Welcome to 2 minute neuroscience, where I simplistically explain neuroscience topics
in 2 minutes or less.
In this installment I will discuss the effects of cocaine on the brain.
Cocaine is a strong stimulant that can cause a range of effects including increased energy,
alertness and euphoria, along with an elevated heart rate and other sympathetic nervous system
Cocaine also has a high potential for abuse and inclines users towards compulsive administration
of the drug.
Although all of the details of how cocaine produces its effects are not known, it is
thought that the main mechanism by which cocaine acts on the brain is through the inhibition
of the reuptake of neurotransmitters called monoamines.
Monoamines are a group of neurotransmitters that includes dopamine, norepinephrine, and
Reuptake is a method of removing neurotransmitters from the synaptic cleft between neurons.
When reuptake is inhibited, it causes increased levels of neurotransmitters in the synaptic
Cocaine inhibits reuptake by blocking the action of the proteins known as transporters
that are normally responsible for it.
By blocking monoamine transporters and inhibiting monoamine reuptake, cocaine causes levels
of dopamine, norepinephrine, and serotonin to increase in the brain, enhancing the activity
of these neurotransmitters at their receptors.
Although cocaine increases levels of dopamine, norepinephrine, and serotonin, it is not very
clear what the individual contribution of each of these neurotransmitters is to the
effects of the drug.
However, it is generally thought that cocaine’s action at dopamine receptors is most important
for making cocaine rewarding and promoting the compulsive use of the drug.
The mesocortical and mesolimbic dopamine pathways, which are sometimes called the mesocorticolimbic
dopamine pathway, are pathways that are rich in dopamine neurons; they project from a dopamine
rich region in the brainstem called the ventral tegmental area to a variety of locations in
the limbic system and frontal cortex.
These areas include a region called the nucleus accumbens, which is considered important to
addiction and is activated whenever we do something rewarding.
Thus, when someone uses cocaine, dopamine activity along the mesocorticolimbic pathway
is increased, causing dopamine levels to rise in regions like the nucleus accumbens.