Cannabis, once a symbol of rebellion and counterculture, is now one of the most commonly used recreational substances. The plant’s primary psychoactive compounds, THC (tetrahydrocannabinol) and CBD (cannabidiol), act on one of the body’s most widespread neurotransmitter systems. The endocannabinoid and the CB1 and CB2 receptors don't work in the usual way we think of. Whereas GABA and Glutamate directly decrease or increase activity in neurons through the opening of pores on the cell's surface, and serotonin and dopamine influence a neuron's reactivity through receptors on the postsynaptic surface, CB1 and CB2 receptors work in almost the reverse way.

This post is not about THC and CBD (we will talk about how they work), it's about the endocannabinoid system itself. We will discuss the unusual nature of this system. The CB1 receptor is found all over the central nervous system. The CB2 receptor is found on peripheral organs like the GI tract and on immune cells.

The endocannabinoid system (ECS) is not unique to humans; it appears across the animal kingdom, from fish to mammals, and always with the same purpose: to maintain homeostasis. It does so through molecules our own cells produce on demand, called endocannabinoids, the best-known........

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