Glossary · Sinh học
Endocannabinoid system
A widespread neuromodulatory system made up of cannabinoid receptors, the body's own cannabinoids (endocannabinoids), and the enzymes that make and break them down. It plays important roles in central nervous system development, synaptic plasticity, and the response to endogenous and environmental insults.
The most abundant cannabinoid receptors are CB1; CB2 receptors, TRP channels and PPAR receptors are also engaged by some cannabinoids. Exogenous cannabinoids such as THC (tetrahydrocannabinol) produce their biological effects through interactions with cannabinoid receptors. The two best-studied endocannabinoids are 2-AG and anandamide; despite similarities in chemical structure, they are made and broken down by distinct enzymatic pathways, which give them fundamentally different physiological and pathophysiological roles.
Long-distance runners describe the runner's high as a sudden pleasant feeling of euphoria, reduced anxiety, sedation and pain relief. A popular belief has been that endorphins mediate these effects, but running raises blood levels of both β-endorphin and anandamide. In mice, Fuss and colleagues (2015) showed that cannabinoid receptors mediate the acute reduction in anxiety and pain after running; sedation, by contrast, was not affected by blocking cannabinoid or opioid receptors, and euphoria cannot be studied in mice.