Neuroscience letters
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Neuroscience letters · Dec 2013
The role of alpha-2 adrenoceptor subtype in the antiallodynic effect of intraplantar dexmedetomidine in a rat spinal nerve ligation model.
The purpose of this study was to examine the effects of intraplantar dexmedetomidine to relieve neuropathic pain and determine the role of peripheral α2-adrenoceptors. Neuropathic pain was induced by ligating the L5 and L6 spinal nerves in male Sprague-Dawley rats, and mechanical allodynia was assessed using von Frey filaments. Several antagonists were injected into the hindpaws to evaluate the mechanisms of action of dexmedetomidine, a nonselective α2-adrenoceptor antagonist yohimbine, an α2A-adrenoceptor antagonist BRL 44408, an α2B-adrenoceptor antagonist ARC 239, and a α2C-adrenoceptor antagonist JP 1302. ⋯ The expression levels of α2B-adrenoceptor and α2C-adrenoceptor genes of plantar skin were upregulated significantly in the model group, whereas α2A-adrenoceptor expression was unchanged. These results suggest that intraplantar injection of dexmedetomidine produced an antiallodynic effect in spinal nerve ligation-induced neuropathic pain. All three types of peripheral α2A, α2B, and α2C-adrenoceptors were involved in the antiallodynic mechanism of dexmedetomidine.
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Neuroscience letters · Nov 2013
The impact of rectification on the electrically evoked long-latency reflex of the biceps brachii muscle.
Long latency reflexes (LLR) were elicited electrically and obtained by full wave rectified and non-rectified data recordings in 10 healthy subjects. After single or train stimuli (sensory radial nerve; interstimulus interval 3ms) amplitude and peak latency values were measured over the bent biceps brachii (BB) muscle, either without or with 1.5kg weight load. After rectification, mean LLR amplitude values made up 30% of the non-rectified data, independent from the stimulus type and weight load. ⋯ This overlap of motor unit potentials forming the LLR obviously results in excess amplitude cancellation after rectification as shown for sine and damped sine waves. Rectification leads to an increase in the frequency content of the data that renders it prone to phase cancellation. In the present study, this cancellation was harmful as it prevented detection of important factors of influence such as stimulus strength and motor unit recruitment level.
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Neuroscience letters · Nov 2013
Suggesting a possible role of CA1 histaminergic system in harmane-induced amnesia.
A number of tremorogenic β-carboline alkaloids such as harmane are naturally present in the human food chain. They are derived from medicinal plants such as Peganum harmala that have been used as folk medicine in anticancer therapy. In the present study, effects of the histaminergic system of the dorsal hippocampus (CA1) on harmane-induced amnesia were examined. ⋯ Moreover, pre-training intra-CA1 injection of a sub-threshold dose of histamine (2.5μg/mouse) could reverse harmane (12mg/kg, i.p.)-induced impairment of memory. On the other hand, pre-training intra-CA1 injection of sub-threshold doses of ranitidine (0.0625μg/mouse) and pyrilamine (2.5μg/mouse) increased harmane-induced impairment of memory. In conclusion, the present findings suggest the involvement of the CA1 histaminergic system in harmane-induced impairment of memory formation.
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Neuroscience letters · Nov 2013
Interleukin-1 alpha (rs1800587) genetic polymorphism is associated with specific cognitive functions but not depression or loneliness in elderly males without dementia.
Inflammatory process is considered to be a pathway that results in neurodegeneration, and numerous plasma cytokines have been examined for their association with cognitive function and depression. Interleukin-1 alpha (IL-1A) genetic polymorphism (rs1800587) has been found to be associated with Alzheimer's disease susceptibility. The aim of this study was to investigate the effect of IL-1A rs1800587 genetic effects on cognitive functions, loneliness and depression severity in elderly males without dementia or major depression. 192 non-demented Chinese elderly male were recruited and underwent Cognitive Abilities Screening Instrument (CASI), Wechsler Digit Span Task, Geriatric Depression Scale-short form, and UCLA Loneliness Scale assessment. ⋯ This polymorphism is not associated with Geriatric Depression Scale-short form or UCLA Loneliness Scale. Our data supports that the T allele of IL-1A rs1800587 genetic polymorphism is associated with better cognitive function in the elderly. Further research will be needed to better understand the molecular mechanism for IL-1A genetic effects on cognitive function in the elderly.
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Neuroscience letters · Nov 2013
Oral gabapentin treatment accentuates nerve and peripheral inflammatory responses following experimental nerve constriction in Wistar rats.
Gabapentin (GBP) is an anti-convulsive drug often used as analgesic to control neuropathic pain. This study aimed at evaluating whether oral GBP treatment could improve nerve inflammation response after sciatic nerve constriction in association with selected pain and motor spontaneous behavior assessments in Wistar rats. We evaluated nerve myeloperoxidase (MPO) and inflammatory cytokines on the 5th day post-injury, time in which nerve inflammation is ongoing. ⋯ GBP (120mg/kg) reduced the anti-inflammatory cytokine IL-10 nerve levels compared with the CCSN saline group. Furthermore, GBP (60 and 120mg/kg) increased carrageenan-induced paw edema and peritoneal macrophage migration compared with the CCSN saline group. Altogether our findings suggest that GBP accentuates nerve and peripheral inflammatory response, however confirmed its analgesic effect likely due to an independent CNS-mediated mechanism, and raise some concerns about potential GBP inflammatory side effects in widespread clinical use.