Cocaine dependence

Cocaine, sometimes called coke, is a powerful psychoactive stimulant that alters how the brain functions—specifically, how we perceive our surroundings.

Cocaine comes from the leaves of the South American coca plant, and has been used for over a thousand years.

In modern times, it’s become a popular “party drug” because cocaine reduces inhibitions and creates a feeling of euphoria or pleasure; this feeling lasts between fifteen and ninety minutes, depending on how the drug’s it’s administered.

Around 18 million people worldwide use cocaine, and because of its strong potential for addiction and overdose, the drug is heavily regulated in many countries.

To understand how cocaine works, let’s zoom into one of the synapses of the brain.

Normally, electrical signals, or action potentials, travel down the axon to the axon terminal, where they trigger the release of chemical messengers called neurotransmitters from synaptic vesicles into the synapse.

The neurotransmitters travel across the synapse and bind to receptors on the postsynaptic neuron, where they give the cell a message.

After the neurotransmitters have done their job, they unbind from the receptors, and can just diffuse away, get degraded by enzymes, or get picked up by proteins and returned to their release site in a process called reuptake.

Cocaine increases the release of certain neurotransmitters, but it’s biggest effect is blocking reuptake receptors on presynaptic axon terminals.

Both of these actions keep neurotransmitters like dopamine, norepinephrine, and serotonin in the synapse longer, increasing their effects.

For example, increased concentrations of dopamine in the brain’s reward pathway (which includes the nucleus accumbens, ventral tegmentum, and prefrontal cortex) produce intense feelings of euphoria, pleasure, and the emotional “high” associated with cocaine.

This physical “high” or feeling of hyper-stimulation is caused by increased norepinephrine concentrations throughout the brain, which produces a variety of effects throughout the body like increased energy, constricted blood vessels, dilated pupils, increased body temperature, increased heart rate, and increased blood pressure. Finally, these higher levels of serotonin are associated with greater confidence.