Neuroscience
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S-nitrosoglutathione (GSNO) has been reported to protect against ischemic brain injury, however, the underlying mechanisms remain to be elucidated. In the present study, we aimed to investigate the effects of GSNO pre-treatment on the S-nitrosylation of Fas and subsequent events in the Fas pathway, and reveal the correlation between Fas S-nitrosylation and nNOS activation in the rat hippocampal CA1 region after global cerebral ischemia. The results showed that GSNO pre-treatment not only facilitated the survival of hippocampal CA1 pyramidal neurons, but also abolished the activation of pro-apoptotic Caspase-8, Bid, Caspase-9 and Caspase-3. ⋯ In addition, pre-administration of GSNO decreased the translocation of Fas to membrane, the formation of CD95(hi) on the membrane, the internalization of Fas aggregates to plasma, as well as the assembly of DISC/hiDISC. These results indicate that GSNO-induced nNOS inactivation associates with the down-regulation of Fas S-nitrosylation and consequent Fas signal cascade, which is responsible for the GSNO-mediated neuronal survival after brain ischemia. The understanding of GSNO neuroprotection provides a novel strategy to find potential therapeutic targets for ischemic stroke.
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Anhedonia, or the inability to experience positive feelings is a hallmark of depression. However, few animal models have relied on decreased positive affect as an index of susceptibility to depression. Rats emit frequency-modulated ultrasonic vocalizations (USVs), designated as "positive" calls in the 50-kHz range. ⋯ However, if a bLR is accompanied by another bLR, there is a significant increase in 50-kHZ USVs emitted by this phenotype. bHRs emitted increases in 50-kHZ UVSs upon first exposure to EC, whereas bLRs showed a similar increase only after repeated exposure. bLRs' increase in positive affect after chronic EC was coupled with significant positive correlations between corticosterone levels and c-fos mRNA in the accumbens. Conversely, a decline in the rate of positive calls in bHRs after chronic EC was associated with a negative correlation between corticosterone and accumbens c-fos mRNA. These studies demonstrate that inborn differences in emotionality interact with the environment to influence positive affect and underscore the potential interaction between glucocorticoids and the mesolimbic reward circuitry in modulating 50-kHz calls.
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The mature neocortex is a unique six-layered mammalian brain region. It is composed of morphologically and functionally distinct subpopulations of primary projection neurons that form complex circuits across the central nervous system. The precisely-timed generation of projection neurons from neural stem cells governs their differentiation, postmitotic specification, and signaling, and is critical for cognitive and sensorimotor ability. ⋯ Indeed, mRNA transcripts undergo many post-transcriptional regulatory steps before the production of functional proteins, which specify neocortical neural stem cells and subpopulations of neocortical neurons. Therefore, particular attention is paid to the differential post-transcriptional regulation of key transcripts by RNA-binding proteins, including splicing, localization, stability, and translation. We also present a transcriptome screen of candidate molecules associated with post-transcriptional mRNA processing that are differentially expressed at key developmental time points across neocortical prenatal neurogenesis.
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In adult animals, the cerebellum is richly innervated by serotonin: serotonergic fibres are the third main afferent fibres into the cerebellum. However, the physiology of the serotonergic system and its functional significance are not fully known during development in the cerebellum. In this review we will focus on the serotonergic regulation of the cerebellum during postnatal development. ⋯ Thus, we propose that serotonin controls cerebellar development in three phases: (1) stimulation of dendritic growth and formation of synapses, (2) hard-wiring of neuronal connections with limits to dendritic growth but ensuring synaptic plasticity, and (3) stabilization of synapses. Taken together, serotonin receptors expressed by different cells in the cerebellum have a specialized role during postnatal development, but with some similar main effects. Distinct spatial and temporal expression of these receptors gives serotonin a powerful and specific role in cerebellar development.
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A number of psychiatric illnesses have been associated with prenatal disturbance of brain development, including autism, attention deficit hyperactivity disorder, and schizophrenia. Individuals afflicted with these disorders exhibit both repetitive motor and cognitive behavior. The potential role that environmental insult to the developing brain may play in generating these aberrant behaviors is unclear. ⋯ Perseverative errors and non-perseverative errors were recorded in early stages of the testing, at the 0 delay interval. While performing DA, FIMs made more errors of perseveration than CONs yet the number of total errors committed did not differ between groups. The presence of motor stereotypies and cognitive perseveration in fetally irradiated non-human primates suggests that environmental insult to the embryonic brain may contribute to repetitive motor and cognitive behaviors in neuropsychiatric diseases.