Neuroscience
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The ventromedial hypothalamic nucleus (VMN) controls glucose counter-regulation, including pituitary growth hormone (GH) secretion. VMN neurons that express the transcription factor steroidogenic factor-1/NR5A1 (SF-1) participate in glucose homeostasis. Research utilized in vivo gene knockdown tools to determine if VMN growth hormone-releasing hormone (Ghrh) regulates hypoglycemic patterns of glucagon, corticosterone, and GH outflow according to sex. ⋯ Ghrh gene knockdown altered Ghrh/SF-1 neuron estrogen receptor-alpha (ERα) and ER-beta transcripts in hypoglycemic male, not female rats, but up-regulated GPR81 lactate receptor mRNA in both sexes. Outcomes infer that VMNdm Ghrh/SF-1 neurons may be an effector of SF-1 control of counter-regulation, and document Ghrh modulation of hypoglycemic patterns of glucose-regulatory neurotransmitter along with estradiol and lactate receptor gene transcription in these cells. Co-transmission of glucose-inhibitory and -stimulatory neurochemicals of diverse chemical structure, spatial, and temporal profiles may enable VMNdm Ghrh neurons to provide complex dynamic, sex-specific input to the brain glucose-regulatory network.
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Intranasal insulin reduces lesion size and enhances memory capacity in traumatic brain injury (TBI) models, but the molecular mechanisms behind this neuroprotective action not yet understood. Here we used Feeney's free-falling method to construct TBI mouse models and administrated intranasal insulin, rapamycin, insulin and rapamycin, or normal saline to assess their effects on neurological functions, cerebral edema, and the expression of Iba1 in microglia through immunofluorescence assay. We also measured concentrations of interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α) in the brain using enzyme immunosorbent assay, investigated apoptosis with TUNEL staining and Western blotting, and evaluated autophagy, endoplasmic reticulum (ER) stress, and PI3K/Akt/mTOR signaling pathway with Western blotting. ⋯ TUNEL assay and Western blotting also indicated that intranasal insulin inhibited ER stress-mediated apoptosis. Interestingly, the mTOR inhibitor rapamycin partially blocked the pro-autophagy and anti-apoptosis effects of intranasal insulin both on days 1 and 3 post TBI. Our results suggest that intranasal insulin can ameliorate TBI by regulating autophagy and ER stress-mediated apoptosis through the PI3K/AKT/mTOR signaling pathway, providing a promising therapeutic strategy for TBI.
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It has been reported that individuals with psychogenic erectile dysfunction (pED) potentially suffer from cognitive declines. Despite that increasing neuroimaging studies have demonstrated abnormalities of cerebral structural changes in pED, the association between altered white matter (WM) structural network and cognitive impairments remains unclear. Hence, this study aimed to explore the relationship between WM structural network connectivity and cognitive performance in patients with pED. ⋯ Compared with HCs, we found that pED patients showed higher fractional anisotropy (FA) values between left transverse temporal sulcus and left supramarginal gyrus, and lower FA values between left suborbital sulcus and left para-hippocampal part of the medial occipito-temporal gyrus in pED patients. Furthermore, the increased FA between left transverse temporal sulcus and left supramarginal gyrus was observed to be negatively associated with impaired delayed memory. Overall, our findings provide new insights into WM network alterations associated with impaired cognitive functions in pED, which may unravel the potential neural mechanisms underlying the cognitive impairments of pED patients.
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Recent evidence suggests that alcohol use disorder (AUD) may manifest itself differently in women compared to men. Women experience AUDs on an accelerated timeline and may have certain regional vulnerabilities. In male rats, neuronal cell death and astrocyte reactivity are noted following induction of alcohol dependence in an animal model of an AUD. ⋯ Vimentin immunoreactivity also occurred at earlier and later time points in some cortical and hippocampal regions. These data suggest that both neuronal cell death and astrocyte reactivity could be more widespread in females compared to males. Therefore, this study provides a framework for specific regions and time points which should be examined in future studies of alcohol-induced damage that include female rats.
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The correlation of early life adversity with adulthood psychopathology has already been revealed by epidemiological studies. To find the biological mechanisms underlying the cross-talk between prenatal adversity and mental health, molecular genetic studies have been performed using animal models of prenatal undernutrition and stress, reporting altered expression of serotonin receptors which modulate the release of many neurotransmitters that regulate a broad range of physiological functions including psychopathology. Unfortunately, no such study has been possible on humans due to ethical reasons. ⋯ In a sex-stratified analysis, the pattern was only significant in females (p-value, 0.019) but not in males. We further tested the DNA methylation patterns specifically in HTR1A, HTR2A and the X-linked HTR2C and found reduced DNA methylation in females for HTR2A (p-value 0.033) and HTR2C (p-value 0.014) but not in males. Overall, this study reveals altered epigenetic regulation of the serotonin receptor signaling pathway in association with prenatal adversity in humans providing novel epigenetic evidence in support of neurodevelopmental origin of psychiatric disorders.