Caffeine Addiction
Caffeine has become a necessity in every busy person’s life. It is a necessity in even a non-busy person’s life. Caffeine is popularly found in coffee. In American culture, coffee is often associated with early mornings and also late nights. It is also the common stereotype associated with college students and exams. However, the consumption of coffee becomes a habit and addiction. This is seen in people who are dependent on caffeine in order to start their day, to continue their day, or to keep up with their day.
So how does caffeine work in our system? To understand caffeine’s mechanism, the adenosine molecule should be understood. Adenosine is a hormone naturally released in the brain and affects many major organs in our body. Adenosine functions by binding only an adenosine receptor located on cell membranes. This in turn causes a “slow down” in the body. For example, while melatonin release is widely known to cause sleepiness, adenosine is also released to allow that mechanism and it works together with melatonin. In addition, adenosine decreases blood flow. When we drink coffee, we typically feel hyper, our heart rates increase, and a higher sense of awareness. This is because caffeine molecules actually bind to adenosine receptor as the two molecules are very similar in shape. This explains why people look to caffeine to wake them up. In the mechanism, adenosine binds to the receptor resulting in the slow down. When caffeine is consumed, caffeine molecules will bind to adenosine receptors. This converts ATP to 2nd messenger cAMP via phosphorylation. 2nd messenger cAMP causes an enzyme cascade, whether inactive enzymes are activated by the other. This causes muscle contractions and increased blood pressure symptoms. This explains why one common complaints of coffee drinkers are needing to use the bathroom. Muscles in the digestive tract contract which promote defecation. Additionally, the smooth muscles in the bladder also contract promoting frequent urination.
Aside from promoting wakefulness, it actually also promotes dopamine function. Dopamine normally functions to give a person the sense of reward. When adenosine receptors are blocked from adenosine and are occupied by caffeine, dopamine functions better. This results in a person who is both feeling rewarded and awake.
In individuals who don’t consume coffee daily, the body automatically increases and decreases specific hormones to allow function. For example, in dark areas to no light, the body releases melatonin and adenosine to promote sleep. But in bright light, the body begins to stop releasing melatonin and adenosine which promote wakefulness. The adenosine molecules easily bind to their designated receptors or are released from the receptors. In individuals who consume coffee occasionally, the caffeine molecules will bind the receptors, preventing the “slow down” symptoms such as sleepiness. In individuals who are dependent on coffee and consume coffee daily will develop more adenosine receptors over time which means they need more caffeine in order to block all adenosine receptors. When adenosine binds to even a few adenosine receptors, the individual will begin to feel tired.
While caffeine is registered as a classified drug, the dependence of caffeine is, while unhealthy, does not produce effects or side effects as gruesome as illegal drug addictions. However, caffeine addicts still feel side effects when they go a day or two without caffeine. Caffeine withdrawal produces symptoms including: anxiety, fatigue, brain fog, headaches, irritability and depression. Symptoms typically go away when the individual consumes caffeine again. Coffee is a common drink associated with people living early mornings and late nights. However, consistent consumption causes dependence and lack of consumption causes withdrawal symptoms and this explains how caffeine is a classified drug. Understanding the mechanism of caffeine and its relationship with adenosine shows how caffeine works as a drug.
References:
https://www.addictioncenter.com/stimulants/caffeine/
https://my.clevelandclinic.org/health/articles/15496-caffeine-how-to-hack-it-and-how-to-quit-it