THC, the psychoactive component of cannabis, binds to receptors in and outside of the brain, causing cells to behave differently. Cannabinoid receptors, named after cannabis, are found in nearly every organ of the human body.
What is the Endocannabinoid System?
Published: September 27, 2021
Onscreen: For thousands of years, humans have cultivated cannabis for its fiber, seeds, and medicinal properties. Ancient Hindu texts claim it was brought by the god Shiva for the pleasure of humanity. The plant contains over 400 chemicals, including cannabinoids, which are most abundant in the resin- glands of budding female plants. In the 1960’s, Israeli scientist Raphael Mechoulam isolated THC, the psychoactive cannabinoid that makes users feel high. The discovery launched a new chapter in neuroscience.
Daniele Piomelli: Cannabis opened a window into the functioning of our body, completely unexpected window. Because what was discovered was that THC binds to receptors in the brain and outside the brain, and when it does so, when it binds to these receptors, the cells now behave differently.
Onscreen: Cannabinoid receptors, named after cannabis, are found on nearly every organ in the body. They bind with our own cannabis-like molecules, called endocannabinoids, which regulate functions like sleep, cognition, memory and mood. Unlike other brain chemicals, they travel backwards, across the synapse, where they control the release of most neurotransmitters.
Staci Gruber: One of the most amazing things that happened was the discovery of the Endocannabinoid system. Every mammal has one. And this is a system of chemicals and receptors throughout the brain and body. And really the primary goal of the endocannabinoid system is homeostasis keeping things in balance.
Onscreen: At Mount Sinai Hospital, neuroscientist Yasmin Hurd remembers the first time she looked for cannabinoid receptors in the human brain—seen here in vivid red, orange and yellow colors.
Yasmin Hurd: The cannabinoid receptor is the most abundant receptor in the brain. When we looked at where these receptors were expressed, they're expressed in brain regions relevant for motor coordination, cognition, memory, emotional regulation, reward. All of these brain areas are key to so many normal behaviors, obviously, but also psychiatric disorders as well.
Onscreen: A key role of the endocannabinoid system is to manage stress. In fact, the first endocannabinoid found in our body was given a Sanskrit name, anandamide, meaning bliss.
Matthew Hill: In response to stress, our body mobilizes an endocannabinoid signal. And so, if something aversive happens to us and we suddenly see a threat in front of us, our body kind of goes into a high alert mode and we shoot up. Once we've been removed from that threat, though, our body needs to turn that stress response back off. And what we have learned is that this burst of endocannabinoids that occurs in response to stress is really critical for that recovery phase.
Onscreen: Scientists suspect this signal goes awry in people with PTSD and that’s why THC, which mimics our own endocannabinoids, might help.
Devin E. Haqq
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