The key difference between acetylcholine and adrenaline is that acetylcholine is a neurotransmitter in both peripheral and central nervous systems in many organisms, while adrenaline is a hormone that helps to react quickly in a stressful situation.
Acetylcholine and adrenaline are two important molecules produced in our body. Acetylcholine is a neurotransmitter that mediates nerve impulses in both central nervous system and peripheral nervous system. Adrenaline, on the other hand, is a hormone as well as a neurotransmitter. It is responsible for the fight or flight response which helps us to react in stressful situations. Acetylcholine is released by the nerve ending to neuromuscular junctions and transported as vesicles while adrenaline is produced by adrenal glands and released into the blood.
CONTENTS
1. Overview and Key Difference
2. What is Acetylcholine
3. What is Adrenaline
4. Similarities Between Acetylcholine and Adrenaline
5. Side by Side Comparison – Acetylcholine vs Adrenaline in Tabular Form
6. Summary
What is Acetylcholine?
Acetylcholine is a neurotransmitter which functions in both central and peripheral nervous systems. It is an organic polyatomic ion. It is the first neurotransmitter that was identified in 1914 by Henry Hallett Dale. Acetylcholine is released by nerve endings into neuromuscular junctions. Then they are transported as vesicles.
Figure 01: Acetylcholine
Acetylcholine is important in synaptic plasticity, including learning and short-term memory. Acetylcholine binds with acetylcholine receptors and acts as an excitatory neurotransmitter at neuromuscular junctions in skeletal muscle in order to activate muscles via inducing the contraction of it. But in cardiac tissue, it gives an inhibitory effect in lowering the heartbeat by inhibiting the contraction of cardiac muscle fibres. Therefore, acetylcholine has both excitatory and inhibitory effects.
What is Adrenaline?
Adrenaline is a hormone produced by adrenal glands. Some of the neurons in the central nervous system also produce adrenaline. It is responsible for preparing our body for fight or flight response during stressful conditions. Hence, adrenaline is also known as fight or flight hormone. It is quickly released into our bloodstream under stressful, exciting, dangerous, or threatening situations. It mediates the actions of increasing the heart rate, increasing blood pressure, expanding the air passages of the lungs, enlarging the pupil in the eye, redistributing blood to the muscles and altering the body’s metabolism. It also works as a neurotransmitter. Therefore, it is a chemical messenger in the brain.
Figure 02: Adrenaline
Adrenaline is also used and administered during many instances such as anaphylaxis, cardiac arrest and during superficial bleeding. The administration of adrenaline is done intravenously. There are side effects of adrenaline treatment. They include excessive sweating, development of anxiety and shakiness.
What are the Similarities Between Acetylcholine and Adrenaline?
- Both, acetylcholine and adrenaline act as neurotransmitters.
- They bind with their respective receptors.
What is the Difference Between Acetylcholine and Adrenaline?
Acetylcholine is a neurotransmitter in the nervous system while adrenaline is a hormone which is responsible for the fight or flight response in our body. So, this is the key difference between acetylcholine and adrenaline. Moreover, certain neurons synthesize acetylcholine and release them into neuromuscular junctions while adrenal glands and some neurons produce adrenaline and release into the bloodstream.
The below infographic shows more details of the difference between acetylcholine and adrenaline.
Summary – Acetylcholine vs Adrenaline
Acetylcholine is a major neurotransmitter in both PNS and CNS. It transmits nerve impulses. It has both excitatory and inhibitory effects. Meanwhile, adrenaline is a hormone produced mainly by adrenal glands. It triggers the body’s fight-or-flight response. It also works as a neurotransmitter in the brain. Thus, this is the key difference between acetylcholine and adrenaline.
Reference:
1. “Neurotransmitters and Receptors.” Lumen, Available here.
2. “Adrenaline.” Hormone Health Network, Available here.
Image Courtesy:
1. “Cholinergic synapse” By Smedlib, based on original work by Pancrat – Own work (CC BY-SA 4.0) via Commons Wikimedia
2. “872345” (CC0) via Pixabay