FoundationalConceptsNeuroscience

productively and safely. The purified chemical has far more apparent
poison qualities and is very prone to dysfunctional patterns of use.
The major identified neurochemical effect of cocaine is the blocking
or inhibition of reuptake transporters for the neurotransmitters
norepinephrine and dopamine. Interfering with reuptake trans-
port means that these neurotransmitters will be slowed in leaving
the synaptic cleft and thus will have a greater effect at the synapse
after their release. Thus, cocaine results in excessive activity at all
synapses in the nervous system that use norepinephrine or dopamine
as aneurotransmitter. Enhanced activity at the noradrenergic and
dopaminergic circuitry in the brain produces the CNS stimulant
effects of increased wakefulness and alertness, focused attention, de-
creased appetite, and increased positive mood. The sympathomimetic
effects in the autonomic nervous system stem from enhanced activity
at noradrenergic synapses in the sympathetic nervous system.
Some of the poisonous qualities of cocaine include overarousal of
the CNS, resulting in anxiety, irritability, and impaired judgment.
Psychosis can also result. Psychosis is a discombobulation of the
perception of what we call reality, characterized by delusions (fixed
false beliefs) and/or hallucinations (perceptual experiences that do
not seem to be generated by ordinary sensory stimuli, such as hearing
or seeing things that are “not there”). Overstimulation of the CNS can
also lead to seizures, which can be fatal. Overstimulation of the sym-
pathetic nervous system can produce cardiovascular stress, leading
to heart and circulatory system damage. There may also be acute, po-
tentially fatal consequences, such as stroke and heart attack. Finally,
another profound poisonous quality of cocaine is its high potential to
promote addictive use.
Why does the coca plant make this weird and poisonous molecule,
cocaine? The answer may be—as is thought to be the case for caffeine