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Adrenergic (adrenaline/epinephrine) Receptors

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In this video, Dr Mike explains the receptors that adrenaline (epinephrine) and noradrenaline (norepinephrine) bind to. These receptors are classified into alpha and beta receptors and located in very distinct regions of the body.

Hi ron dr. mike here in this video we’re going to talk about adrenergic receptors you want to say adrenergic receptors you should think adrenaline and these are parts of our body that have receptors that specifically respond to the release of adrenaline now when you think adrenaline you should also think the sympathetic nervous system this is our fight or flight

System and you know what happens to your body when you stimulate the fight-or-flight system when you get scared for example your pupils dilate your heart starts to beat harder and faster your airways open up you become quite pale because your peripheral blood vessels have constricted shunting that blood to your skeletal muscles and deeper organs of your body these

Are just some of the effects of stimulating the sympathetic nervous system releasing adrenaline and stimulating adrenergic receptors so first thing is when we look at this sympathetic nervous system we’ve got our brain and spinal cord we know that there’s going to be a huge number of nerves that are going to be coming out of the spinal cord and you’ll find for the

Sympathetic nervous system these nerves come out specifically at the thoracic region and the lumbar region together which we call the thoracolumbar region this is where all the nerves for the sympathetic nervous system come out of the spinal cord now we know that there’s two neurons that come out one from the central nervous system which we called the presynaptic

Neuron and one called the postsynaptic neuron that speaks to the particular organ that we want to stimulate for the sympathetic nervous system to neuron chain if we look at the first neuron that we call the presynaptic neuron when it sends a signal out from the thoracolumbar region it in order to speak to the next neuron needs to release a neurotransmitter now

The neurotransmitter released by the presynaptic neuron for the sympathetic nervous system will always be acetyl choline that means acetylcholine is sitting in this cleft this little space between the presynaptic neuron and the postsynaptic neuron and in order to tell the postsynaptic neuron to send a signal it needs to bind to receptors these receptors are called

Nicotinic receptors presynaptic neuron releases acetylcholine binds to kkuk receptors and then continues to send a signal down the postsynaptic neuron which is now going to the organ that we want to talk to for example some organs that we talk to include blood vessels again the peripheral blood vessels we want to stimulate to constrict if we constrict them we move

The blood away from our surface and bring it to a skeletal muscles and our deeper tissues that means this neuron postsynaptic neuron in order to speak to that organ must also release a neurotransmitter to cross that boundary and the neurotransmitter here is noradrenaline or if your american norepinephrine and again it must bind to a receptor that can stimulate that

Organ now if we look down at the heart same thing happens noradrenaline is released and binds to specific receptors for noradrenaline same things going to happen in the airways of our lungs the receptors that noradrenaline binds to a called adrenergic receptors adrenaline binds to adrenergic receptors okay great now there’s different types of our genetic receptors

You’ve got alpha and beta there’s two kinds of alpha 3 kinds of beta now i’ve drawn up a quick cheat sheet here on how to remember them alpha 1 beta 1 alpha 2 beta 2 you probably think in where’s beta 3 or beta 3 receptors are found on fat cells and we don’t really have too many drugs that deal with that so just forget about it if you write down alpha 1 alpha 2

You’ll find that when adrenaline is released it will stimulate alpha 1 receptors and stimulate beta 2 receptors so both of them are stimulatory receptors now this is what happens is all smooth muscle organs and glands have alpha 1 receptors except the cardiac muscle and the juxtaglomerular cells of our kidneys don’t stress too much about that juxtaglomerular cells

Release something called renin that increases our blood pressure i’ll do that in another video okay so adrenaline is released it goes to alpha on receptors that are located on all smooth muscle organs and glands associated with the sympathetic nervous system except cardiac muscle and juxtaglomerular cells so that means that if i were to stimulate the heart to beat

Harder and faster its stimulating beta 1 receptors another quick way to remember this is how many hearts do you have one beta one easy now if we go over to alpha 2 and beta 2 the way you look at it is when adrenaline is released and if they bind to these receptors they actually inhibit these glands from these muscles and glands or tissues from doing their action

For example jenyns released if it binds to beta 2 receptors it inhibits it in actual fact beta 2 receptors are found on all smooth muscle organs and glands except presynaptic membranes that actually means the presynaptic membranes of sympathetic nervous system it’s actually a way for it to self inhibit itself ok now where do you find beta 2 well all smooth muscle

Organs and glands associated with the sympathetic nervous system that needs to be inhibited that includes the lungs so when adrenaline is released it binds to beta 2 receptors in our airways inhibits it which means it relaxes and their airways open up all right now for example you’re going to find where do we find alpha 1 well we find alpha 1 on our blood vessels

And what’s it do stimulates them if it stimulates them they’re going to constrict if they constrict they’d shunt blood elsewhere so that’s a very quick run through of adrenergic receptors

Transcribed from video
Adrenergic (adrenaline/epinephrine) Receptors By Dr Matt \u0026 Dr Mike