The anatomical record : advances in integrative anatomy and evolutionary biology
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Activation of extracellular signal-regulated kinase-1/2 (ERK1/2) and its involvement in regulating gene expression in spinal dorsal horn, cortical and subcortical neurons by peripheral noxious stimulation contribute to pain hypersensitivity. Transcutaneous electrical nerve stimulation (TENS) is a treatment used in physiotherapy practice to promote analgesia in acute and chronic inflammatory conditions. In this study, a total number of 114 rats were used for three experiments. ⋯ TENS on Yongquan acupoint for 20 min produced obvious analgesic effects as demonstrated with increased HPL to thermal stimuli of CFA-treated rats. In addition, TENS application suppressed the CFA-induced ERK2 activation and c-Fos protein expression. These results suggest that down-regulation of ERK2 phosphorylation and c-Fos expression were involved in TENS inhibition on CFA-induced thermal hyperalgesia of rats.
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The phenomenon of ischemic tolerance perfectly describes this quote "What does not kill you makes you stronger." Ischemic pre- or postconditioning is actually the strongest known procedure to prevent or reverse neurodegeneration. It works specifically in sensitive vulnerable neuronal populations, which are represented by pyramidal neurons in the hippocampal CA1 region. However, tolerance is effective in other brain cell populations as well. ⋯ Delayed neuronal death is the slow development of postischemic neurodegeneration. This allows an opportunity for a great therapeutic window of 2-3 days to reverse the cellular death process. Moreover, it seems that the mechanisms of ischemic tolerance-delayed postconditioning could be used not only after ischemia but also in some other processes leading to apoptosis.
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As has happened in all facets of neuroimaging, cross-sectional imaging has dramatically changed our approach and understanding of the anatomy and pathology of paranasal sinuses. We have moved away from plain film radiographs to modern high-resolution sinus computerized tomography (CT) and magnetic resonance imaging (MRI) that helps us better depict underlying normal anatomy and evaluate pathology. Recent advances in PET/CT imaging have introduced a physiologic aspect to anatomical imaging and holds promise to better stage and restage head and neck tumors. In this article, we describe the various imaging techniques, concerns, advantages and disadvantages of the individual techniques, and provide an overview of the various pathologies involving the paranasal sinuses.
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GABA (gamma-aminobutyric acid)ergic neurons in the spinal dorsal horn have been reported to be divided into distinctive populations, with different cotransmitters and neuropeptides. In this study, we examined the colocalization of enkephalin (ENK) mRNA with GABA in the spinal dorsal horn using the glutamic acid decarboxylase (GAD)(67)-green fluorescence protein (GFP) knock-in mouse. Our approach was to perform in situ hybridization histochemistry to detect mRNA for preproenkephalin (PPE, the precursor protein for ENK), combined with immunohistochemistry for GFP to reveal GABAergic neurons. ⋯ While 53.9% (2967/5501) of PPE mRNA-expressing neurons were immunoreactive for GFP. The double-labeled neurons were observed throughout the spinal dorsal horn, although they had a preferential localization in superficial layers. The present results provide a detailed morphological evidence that ENK and GABA colocalized in a subpopulation of neurons in the spinal dorsal horn, which are likely to represent local inhibitory dorsal horn interneurons involved in the modulation of pain transmission.
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The hierarchical relationship of the rat primary somatosensory cortex (S1) and secondary somatosensory cortex (S2) is controversial. The existence of a direct thalamocortical projection from ventral posterolateral thalamic nucleus (VPL) to S2 is a key factor in determining the relative position of S2 in the processing flow. In this study, the inter-connections of forepaw and hindpaw representations in VPL, S1, and S2 were examined by neuroanatomical tracing and electrophysiological approaches. ⋯ In the electrophysiological studies, paired somatic evoked multiunit responses in S1 and S2 were compared. Our results revealed that: (1) VPL forepaw and hindpaw neurons projected to corresponding S1 and S2 areas in a parallel and somatotopic manner; (2) very low percentage of double projecting VPL neurons were found, indicating parallel and independent pathways from forepaw VPL to S1 and S2; (3) forepaw S1 and S2 were symmetrically and reciprocally connected; (4) response latencies of the S1 and S2 multiunits to forepaw stimulation were in accordance with a direct and parallel pathway. This study provides further evidence to support the equivalent hierarchy of S1 and S2 in processing sensory information of the rat.