Neurons and
neurotransmission
on the scrap piece of paper, draw a neuron…
By the end of today you will
Understand the parts of a neuron
Understand how signals are transported between
neurons
Understand how dopamine neurotransmission works
in the reward system
Major Concept of today
The plan
20 minutes of notes & video clips (anatomy of a
neuron)
20 minutes of analyzing neurotransmitters
5 minute to wrap up
Anatomy of a
neuron…anatomy of a synapse
Anatomy of a neuron
What do you think this
picture represents?
The cell that sends info
the cell that receives info
Neurotransmitters & Receptors
Neurotransmitters:
- chemicals that carry messages from one neuron to another
across the synapse (messages travel really fast!)
Receptors:
- Protein molecules that receive and translate the chemical message
How does neurotransmission
work?
Neurotransmission
Neurotransmission: From NIH
Harvard edu
Working with a partner, fill
in the table on the front of
page 2.
#1
The presynaptic neuron ending has
large circles in it. The large circles
have smaller circles inside. There are
two sets of bars that cross the end
(membrane) of the presynaptic
neuron. The postsynaptic neuron
has two rectangular-shaped boxes on
the end (membrane) of the neuron.
#2
Nothing has changed except that
there is a lightning bolt (electrical
signal) and an arrow indicating that
the lightning bolt is moving toward
the end of the presynaptic neuron.
#3
One of the larger circles is now in
contact with the end of the
presynaptic neuron. Another circle is
now releasing the small circles into
the space between the neurons.
#4
The small circles are in the space
between the neurons, and one small
circle is now attached to the boxshaped figures on the end of the
postsynaptic neuron.
#5
The lightning bolt symbol (electrical
signal) is at the postsynaptic neuron
now. The arrow indicates that it is
moving away from the neuron
ending.
#6
The small circles are no longer
attached to the box-shaped figures
on the postsynaptic neurons. The
arrows seem to indicate that the
small circles are now moving back
into the presynaptic neuron and
going back into the larger circles.
Drugs Disrupt
Neurotransmission
Homework: The Mouse
party…
Mouse Party...
Let’s see if you are right.
Here’s what happens..
Methamphetamine alters dopamine neurotransmission
in two ways. Methamphetamine enters the neuron by
passing directly through nerve cell membranes. It is
carried to the nerve cell terminals by transporter
molecules that normally carry dopamine or
norepinephrine. In the nerve terminal,
methamphetamine enters the dopamine- or
norepinephrine-containing vesicles and causes the
release of neurotransmitter. Methamphetamine also
blocks the dopamine transporter from pumping
dopamine back into the transmitting neuron.
Methamphetamine acts similarly to cocaine in this way.
How is nicotine different from
methamphetamines?
Nicotine…
binds to specific receptors on the presynaptic neuron.
When nicotine binds to receptors at the cell body, it
excites the neuron so that it fires more action
potentials (electrical signals) that move toward the
synapse, causing more dopamine release (not shown in
figure). When nicotine binds to nicotine receptors at
the nerve terminal (shown above), the amount of
dopamine released in response to an action potential is
increased.
Cocaine
What are three ways drugs can
affect neurotransmitters?
1. Drugs can bind at the cell body and send
more action potential through the
neuron, increasing the amount of
dopamine released.
Example:
2.
Drugs can bind to the terminal end
of the presynaptic neuron, releasing
more dopamine for each action
potential.
Example:
3. Drugs
can block the dopamine
transporter (retake pump) that
removes dopamine from the synapse.
This results in a rapid rise of
dopamine in the synapse, leading to
feelings of euphoria.
Example:
Route of administration and
drug effects
Drug delivery methods
The dose and how it enters into a person’s
body, changes the drug’s effect.
Once a certain amount of the drug enters the bloodstream, a
response can then be measured. This point is known as the
threshold. As the amount of drug taken increases, so does the
response. At higher doses, opiates are toxic and can cause a fatal
response by halting respiration.
Drugs enter the body in
different ways
Drug delivery methods
Inhalation
Ingestion
Injection
Snorting/Sniffing
Summary of ways in which drugs affect
neurotransmission