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Open Collection of Student Writing (OCSW)

Cognitive Impairment Induced by Delta9-tetrahyracannabinol (THC)

This study was conducted by the University of Barcelona in Spain. The abstract begins by describing the negative and neutral impacts that Delta9-Tetrahydracannabinol (THC) has on the mind. THC, being the main psychoactive compound found in the Cannabis plant. Which is interesting, due to the nature of its use, primarily being prescribed for its therapeutic effects, such as anxiety relief, sleep aid, and appetite stimulant. The compound THC has a direct correlation with the receptors it binds to in the brain, called Serotonin 5-HT2A and CB1 receptors. When cannabis is ingested into the body, whether through edible ingestion or ignition and inhalation through the lungs, the active compound, THC, enters the blood stream and eventually passes through the brain. The brain has regular receptors for a naturally occurring compound called serotonin which regulates mood, well-being, reward, and in extreme cases of fluctuating levels, may cause psychosis, schizophrenia, and memory impairment. When THC enters the brain via the blood stream, it interacts with both the 5-HT2A and CB1 receptors through heteromers, or the combination of the two receptors, with an alike substance.

As scientists were introducing THC to mice they were seeking to understand how these heteromers were able to interact in the cells of the receptors and cause any affect. As they discovered, “Synthetic peptides with the sequence of transmembrane helices 5 and 6 of CB1R, fused to a cell-penetrating peptide, were able to disrupt receptor heteromerization in vivo, leading to a selective abrogate ion of memory impairments caused by exposure to THC.”

The study compares the two varying properties that THC can provide, being, analgesic and amnesic. Analgesic has to do with pain relief and muscle relaxation. Amnesic has to do with memory impairment, dependence, and anxiety. These two effects are interdependent of each other in mice lacking the 5-HT2A receptor, but in mutant mice, THC induced amnesia was not apparent. Therefore, the acute amnesic affects of THC correspond only with the 5-HT2A receptor and not the CB1. This gives scientists an exciting channel to study, in seeking to derive the analgesic attributes while ensuring the brain is exempt from receiving the amnesic impairments.  The mechanisms that separate these two properties are still unknown to scientists, but it is known that heteromers are the connecting influence that bind the affects between the two receptors introspectively.

The detrimental influences of THC correspond with the 5-HT2A receptor which are responsible for serotonin reception, as previously described. This appears to be the premise of the research, and the coinciding hypothesis, is conjunctively, cognitive impairment occurs through the chemical reaction in the brain with THC and these receptors. Although up to this point, the biggest negative factors of cognitive impairment coincide only with the 5-HT2A receptor, while it is interesting to note that the CB1R receptor happens to be part of a larger physiological biological system called the endocannabinoid system, that handles the interaction of cannabis with the body, affecting appetite, mood, pain, and memory. Because of the heteromers, cannabis can affect both receptors, but the CB1R receptor appears to be part of a biological adaptation in the body to receive and process the THC compound. In order to observe the detrimental affects of THC on cognitive function, an observation was necessary in the heteromers to show an interacting connection between the two receptors.  This shows the signs of intracellular signaling, and “protein interaction that can modify receptor function.”

Interesting to note were the maze experiments showing a direct impact of THC on the mice. The maze was running 3 days in a row, with slight variations each time. The mouse with THC injections took 30% longer after inducement reflecting a lack of memory retention. Along with various other methods, the mice were shown to have a clear detrimental impact on cognitive function via the inducement of Delta9-Tetrahyracannabinol.

Evaluating the information in this assay was rather difficult to understand because of the technical nature in which it was written. There were various experiments conducted to determine evidence that supported the hypothesis. As far as recognizing the various methods, little was comprehendible. I did however appreciate the readability of the author’s note and the abstract. These gave me a perfunctory idea of the overall article, which knowledge I was then able to apply in the rest of the research study. To make sense of everything, I had to look up various definitions. After I was able to determine to bigger picture of what the scientists were trying to explain, I found writing the paper a lot easier.


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