Checkpoint 3: Phytocannabinoid Pharmacology

1Which of the following best characterizes the receptor interactions and primary pharmacological mechanisms of cannabidiol (CBD) in contrast to delta-9-tetrahydrocannabinol (THC)?

A. CBD acts as a high-affinity orthosteric agonist at CB1 receptors, whereas THC functions as a competitive antagonist. B. CBD functions as a negative allosteric modulator (NAM) at CB1 receptors and indirectly elevates anandamide by inhibiting fatty acid amide hydrolase (FAAH), whereas THC acts as a partial agonist at CB1 and CB2 receptors. ✓ C. CBD selectively stimulates monoacylglycerol lipase (MAGL) to reduce endogenous 2-arachidonoylglycerol (2-AG) levels, whereas THC irreversibly inactivates TRPV1 ion channels. D. CBD acts exclusively as a full agonist at central GPR55 receptors without engaging non-cannabinoid signaling pathways.

Explanation: Cannabidiol (CBD) exhibits low orthosteric affinity for CB1 and CB2 receptors. Instead, it functions as a negative allosteric modulator (NAM) at the CB1 receptor, altering the receptor's tertiary structure to decrease orthosteric ligand binding affinity and signal transduction (thereby attenuating THC-induced psychotropic adverse effects). CBD also inhibits FAAH, increasing endogenous anandamide levels. Conversely, delta-9-THC functions as a partial agonist at orthosteric sites on both CB1 and CB2 receptors.

2Regarding botanical synergy and terpene pharmacology within full-spectrum phytocannabinoid formulations, which of the following mechanisms are supported by scientific literature? (Select all that apply)

Select all that apply

A. Beta-caryophyllene acts as a selective functional agonist at peripheral CB2 receptors, exerting anti-inflammatory action without activating central CB1 receptors. ✓ B. Myrcene increases cell membrane permeability and may enhance blood-brain barrier transport of lipophilic phytocannabinoids. ✓ C. Terpenes such as linalool and alpha-pinene exhibit complementary neurological actions via modulation of GABAergic and cholinergic pathways, respectively. ✓ D. Terpenes irreversibly disable hepatic cytochrome P450 enzymes (CYP3A4/CYP2C19), preventing any metabolic clearance of phytocannabinoids in canine patients.

Explanation: Beta-caryophyllene is a dietary sesquiterpene that acts as a selective agonist at CB2 receptors. Myrcene enhances biological membrane permeability, facilitating central phytocannabinoid penetration. Linalool interacts with GABAergic signaling to exert anxiolytic effects, and alpha-pinene acts as an acetylcholinesterase inhibitor. Option D is incorrect because terpenes modulate/inhibit CYP450 pathways reversibly or weakly, but do not irreversibly disable or eliminate metabolic clearance.

Checkpoint 3: Phytocannabinoid Pharmacology

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