Neurotransmitters
Summary
TLDRThis video delves into the world of neurotransmitters, exploring their role as chemical messengers in the brain and body. It explains how these molecules, derived from amino acids, peptides, and other substances, influence our cognitive functions, emotions, and physical responses. The video highlights key neurotransmitters like acetylcholine, dopamine, and serotonin, and their effects on muscle contraction, motivation, and mood regulation. It also discusses how drugs interact with these neurotransmitters, either enhancing or inhibiting their functions, leading to various psychological and physiological outcomes.
Takeaways
- 🧠 Neurotransmitters are chemical molecules that transmit signals across a synapse to target cells, influencing brain function and body responses.
- 🔗 When neurotransmitters bind to receptors, they can either excite (EPSP) or inhibit (IPSP) the target cell, affecting its electrical charge and behavior.
- 💊 Neurotransmitters are derived from various sources including amino acids, peptides, proteins, and other substances like nitric oxide and adenosine.
- 🏃♂️ Acetylcholine is a key neurotransmitter for muscle contraction and cognitive functions like thinking, learning, and memory.
- 🎯 Dopamine plays a crucial role in motivation, attention, reward behaviors, and motor control, with deficiencies potentially leading to Parkinson's disease.
- 🏃♀️ Endorphins are associated with the 'runner's high' and act as natural painkillers, contributing to feelings of pleasure.
- 📚 Glutamate is the most prevalent excitatory neurotransmitter, essential for cognitive functions, but excessive amounts can lead to anxiety and excitotoxicity.
- 😌 GABA and glycine are inhibitory neurotransmitters that promote calmness and reduce anxiety when balanced with excitatory neurotransmitters.
- 🌙 Serotonin is linked to feelings of calmness and contentment, and its imbalance can be associated with depression and mood regulation.
- ☕ Adenosine increases with energy expenditure and contributes to feelings of tiredness, influencing the sleep cycle.
- 🌿 Anandamide acts on cannabinoid receptors to reduce inflammation and decrease pain, while histamine, apart from allergies, is an excitatory neurotransmitter involved in thinking.
Q & A
What are neurotransmitters and what role do they play in the nervous system?
-Neurotransmitters are chemical molecules released from the synapse of a neuron that move across the synaptic cleft and bind to a target cell. They play a crucial role in communication within the nervous system, affecting how the brain and body function by either exciting or inhibiting the target cells.
How do neurotransmitters affect the movement of ions across the cell membrane?
-When neurotransmitters bind to a receptor on the target cell, they can either excite the cell by causing a positive charge to build up inside (EPSP) or inhibit the cell by causing a negative charge to build up or positive charges to leave (IPSP), thus affecting the movement of ions across the cell membrane.
What is the primary neurotransmitter responsible for muscle contraction and what other roles does it play?
-Acetylcholine is the primary neurotransmitter responsible for muscle contraction. It is also important for cognitive functions such as thinking, learning, and memory. In people with Alzheimer's, the production of acetylcholine is reduced, which affects these cognitive processes.
How does dopamine affect motivation, attention, and reward behaviors?
-Dopamine is involved in motivational behavior, focusing attention, and reward behaviors. It helps with paying attention, concentrating, and completing tasks. Dopamine also plays a role in addictive behaviors and controlling motor movements, with a lack of dopamine in the midbrain leading to conditions like Parkinson's disease.
What are endorphins and what is their function in the body?
-Endorphins are neurotransmitters that act as natural painkillers and contribute to feelings of pleasure. They are often associated with the 'runner's high' and can be released during physical activity to reduce pain and increase feelings of well-being.
What is the most prevalent excitatory neurotransmitter in the brain and what are its functions?
-Glutamate is the most prevalent excitatory neurotransmitter in the brain. It is crucial for cognitive functions such as thinking, planning, and problem-solving. However, excess amounts of glutamate can lead to anxiety, seizures, and excitotoxicity, potentially causing neuronal damage.
How do stress hormones like epinephrine and norepinephrine impact the body during a stress response?
-Epinephrine and norepinephrine, produced by the autonomic nervous system during a stress response, cause various physiological changes such as dilating pupils, increasing heart rate, and dilating bronchial tubes and blood vessels, preparing the body for a 'fight or flight' reaction.
What are the roles of inhibitory neurotransmitters GABA and glycine in the body?
-GABA (gamma-aminobutyric acid) and glycine are inhibitory neurotransmitters that play a role in creating a sense of calm and reducing anxiety. They help balance the excitatory effects of neurotransmitters like glutamate, contributing to a relaxed state and preventing over-excitement.
How does serotonin contribute to feelings of calm and contentment, and what are its other functions?
-Serotonin is associated with feelings of calm, contentment, and satisfaction. It plays a significant role in regulating mood and appetite. Low levels of serotonin can increase the risk of depression, while higher levels are linked to a sense of well-being and comfort.
What is the relationship between adenosine and sleep, and how does caffeine interact with adenosine?
-Adenosine is a molecule that increases with energy usage and can bind to receptors to make us feel tired, promoting sleep. Caffeine works by inhibiting adenosine receptors, thus reducing feelings of sleepiness and keeping us awake.
How do drugs interact with neurotransmitters, and what are some examples of drugs that affect specific neurotransmitter systems?
-Drugs can act as agonists or antagonists, increasing or decreasing the effects of neurotransmitters by binding to specific receptors. For example, nicotine affects acetylcholine and dopamine receptors, influencing cognitive functions and reward. Ritalin and Adderall are stimulants that primarily act on dopamine receptors to improve focus, used to treat attention deficit disorders.
Outlines
🧠 Neurotransmitters: The Chemical Messengers of the Brain
This paragraph introduces neurotransmitters as chemical molecules that transmit signals across the synaptic cleft to target cells such as neurons, muscle cells, or glands. It explains how neurotransmitters can excite or inhibit cells, leading to either depolarization or hyperpolarization. The paragraph also touches on the various sources of neurotransmitters, including amino acids, peptides, proteins, and other substances like nitric oxide or adenosine. An example is provided with acetylcholine, which is crucial for muscle contraction and cognitive functions, and its reduction in Alzheimer's disease is highlighted.
🚀 Dopamine and Other Key Neurotransmitters
Dopamine is discussed as a neurotransmitter involved in motivation, attention, and reward, with a role in addictive behaviors and motor control, linking its deficiency to Parkinson's disease. Endorphins are mentioned as natural painkillers and mood elevators, associated with the 'runner's high.' The paragraph then summarizes neurotransmitters like glutamate, which is vital for cognitive functions but can lead to anxiety or excitotoxicity in excess. It also covers stress hormones epinephrine and norepinephrine, inhibitory neurotransmitters GABA and glycine, and serotonin, which contributes to feelings of calm and contentment.
💤 Neurotransmitters and Their Impact on Sleep, Mood, and Pain
This section delves into adenosine, which is linked to feelings of tiredness, and anandamide, which reduces inflammation and pain while increasing pleasure. Histamine's dual role as an allergy molecule and an excitatory neurotransmitter in the brain is also mentioned. The paragraph then transitions into a comparison of how different drugs affect neurotransmitter levels, either as agonists enhancing their effects or antagonists blocking them. Examples include nicotine's impact on acetylcholine and dopamine, and how alcohol can both stimulate and depress the nervous system by affecting various neurotransmitters.
💊 The Effects of Medications on Neurotransmitters
The final paragraph focuses on how various medications interact with neurotransmitters. It discusses stimulants like Ritalin and Adderall that act on dopamine receptors to treat attention deficit disorders. Alcohol's complex effects, including its influence on dopamine, acetylcholine, glutamate, and GABA, are explored. The paragraph also covers opiates' pain-inhibiting properties, the use of ephedrine in non-drowsy medications, benzodiazepines' impact on GABA for treating anxiety and insomnia, SSRIs' effect on serotonin to combat depression, caffeine's inhibition of adenosine to promote wakefulness, and the psychoactive effects of cannabis and hallucinogens on cannabinoid and serotonin receptors.
Mindmap
Keywords
💡Neurotransmitters
💡Synaptic Cleft
💡EPSP (Excitatory Postsynaptic Potential)
💡IPSP (Inhibitory Postsynaptic Potential)
💡ACh (Acetylcholine)
💡Dopamine
💡Endorphins
💡Glutamate
💡GABA (Gamma-Aminobutyric Acid)
💡Serotonin
💡Adenosine
Highlights
Neurotransmitters are chemical molecules that transmit signals across a synapse.
Neurotransmitters can bind to neurons, muscle cells, or glands, affecting different parts of the body.
Binding of neurotransmitters to receptors can cause excitation (EPSP) or inhibition (IPSP) of a cell.
Neurotransmitters are typically derived from amino acids, peptides, proteins, or other substances like nitric oxide.
Acetylcholine is a key neurotransmitter for muscle contraction and cognitive functions.
Dopamine is involved in motivation, attention, and reward behaviors, and is linked to Parkinson's disease.
Endorphins are natural painkillers that contribute to the 'runner's high' and feelings of pleasure.
Glutamate is the most prevalent excitatory neurotransmitter, crucial for cognitive functions.
Epinephrine and norepinephrine are stress hormones that trigger the body's stress response.
GABA and glycine are inhibitory neurotransmitters that promote calmness and reduce anxiety.
Serotonin is associated with feelings of calmness, contentment, and plays a role in regulating appetite and mood.
Adenosine increases with energy use and contributes to feelings of tiredness and sleepiness.
Anandamide binds to cannabinoid receptors and is involved in reducing inflammation and increasing pleasure.
Histamine acts as an excitatory neurotransmitter in the brain and is involved in allergic reactions.
Drugs can act as agonists or antagonists, affecting neurotransmitter function by increasing or decreasing their effects.
Nicotine affects acetylcholine and dopamine receptors, impacting cognitive functions and reward.
Alcohol impacts multiple neurotransmitters, acting as both a stimulant and a depressant.
Opiates are inhibitory neurotransmitters that bind to opiate receptors and reduce pain.
Benzodiazepines impact GABA receptors and are used to treat anxiety and insomnia but can be addictive.
SSRIs are antidepressants that increase serotonin levels in the synapse to alleviate depression.
Caffeine inhibits adenosine receptors, reducing feelings of sleepiness and increasing alertness.
Cannabis and THC bind to cannabinoid receptors, increasing pleasure and reducing pain.
Hallucinogens cause distorted perceptions by binding to serotonin receptors, leading to hallucinations.
Transcripts
[Music]
in this video we're going to talk about
neurotransmitters
these are the chemical molecules that
are released from the synapse of a
neuron
that move across the synaptic cleft and
bind to a target cell
neurotransmitters can bind to other
neurons or
muscle cells like skeletal or smooth
muscles or glands like your adrenal
gland and where those neurotransmitters
bind
what part of the brain or what part of
the body that will determine what kind
of an effect they have
when neurotransmitters move across the
synapse and bind to a receptor
on the target cell we call that receptor
a
chemically gated channel or a ligand
gated channel
and most of the time those channels will
let ions
move into or out of the cell
so with neurotransmitters when they bind
to the target cell they can
excite that cell in epsp
or they can inhibit that cell and ipsp
so excitatory postsynaptic potentials
are going to trigger the movement of
ions
so that inside of the cell becomes more
positive
and brings it closer to the threshold
level for depolarization
whereas an inhibitory postsynaptic
potential
will cause a negative charge to either
build up inside of the cell or positive
charges to leave
so that the cell becomes hyper polarized
and further away from the threshold
level neurotransmitters
most of the time they're made from amino
acids but sometimes they can be peptides
and sometimes they can be proteins and
sometimes they can be other substances
like
nitric oxide or adenosine and i'll talk
a little bit about adenosine because
it's cool
so just to refresh your memory we have
an axon terminal here and we are showing
the synaptic cleft
so in the axon terminal there was an
action potential
that came down and changed the charge of
the cell
when we depolarize the membrane we move
positive charges in
and that action potential charge change
triggers voltage-gated calcium channels
calcium moves in and neurotransmitters
move
out when these neurotransmitters are
released
they bind to specific receptors on the
target cell
if the target cell becomes more
positively charged inside
that is an epsp or an excitatory
postsynaptic potential
if the cell becomes more negatively
charged that is
an ipsp so the type of neurotransmitter
and the type of receptor and the target
cell
all determine what kind of an effect
that neurotransmitter is going to have
so what we're going to do in this video
is look at a bunch of different kinds of
neurotransmitters
and we are going to look at their
general characteristics and what kinds
of effects they generally cause
okay so the first one is acetylcholine
it is made from the choline portion of a
phospholipid and
the acetyl-coa that we have talked about
before
when we oxidize pyruvate in the krebs
cycle
when you put acetyl coa and choline
together you have acetylcholine
acetylcholine is the primary
neurotransmitter
that causes muscle contraction so in our
somatic system
we can voluntarily control our skeletal
muscles
and when we decide to contract a muscle
that neurotransmitter is
always going to be acetylcholine when
acetylcholine binds it is always
excitatory and always causes muscle
contraction
acetylcholine is also important for
thinking we use it in our brain for
cognitive functions so thinking learning
and memory
is very important role of acetylcholine
and people that have alzheimer's
have reduced acetylcholine making
thinking learning and memory much more
difficult there are other aspects to
that but generally in people with
alzheimer's
they decrease the number of neurons that
produce acetylcholine
dopamine is one of my favorites because
it's involved in
motivational behavior and focusing your
attention
when you're trying to study and you
can't and you're distracted and your
brain is all over the place and you try
to focus and you're just not
absorbing the information that's because
your dopamine is low
so we need a certain amount of stress
not tons of it but just enough
to give us enough dopamine to be
motivated to do things
so dopamine is very important for paying
attention
focusing concentrating and getting a
task done
dopamine is also really important in the
reward
behaviors so anything that is addictive
dopamine is playing a role in that and
then dopamine
actually also has another role in your
midbrain
part of your brain at the top of your
brainstem dopamine will
inhibit motor neurons and this is
important for controlling motor
movements
so without dopamine in the midbrain
then you have uncontrolled muscle
movements
and that actually is what is involved in
parkinson's disease
endorphins these are also great because
they are like the runners-high
molecules they are pain killers so they
reduce pain
and they make us feel good and
pleasurable think about the next time
you go for a run and you feel really
good then that's endorphins
if you don't feel good then it's
something else and here's a little
summary
so next we will talk about two
excitatory neurotransmitters
that are very important for thinking
learning in memory
okay so glutamate is the first one
glutamate is probably
expressed by 90 of the neurons in your
brain
it is the most prevalent excitatory
neurotransmitter
and without glutamate you have very
decreased cognitive functions so we need
to have glutamate
so that we can think and plan and
problem solve and do all of that stuff
but excess amounts of glutamate can
cause
anxiety because it's very stimulating
excess glutamate can also be involved in
seizures
and it can cause excitotoxicity
way too much glutamate can actually kill
neurons
and i'm going to talk about this a
little bit again in a few minutes when i
talk about
some drugs and how drugs impact
neurotransmitters
then we have our stress hormones
epinephrine
and norepinephrine these are made by the
autonomic nervous system
when we have a sympathetic nervous
system reaction
and these will cause all of the typical
stress response things to happen
like dilating your pupils increasing
your heart rate
dilating bronchial tubes and blood
vessels
next we have two inhibitory
neurotransmitters
one is called gaba stands for gamma
aminobutyric acid
and the other one is glycine glycine is
an amino acid
and gaba is made from an amino acid
called glutamine
actually glutamate is also made from
glutamine
glutamate the excitatory
neurotransmitter and
gaba the inhibitory neurotransmitter
they should be balanced if you have too
much
gaba you're going to feel tired and if
you have too much glutamate you're going
to feel
anxiety so we want those
neurotransmitters to be balanced
so gaba and glycine play an important
role in making you feel
calm they're your natural anti-anxiety
neurotransmitters
next is serotonin this is our
calm and content neurotransmitter
so serotonin is associated with
depression if you have low serotonin
then you tend to have a higher risk of
depression
people often think of serotonin as your
happy hormone
but serotonin doesn't actually make you
happy excited happy
okay excited happy is gonna come from
dopamine
and norepinephrine and some
acetylcholine
probably glutamate too the excitatory
ones but serotonin
the best way that i i can explain how
serotonin feels
think about the last time you had a
really delicious dinner
that feeling after you've eaten really
good food
where you're just calm and content and
relaxed and satisfied and you feel very
good that is serotonin and we actually
make more serotonin in our digestive
tract than we do in our brain
the serotonin that we make in our
digestive tract
impacts our brain and tells us that we
feel
good and comfortable and content
serotonin plays an important role in
regulating our appetite
and our mood
three more neurotransmitters one is
called adenosine
do you remember atp adenosine
triphosphate that's our energy molecule
when we use up atp then we produce
some excess free adenosine and that
can bind to receptors and it makes us
feel
tired that's logical right you use up
energy
and then you start to feel tired and so
when adenosine increases
it makes us tired and we fall asleep
next we have anandamide anandamide
binds to cannabinoid receptors
the same receptors like cannabis
marijuana binds to
and in our body it's not psychoactive
but it does play a role
in reducing inflammation and decreasing
pain
and increasing pleasurable feelings and
then lastly
histamine i want to mention this one
because we often think of histamine
as our allergy molecule which is true
you increase the amount of histamine you
produce when you have an allergic
reaction
but it's also involved in thinking
it is an excitatory neurotransmitter in
our brain
and this is why sometimes if you take an
antihistamine
medication for allergies that it makes
you feel
tired
and now i just want to compare some
drugs that we know about and what
neurotransmitter they
impact now when drugs have an effect on
our brain and our body
they can increase the effect of the
neurotransmitter
so they're called an agonist if they
increase
that effect or they can block an effect
and then they are called an antagonist
so drugs can act by increasing or
decreasing the function of
neurotransmitters
depending on where they bind and how
they bind
we will go through a few interesting
examples
nicotine acts on two different receptors
primarily acetylcholine and dopamine
acetylcholine remember is involved in
cognitive thinking
and learning and memory and dopamine
is involved in motivation and reward
nicotine is extremely addictive drugs
like
ritalin or adderall are amphetamines
and they are stimulants and they
primarily
act on dopamine receptors and this is
used to treat
attention deficit disorder so remember
dopamine is the primary neurotransmitter
involved in making you focus your
attention
alcohol has a lot of interesting effects
alcohol impacts multiple
neurotransmitters it increases some and
it decreases some
and it has the weird ability to be a
stimulant
and a depressant so it increases
dopamine
which is reward and pleasure and
motivation
and this is where it can make you
motivated to do things
okay maybe not smart things because
you also decrease acetylcholine and we
need acetylcholine for
thinking and making choices so
that is decreased we also decrease
glutamate
so glutamate also a thinking molecule
when you decrease glutamate you decrease
anxiety
and this is why alcohol feels relaxing
so you're decreasing the glutamate
molecules but you're also
decreasing your thinking abilities it's
dose dependence so the more alcohol
consumed the more these effects will
occur
another thing that is affected is gaba
gaba is our
anti-anxiety neurotransmitter and it
makes us feel calm
and relaxed and then it also produces
some serotonin which makes you feel
content and maybe more social
acetylcholine also remember plays a role
in muscle contraction and
if you decrease acetylcholine in a part
of your brain called the cerebellum
it is the part of your brain at the back
of your brain that helps you
coordinate muscle movements and
alcohol highly targets the cerebellum
which makes you
lose your coordination abilities and
then the last thing i want to mention is
the glutamate aspect
okay glutamate is excitatory when you
decrease glutamate you feel calm and
relaxed
with alcohol there's a rebound effect
the next day the glutamate that was
decreased
during the alcohol consumption the next
day that will be
increased and so alcohol consumption can
actually
increase anxiety opiates are
neurotransmitters
that inhibit pain so these are
inhibitory some examples would be
codeine morphine and heroin
they are types of opiates opiates are
extremely addictive so they are binding
to
opiate receptors like our endogenous
endorphins ephedrine
is a drug that affects epinephrine
so epinephrine remember is our stress
response our autonomic nervous system
releases epinephrine through the
sympathetic pathways
so ephedrine is a stimulant sometimes
ephedrine is put
into medications that make you tired so
if you have
non-drowsy versions of medications like
cold medication or allergy medication
it usually has a little bit of ephedrine
in it
next we have benzodiazepines
these are drugs like valium diazepam
clonazepam
lorazepam adivan any of those azepams
are benzodiazepines and they impact
gaba receptors remember that gaba is our
anti-anxiety neurotransmitter so
benzodiazepines are used to treat
panic attacks and sometimes insomnia
but they can be very addictive your
brain can adapt to these
and stop producing its own gaba and then
you become dependent serotonin reuptake
inhibitors or
ssris they are depression medications
they are used to treat
depression when serotonin is released
from the neurotransmitter
and serotonin goes into the synapse
normally the serotonin is taken back up
and then it'll be released again when
it's signaled so a serotonin reuptake
inhibitor prevents the reuptake and that
means the serotonin stays in the synapse
and it can keep acting on the target
cell to make you feel
less depressed because so much serotonin
is actually produced by the digestive
system
there can be some digestive system side
effects in the beginning of taking
serotonin
reuptake inhibitors
caffeine caffeine keeps us awake because
it inhibits adenosine remember we talked
about
how adenosine makes us sleepy so if
caffeine
blocks those receptors then it is going
to
decrease sleep
cannabis or thc is a psychoactive drug
and it binds to our cannabinoid
receptors
and it increases pleasure and reduces
pain
and lastly hallucinogens
hallucinogenic drugs like acid or
psilocybin which is
mushrooms they cause distorted
perceptions
by binding to serotonin receptors
so normally serotonin makes us feel calm
and good
but extreme amounts of serotonin
causes hallucinations so there we go
check out the description below for the
downloadable pdf and see if you can
match
the neurotransmitter to the function and
the drug to the neurotransmitter
[Music]
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