As our country slowly shifts its stigma on marijuana, there are many issues that need to be discussed. Some of these issues include its medicinal properties, if research should be funded and conducted on marijuana, if it should remain a schedule I drug, and if it is safe among other questions. Many people only have a small idea of how marijuana actually affects the body, as we have been told since we were younger that pot is bad for you and smoking it causes the person to be high. With the broad scope and many issues surrounding this topic, I wanted to give a short background on the body’s natural endocannabinoid system (i.e. the system that marijuana is working on) and why studies have shown it to have damaging effects on the developing brain with extensive use. Other than the actual effects of smoke in a person’s lungs, studies on the effects of marijuana on the developing brain are the reasons we hear that “pot is bad.” Under medical circumstances, without smoke, and in moderation – medical marijuana actually has some useful qualities that need to be further researched. So let’s start by looking into some of the science behind marijuana.
To begin, our bodies have many different substances, like hormones or neurotransmitters, that are released from cells and that bind to other cells on a receptor that is generally specific to that substance. This is how our body communicates with itself and responds to the environment around us. Our bodies naturally have substances called endocannabinoids (endo meaning produced in the body). These endocannabinoids have receptors in the body, CB1 and CB2 that they bind with to cause reactions. They are involved in a variety of physiological processes including appetite, pain-sensation, mood, and memory, and they mediate the psychoactive effects of cannabis. The active drug in cannabis is THC, which binds to that receptor and causes an abnormal effect – resulting in the high that people feel. During development, the endocannabinoid system helps the brain to create and refine neural connections. Heavy marijuana use during development has been shown to alter the growth of neural connections.
According to the National Institute on Drug Abuse (NIDA), THC exposure during development can cause long-term notable problems with learning and memory tasks later in life. The THC is binding to the CB receptors in the hippocampus, the main area of the brain associated with memory. In studies on rats, they found that THC exposure during development caused structural and functional changes in the hippocampus. Fully developed adult brains did not show this effect. Image studies in humans revealed impaired neural connectivity in areas affecting memory, learning, and impulse control as it was altering how information was processed in the hippocampus.
As people age, they lose neurons in the hippocampus which decreases their ability to learn new information. Chronic THC exposure during development may speed up that process. This is how researchers are explaining the memory issues found in younger adults who used THC chronically when they were developing their brains as teenagers. There is a great need for more studies involving the actual pathways that cannabis takes in our bodies so we can understand its full effects and use them to our advantage without damaging our brains.
Basics of Endocannabinoids and the Developing Brain
I so look forward to reading these student contributions to our understanding of science every Fall.
The pathway by which THC likely leads to memory problems and hallucinations is via g protein-coupled receptors and the subsequent activation (and perhaps eventual hypofunction) of NMDA receptors. Cannabidiols do neither and do not appear to affect memory or cause hallucinations.
Over-activation of g protein-coupled receptors can also be involved in the onset of Alzheimer’s disease. However, peroxynitrite–a potent oxidant involved in Alzheimer’s disease–disables a variety of g protein-coupled receptors including those involved in smell, sleep, alertness, mood, social recognition, and short-term memory. So THC may not have the same effect on most people with Alzheimer’s disease as it does on most people who do not have the disease. Moreover, THC is a peroxynitrite scavenger (as are cannabidiols) and may have some usefulness in the treatment of Alzheimer’s disease.
The breakthroughs that will come in the next decade in medicine are amazing to think about. Thank you for your interest in our class discussions!
It’s good to hear from you again, Lane. Thanks for checking in! We plan to discuss nitric oxide later in the semester – stay tuned 🙂
Thought you may be interested in our site – http://www.thctotalhealthcare.com/
We have pulled thousands of medical case studies and articles related to the endocannabinoid system and organized them by disease. So you can search your illness and find a lot of research specific to it.