We measured (-)-5-(1,1-dimethylheptyl)-2-[5-hydroxy-2-(3-hydroxypropyl)cyclohe xyl]-phenol (CP 55,940)-, (-)11-OH-delta8-tetrahydrocannabinol-dimethylheptyl (HU-210)-, anandamide- and delta9-tetrahydrocannabinol-stimulated G protein activation in mouse brain using the [35S]GTPgammaS functional assay. The Ki values for these drugs were determined by agonist competition binding with the cannabinoid CB1 receptor antagonist [3H]N-(piperidin-1-yl-5-(4-chlorophenyl)-1-(2,4-dichlorophenyl)-4- methyl-1H-pyrazole-3-carboxamidehydrochloride ([3H]SR141716A). This information was used to calculate the efficacy for drug stimulation of G protein activity. The rank order of efficacy was CP 55,940 > HU-210 > anandamide > delta9-tetrahydrocannabinol with the latter two drugs being partial agonists. Since efficacy values relate receptor occupancy to functional responses, we believe efficacy values are a better measure of drug-mediated functional responses compared with measurements of drug potency.
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http://dx.doi.org/10.1016/s0014-2999(97)01255-7 | DOI Listing |
ACS Chem Neurosci
January 2025
National Center for Natural Products Research, University of Mississippi, University, Mississippi 38677, United States.
Cannabinoid receptor 1 (CB1R) has been extensively studied as a potential therapeutic target for various conditions, including pain management, obesity, emesis, and metabolic syndrome. Unlike orthosteric agonists such as Δ-tetrahydrocannabinol (THC), cannabidiol (CBD) has been identified as a negative allosteric modulator (NAM) of CB1R, among its other pharmacological targets. Previous computational and structural studies have proposed various binding sites for CB1R NAMs.
View Article and Find Full Text PDFJ Nat Prod
January 2025
Charlotte's Web, 700 Tech Court, Louisville, Colorado 80027, United States.
Cannabicyclol ((±)-CBL), a minor phytocannabinoid, is largely unexplored, with its biological activity previously undocumented. We studied its conversion from cannabichromene (CBC) using various acidic catalysts. Montmorillonite (K30) in chloroform at room temperature had the highest yield (60%) with minimal byproducts.
View Article and Find Full Text PDFEur J Neurosci
January 2025
Department of Pharmacology, University of Oxford, Oxford, UK.
Cannabinoid receptor 1 (CB1) regulates synaptic transmission through presynaptic receptors in nerve terminals, and its physiological roles are of clinical relevance. The cellular sources and synaptic targets of CB1-expressing terminals in the human cerebral cortex are undefined. We demonstrate a variable laminar pattern of CB1-immunoreactive axons and electron microscopically show that CB1-positive GABAergic terminals make type-2 synapses innervating dendritic shafts (69%), dendritic spines (20%) and somata (11%) in neocortical layers 2-3.
View Article and Find Full Text PDFElectroencephalographic (EEG) recordings in individuals with Fragile X Syndrome (FXS) and the mouse model of FXS ( KO) display cortical hyperexcitability at rest, as well as deficits in sensory-driven cortical network synchrony. A form of circuit hyperexcitability is observed in cortical slices of KO mice as prolonged persistent activity, or Up, states. It is unknown if the circuit mechanisms that cause prolonged Up states contribute to FXS-relevant EEG phenotypes.
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