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AlKhelb D, Burke EL, Zvonok A, Iliopoulos-Tsoutsouvas C, Georgiadis MO, Jiang S, Ho TC, Nikas SP, Makriyannis A, Desai RI. Effects of cannabinoid agonists and antagonists in male rats discriminating the synthetic cannabinoid AM2201. Eur J Pharmacol 2023; 960:176168. [PMID: 38059442 DOI: 10.1016/j.ejphar.2023.176168] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Revised: 09/30/2023] [Accepted: 10/26/2023] [Indexed: 12/08/2023]
Abstract
The synthetic forms of delta-9-tetrahydrocannabinol (Δ9-THC), dronabinol or nabilone, have been approved to treat several indications. However, due to safety concerns their clinical utility remains limited. Consequently, there is a need for developing cannabinoid (CB) ligands that display better behavioral pharmacological profiles than Δ9-THC. Here, we utilized drug discrimination methods to compare the interoceptive effects of CB ligands that vary in potency, efficacy, and selectivity at the CB receptors, including two ligands, AM411 and AM4089, that show CB1 partial agonist-like actions in vitro. Male rats were trained to discriminate 0.1 mg/kg AM2201 from saline under a fixed-ratio (FR) 10 response schedule of food reinforcement. After establishing AM2201's discriminative-stimulus effects, pretreatment tests with the CB1 antagonist/inverse agonist rimonabant blocked AM2201's effects, whereas the peripherally-restricted antagonist AM6545 had no effect. Next, the generalization profiles of AM411 and AM4089 with CB1 full agonists (JWH-018, CP-55,940, AM8936), partial agonist (Δ9-THC), and non-cannabinoids (fentanyl, atropine) were compared. The CBs either fully (AM2201, CP-55,940, JWH-018, AM8936, Δ9-THC) or partially (AM411, AM4089) substituted for AM2201, whereas fentanyl and atropine did not produce AM2201-like effects. All CB drugs were more potent than Δ9-THC and correlation analysis confirmed that the relative behavioral potencies of CBs corresponded strongly with their relative affinities at the CB1 but not CB2 receptors. Together, our results further demonstrate that AM411 and AM4089 exhibit better pharmacological profiles compared to Δ9-THC, in that they are more potent and display in vivo partial agonist-like actions that are centrally mediated via CB1 receptors.
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Affiliation(s)
- Dalal AlKhelb
- Center for Drug Discovery, Departments of Chemistry and Chemical Biology and Pharmaceutical Sciences, Northeastern University, Boston, MA, 02115, USA; Department of Pharmacology and Toxicology, College of Pharmacy, King Saud University, Riyadh, 12371, Saudi Arabia
| | - Emily L Burke
- Center for Drug Discovery, Departments of Chemistry and Chemical Biology and Pharmaceutical Sciences, Northeastern University, Boston, MA, 02115, USA
| | - Alexander Zvonok
- MAK Scientific LLC, 151 South Bedford Street, Burlington, MA, 01803, USA
| | - Christos Iliopoulos-Tsoutsouvas
- Center for Drug Discovery, Departments of Chemistry and Chemical Biology and Pharmaceutical Sciences, Northeastern University, Boston, MA, 02115, USA
| | - Markos-Orestis Georgiadis
- Center for Drug Discovery, Departments of Chemistry and Chemical Biology and Pharmaceutical Sciences, Northeastern University, Boston, MA, 02115, USA
| | - Shan Jiang
- Center for Drug Discovery, Departments of Chemistry and Chemical Biology and Pharmaceutical Sciences, Northeastern University, Boston, MA, 02115, USA
| | - Thanh C Ho
- Center for Drug Discovery, Departments of Chemistry and Chemical Biology and Pharmaceutical Sciences, Northeastern University, Boston, MA, 02115, USA
| | - Spyros P Nikas
- Center for Drug Discovery, Departments of Chemistry and Chemical Biology and Pharmaceutical Sciences, Northeastern University, Boston, MA, 02115, USA
| | - Alexandros Makriyannis
- Center for Drug Discovery, Departments of Chemistry and Chemical Biology and Pharmaceutical Sciences, Northeastern University, Boston, MA, 02115, USA; MAK Scientific LLC, 151 South Bedford Street, Burlington, MA, 01803, USA.
| | - Rajeev I Desai
- Center for Drug Discovery, Departments of Chemistry and Chemical Biology and Pharmaceutical Sciences, Northeastern University, Boston, MA, 02115, USA; Department of Psychiatry, Behavioral Biology Program, Integrative Neurochemistry Laboratory, McLean Hospital - Harvard Medical School, Belmont, MA, 02478, USA.
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Schurman LD, Lu D, Kendall DA, Howlett AC, Lichtman AH. Molecular Mechanism and Cannabinoid Pharmacology. Handb Exp Pharmacol 2020; 258:323-353. [PMID: 32236882 PMCID: PMC8637936 DOI: 10.1007/164_2019_298] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Since antiquity, Cannabis has provoked enormous intrigue for its potential medicinal properties as well as for its unique pharmacological effects. The elucidation of its major cannabinoid constituents, Δ9-tetrahydrocannabinol (THC) and cannabidiol (CBD), led to the synthesis of new cannabinoids (termed synthetic cannabinoids) to understand the mechanisms underlying the pharmacology of Cannabis. These pharmacological tools were instrumental in the ultimate discovery of the endogenous cannabinoid system, which consists of CB1 and CB2 cannabinoid receptors and endogenously produced ligands (endocannabinoids), which bind and activate both cannabinoid receptors. CB1 receptors mediate the cannabimimetic effects of THC and are highly expressed on presynaptic neurons in the nervous system, where they modulate neurotransmitter release. In contrast, CB2 receptors are primarily expressed on immune cells. The endocannabinoids are tightly regulated by biosynthetic and hydrolytic enzymes. Accordingly, the endocannabinoid system plays a modulatory role in many physiological processes, thereby generating many promising therapeutic targets. An unintended consequence of this research was the emergence of synthetic cannabinoids sold for human consumption to circumvent federal laws banning Cannabis use. Here, we describe research that led to the discovery of the endogenous cannabinoid system and show how knowledge of this system benefitted as well as unintentionally harmed human health.
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Affiliation(s)
- Lesley D Schurman
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, VA, USA
| | - Dai Lu
- Rangel College of Pharmacy, Health Science Center, Texas A&M University, Kingsville, TX, USA
| | - Debra A Kendall
- Department of Pharmaceutical Sciences, University of Connecticut, Storrs, CT, USA
| | - Allyn C Howlett
- Department of Physiology and Pharmacology and Center for Research on Substance Use and Addiction, Wake Forest School of Medicine, Winston-Salem, NC, USA
| | - Aron H Lichtman
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, VA, USA.
- Department of Medicinal Chemistry, Virginia Commonwealth University, Richmond, VA, USA.
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Leonard MZ, Alapafuja SO, Ji L, Shukla VG, Liu Y, Nikas SP, Makriyannis A, Bergman J, Kangas BD. Cannabinoid CB 1 Discrimination: Effects of Endocannabinoids and Catabolic Enzyme Inhibitors. J Pharmacol Exp Ther 2017; 363:314-323. [PMID: 28947487 DOI: 10.1124/jpet.117.244392] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Accepted: 09/14/2017] [Indexed: 11/22/2022] Open
Abstract
An improved understanding of the endocannabinoid system has provided new avenues of drug discovery and development toward the management of pain and other behavioral maladies. Exogenous cannabinoid type 1 (CB1) receptor agonists such as Δ9-tetrahydrocannabinol are increasingly used for their medicinal actions; however, their utility is constrained by concern regarding abuse-related subjective effects. This has led to growing interest in the clinical benefit of indirectly enhancing the activity of the highly labile endocannabinoids N-arachidonoylethanolamine [AEA (or anandamide)] and/or 2-arachidonoylglycerol (2-AG) via catabolic enzyme inhibition. The present studies were conducted to determine whether such actions can lead to CB1 agonist-like subjective effects, as reflected in CB1-related discriminative stimulus effects in laboratory subjects. Squirrel monkeys (n = 8) that discriminated the CB1 full agonist AM4054 (0.01 mg/kg) from vehicle were used to study, first, the inhibitors of fatty acid amide hydrolase (FAAH) or monoacylglycerol lipase (MGL) alone or in combination [FAAH (URB597, AM4303); MGL (AM4301); FAAH/MGL (JZL195, AM4302)] and, second, the ability of the endocannabinoids AEA and 2-AG to produce CB1 agonist-like effects when administered alone or after enzyme inhibition. Results indicate that CB1-related discriminative stimulus effects were produced by combined, but not selective, inhibition of FAAH and MGL, and that these effects were nonsurmountably antagonized by low doses of rimonabant. Additionally, FAAH or MGL inhibition revealed CB1-like subjective effects produced by AEA but not by 2-AG. Taken together, the present data suggest that therapeutic effects of combined, but not selective, enhancement of AEA or 2-AG activity via enzyme inhibition may be accompanied by CB1 receptor-mediated subjective effects.
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Affiliation(s)
- Michael Z Leonard
- Harvard Medical School, Department of Psychiatry, Boston, Massachusetts (J.B., B.D.K.); McLean Hospital, Preclinical Pharmacology Laboratory, Belmont, Massachusetts (M.Z.L., J.B., B.D.K.); MakScientific LLC, Burlington, Massachusetts (S.O.A.); and Center for Drug Discovery, Northeastern University, Boston, Massachusetts (L.J., V.G.S., Y.L., S.P.N., A.M.)
| | - Shakiru O Alapafuja
- Harvard Medical School, Department of Psychiatry, Boston, Massachusetts (J.B., B.D.K.); McLean Hospital, Preclinical Pharmacology Laboratory, Belmont, Massachusetts (M.Z.L., J.B., B.D.K.); MakScientific LLC, Burlington, Massachusetts (S.O.A.); and Center for Drug Discovery, Northeastern University, Boston, Massachusetts (L.J., V.G.S., Y.L., S.P.N., A.M.)
| | - Lipin Ji
- Harvard Medical School, Department of Psychiatry, Boston, Massachusetts (J.B., B.D.K.); McLean Hospital, Preclinical Pharmacology Laboratory, Belmont, Massachusetts (M.Z.L., J.B., B.D.K.); MakScientific LLC, Burlington, Massachusetts (S.O.A.); and Center for Drug Discovery, Northeastern University, Boston, Massachusetts (L.J., V.G.S., Y.L., S.P.N., A.M.)
| | - Vidyanand G Shukla
- Harvard Medical School, Department of Psychiatry, Boston, Massachusetts (J.B., B.D.K.); McLean Hospital, Preclinical Pharmacology Laboratory, Belmont, Massachusetts (M.Z.L., J.B., B.D.K.); MakScientific LLC, Burlington, Massachusetts (S.O.A.); and Center for Drug Discovery, Northeastern University, Boston, Massachusetts (L.J., V.G.S., Y.L., S.P.N., A.M.)
| | - Yingpeng Liu
- Harvard Medical School, Department of Psychiatry, Boston, Massachusetts (J.B., B.D.K.); McLean Hospital, Preclinical Pharmacology Laboratory, Belmont, Massachusetts (M.Z.L., J.B., B.D.K.); MakScientific LLC, Burlington, Massachusetts (S.O.A.); and Center for Drug Discovery, Northeastern University, Boston, Massachusetts (L.J., V.G.S., Y.L., S.P.N., A.M.)
| | - Spyros P Nikas
- Harvard Medical School, Department of Psychiatry, Boston, Massachusetts (J.B., B.D.K.); McLean Hospital, Preclinical Pharmacology Laboratory, Belmont, Massachusetts (M.Z.L., J.B., B.D.K.); MakScientific LLC, Burlington, Massachusetts (S.O.A.); and Center for Drug Discovery, Northeastern University, Boston, Massachusetts (L.J., V.G.S., Y.L., S.P.N., A.M.)
| | - Alexandros Makriyannis
- Harvard Medical School, Department of Psychiatry, Boston, Massachusetts (J.B., B.D.K.); McLean Hospital, Preclinical Pharmacology Laboratory, Belmont, Massachusetts (M.Z.L., J.B., B.D.K.); MakScientific LLC, Burlington, Massachusetts (S.O.A.); and Center for Drug Discovery, Northeastern University, Boston, Massachusetts (L.J., V.G.S., Y.L., S.P.N., A.M.)
| | - Jack Bergman
- Harvard Medical School, Department of Psychiatry, Boston, Massachusetts (J.B., B.D.K.); McLean Hospital, Preclinical Pharmacology Laboratory, Belmont, Massachusetts (M.Z.L., J.B., B.D.K.); MakScientific LLC, Burlington, Massachusetts (S.O.A.); and Center for Drug Discovery, Northeastern University, Boston, Massachusetts (L.J., V.G.S., Y.L., S.P.N., A.M.)
| | - Brian D Kangas
- Harvard Medical School, Department of Psychiatry, Boston, Massachusetts (J.B., B.D.K.); McLean Hospital, Preclinical Pharmacology Laboratory, Belmont, Massachusetts (M.Z.L., J.B., B.D.K.); MakScientific LLC, Burlington, Massachusetts (S.O.A.); and Center for Drug Discovery, Northeastern University, Boston, Massachusetts (L.J., V.G.S., Y.L., S.P.N., A.M.)
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