Cocaine and the brain
Research on cocaine illustrates that many dimensions may be involved in a single drug’s interaction with the activity of a single neurotransmitter. Studies show that cocaine alters dopamine neurotransmission with effects on:
Cocaine causes the pleasurable feelings that motivate drug abuse by raising dopamine
concentrations in the synapses of the reward system.
Besides keeping dopamine in the synapses by blocking the transporters, cocaine can
indirectly promote release of additional dopamine into the synapses by mobilizing a supply
that the sending cells normally hold in reserve. Cocaine’s yield of pleasurable feelings arises
largely through the activity of one particular set of dopamine receptors, called D3 receptors.
Individuals believe they are functioning more efficiently when on Cocaine and report a
feeling of clarity when performing tasks or interacting with other people.
Some studies indicate that the transition from casual cocaine abuse to addiction begins with
the abuser’s very first doses. For example, a single exposure to cocaine causes some cells
in the brain’s reward system to increase their responsiveness to subsequent stimulations.
In living animals with minimal exposure to cocaine, the drug alters the dopamine
responsiveness for at least a week. After chronic cocaine abuse dopamine ticks up in the
reward system when the abuser encounters a cue associated with the drug.
Brains normally sprout new neurotransmitter receiving structures in the process of turning
new experience into learning. Cocaine accelerates this process, which may help account for
the drug’s unusual hold on an addicted individual’s attention.
Vulnerability to Abuse
A young person’s marked taste for novelty may be an indication that dopamine activity in his
or her brain’s reward system is especially sensitive to cocaine. An individual’s attraction to
cocaine’s dopamine-stimulating effects also may relate to his or her social circumstances.
The effects of Cocaine in “Re-Wiring” the brain and an individual’s reward system greatly
increase the chances of becoming addicted. The effect on neurotransmitters is so rapid, the
reward system becomes accustomed to Cocaine very quickly and this makes the substance