Neuroscience letters
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Neuroscience letters · Jun 2014
Effect of inflammatory challenge on hypothalamic neurons expressing orexinergic and melanin-concentrating hormone.
Neurons containing the hypothalamic peptides orexin-A (hypocretin 1) and melanin-concentrating hormone (MCH) have been reported numerous roles in the regulation of the sleep-wake cycle, energy balance and feeding behavior. We investigated the response of these cells to repeated administration of low doses of endotoxin lipopolysaccharide (LPS) in mice. ⋯ Orexin expression entirely returned to control levels 30 days after the last LPS injection in mice treated for 8 weeks. These data strongly suggest the occurrence of selective alterations of orexinergic system, reversible over time, following repeated and intermittent systemic inflammatory challenge in mice.
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Neuroscience letters · Jun 2014
Cortical responses to C-fiber stimulation by intra-epidermal electrical stimulation: an MEG study.
Intra-epidermal electric stimulation (IES) is an alternative to laser stimulation for selective activation of cutaneous Aδ-fibers. IES is based on the fact that nociceptive fiber terminals are located in the epidermis, whereas receptors of other fibers end deep in the dermis. IES can selectively stimulate C-fibers if the electrode structure and stimulation parameters are carefully selected. ⋯ IES elicited somatosensory evoked fields in all subjects. The mean peak latency was 1,327 ± 116 ms in the opercular region contralateral to the stimulated side, 1,318 ± 90 ms in the opercular region ipsilateral to the stimulated side, and 1350 ± 139 ms in the primary somatosensory cortex. These results indicate that IES performed using the modified electrode can selectively stimulate C-fibers and may be a useful tool for pain research as well as clinical evaluation of peripheral small fiber function.
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Neuroscience letters · Jun 2014
Association of CREB1 gene polymorphism with drug seeking behaviour in eastern Indian addicts.
cAMP response element binding protein (CREB) is a major transcription factor which plays an important role in a wide array of cellular functions. CREB also has a significant function in developing substance abuse. A study was undertaken to identify the single nucleotide polymorphisms (SNP) at selective areas of CREB1 gene in heroin as well as in alcohol addicts in comparison with control population. ⋯ One SNP in exon 3, rs35349697, demonstrated a significant correlation with opioid addiction as well as with alcohol addiction. A novel SNP, also located in exon 3, was identified which showed epistatic interaction with rs35349697 to decrease susceptibility to narcotic addiction in the population. The study is the first report on the identification of a role of CREB1 gene polymorphism with addiction.
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Neuroscience letters · Jun 2014
Deficits of synaptic functions in hippocampal slices prepared from aged mice null α7 nicotinic acetylcholine receptors.
Alpha 7 (α7) nicotinic acetylcholine receptor (α7-nAChR) is one of most high expressed nAChR subtypes in the brain. The activation of nAChRs enhances animal cognitive, learning and memory abilities. However, the role of genetic knockout (KO) of α7-nAChRs in animal cognition-associated behaviors is still obscure. ⋯ However, adult α7-nAChR KO mice did not show a clear deficit in LTP although the basic synaptic transmission was also reduced compared to adult WT mice. In both age groups, there was no significant difference of paired-pulse facilitation between α7-nAChR KO and WT mice. Collectively, this study provides direct evidence, for the first time, that the impaired synaptic function occurs in aged α7-nAChR KO mice, suggesting an importance of α7-nAChRs in maintaining cognitive function during aging process.
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Neuroscience letters · Jun 2014
Descending effect on spinal nociception by amygdaloid glutamate varies with the submodality of noxious test stimulation.
Amygdala has an important role in the processing of primary emotions, such as fear. Additionally, amygdala is involved in processing and modulation of pain. While the amygdala, particularly its central nucleus (CeA), has been shown to contribute to pain control, the descending pain regulation by the CeA is still only partly characterized. ⋯ In contrast, mechanical antinociception lasted longer (>20 min), was predominantly contralateral and reversed by blocking the amygdaloid NMDA receptor. At an antinociceptive dose, amygdaloid glutamate failed to influence motor performance. The results indicate that independent of the brain hemisphere, the spatial extent and duration of the descending antinociceptive effect induced by amygdaloid glutamate varies with the amygdaloid glutamate receptor and the submodality of pain.