We previously identified a pyridomorphinan (, SRI-22138) possessing a 4-chlorophenyl substituent at the 5'-position on the pyridine and a 3-phenylpropoxy at the 14-position of the morphinan as a mixed μ opioid receptor (MOR) agonist and δ/κ opioid receptor (DOR/KOR) antagonist with potent antinociceptive activity and diminished tolerance and dependence in rodents. Structural variations at the 5'- and 14-positions of this molecule gave insights into the structure-activity relationships for binding and functional activity. Subtle structural changes exerted significant influence, particularly on the ability of the compounds to function as agonists at the MOR. In vivo evaluation identified compound (SRI-39067) as a MOR agonist/DOR antagonist that produced systemically active potent antinociceptive activity in tail-flick assay in mice, with diminished tolerance, dependence/withdrawal, reward liability, and respiratory depression versus morphine. These results support the hypothesis that mixed MOR agonist/DOR antagonist ligands may emerge as novel opioid analgesics with reduced side effects.
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http://dx.doi.org/10.1021/acs.jmedchem.0c00503 | DOI Listing |
Curr Mol Med
January 2025
Department of Anesthesiology, Baoan Central Hospital of Shenzhen, Shenzhen, Guangdong Province, China.
Background: Morphine, a mu-opioid receptor (MOR) agonist commonly utilized in clinical settings alongside chemotherapy to manage chronic pain in cancer patients, has exhibited contradictory effects on cancer, displaying specificity toward certain cancer types and doses.
Objective: The aim of this study was to conduct a systematic assessment and comparison of the impacts of morphine on three distinct cancer models in a preclinical setting.
Methods: Viability and apoptosis assays were conducted on a panel of cancer cell lines following treatment with morphine, chemotherapy drugs alone, or their combination.
ACS Pharmacol Transl Sci
January 2025
Department of Medicinal Chemistry and Institute for Translational Neuroscience, University of Minnesota, Minneapolis, Minnesota 55455, United States.
Opioid agonist ligands bind opioid receptors and stimulate downstream signaling cascades for various biological processes including pain and reward. Historically, before cloning the receptors, muscle contraction assays using isolated organ tissues were used followed by radiolabel ligand binding assays on native tissues. Upon cloning of the opioid G protein-coupled receptors (GPCRs), cell assays using transfected opioid receptor DNA plasmids became the standard practice including S-GTPγS functional and cAMP based assays.
View Article and Find Full Text PDFExpert Opin Ther Pat
January 2025
Department of Pharmaceutical and Biomedical Sciences, Rudolph H. Raabe College of Pharmacy, Ohio Northern University, Ada, OH, USA.
Introduction: Opioids have served as a cornerstone in pain management for decades. However, the emergence of increasingly potent synthetic analogs brings forth a range of side effects, including respiratory depression, tolerance, dependence, constipation, and, more importantly, the development of severe and debilitating opioid use disorder (OUD). Search for therapeutics to mitigate OUD has been challenging and this has called for novel approaches that include design of small molecules targeting neuronal circuits involved in addiction (opioid, dopamine, serotonin, norepinephrine, and glutamate receptors, etc.
View Article and Find Full Text PDFSci Adv
January 2025
Laboratory for Biofunction Dynamics Imaging, RIKEN Center for Biosystems Dynamics Research, 6-7-3 Minatojima-Minamimachi, Chuo-ku, Kobe, Hyogo 650-0047, Japan.
Placebo analgesia is caused by inactive treatment, implicating endogenous brain function involvement. However, the neurobiological basis remains unclear. In this study, we found that μ-opioid signals in the medial prefrontal cortex (mPFC) activate the descending pain inhibitory system to initiate placebo analgesia in neuropathic pain rats.
View Article and Find Full Text PDFAm J Psychiatry
January 2025
Biobehavioral Imaging and Molecular Neuropsychopharmacology Section, NIDA, Baltimore (Levinstein, Budinich, Michaelides); Department of Pathology and Experimental Therapeutics, Institute of Neurosciences, University of Barcelona, L'Hospitalet de Llobregat, Barcelona (Bonaventura); Neuropharmacology and Pain Group, Neuroscience Program, IDIBELL-Bellvitge Biomedical Research Institute, L'Hospitalet de Llobregat, Barcelona (Bonaventura); Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Stanford (Schatzberg); Experimental Therapeutics and Pathophysiology Branch, NIMH, Bethesda (Zarate); Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore (Michaelides).
Ketamine is a racemic compound and medication comprised of ()-ketamine and ()-ketamine enantiomers and its metabolites. It has been used for decades as a dissociative anesthetic, analgesic, and recreational drug. More recently, ketamine, its enantiomers, and its metabolites have been used or are being investigated for the treatment of refractory depression, as well as for comorbid disorders such as anxiety, obsessive-compulsive, and opioid use disorders.
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