Neuroscience
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The neural network undergoes remodeling in response to neural activity and interventions, such as antidepressants. Cell adhesion molecules that link pre- and post-synaptic membranes are responsible not only for the establishment of the neural circuitry, but also for the modulation of the strength of each synaptic connection. Among the various classes of synaptic cell adhesion molecules, a non-clustered protocadherin, Arcadlin/Paraxial protocadherin/Protocadherin-8 (Acad), is unique in that it is induced quickly in response to neural activity. ⋯ This treatment reduced spine density in the dentate gyrus and CA1. Chronic fluoxetine treatment did not suppress spine density in Acad-/- mice, suggesting that fluoxetine-induced decrease in spine density is largely due to Arcadlin. The present findings confirm the spine-repulsing activity of Arcadlin and its involvement in the remodeling of hippocampal neurons in response to antidepressants.
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CA1 pyramidal neurons undergo intense morphological and electrophysiological changes from the second to third postnatal weeks in rats throughout a critical period associated with the emergence of exploratory behavior. Using whole cell current-clamp recordings in vitro and neurochemical methods, we studied the development of the somatic action potential (AP) waveform and some of the underlying channels in this critical period. At the third postnatal week, APs showed a more hyperpolarized threshold, higher duration and amplitude. ⋯ Repetitive stimulation with high frequency trains (50 Hz) reproduced AP broadening associated to inactivation of the A-type current in immature cells. Moreover, repetitive firing showed changes in AP amplitude consistent with the inactivation of both sodium and potassium subthreshold currents, which resulted in higher AP amplitudes in the more immature neurons. We propose that maturation of AP waveform and excitability in this critical developmental period could be related to the onset of exploratory behaviors.
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Choline acetyltransferase (ChAT) synthesizes the neurotransmitter acetylcholine (Ach). Exogenous supplementation with ChAT can functionally compensate for decreased Ach levels and ameliorate memory and cognitive deficits. In this paper, the treatment efficacy of recombinant ChAT (peptide transduction domain (PTD)-ChAT) and donepezil were compared in aged dementia mice, and their mechanisms were explored by performing the gene function annotation and enrichment analysis of differentially expressed genes. ⋯ Donepezil was significantly correlated with the immune inflammatory response and the insulin and IGF-1 signaling pathways. Therefore, although PTD-ChAT and donepezil were both effective in the treatment of aged dementia mice, their mechanisms were significantly different. Our research indicated that PTD-ChAT has potential promise for research on new drugs for AD treatment.
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Recent studies indicate that neuroimmune factors, including the cytokine interleukin-6 (IL-6), play a role in the CNS actions of alcohol. The cerebellum is a sensitive target of alcohol, but few studies have examined a potential role for neuroimmune factors in the actions of alcohol on this brain region. A number of studies have shown that synaptic transmission, and in particular inhibitory synaptic transmission, is an important cerebellar target of alcohol. ⋯ Multiple cerebellar synaptic proteins were assessed by Western blot. Results show that IL-6 and CIE/withdrawal have both unique and common actions that affect synaptic protein expression. These common targets could provide sites for IL-6/alcohol exposure/withdrawal interactions and play an important role in cerebellar symptoms of alcohol use such as ataxia.
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Acupuncture is a mild therapy in rehabilitation practice of peripheral nerve injury. Previous studies confirmed the deep participation of brain plasticity in the process of functional restoration. The therapeutic effect of acupuncture is also believed to be closely associated with brain plasticity, especially in the hypothalamus and limbic system. ⋯ It induces changes of neural plasticity in several sub-networks instead of whole brain network. We attributed the changes to the enhancement of the short-term compensatory adaptation and the reduction of the long-term overacting regional information transmission. The present study may shed light on the vague distinction of large-scale property of brain networks after electroacupuncture, which leads to a better understanding of this ancient traditional Chinese therapy.