Drugs Change the way Neurons
communicate
Drugs change the way
neurons communicate
• Drugs of abuse interfere with and disrupt
the process of neurotransmission
• When neurons do not communicate
normally, the brain does not function
normally either
http://learn.genetics.utah.edu/content/addiction/drugs/mous
e.html
Cocaine (opiate)
Cocaine blocks dopamine transporters (re-uptake
pumps), causing an increase in dopamine in the
synaptic cleft thus inducing euhporia
Methamphetamine(stimulant)
Methamphetamine
1. Methamphetamine blocks dopamine
transporters.
2. Meth passes directly through the neuronal
cell membrane and is carried into the
axon terminals where it enters the
vesicles that contain dopamine.  This
triggers the vesicles to be released, even
without an action potential.
Combined, this causes a surge of dopamine
to be present in the synaptic cleft, leading to
overactivation of neurons and an extreme
‘high’.
Nicotine
Nicotine
• Nicotine binds to nicotinic receptors
on the axon terminal of the
presynaptic neuron. When this
occurs the amount of dopamine
released in response to an action
potential is increased.
Alchohol
Alcohol
• Alcohol binds to GABA receptors on the
dendrites of neurons which release GABA
as their neurotransmitter.
• Alcohol is an inhibitory signal (CNS
depressant) so it reduces the activity of
the presynaptic neuron (which releases
GABA as its neurotransmitter).
• The presynaptic neuron will release less
GABA in response to alcohol in the brain.
• GABA is inhibitory, so less release into the
synaptic space creates less inhibition of
the postsynaptic neuron. Less inhibition
means more excitation, causing more
dopamine to be released in the reward
system when alcohol is present.