Addiction: Dopamine and Brain Essay

Submitted By hapa
Words: 859
Pages: 4

Cocaine is a stimulant but is not normally prescribed therapeutically for its stimulant properties, although it sees clinical use as a local anesthetic, particularly in ophthalmology. On a short-term basis, stimulants exert their effects by disrupting or modifying the normal communication that occurs among brain neurons and brain circuits. Cocaine has been shown to specifically disrupt the dopamine neurotransmitter system. This disruption is accomplished by overstimulation the receptors on the postsynaptic neuron, either by increasing the amount of dopamine in the synapse through excessive presynaptic release or by inhibiting dopamine's pattern of reuptake or chemical breakdown. The use of cocaine increases the amount of available dopamine in the brain, which leads to mood elevation (e.g., feelings of elation or euphoria) and increased motor activity. With cocaine, the effects are short-lived. As the stimulant level in the brain decreases, the dopamine levels subside to normal, and the pleasurable feelings dwindle away. All drugs have a negative effect on the nervous system, but few can match the dramatic impact of cocaine. Cocaine is one of the most potent, addictive, and unpredictable recreational drugs, and thus can cause the most profound and irreversible damage to the nervous system. The high risk associated with cocaine remains the same regardless of whether the drug is snorted, smoked, or injected into the user's bloodstream. In addition to the intense damage cocaine can cause to the liver, intestines, heart, and lungs, even casual use of the drug will impair the brain and cause serious damage to the central nervous system. Although cocaine use affects many components of the body, including vision and appetite, the most significant damage cause by cocaine takes place in the brain and central nervous system.
Cocaine produces its pleasurable high by interfering with the brain's "pleasure centers" where such chemicals as dopamine are produced. The drug traps an excess amount of dopamine in the brain, causing an elevated sense of well being. Cocaine acts as a stimulant to the body. In turn, the drug cause blood vessels to restrict, increases the body's temperature, heart rate, and blood pressure, and cause the pupils to dilate (4). Cocaine also increases one's breathing rate. Cocaine causes such pleasurable effects as reduced fatigue, increased mental clarity, and a rush of energy. However, the more one takes cocaine, the less one feels its pleasurable effects, which causes the addict to take higher and higher doses of cocaine in an attempt to recapture the intensity of that initial high (1). In any case, a cocaine high does not last very long. The average high a user gets from snorting cocaine only lasts for 15-30 minutes. These highs are less intense, as it takes longer for the drug to be absorbed into the bloodstream when snorted. A smoking high, although more intense due to the rapidity in which the drug is absorbed into the bloodstream, lasts for an even shorter period of only about five to ten minutes (5). After the euphoric high comes the crashing low, in which the addict craves more of the drug and in larger doses (2).
Cocaine can cause serious long-term effects to the central nervous system, including an increased chance of heart attack, stroke, and convulsions, combined with a higher likelihood of brain seizures, respiratory failures, and, ultimately, death (2). An overdose of cocaine raises blood pressure to unsafe