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Pharmacology of Cannabis. Nathaniel Chow Robert Doan Samantha Polito Jason Tang Nov 27/13. PHM142 Fall 2013 Instructor: Dr. Jeffrey Henderson. What is Cannabis . What is Cannabis . Over 400 chemicals 61 are Cannabinoids Cannabinoids are pharmacologically active
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Pharmacologyof Cannabis Nathaniel Chow Robert Doan Samantha Polito Jason Tang Nov 27/13 PHM142 Fall 2013 Instructor: Dr. Jeffrey Henderson
What is Cannabis • Over 400 chemicals • 61 are Cannabinoids • Cannabinoids are pharmacologically active • aryl-substituted meroterpenes • Lipid soluble and neutral
Cannabinoids • Delta 9 Tetrahydrocannabinol-most potent of cannabinoids • the main active ingredient for psychoactive properties • Delta 8 THC and Cannabinol also have psychoactive properties -but are far less potent than Delta 9 THC • Cannabidiol has reported to have anticonvulsant activity
Pharmacology of THC and Cannabinoid Receptors • THC binds to a special class of endogenous receptors: cannabinoid receptors • Membrane bound G protein receptors responsible for psychoactive effects of cannabis. • Effects are mediated by G couple second messenger cascade • 2 major receptors: CB1 in the brain and CB2 in the peripheral nervous system. • THC binding to CB1 receptors in the brain causes psychoactive effects
THC vs Endogenous Cannabinoids Anandamide
THC vs Endogenous Cannabinoids • THC does not resemble the structure of endogenous cannabinoids • No nitrogen • Mimics the effect • binds non specifically • shown to bind to variety of targets: opioid and benzodiazepine receptors, pathway for prostaglandin synthesis.
Metabolism of THC hydroxylation oxidation excretion
Metabolism • Metabolized in the liver • Hydroxylation generates most potent metabolite 11 hydroxyl THC • Oxidized to inactive THC-COOH • Reactions catalyzed by cytochrome p450 enzymes
Absorption • Inhalation: most effective absorption of THC • THC enters the lungs and subsequently the bloodstream, where it will eventually reach the brain • Effects are fully apparent in minutes • Oral aborption: effects take longer to manifest (delayed about 0.5-2 hrs), but last longer due to slow absorption from the gut • Blood concentration is lower than inhalation due to first-pass metabolism in the liver
Summary • Cannabinoids – Aryl-substituted meroterpenes • Lipid soluble and neutral, thus are well absorbed • Delta 9 Tetrahydrocannabinol (THC) is the most potent cannabinoid • THC binds to membrane-bound G-protein coupled receptors: primarily CB1in the brain & CB2 in the peripheral nervous system • Activation of CB1 receptors are involved in pleasure perception and reward • THC binds with lower avidity to receptors compared to endogenous cannabinoids (i.e. anandamide) • Metabolized in the liver, where hydroxylation produces the most potent reactive metabolite 11-OH-THC • Oxidized to inactive THC-COOH in the liver. Reaction is catalyzed by cytochrome p450 enzymes • THC absorption is most effective via inhalation, while oral absorption reaches lower blood concentration levels
References • Ashton, H. (2013). Cannabis. Retrieved 2013, from British Journal of Psychiatry: http://bjp.rcpsych.org/content/178/2/101/F1.large.jpg • Ashton, H. (2001). Pharmacology and effects of cannabis: a brief review†. British Journal of Psychiatry , 178, 101-106. • Hill, D. (2013). How Cannabis Oil Works. Retrieved 2013, from http://www.cureyourowncancer.org/how-cannabis-oil-works.html • Sharma, P., Murthy, P., & Bharath, M. S. (2012). Chemistry, Metabolism, and Toxicology of Cannabis: Clinical Implications. Iranian Journal of Psychiatry , 7 (4), 149–156. • Stahl, S. (2013). Getting Stoned Without Inhaling: Anandamide Is the Brain's Natural Marijuana. Retrieved 2013, from Psychiatrist: http://www.psychiatrist.com/pcc/brainstorm/br591101.htm