Neuroscience
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Chemokines are important regulators of immune, inflammatory, and neuronal responses in peripheral and central pain pathway. The aim of this study was to investigate whether chemokine (C-X-C motif) ligand 13 (CXCL13) and its receptor (C-X-C chemokine receptor type 5, CXCR5) involve in the development of bone cancer pain (BCP) and the regulation of morphine analgesia in rats. The change of pain behaviors in BCP rats were measured by testing paw withdrawal threshold (PWT). ⋯ While blocking the activation of p-p38, p-ERK and p-AKT, morphine analgesia was enhanced. These results suggest CXCL13 participated in bone cancer pain and opposed morphine analgesia via p38, ERK and AKT pathways. It may be a target to enhance pain management in cancer pain patients.
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Methamphetamine (MA), neurotoxic drug of abuse, causes cell death in vitro and in vivo via several mechanisms such as mitochondrial dysfunction. In this study we evaluated the effect of MA on cell viability and mitochondrial biogenesis in primary midbrain culture. Primary mesencephalon cells prepared from E14.5 rat embryo were treated with 0.2-5 mM MA concentrations for 24, 48, and 72 h. ⋯ The results indicated that MA effect on cell viability occurs in a dose-dependent manner. While moderate concentrations increased cell viability, the higher ones reduced it and caused cell death. Mitochondrial biogenesis activation, as a compensatory mechanism, did not prevent neuronal and glial cell death following high MA concentration.
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Sensory perception is neither static nor simple. The senses influence each other during multisensory stimulation and can be both suppressive and super-additive. As most knowledge of human olfactory perception is derived from functional neuroimaging studies, in particular fMRI, our current understanding of olfactory perception has systematically been investigated in an environment with concurrent loud sounds. ⋯ For this, 50 subjects were tested in both a silent setting and an fMRI-noise setting, in a randomised order. We found that fMRI-related acoustic noise had a significant negative effect on the olfactory detection threshold score. No significant effects were identified on olfactory discrimination, identification, identification certainty, hedonic rating, or intensity rating.
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Mirror Activity (MA) is a phenomenon that is characterized by involuntarily occurring muscular activity in homologous contralateral limbs during unilateral movements. Even in neurologically healthy humans, MA of a small extent has been described, which does not directly lead to visible movements, but nonetheless, it is still detectable with surface electromyography (EMG) and therefore defined as physiological MA (pMA). The present study investigated latency- and amplitude-characteristics of pMA during repetitive unimanual isometric contractions with high but constant force requirements (80% maximum force). ⋯ Furthermore, based on the previously proposed hypothesis of motor overflow, we explored the possibility of pMA modulation through anodal and cathodal transcranial direct current stimulation (tDCS) applied to the ipsilateral primary motor cortex (M1), relative to a voluntarily contracting hand. Neither anodal nor cathodal tDCS is able to modulate amplitude or latency of pMA compared to sham tDCS. In conclusion, our results extend the existing knowledge of pMA occurring due to high-effort unilateral contractions with constant force requirements to the aspect of its latency and the inverse association with its amplitude.
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Neurons containing melanin-concentrating hormone (MCH) in the lateral hypothalamic area (LH) have been shown to promote rapid eye movement sleep (REMs) in mice. However, the downstream neural pathways through which MCH neurons influence REMs remained unclear. ⋯ We found that inhibition of MCH terminals in the vlPAG/LPT significantly reduced transitions into REMs during spontaneous sleep-wake cycles and prevented the increase in REMs transitions observed after chemogenetic activation of MCH neurons. These results strongly suggest that the vlPAG/LPT may be an essential relay through which MCH neurons modulate REMs.