Running head: Cannabinoids Effect On Depression Alterations in the Endocannabinoid System; an Animal Model of Depression Alterations in the Endocannabinoid System; an Animal Model of Depression Depressive illness is widespread and exhibits a lifetime prevalence rate of 16% (Kessler et al. 2003). Depressive illnesses can be characterized by an array of disturbances, emotional behavior, memory, neuro-vegetative functions and hedonic processing.
The neurobiological mechanisms subserving the development, manifestation and treatment of depression are complex, and there is ample evidence that disturbances in monoaminergic signaling, glucocorticoid activity and neurotrophic/neuroplastic processes are involved (Ressler and Nemeroff 2000; Holsboer 2000; Duman and Monteggia 2006; McEwen 2005). A wide range of people I know suffer from depression and currently use prescribed medication in order to alleviate the symptoms; for this reason, I chose this article.
Cannabinoids are a diverse class of compounds that activate cannabinoid receptors CB1 and CB2. I want to explore the effect of cannabinoids on people who have been subjected to Chronic Unpredicted Stress (CUS). This CUS is one of the leading causes of depression in teenagers. This article really discovers the effects of cannabinoids on rats which have had a prolonged exposure to CUS. The colleagues tested Long-Evans rats who were 70 days old with an independent variable as the amount of cannabinoids used on a CUS induced rat and the dependent variable as the amount of depression the rats had.
A main method the researchers used to analyze the depression in rats was their sexual activity. All the behavioral testing was performed during the middle of the third light cycle. They found that this resulted in a signi? cant increase in CB1 receptor binding site density in the prefrontal cortex and a decrease in CB1 receptor binding site density in the hippocampus, hypothalamus and ventral striatum. Besides the hippocampus, these CUS-induced alterations in CB1 receptor binding site density were attenuated by concurrent antidepressant treatment (Hill et al. 008). They also found that in the prefrontal cortex (PFC), the agonist binding site density of the CB1 receptor was signi? cantly increased in rats exposed to CUS compared to non-stressed controls. When reviewing the findings of the animal’s model, the rats that were subject to the stress testing regained a sense of motivation with cannabinoids. Having sexual activity be the indicator of motivation, the rats showed a definite increase in motivation. When projecting these findings on a group of humans, anhedonia, a de? it in motivational drive and the ability to experience pleasure, would decrease with an increased consumption of cannabinoids. One of the major signs of depression is a lack of motivation for rewarding activities; this is frequently manifested as a loss of sex drive (Williams and Reynolds 2006). When compared to the rats, humans produce some of the same symptoms of depression, and with cannabinoids in their system, signs of human depression will be signi? antly reduced, and an increase in the CB1 receptor binding site density in the hippocampus, hypothalamus and ventral striatum and an overall increased density in the pre-frontal cortex. When it comes to understanding the validity in these researchers claims that a lower sex drive is a sign of depression, I don’t know exactly how it compares to humans, but I do understand that many people consume cannabinoids in order to drive away the symptoms of depression, and with them the consumer will feel a gain in motivation, or at the very least, a better sex drive.
References Hill, M. N. , Carrier, E. J. , McLaughlin, R. J. , Morrish, A. C. , Meier, S. E. , Hillard, C. J. , & Gorzalka, B. B. (2008). Regional alterations in the endocannabinoid system in an animal model of depression: effects of concurrent antidepressant treatment. Journal Of Neurochemistry,106(6), 2322-2336. doi:10. 1111/j. 1471-4159. 2008. 05567. x