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Neurotransmitters and the Synapse
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What are ways in which you communicate
with your friends?
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Neurotransmitters are the means of
communication for neurons. However, they
can illicit action or stop all communication.
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How are neurotransmitters and the neuron
linked to psychology? What is their
importance?
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Quick review of the Neuron parts
Lecture
 Covering neurotransmitters
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Activity
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http://www.youtube.com/watch?v=HXx9qlJe
tSU
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What neurotransmitters do
Neurotransmitters are central to memory,
learning, mood, behavior, sleep, pain
perception and sexual urge. They operate
at the junctions between neurons,
allowing communication between cells.
involved in voluntary movement,
learning, memory, and sleep
 Too much acetylcholine is
associated with depression, and
too little in the hippocampus has
been associated with dementia.
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inhibits excitation and anxiety
 Major inhibitory neurotransmitter in
Brain
 Too
little GABA is associated
with anxiety and anxiety
disorders. Some anti-anxiety
medication increases GABA at
the receptor sites.
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Common neurotransmitter in the brain
Always excitatory and driven by the SodiumPotassium pump
Receptors concentrated in the Cerebral
Cortex especially the hippocampus
Reabsorption of Glutamate is affected during
mercury poisoning

plays a role in mood, sleep, appetite,
and impulsive and aggressive behavior
 Too little serotonin is associated with
depression and some anxiety disorders,
especially obsessive-compulsive
disorder. Some antidepressant
medications increase the availability of
serotonin at the receptor sites.
involved in energy, and
glucose metabolism
 Too little epinephrine has
been associated with
depression.

 associated
with eating,
alertness
 § Too little norepinephrine has
been associated with
depression, while an excess
has been associated with
schizophrenia.
•
correlated with movement,
attention, and learning
– Too much dopamine has been
associated with schizophrenia, and
too little is associated with some
forms of depression as well as the
muscular rigidity and tremors found
in Parkinson’s disease.

involved in pain relief and feelings of
pleasure and contentedness
PERIPHERAL NERVOUS
SYSTEM

Only two
neurotransmitters
 Acetylcholine (Ach)
 Norepinephrine
CENTRAL NERVOUS SYSTEM

Many Neurotransmitters
 Why?
▪ Brain functions are not as
uniformed
▪ Many neurotransmitters to
perform many different tasks

http://www.youtube.com/watch?v=90cj4NX8
7Yk
 Many drugs and chemicals influence
synaptic transmission
 Drugs can be agonistic or
antagonistic
 But not all drugs increase dopamine
levels in the brain in the same way.
Some substances imitate natural neuromediators and
take their place on their receptors. Morphine, for
example, binds to the receptors for endorphin (a
natural "morphine" produced by the brain), while
nicotine binds to the receptors for acetylcholine.
• Other substances increase the secretion of natural
neuromediators. Cocaine, for example, mainly
increases the amount of dopamine in the synapses,
while ecstasy mainly increases the amount of
serotonin.
• Still other substances block a natural neuromediator.
Alcohol, for example, blocks the NMDA receptors.
•
•
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•
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Increase synthesis of neurotransmitter
Increase release of neurotransmitter
Activate receptors, mimic
neurotransmitter
Inhibit reuptake of neurotransmitter
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Interfere with release of neurotransmitter
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Occupy and block neurotransmitter sites
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Cause neurotransmitter loss from vesicles.
Agonists mimic the neurotransmitter by binding to
the receptor sites just as the neurotransmitters do
and having the same effect on the receiving neuron.
Agonists are used when it is believed that there is
not enough neurotransmitter
• Antagonists BLOCK the neurotransmitter by
binding to the receptor sites without affecting the
receiving neuron in the same way. Because they
“fill” the receptor sites, the neurotransmitters can’t
bind to the neuron. Antagonists are used when it is
believed that there is TOO much of the
neurotransmitter in the body.
•
•
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When there is TOO LITTLE neurotransmitter
in the body, drugs may also help by blocking
reuptake and thus increasing the amount of
neurotransmitter that remains in the synapse
Prozac is an example of this sort of drug.
Prozac falls in a class of drugs called SSRI’s
(Selective Serotonin Reuptake Inhibitor) and
by inhibiting reuptake of serotonin, they
increase the levels of this neurotransmitter in
the brain.