Neuroscience letters
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Neuroscience letters · Mar 2016
The effects of an intraperitoneal single low dose of ketamine in attenuating the postoperative skin/muscle incision and retraction-induced pain related to the inhibition of N-methyl-D-aspartate receptors in the spinal cord.
Chronic postoperative pain (CPOP) is a common clinical problem which might be related to central sensitization. It has been widely accepted that NMDA (N-methyl-D-aspartate) receptors are among the triggers of central sensitization. Ketamine is a non-competitive NMDA receptor antagonist that is widely used in alleviating postoperative pain, but its effect on CPOP has been rarely reported. In the present study, the skin/muscle incision and retraction (SMIR) model was used to investigate the role of NMDARs in chronic postoperative pain and the effect of an intraperitoneal single low dose ketamine (10mg/kg) of attenuating SMIR-induced CPOP. ⋯ Our datas suggested that NMDARs play important roles in SMIR-induced CPOP. A single intraperitoneal low dose of ketamine could attenuate SMIR-induced CPOP, which might be associated with the inhibition of NMDARs. Our finding might provide a new, simple method of addressing CPOP.
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Neuroscience letters · Mar 2016
Neuroprotective effects of stemazole in the MPTP-induced acute model of Parkinson's disease: Involvement of the dopamine system.
Parkinson's disease is a neurodegenerative disorder characterized by a loss of nigrostriata dopaminergic neurons, which has been thought, at least in part, to result from oxidative stress. The present study aims to investigate the neuroprotective effects of stemazole (ST) on the dopamine (DA) system and its possible mechanisms of action in a mouse model of PD. Mice were injected intraperitoneally with MPTP (20mg/kg) four times at 2-h intervals for one day to induce Parkinsonism, and then treated with ST (10, 30 and 50mg/kg) or Madopar (120mg/kg) for 7days. ⋯ In addition, SOD and GSH-PX activities were elevated notably in ST treatment groups compared with the vehicle group. In conclusion, these results suggest that ST has neuroprotective effect on the impaired DA system, potentially through enhancement of the cell's anti-oxidative capacity. Hence it may be used as a potential therapeutic agent for Parkinson's disease.
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Neuroscience letters · Mar 2016
Non-Gaussian diffusion alterations on diffusion kurtosis imaging in patients with early Alzheimer's disease.
To evaluate non-Gaussian diffusion changes of the whole-brain and its correlation with cognitive performance in patients with early Alzheimer's disease (AD), using diffusion kurtosis imaging (DKI). ⋯ Early AD patients already have microstructural changes in both WM and GM. DKI can provide supplementary information in reflecting these changes and may be sensitive in diagnosing early AD.
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Neuroscience letters · Feb 2016
Effect of spinal monoaminergic neuronal system dysfunction on pain threshold in rats, and the analgesic effect of serotonin and norepinephrine reuptake inhibitors.
Dysfunction in the central serotonin (5-HT) and norepinephrine (NE) systems cause depression and pain. Descending spinal pain modulatory pathways are important in the analgesic mechanisms of antidepressants, particularly serotonin and norepinephrine reuptake inhibitors (SNRIs). While many non-clinical studies have demonstrated the roles of central monoaminergic systems in pain, there is little evidence to illuminate the direct contribution of spinal descending pain modulatory systems independently of depressive-like behavior. ⋯ Lumbar-intrathecal reserpine did not deplete brain monoamines or bring about depressive-like behavior in the forced swim test. Spinal monoamines depletion-induced pain sensitivity was ameliorated by lumbar-intrathecal administration of the SNRIs (duloxetine and milnacipran) in dose-dependent manners. These suggest that increased pain sensitivity could be induced by dysfunction solely of the descending pain modulatory system, regardless of depressive-like behavior, and lumbar-intrathecal administration of SNRIs could ameliorate the pain sensitivity which might be mediated by affecting the descending pain modulatory system in the spinal cord, not via their antidepressant effects.
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Neuroscience letters · Feb 2016
Electrophysiological evidence for the existence of a rare population of C-fiber low threshold mechanoreceptive (C-LTM) neurons in glabrous skin of the rat hindpaw.
The mammalian skin in innervated by distinct classes of low-threshold mechanoreceptive (LTM) primary afferent neurons that are classified as Aβ-, Aδ- or C-LTMs according to their axonal conduction velocities (CVs). C-LTMs are thought to signal pleasant and erotic touch sensations in humans, and to exist only in the hairy skin of primates and other species. Using intracellular recordings from rat L4/L5 dorsal root ganglion (DRG) neurons that were classified in vivo as C-nociceptors or C-LTMs, according to their dorsal root CVs and their responses to mechanical and thermal stimuli, the present study provides the first electrophysiological evidence that C-LTMs exist in the glabrous skin of the rat's hindpaw. ⋯ They also exhibited faster action potential and afterhyperpolarization kinetics than C-HTMs. The present study lends support to previous studies that have provided indirect evidence for the presence of C-LTMs in glabrous skin. If C-LTMs are present in human glabrous skin, they may, in this type of skin, represent a novel peripheral neuronal substrate for the pleasant/social touch sensation, and account for or contribute to touch hypersensitivity after injury.