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Analogues of endomorphin (Dmt-Pro-Xaa-Xaa-NH2) modified at position 4 or at positions 4 and 3, and tripeptides (Dmt-Pro-Xaa-NH2) modified at position 3, with various phenylalanine analogues (Xaa=Trp, 1-Nal, 2-Nal, Tmp, Dmp, Dmt) were synthesized and their effects on in vitro opioid activity were investigated. Most of the peptides exhibited high μ-opioid (MOP) receptor binding affinity (KiMOP=0.13-0.81nM), modest MOP-selectivity (Kiδ-opioid (DOP)/KiMOP=3.5-316), and potent functional MOP agonism (GPI, IC50=0.274-249nM) without DOP and κ-opioid (KOP) receptor agonism. Among them, compounds 7 (Dmt-Pro-Tmp-Tmp-NH2) and 9 (Dmt-Pro-1-Nal-NH2) were opioids with potent mixed MOP receptor agonism/DOP receptor antagonism and devoid of β-arrestin2 recruitment activity. They may offer a unique template for the discovery of potent analgesics that produce less respiratory depression, less gastrointestinal dysfunction and that have a lower propensity to induce tolerance and dependence compared with morphine.
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http://dx.doi.org/10.1016/j.bmc.2014.02.015 | DOI Listing |
Mol Nutr Food Res
July 2025
Department of Nutritional Sciences, Temerty Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada.
Diet-induced obesity and insulin resistance (IR) are associated with alterations in one-carbon (1C) metabolism, gene methylation, and expression. Folate, a methyl donor in 1C metabolism, is essential in gene methylation and expression and has been shown to reduce IR but the precise mechanism(s) remains unclear. Therefore, we investigated whether reduced IR can be explained by 1C metabolism modifications and differences in hypothalamic and hepatic IR-related genes expression and methylation patterns.
View Article and Find Full Text PDFMol Neurobiol
July 2025
Faculty of Pharmaceutical Sciences, The University of British Columbia, Vancouver, BC, Canada.
G-protein-coupled receptors (GPCRs) regulate multiple cellular functions, including neurite formation and maturation, processes often disrupted in neurodegenerative diseases. Like GPCRs, microtubule-associated proteins (MAPs, including MAP2 and Tuj1) and the synaptic vesicle protein synaptophysin are essential for neurite formation, maturation, and organization, which underpin brain development and cognitive function. Despite their importance, the functional crosstalk between GPCRs and MAPs, particularly in neurogenesis and pathological conditions such as Alzheimer's disease (AD), remains poorly understood.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
June 2025
Department Anatomy, University of California, San Francisco, CA 94158.
Our understanding of neural circuits that respond to skin dysfunction, triggering itch, and pathophysiological scratching remains incomplete. Here, we describe a profound chronic itch phenotype in transgenic mice expressing the tetracycline transactivator (tTA) gene within the Phox2a lineage. Phox2a; tTA mice exhibit intense, localized scratching and regional skin lesions, controllable by the tTA inhibitor, doxycycline.
View Article and Find Full Text PDFZhongguo Dang Dai Er Ke Za Zhi
May 2025
Department of Hematology and Oncology, Anhui Provincial Children's Hospital, Hefei 230022, China.
Objectives: To study the clinical and genetic characteristics of osteopetrosis (OPT) in children.
Methods: A retrospective analysis was performed on the clinical data of 14 children with OPT. Whole-exome sequencing was used to detect pathogenic genes, and clinical phenotypes and genotypic features were summarized.
Nat Commun
June 2025
Laboratory of Molecular Oncology, Institut de recherches cliniques de Montréal (IRCM), Montréal, QC, Canada.
Targeting macrophage inhibitory receptors like signal regulatory protein α (SIRPα) is a promising avenue in cancer treatment. Whereas the ligand of SIRPα, CD47, is widely expressed on tumor cells, its simultaneous presence on all normal cells raises concerns about toxicity and efficacy. This study identifies CD200R1, which binds CD200 on specific tumor types and limited normal cells, as an alternative inhibitory checkpoint for phagocytosis.
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