Let’s get a picture of the effect cocaine has on the brain by first taking a snapshot of the brain without cocaine’s influence.
Neurotransmitters are brain chemicals released at the end of nerve fibers, which occurs when stimulated by a nerve impulse. The neurotransmitter flows across a synapse, causing the transfer Synapse xt of the nerve impulse to flow to another nerve fiber, a muscle fiber, or another physiological structure. Then the neurotransmitter returns to the synaptic site and is carried back to its original brain cell by a transporter protein, to perform the cycle again.
Dopamine, serotonin and norepinephrine are neurotransmitters. The above process is how they function in the brain. But cocaine (benzoylmethyl ecgonine), derived from coca plant leaves, is a serotonin, norepinephrine and dopamine reuptake inhibitor.
Let’s consider this experience on just one of the neurotransmitters, dopamine, which has had the most extensive study regarding its relationship with the use of cocaine. At the point that dopamine would be carried back to its “home position” in the brain by the reuptake process, it is blocked by cocaine.
So dopamine accumulates where the synapse occurs because it continues to travel through the synapse. But it’s held there instead of returning to its home location. It’s as if the dopamine is at a large airport where all the flights are allowed to arrive, but none are permitted to depart.
The effect of dopamine being held in what’s called the “synaptic cleft” is that it rises to levels that are abnormal, initially bringing about a state of euphoria and high energy. But over time this blocking damages the brain’s ability to process dopamine properly. The cocaine user takes more and more cocaine, hoping for that feeling of euphoria and energy, but, instead, even normal levels of pleasurable emotion disappear. Chronic users experience depression, paranoia and anxiety, while addicts exhibit paranoid schizophrenic symptoms of delusions, repetitive behaviors and serious mood disturbances.
Cocaine causes strokes and heart attacks by constricting blood vessels. The constricted blood vessel stops blood flow, or causes a blood vessel to leak or burst, resulting in strokes. Heart attacks occur because cocaine makes the heart beat stronger and faster increasing the need for oxygen, but at the same time cocaine has constricted blood vessels, and the heart cannot function without the amount of oxygen-carrying blood it needs.