Allosteric Modulation
Modification of a receptor's activity by a molecule binding to a site other than the primary (orthosteric) binding site, altering the receptor's response to its primary ligand.
In Depth
CBD acts as a negative allosteric modulator (NAM) at CB1 receptors — it binds to a site distinct from where THC binds and reduces CB1 receptor signaling efficiency. This may explain how CBD can moderate THC's psychoactive effects without directly blocking THC binding. Allosteric modulation offers therapeutic advantages: effects are only produced when the receptor is being activated by its endogenous ligand, providing a more physiologically nuanced modulation than direct agonism or antagonism.
Related Terms
More in Pharmacology
Endocannabinoid System (ECS)
A lipid-based retrograde neurotransmitter system comprising endogenous cannabinoids (endocannabinoids), their receptors (CB1, CB2), and metabolic enzymes.
CB1 Receptor
Cannabinoid receptor type 1. A G protein-coupled receptor (GPCR) primarily expressed in the central nervous system. The primary target of THC's psychoactive effects.
CB2 Receptor
Cannabinoid receptor type 2. A GPCR primarily expressed in immune tissues and peripheral organs. Less abundant in the CNS than CB1.
Anandamide (AEA)
N-arachidonoylethanolamine. The first endocannabinoid identified. A partial agonist at CB1 and CB2 receptors, named from the Sanskrit word "ananda" meaning bliss.
2-Arachidonoylglycerol (2-AG)
The most abundant endocannabinoid in the brain. A full agonist at both CB1 and CB2 receptors.