Ghrelin is a circulating peptide hormone that promotes feeding and regulates metabolism in humans and rodents. The action of ghrelin is mediated by the growth hormone secretagogue receptor type 1a (GHSR-1a) that is widely distributed in the brain, including the hippocampus. Studies have demonstrated the critical role of hippocampal ghrelin/GHS-R1a signaling in synaptic physiology and memory. However, those findings are controversial, and the mechanism underlying ghrelin modulation of learning and memory is uncertain. Here, we report that micro-infusion of ghrelin in the CA1 region of the dorsal hippocampus during training specifically impairs memory acquisition. The activation of GHS-R1a and the subsequent PI3K/Akt/GSK3β signaling cascades are involved in this process. Moreover, we report that bath application of ghrelin suppresses the intrinsic excitability of dCA1 pyramidal neurons through activating GHS-R1a, and PI3K inhibitor LY294002 blocks ghrelin's effect. However, LY294002 fails to rescue ghrelin-induced LTP impairment. Our findings support an adverse effect of ghrelin-dependent activation of GHS-R1a on memory acquisition, and suggest that PI3K/Akt/GSK3β signaling-dependent repression of neuronal intrinsic excitability is an important novel mechanism underlying memory inhibition of ghrelin in the hippocampus.
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http://dx.doi.org/10.1016/j.neuropharm.2021.108871 | DOI Listing |
Cancer Metastasis Rev
January 2025
Research and Scientific Studies Unit, College of Nursing and Health Sciences, Jazan University, Jazan, Saudi Arabia.
Lung cancer is a leading global cause of mortality, with non-small cell lung cancer (NSCLC) accounting for a significant portion of cases. Immune checkpoint inhibitors (ICIs) have transformed NSCLC treatment; however, many patients remain unresponsive. ICI resistance in NSCLC and its association with cellular plasticity, epithelial-mesenchymal transition (EMT), enhanced adaptability, invasiveness, and resistance is largely influenced by epigenetic changes, signaling pathways, tumor microenvironment, and associated immune cells, fibroblasts, and cytokines.
View Article and Find Full Text PDFBr J Dev Psychol
January 2025
Department of Psychology, Trinity University, San Antonio, Texas, USA.
This study investigates whether the context in which a word is learnt affects noun and verb learning. There is mixed evidence in studies of noun learning, and no studies of background perceptual context in verb learning. Two-, three-, and four-year-olds (n = 162) saw a novel object moved in a novel way while hearing four novel words, either nouns or verbs.
View Article and Find Full Text PDFInfancy
January 2025
Language and Linguistic Science Department, University of York, York, UK.
Current research indicates likely developmental connections between the evolution of sleep patterns, motor skills progression, and the expansion of vocabulary. These connections are grounded in the well-established role of sleep in memory and learning, as well as in the cascading effects on language development of the acquisition of new motor skills. However, no study has so far undertaken a comprehensive and systematic examination of these connections or explored their developmental trajectory over time.
View Article and Find Full Text PDFBioengineering (Basel)
December 2024
Department of Electrical Engineering and Information Technology (DIETI), University of Naples Federico II, 80125 Naples, Italy.
Diabetes is a chronic condition, and traditional monitoring methods are invasive, significantly reducing the quality of life of the patients. This study proposes the design of an innovative system based on a microcontroller that performs real-time ECG acquisition and evaluates the presence of diabetes using an Edge-AI solution. A spectrogram-based preprocessing method is combined with a 1-Dimensional Convolutional Neural Network (1D-CNN) to analyze the ECG signals directly on the device.
View Article and Find Full Text PDFEur J Nucl Med Mol Imaging
January 2025
Laboratory of Neuroimaging and Innovative Molecular Tracers (NIMTlab), Geneva University Neurocenter and Faculty of Medicine, University of Geneva, Geneva, Switzerland.
Purpose: As dual-phase amyloid-PET can evaluate amyloid (A) and neurodegeneration (N) with a single tracer injection, dual-phase tau-PET might be able to provide both tau (T) and N. Our study aims to assess the association of early-phase tau-PET scans and F-fluorodeoxyglucose (FDG) PET and their comparability in discriminating Alzheimer's disease (AD) patients and differentiating neurodegenerative patterns.
Methods: 58 subjects evaluated at the Geneva Memory Center underwent dual-phase F-Flortaucipir-PET with early-phase acquisition (eTAU) and F-FDG-PET within 1 year.
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