4
views
0
recommends
+1 Recommend
0 collections
    0
    shares
      • Record: found
      • Abstract: found
      • Article: not found

      Affinity and Efficacy Studies of Tetrahydrocannabinolic Acid A at Cannabinoid Receptor Types One and Two

      Read this article at

      ScienceOpenPublisherPMC
      Bookmark
          There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

          Abstract

          Introduction: Cannabis biosynthesizes Δ 9-tetrahydrocannabinolic acid (THCA-A), which decarboxylates into Δ 9-tetrahydrocannabinol (THC). There is growing interest in the therapeutic use of THCA-A, but its clinical application may be hampered by instability. THCA-A lacks cannabimimetic effects; we hypothesize that it has little binding affinity at cannabinoid receptor 1 (CB 1).

          Materials and Methods: Purity of certified reference standards were tested with high performance liquid chromatography (HPLC). Binding affinity of THCA-A and THC at human (h) CB 1 and hCB 2 was measured in competition binding assays, using transfected HEK cells and [ 3H]CP55,940. Efficacy at hCB 1 and hCB 2 was measured in a cyclic adenosine monophosphase (cAMP) assay, using a Bioluminescence Resonance Energy Transfer (BRET) biosensor.

          Results: The THCA-A reagent contained 2% THC. THCA-A displayed small but measurable binding at both hCB 1 and hCB 2, equating to approximate K i values of 3.1μM and 12.5μM, respectively. THC showed 62-fold greater affinity at hCB 1 and 125-fold greater affinity at hCB 2. In efficacy tests, THCA-A (10μM) slightly inhibited forskolin-stimulated cAMP at hCB 1, suggestive of weak agonist activity, and no measurable efficacy at hCB 2.

          Discussion: The presence of THC in our THCA-A certified standard agrees with decarboxylation kinetics (literature reviewed herein), which indicate contamination with THC is nearly unavoidable. THCA-A binding at 10μM approximated THC binding at 200nM. We therefore suspect some of our THCA-A binding curve was artifact—from its inevitable decarboxylation into THC—and the binding affinity of THCA-A is even weaker than our estimated values. We conclude that THCA-A has little affinity or efficacy at CB 1 or CB 2.

          Related collections

          Most cited references 36

          • Record: found
          • Abstract: found
          • Article: not found

          Taming THC: potential cannabis synergy and phytocannabinoid-terpenoid entourage effects.

           Ethan Russo (2011)
          Tetrahydrocannabinol (THC) has been the primary focus of cannabis research since 1964, when Raphael Mechoulam isolated and synthesized it. More recently, the synergistic contributions of cannabidiol to cannabis pharmacology and analgesia have been scientifically demonstrated. Other phytocannabinoids, including tetrahydrocannabivarin, cannabigerol and cannabichromene, exert additional effects of therapeutic interest. Innovative conventional plant breeding has yielded cannabis chemotypes expressing high titres of each component for future study. This review will explore another echelon of phytotherapeutic agents, the cannabis terpenoids: limonene, myrcene, α-pinene, linalool, β-caryophyllene, caryophyllene oxide, nerolidol and phytol. Terpenoids share a precursor with phytocannabinoids, and are all flavour and fragrance components common to human diets that have been designated Generally Recognized as Safe by the US Food and Drug Administration and other regulatory agencies. Terpenoids are quite potent, and affect animal and even human behaviour when inhaled from ambient air at serum levels in the single digits ng·mL(-1) . They display unique therapeutic effects that may contribute meaningfully to the entourage effects of cannabis-based medicinal extracts. Particular focus will be placed on phytocannabinoid-terpenoid interactions that could produce synergy with respect to treatment of pain, inflammation, depression, anxiety, addiction, epilepsy, cancer, fungal and bacterial infections (including methicillin-resistant Staphylococcus aureus). Scientific evidence is presented for non-cannabinoid plant components as putative antidotes to intoxicating effects of THC that could increase its therapeutic index. Methods for investigating entourage effects in future experiments will be proposed. Phytocannabinoid-terpenoid synergy, if proven, increases the likelihood that an extensive pipeline of new therapeutic products is possible from this venerable plant. http://dx.doi.org/10.1111/bph.2011.163.issue-7. © 2011 The Author. British Journal of Pharmacology © 2011 The British Pharmacological Society.
            Bookmark
            • Record: found
            • Abstract: found
            • Article: not found

            Phytocannabinoids: a unified critical inventory.

            Covering up to January 2016Cannabis sativa L. is a prolific, but not exclusive, producer of a diverse group of isoprenylated resorcinyl polyketides collectively known as phytocannabinoids. The modular nature of the pathways that merge into the phytocannabinoid chemotype translates in differences in the nature of the resorcinyl side-chain and the degree of oligomerization of the isoprenyl residue, making the definition of phytocannabinoid elusive from a structural standpoint. A biogenetic definition is therefore proposed, splitting the phytocannabinoid chemotype into an alkyl- and a β-aralklyl version, and discussing the relationships between phytocannabinoids from different sources (higher plants, liverworts, fungi). The startling diversity of cannabis phytocannabinoids might be, at least in part, the result of non-enzymatic transformations induced by heat, light, and atmospheric oxygen on a limited set of major constituents (CBG, CBD, Δ(9)-THC and CBC and their corresponding acidic versions), whose degradation is detailed to emphasize this possibility. The diversity of metabotropic (cannabinoid receptors), ionotropic (thermos-TRPs), and transcription factors (PPARs) targeted by phytocannabinoids is discussed. The integrated inventory of these compounds and their biological macromolecular end-points highlights the opportunities that phytocannabinoids offer to access desirable drug-like space beyond the one associated to the narcotic target CB1.
              Bookmark
              • Record: found
              • Abstract: found
              • Article: not found

              Meta-analysis of cannabinoid ligand binding affinity and receptor distribution: interspecies differences.

              A meta-analysis, unlike a literature review, synthesizes previous studies into new results. Pooled data from 211 studies measured ligand binding affinities at human (Hs) or rat (Rn) cannabinoid receptors CB1 and CB2. Cochrane methods were modified for this non-clinical analysis. Meta-regression detected data heterogeneity arising from methodological factors: use of sectioned tissues, lack of PMSF and choice of radioligand. Native brain tissues exhibited greater affinity (lower nM) than transfected cells, but the trend fell short of significance, as did the trend between centrifugation and filtration methods. Correcting for heterogeneity, mean Ki values for delta 9-tetrahydrocannabinol differed significantly between HsCB1 and RnCB1 (25.1 and 42.6 nM, respectively) but not between HsCB1 and HsCB2 (25.1 and 35.2). Mean Kd values for HsCB1, RnCB1 and HsCB2 of CP55,940 (2.5, 0.98, 0.92) and WIN55,212-2 (16.7, 2.4, 3.7) differed between HsCB1 and RnCB1 and between HsCB1 and HsCB2. SR141716A differed between HsCB1 and RnCB1 (2.9 and 1.0 nM). Anandamide at HsCB1, RnCB1 and HsCB2 (239.2, 87.7, 439.5) fell short of statistical differences due to heterogeneity. We consider these Kd and Ki values to be the most valid estimates in the literature. Sensitivity analyses did not support the numerical validity of cannabidiol, cannabinol, 2-arachidonoyl glycerol and all ligands at RnCB2. Aggregate rank order analysis of CB(1) distribution in the brain (pooled from 119 autoradiographic, immunohistochemical and in situ hybridization studies) showed denser HsCB1 expression in cognitive regions (cerebral cortex) compared to RnCB1, which was relatively richer in movement-associated areas (cerebellum, caudate-putamen). Implications of interspecies differences are discussed.
                Bookmark

                Author and article information

                Journal
                Cannabis Cannabinoid Res
                Cannabis Cannabinoid Res
                can
                Cannabis and Cannabinoid Research
                Mary Ann Liebert, Inc. (140 Huguenot Street, 3rd FloorNew Rochelle, NY 10801USA )
                2378-8763
                01 May 2017
                2017
                01 May 2017
                : 2
                : 1
                : 87-95
                Affiliations
                [ 1 ]GW Pharmaceuticals , Salisbury, United Kingdom.
                [ 2 ]Department of Family Medicine, University of Vermont , Burlington, Vermont.
                [ 3 ]Department of Pharmacology & Clinical Pharmacology, University of Auckland , Auckland, New Zealand.
                [ 4 ]School of Chemical Sciences, University of Auckland , Auckland, New Zealand.
                Author notes
                [ * ]Address correspondence to: John M. McPartland, DO, MS, 53 Washington Street Ext., Middlebury, VT 05753, E-mail: mcpruitt@ 123456myfairpoint.net
                Article
                10.1089/can.2016.0032
                10.1089/can.2016.0032
                5510775
                28861508
                © John M. McPartland et al. 2017; Published by Mary Ann Liebert, Inc.

                This is an Open Access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Mary Ann Liebert, Inc. offers reprint services for those who want to order professionally produced copies of articles published under the Creative Commons Attribution (CC BY) license. To obtain a price quote, email Reprints@ 123456liebertpub.com . Please include the articlés title or DOI, quantity, and delivery destination in your email.

                Page count
                Figures: 4, Tables: 1, References: 34, Pages: 9
                Product
                Categories
                Original Research

                Comments

                Comment on this article