Neuroscience
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Substantia nigra pars reticulata is the output station in basal ganglia; its GABAergic neurons control the activity of thalamo-cortical premotor nuclei, thus controlling motor behavior. D1-like and D2-like presynaptic dopamine receptors on subthalamo-nigral afferents by modulation of glutamate release change the firing rate of nigral neurons; however, their relative contribution to the control of glutamate release and their pharmacological properties have not been studied. This is important since the prevalence of the inhibition or stimulation of release determines the firing rate of nigral neurons, therefore motor activity. ⋯ We also co-activated these to test their interaction; an antagonist interaction of D1-like with D2 and D3R, and an additive between D2 and D3R were found. Pharmacological receptor antagonist effects in release from reserpinized vs. non-reserpinized slices were similar, suggesting that endogenous dopamine stimulates receptors in the same way. These findings suggest differences in the control of glutamate release by different dopamine receptors in the substantia nigra, which could contribute to explaining the effect of dopamine and its agonists on motor behavior.
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The comparative roles of the human amygdala and orbitofrontal cortex in emotional processing are under substantial debate, supported prominently by invasive primate studies. Noninvasive studies in humans are restricted by the limitations of electro- and magneto-encephalographic methods, which are hampered by the closed-field architecture and deep location of these structures. Here we employ whole-brain functional magnetic resonance imaging at an effective sampling rate of 300 ms to define the latency of enhanced blood oxygen level dependent (BOLD) contrast within structures activated by emotionally evocative relative to neutral scenes, in an effort to assess the hypothesized primacy of amygdala-inferotemporal co-activity in human emotional perception, relative to orbitofrontal cortex. ⋯ Subcortical structures including the amygdala, locus coeruleus, and basal forebrain also showed reliably increased activity during emotional scene perception. The latency at which emotional BOLD signal enhancement varied considerably across structures, ranging from 2 to 6 seconds after scene onset. Though coarse, the spatiotemporal pattern of emotion-enhanced activity identified here is consistent with the idea that the amygdala and inferior temporal fusiform gyrus are the first regions to discriminate scene emotionality, which may then distribute this categorical information to other cortical and subcortical structures.
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Exploring sexual dimorphisms in the brain morphology is important for their impact and therapeutic implications for several neurological diseases. The hypothesis that sex could influence the transcriptome of brain cells could be the basis regarding the different response to cognitive decline identified in men and women. In this paper, we analyzed several prefrontal cortices (PFC) microarrays datasets of young/middle-aged healthy subjects and then Alzheimer's disease (AD) patients, according to the sex. ⋯ In addition, the sex-matched analysis of transcriptome identified a convergent molecular signature in men and women AD patients. Furthermore, the WPSEG belonging to CNS cells in PFC of healthy middle-aged subjects was correlated to AD profiles according to the sex. Since our results, it is possible to conclude that during the aging the PFC' cells adopt transcriptional strategies sex-dependent that could potentially control the development of neurodegenerative diseases.
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Despite the high incidence of neuropathic pain, its mechanism remains unclear. Oxytocin (OXT) is an established endogenous polypeptide produced in the supraoptic nucleus (SON) and paraventricular nucleus (PVN) of the hypothalamus. OXT, which is synthesized by OXT neurons in the SON and the magnocellular part of the PVN (mPVN), is delivered into the posterior pituitary (PP), then released into the systemic blood circulation. ⋯ Furthermore, OXT-mRFP1 granules with positive fluorescent reaction were remarkably increased in laminae I and II of the ipsilateral dorsal horn. Although the plasma concentrations of OXT did not significantly change, a significant increase of the mRNA levels of OXT and mRFP1 in the SON, mPVN, and pPVN were observed. These results suggest that neuropathic pain induced by PSL upregulates hypothalamic OXT synthesis and transportation to the OXTergic axon terminals in the PP and spinal cord.
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Binge alcohol drinking is a well characterized consumption pattern related with drinking five or more alcoholic beverages during a short period of time followed by a non-drinking period. Several studies showed that this pattern of alcohol intake is becoming very popular among adolescents. However, little is known about the cellular mechanisms involved in ethanol toxicity under these conditions and if these negative changes could be extending to the adulthood. ⋯ Adolescent binge-like ethanol exposure reduced the expression of the mitochondrial respiration complexes, induced mitochondrial depolarization, increased mitochondrial calcium levels, and reduced ATP production in the adult hippocampus. Altogether, our results indicate that adolescence binge alcohol drinking affects the electron transport chain components expression resulting in mitochondrial failure and loss of calcium buffering in the adult hippocampus. Therefore, we reported for first time that adolescent binge-alcohol consumption has severe repercussions on mitochondrial bioenergetics during the adulthood; and that this is not a transitory change until the state of drunkenness disappears as previously believed.