THC antagonist and cannabinoid receptor. Computer-generated molecular model of cannabinoid receptor 1 (CB1) complex (multicoloured) with THC tetrahydrocannabinol (THC) antagonist AM6538 (upper centre). CB1 is a cell membrane receptor found mainly in the nervous system. The natural neurotransmitter anandamide (upper left, red, blue and white) and THC, the principle psychoactive constituent of cannabis, both bind to the CB1 receptor, inducing cellular responses and playing a role in memory, regulation of feeding behaviour and motivation. AM6538 inhibits the binding of both anandamide and THC. CB1 is a promising therapeutic target for pain management, inflammation, obesity, and substance abuse disorders.