Difference Between Adrenergic and Cholinergic (With Table)

The adrenergic and cholinergic receptors are vital for binding the neurotransmitters. Sympathetic and parasympathetic nervous systems together make the autonomic nervous systems.
There are many actions or acts done by humans without conscious recognition or any efforts given by human beings.

These actions would be controlled by the autonomic nervous system. These receptors are known for different functions in the human body. The role of adrenergic receptors would be to overall help the human body in showing better performance.

On the other side, the cholinergic receptors would be responsible for countering the functions of the adrenergic receptors. Both of these reports are pivotal for balancing and managing each other’s functions for making the human body’s nervous system work well.

Adrenergic vs Cholinergic

The main difference between the adrenergic and cholinergic is that both these receptors use different neurotransmitters present inside the human body. The adrenergic would be binding with the neurotransmitters, while the cholinergic receptors would bind the acetylcholine neurotransmitters.

The adrenoceptors are mainly present in the body for showing the acute stress response. Intense or stressful situations, the adrenergic receptors would work for showing their effectiveness against any acts or actions that need a fight or flight response.

To balance out the functions of adrenoceptors, another receptor is found in the human body which is known as a cholinergic receptor. The presence of cholinergic receptors is linked with the PNS (parasympathetic nervous system). The human digestive tracts work in an efficient manner due to the presence of cholinergic receptors.

Comparison Table Between Adrenergic and Cholinergic

ParametersAdrenergic Cholinergic
DefinitionAdrenergic receptors bind to noradrenaline, and adrenaline is an organic chemical found that belongs to the catecholamine family.Cholinergic receptors bind to acetylcholine that is an organic chemical.
Nervous systemThe main working mechanism of the adrenergic is linked with the sympathetic nervous systemThe main working mechanism of cholinergic is linked with the Parasympathetic nervous system
NeurotransmittersAdrenaline and NoradrenalineAcetylcholine
TypesAlpha and BetaNicotinic and muscarinic
ResponseFight or flight responseDigest and rest response

What is Adrenergic?

There are many natural chemicals that our body releases on a daily basis. Organic chemicals such as epinephrine and norepinephrine are secreted from the sympathetic nerve endings.

These organic chemicals are identified by the adrenergic receptors. Then the receptors would bind with the organic chemicals for showing carrying out its function.

The adrenergic receptors The alpha receptors are further classified into alpha 1 and 2. The beta receptors are further classified into beta 1, 2, and 3. The alpha receptors have huge rapport towards noradrenaline, while the beta 2 receptors have huge empathy towards the adrenaline.

The excitation response is done by alpha 1 and beta 1. The inhibition response is induced by the alpha 2 and beta 2 receptors. The adrenergic nerves host the adrenergic receptors.

The neurotransmitters related to the adrenergic receptors are also known for their fight or flight response. The heart activity would increase when the neurotransmitters bind with the sympathetic nerve endings in the heart.

The myocardial contractibility and conduction velocity would increase after the neurotransmitters bind with the sympathetic nerve endings.

The adrenergic receptors are also responsible for improving the overall performance of the body by regulating the flow of blood from insignificant parts to the skeletal muscles. The adrenergic receptors are also liable for increasing the blood pressure level, and dilation of the pupils.

What is Cholinergic?

Cholinergic pathways are linked to the parasympathetic nervous system which deals with the working effectiveness of the cholinergic receptors. The neurotransmitter Acetylcholine is responsible for activating the cholinergic receptors.

The cholinergic receptors are known for their digest and rest response. Acetylcholine neurotransmitters carry out their function after binding with the muscarinic and nicotinic receptors. The heart’s function is down-regulated by the cholinergic receptors.

The cholinergic receptors or system helps in balancing the body by reducing blood pressure and heartbeat. Cholinergic receptors are also responsible for smooth muscles contraction and dilation of blood vessels.

The cholinergic receptors would be present in the whole body, but there are a few parts where these receptors are mainly found. These parts include sensory glands, heart, eyes, and respiratory tracts. The gastrointestinal tract also has cholinergic receptors.

The cholinergic receptors are components of the autonomic and somatic nervous systems. Muscarinic receptors are responsible for binding to the muscarine, whereas the nicotinic receptors would bind to the nicotine.

The parasympathetic nervous ending in the heart allows the cholinergic effects on it. The cholinergic receptors are capable enough to balance the effects of adrenergic receptors.

Main Differences Between Adrenergic and Cholinergic

  1. The receptors such as cholinergic and adrenergic are vital parts of the nervous systems that are required for various functions. Both of these receptors deal with two different divisions of the nervous system.
  2. Both of these receptors use different types of neurotransmitters. The adrenergic receptors use the noradrenaline and adrenaline neurotransmitters, whereas the cholinergic receptors use the Acetylcholine neurotransmitters.
  3. The adrenergic receptors work for the overall improvement of the body by increasing the heart rate, whereas the cholinergic receptors work for the down-regulating effects of the body.
  4. The type of adrenergic receptors is different from the cholinergic receptors. The adrenergic receptors include alpha and beta receptors. The cholinergic receptors include the muscarinic and nicotinic receptors.
  5. The main mechanism of adrenergic receptors is G-protein coupling, whereas the cholinergic receptors are metabotropic and inotropic-ligand-gated.

Conclusion

Adrenergic and cholinergic receptors both are important components or parts of the autonomic nervous system. The working functions of the receptors depend on the binding of the neurotransmitter.

Both of these receptors are linked to different divisions of the nervous system. The adrenergic receptor is a vital component of the sympathetic nervous system, while the cholinergic receptors work for the parasympathetic nervous system.

The adrenergic receptors are responsible for increasing the heart rate of the person, while the cholinergic receptors are capable of reducing or down-regulating the heart rates.

The adrenergic receptors are responsible for increasing the blood pressure of people, whereas the cholinergic receptors have no function in increasing the blood sugar level.

The glucose availability would be increased by the adrenergic receptors as they provide blood to the skeletal muscles. The adrenergic receptors are responsible for dilating the pupils, whereas the cholinergic receptors are responsible for dilating the blood vessels.

The adrenergic receptors are classified into alpha and beta receptors, which have further classification. The cholinergic receptors are classified into muscarinic and nicotinic receptors which have no further classification.

The adrenergic and cholinergic receptors are responsible for triggering the nerve impulse, but both work differently.

References

  1. https://www.ahajournals.org/doi/abs/10.1161/01.CIR.101.5.558
  2. https://www.sciencedirect.com/science/article/pii/S0021925818541557