunctions. Free radical-mediated lipid peroxidation is the main cause of neurotoxicity including neonatal brain damage. Edaravone (3-methyl-1-phenyl-2-pyrazolin-5-one) is a novel anti-oxidant agent and the drug of choice in the treatment of acute ischemic brain disorders in adult patient. ⋯ Edaravone at 5 microM significantly increased the EPR signals compared to control. This study shows that edaravone directly and dose-dependently inhibited the formation of lipid free radicals produced during hypoxic-ischemic insult in the neonatal rat brain. These results suggest that edaravone is able to attenuate neuronal damage in the rat neonatal brain by inhibiting the formation of lipid radicals.
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Neuroscience letters · Feb 2007
Involvement of microglia in the ethanol-induced neuropathic pain-like state in the rat.
Central mechanisms of neuropathy induced by chronic ethanol treatment are almost unknown. In this study, rats were treated with ethanol-diet for 72 days. ⋯ Furthermore, hypertrophy of microglia was clearly observed following chronic ethanol consumption. These findings support the idea that the activation and hypertrophy of microglia in the spinal cord may be, at least in part, associated with in the induction of ethanol-dependent neuropathic pain-like state.
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Neuroscience letters · Feb 2007
Comparative StudyFirst detection of olfactory marker protein (OMP) immunoreactivity in the olfactory epithelium of a cartilaginous fish.
Olfactory marker protein (OMP) is a protein expressed in the mature olfactory and vomeronasal neurons of many vertebrates, such as mammals, amphibians and bony fishes. Aim of this work was to investigate the OMP expression in the olfactory epithelium of the shark Scyliorhinus canicula (Linnaeus, 1758), by immunohistochemistry (IHC). ⋯ Although very little is known about the OMP's function, its involvement in synaptogenesis, transduction cascade, neurogenesis and development of olfactory system has been suggested. The present work shows for the first time OMP's presence in a cartilaginous fish.
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Neuroscience letters · Feb 2007
Pentoxifylline attenuates the development of hyperalgesia in a rat model of neuropathic pain.
Pentoxifylline, a non-specific cytokine inhibitor, has shown to be beneficial in inflammatory pain in both experimental and clinical studies. The present study demonstrates for the first time, to our knowledge, the antihyperalgesic effect of pentoxifylline in the neuropathic pain using L5 spinal nerve transection rat model. In a preventive paradigm, pentoxifylline (12.5, 25, 50, or 100mg/kg intraperitoneally) was administered systemically daily, beginning 1h prior to nerve transection. ⋯ Furthermore, we investigated the activity of nuclear factor kappa B (NF-kappaB) in the contralateral brain on days 7 after surgery. In accordance with the change of proinflammatory cytokines, Pentoxifylline (50 or 100mg/kg) significantly inhibited the activation of NF-kappaB in the brain. This research supports a growing body of literature emphasizing the importance of neuroinflammation and neuroimmune activation in the development of neuropathic pain states, and the potential preventive value of pentoxifylline in the treatment of neuropathic pain.