Neuroscience
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This study examined the relationship between head and trunk sway during quiet stance and compared this relationship with that of the pelvis to the trunk. Sixteen younger and 14 elderly subjects participated, performing four different sensory tasks: standing quietly on a firm or foam support surface, with eyes open or closed. Roll and pitch angular velocities were recorded with six body-worn gyroscopes; a set of two mounted at the upper trunk, an identical set at the hips, and another set on a head band. ⋯ These data indicate that during quiet stance body motion increases in the order of pelvis, trunk, head and quiet stance involves control of at least two separate links: trunk on pelvis and head on trunk dominated by head resonance. The head is locked to the trunk for low-frequency motion possibly because motion is just supra-vestibular threshold. The head is not stabilised in space during stance, rather the pelvis is.
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Trigeminal ganglia neurons express the GABA(A) receptor subunit alpha 6 (Gabrα6) but the role of this particular subunit in orofacial hypersensitivity is unknown. In this report the function of Gabrα6 was tested by reducing its expression in the trigeminal ganglia and measuring the effect of this reduction on inflammatory temporomandibular joint (TMJ) hypersensitivity. Gabrα6 expression was reduced by infusing the trigeminal ganglia of male Sprague Dawley rats with small interfering RNA (siRNA) having homology to either the Gabrα6 gene (Gabrα6 siRNA) or no known gene (control siRNA). ⋯ Gabrα6 siRNA infusion reduced Gabrα6 gene expression by 30% and significantly lengthened meal duration in rats with TMJ inflammation. Gabrα6 siRNA infusion also significantly increased p-ERK expression in the trigeminal ganglia of rats with TMJ inflammation and increased electrical activity in the spinal cord of rats without TMJ inflammation. These results suggest that maintaining Gabrα6 expression was necessary to inhibit primary sensory afferents in the trigeminal pathway and reduce inflammatory orofacial nociception.
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Peripherally restricted analgesics are desirable to avoid central nervous system (CNS) side effects of opioids. Nonsteroidal anti-inflammatory drugs produce peripheral analgesia but have significant toxicity. GABA(B) receptors represent peripheral targets for analgesia but selective GABA(B) agonists like baclofen cross the blood-brain barrier. ⋯ In a mouse model of osteoarthritis, isovaline restored performance during forced exercise to baseline values. Immunohistochemical staining of cutaneous layers of the analgesic test site demonstrated co-localization of GABA(B1) and GABA(B2) receptor subunits on fine nerve endings and keratinocytes. Isovaline represents a new class of peripherally restricted analgesics without CNS effects, mediated by cutaneous GABA(B) receptors.
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During exercise, intense brain activity orchestrates an increase in muscle tension. Additionally, there is an increase in cardiac output and ventilation to compensate the increased metabolic demand of muscle activity and to facilitate the removal of CO(2) from and the delivery of O(2) to tissues. Here we tested the hypothesis that a subset of pontomedullary and hypothalamic neurons could be activated during dynamic acute exercise. ⋯ In summary, we show for the first time that after acute exercise there is an intense activation of brain areas crucial for cardiorespiratory control. Possible involvement of the central command mechanism should be considered. Our results suggest whole brain-specific mobilization to correct and compensate the homeostatic changes produced by acute exercise.
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Gamma-amino butyric acid (GABA)ergic cells play an important inhibitory role in epilepsy. Until now, there are no reports on promoting transplanted bone marrow stromal cells (BMSCs) to differentiate into GABAergic cells for treatment of epilepsy. In this study, hairy and enhancer of split 1 (Hes1)-down regulated BMSCs (H-BMSCs) were transplanted into an epileptic rat model to induce GABAergic cells differentiation to improve the function recovery and neuronal regeneration. ⋯ The results showed that the rate of mortality, frequency of spontaneous recurrent seizures (SRS) and incidence of epileptiform waves presented a tendency to decrease after H-BMSCs transplantation. The histology results showed that (1) the transplanted H-BMSCs which migrated to the adjacent parahippocampal cortical areas expressed glutamate decarboxylase (GAD) 67, neuron-specific enolase (NSE) and some glial fibrillary acidic protein (GFAP), and (2) the neuronal density of corresponding cortical areas was significantly increased (P<0.01 VS. experimental group I or positive control group). Given these results and other advantages of BMSCs, such as easy harvest and minimal immunogenicity, transplantation of H-BMSCs could be a promising approach to improve the functional recovery and neuronal regeneration of epileptic model in the early stage.