If you’re like us, then you haven’t been able to escape the media blast about the legalization of Cannabis, throughout the United States, whether for medicinal or recreational uses. In recent years, Cannabis has become a central contemporary issue in our society. All over the US, we see an increase of recognition of legalizing marijuana laws. In 1970, it was not even considered by state legislatures, but much has changed. Today it has been addressed by over half of the states in the country, being legalized for medical uses in 15 states, and fully legalized in 2. This rapidly rising contemporary issue has also given rise to some questions on our part. What is it like chemically? How does it affect the brain? Since it is a popular topic in our society, it is our responsibility to know the answers to these questions. After all, it may, if not already, have a direct impact on our lives.
The Endocannabinoid System
To understand how Cannabis affects the brain, first you need to understand the endocannabinoid system, part of our own brains. Notice a similarity between the plant and the biological system? We did too; the endocannabinoid system is named for the plant that led to its discovery, and the similarity in their names will serve as an indicator of exactly how closely related. The endocannabinoid system is the system in the body that maintains homeostasis, the body’s equilibrium. Wherever and whenever there is injury, the endocannabinoid system is stimulated by the binding of cannabinoids, or proteins that affect the endocannabinoid system, to their receptors, or doorways to the endocannabinoid system. These receptors are found throughout the body: in the brain, organs, connective tissues, glands and immune cells. When a cannabinoid binds to its receptor, it tells that endocannabinoid system, “Hey! You need to make some of this to make that better!” or “Over here! There’s not enough of this! You need to make more!” This is basically how the endocannabinoid system works to maintain homeostasis in the body – it maintains the equilibrium between various necessary chemicals in the body.
Now that you have a basic understanding of how the endocannabinoid system works, it’s time to get more specific. Scientists have identified two cannabinoid receptors: CB1, in the nervous system, connective tissues, gonads, glands, and organs; and CB2, in the immune system. When each one of these receptors is activated, the each result in a different action. The receptors are like the reactants to a chemical reaction. Once the reactants (receptors) are activated, they undergo a reaction (a chemically signaled process) that leads to unique products (effects). While not all are well understood, there are some that are.
The cannabinoids we know more of are known as anandamide and 2-arachidonoylglycerol (2-AG). They are synthesized on-demand in the cell, and don’t have an effect that moves far outside the region they were synthesized in. This is where we get back to Cannabis.
There is a special class of cannabinoids known as phytocannabinoids, which are similar enough to the cannabinoids produced in the human body to bind to the cannabinoid receptors. Delta-9- tetrahydrocannabinol (THC) is the most active cannabinoid in the Cannabis plant. In the picture here, the chemical structures of anandamide, the human cannabinoid, and THC, the phytocannabinoid, are shown. Check out the similarities in their structures.
The Brain: Recreation
These similarities allow THC to bind to the cannabinoid receptors in the brain. The receptors are found in the regions of the brain that influence pleasure, memory, thinking, concentration, movement, coordination, and sensory and time perception, all of which are affected by the use of Cannabis. This stimulates the brain cells to release dopamine, the chemical agent responsible for pleasure. Overall, this process is like adding more reactant to a chemical reaction – the reactant is THC, and the product is dopamine. Because more reactant has been added, the reaction will shift toward the products, thus resulting in the advanced release of dopamine.
However, there are more effects to the use of Cannabis than the short-term ones mentioned above. The long-term effects are the result of frequent use that permanently shifts the equilibrium of the system. The receptors need less and less stimulation to produce the same amount of dopamine and other chemicals (you need less reactant to get the same amount of product). The heightened release of these chemicals disrupts coordination, balance, and cognitive ability. They affect the ability of the brain to form new memories, and when the concentration of THC is high enough it can result in episodes of psychosis due to extreme release of chemicals.
The Brain: Medicine
Now that we’ve discussed the effects of recreational Cannabis use, let’s not forget the medical uses. As you (hopefully) know at this point, Cannabis affects the endocannabinoid system, which maintains homeostasis. A functional endocannabinoid system is essential for homeostasis and consequently good health. Small doses of Cannabis can stimulate the body to make more cannabinoids and build more cannabinoid receptors, which can help the body maintain homeostasis more easily and thus combat the negative effects of a wide range of illnesses. It helps diseases for the same reasons it causes long-term side effects.
The recent changes in attitude towards Cannabis use makes the study of Cannabis important. The popularity of this drug is attributed to the chemical effects of its use. The presence of cannabinoids in the human body produces these effects. When Cannabis is ingested the THC in it is similar enough to the body’s cannabinoids to be recognized, and thus disturbs the body’s equilibrium. Using the same process, if the equilibrium is disturbed, Cannabis can be used to restore it, which is why it can be called “medical marijuana”. While many articles focus on the legal and moral issues, sometimes it can help to take a look at the science behind all this.