Cocaine was isolated from coca leaves by scientists. It was not merely a chemical process; cultural attributes were also stripped away. Now, it is a packaged commodity everyone can buy, rather than drugs doctors dispense to patients, or substance for special rituals.
How does cocaine lead to addiction?
When we engage in activities that are beneficial to survival and reproduction, dopamine is released by brain's reward system to bind with its receptors, bringing a sense of pleasure and motivating the repeated behavior. Subsequently, dopamine falls off the receptors spontaneously and recycled by transport proteins for next use. However, cocaine binds tightly to transport proteins to block recycling mechanism. These dopamines accumulate at the junctions of nerve cells, and they bind to and fall off the receptors to continuously generate electrical impulses for euphoria and excitement, and resistance to hunger. People feel that their muscles and intellect are more vigorous. This wonderful sensation is fleeting, and it lasts only a few minutes to an hour (depending on the dose and method of intake), because cocaine is gradually metabolized. Afterwards, users may experience comedown symptoms such as fatigue, anxiety, depression. Appetite may not recover for several hours. Addicts will seek to ingest cocaine again. Such behavior becomes habitual and dependent, and result in addiction within weeks.
High levels of dopamine and persistent neural impulses are regarded as abnormal signals by the cells: too much dopamine. They make various adjustments to maintain homeostasis. Dopamine synthesis and receptor expression undergo downregulation. At the same time, signal downstream and the way nerve cells connect in reward system change. As result, addicts have to ingest more cocaine to feel same euphoria.
Effects of Snorting, Oral Ingestion, and Injection of Cocaine
Cocaine in the early 20th century was an acidic water-soluble salt produced by pharmaceutical companies. With a high melting point, it was difficult to volatilize through smoking. Injection was still a novel technique at that time, so oral ingestion was the best choice for most addicts. Any substance that enters bloodstream through digestive system does not immediately reach our brain. They are first filtered in liver to remove toxicity, a protective mechanism of human body. Most cocaine is metabolized by liver into inactive substances, and only a small amount reaches brain. It takes more time for orally ingested cocaine to reach brain after following a much longer and winding path. Less euphoria and excitement will come on within 30 minutes and subside within an hour. Therefore, oral administration is not very addictive and it is relatively easy to quit.
Snorting, smoking, and injection bypass liver and directly affect the central nervous system, so even a small amount can produce intense euphoria and excitement. During snorting, cocaine adheres to nose mucous membranes and enters the capillaries. It returns to heart through veins and are transported to brain by arteries and capillaries. The pleasure feeling will begin after 10 minutes, if addicts snort it.
By the late 20th century, pharmaceutical companies had ceased producing cocaine due to its illegality and superior alternatives. The cocaine was extracted in the drug cartel's clandestine laboratories that was located in jungle. It was alkaline, hydrophobic free bases that has no charge. The molecules were accumulated by Van der Waals force instead of electrostatic force. Therefore, it was very volatile and emitted a crackling sound when heated, so it was also called crack cocaine. The unique characteristics make it ideal for smoking. Cocaine enters the circulation system through capillaries on the alveoli, and then pumped directly from heart into brain. The free base penetrates cell membranes more rapidly to induce excitement within minutes.
Injection is a completely different method, but the time and effects are similar. The time interval from injecting cocaine to feeling pleasure and excitement is only about a few minutes, and lasts approximately 10 minutes. Cocaine enters the circulation system directly from the veins and is then pumped from heart into brain. Intravenous injection can easily lead to overdose and death among addicts, as cocaine concentration in blood is extremely high in a moment.