Cannabis: Reaching a New “High”
We humans have a close relationship with the kingdom of plants. Produce graces our table each night at dinner with a cornucopia of colors and flavors. Age-old oaks stand tall in their glory providing shade over our parks and dropping leaves for our children to pile. And who can forget the marvelous flowers that fill the air with delicious scents? But there is a plant the strikes controversy in the general public. Some give it praise for its effects while others shun it for the same reason. This plant is cannabis.
Cannabis is notoriously associated with the production of marijuana, a drug that causes a slew of physical and psychoactive effects. But it is not the whole cannabis plant that causes these effects. Within the plant is a chemical called Δ9-tetrahydrocannabinol which is much more commonly known as THC. THC is the active ingredient in marijuana that is responsible for the variety of effects on the body. So how exactly does this happen?
When THC is ingested, it travels through the cells of the body searching for two specific proteins that will receive the THC with warm welcome. These proteins are called CB1 and CB2 and are specialized types of proteins called receptors. While many proteins in the body are used to process the nutrients we eat or to stimulate growth of our muscles, these receptors are used as our body’s communication network.
Imagine that you have just received a text message from your spouse that reads “Can you stop and pick up milk on your way home from work?” Assuming that you don’t reply “I’m pretty busy, can you do it instead?” this text would signal a response from you that would cause you to stop at the grocery store and coincidentally purchase a gallon of milk. This same situation can be applied to how THC affects the CB1 and CB2 receptors. Think of THC as the text message that signals you, acting as the CB1/CB2 receptor, to respond. After receiving the message, you then work to accomplish the task that was asked of you.
Ok, perhaps radio waves from cell phone towers are slightly different that chemical signaling between the cells of the body, but you get the point. Anyway, these CB1 receptors are found throughout your body, but happen to be concentrated in the brain while CB2 receptors tend to localize in the immune system. When THC locates and binds to these receptors, it triggers them to inhibit another protein called adenylyl cyclase. Adenylyl cyclase may be hard to pronounce, but it is central in activating and stopping many responses carried out by the body. You can think of adenylyl cyclase as a sort of “headquarters” that receives the signals from many receptors and coordinates the variety of chemical signals it receives and translates them into physical actions, or in the case of marijuana, the well-known list of physical and psychological changes in the body such as appetite, pain and pleasure, memory, and mood.
But why are these receptors found in our body in the first place? Were they placed in us simply because God wanted us to experience the effects of cannabis? Of course not! The human body is very efficient, and the CB1 and CB2 receptors do in fact have a normal purpose that does not include marijuana. Normally, these receptors are stimulated by two chemicals called anandamide (AEA) and 2-arachidonoylglycerol (2-AG) that the body produces naturally. These two molecules are called endocannabinoids (endo = in, cannabinoid = cannabis-like, i.e.- cannabis-like chemicals produced in the body) are the intended targets of the CB1/CB2 receptors. Although these two molecules do not cause the same psychotropic effects found in THC, they still regulate many of the same body functions such as appetite, cardiovascular activity, sensation of pain, and even bone mass!
So then, how can we use this information for the advancement of modern medicine? Interestingly, researchers are looking into developing pharmaceuticals that are similar to THC, but that do not cause the psychotropic effects that complicate prescribing them to the general public. So far, a drug called cannabidiol is emerging as a likely contender for this job. Already we know that these drugs can stimulate appetite and can be used for the treatment of glaucoma or pain, but new findings suggest that they might also be useful in the treatment of cancer as well.
I don’t want to bore you to death with in depth explanations about each of these, but the moral of the story is that it is very likely that we will see advances in the treatment of many medical conditions by using the information gained from studying these cannabis-like molecules.
It all started with a little plant called cannabis. And when we just so happened to set it on fire, we discovered that there were some effects! It was this creativity that sparked a revolutionary movement to learn more about the human body, unearthing a new class of useful medications and functions in the process. Cannabis certainly is a controversial little plant in popular culture, but its usefulness will likely help us to achieve the next pinnacle in medicine, or perhaps appropriately put, a new high.
Final thoughts on Endocannabinoids written by Steven Dotzler
Cannabis: Reaching a New “High”
