The key difference between catecholamines and acetylcholine is that catecholamines are a type of neurotransmitter derived from amino acid tyrosine, while acetylcholine is a type of neurotransmitter derived from acetylcholine A.
Neurotransmitters are signaling molecules secreted by neurons. They affect another cell across a synapse. The cell receiving the signal may be another neuron, gland, or muscle cell. There are many different types of neurotransmitters. They can be amino acids (glutamate, aspartate), peptides (oxytocin, somatostatin), monoamines (dopamine, norepinephrine, epinephrine), purines (ATP, adenosine), or others (acetylcholine, anandamide).
CONTENTS
1. Overview and Key Difference
2. What are Catecholamines
3. What is Acetylcholine
4. Similarities – Catecholamines and Acetylcholine
5. Catecholamines vs Acetylcholine in Tabular Form
6. Summary – Catecholamines vs Acetylcholine
What are Catecholamines?
Catecholamines are a type of neurotransmitter derived from the amino acid tyrosine. They are organic compounds that have catechol and a side-chain amine. Tyrosine amino acid is usually derived from dietary sources. Tyrosine can also be synthesized in the human body via phenylalanine. Catecholamines are water-soluble molecules. They are also 50 % bound to plasma proteins in the circulation. A few prominent examples of catecholamines include epinephrine, norepinephrine, and dopamine.
Figure 01: Catecholamines Biosynthesis
Catecholamine synthesis is a complex process. Tyrosine is created from phenylalanine by the phenylalanine hydroxylase enzyme. Catecholamine-secreting cells use a few reactions to convert tyrosine serially to L-DOPA and then to dopamine. Moreover, depending on the cell type, dopamine can be further converted to norepinephrine or even further converted to epinephrine. The two catecholamines, norepinephrine and dopamine, act as neuromodulators in the central nervous system (they perform important functions in the central nervous system, such as motor control, cognition, emotion, memory processing, and endocrine modulation). They also act as hormones in blood circulation. Epinephrine plays a role in metabolism, attention, focus, panic, and excitement. Furthermore, they have also been found in 44 plant families. In plants, they are precursors for alkaloids, which are active ingredients of many medicinal plant extracts.
What is Acetylcholine?
Acetylcholine is an organic chemical that functions in the brain and other parts of the human body (including animals) as a neurotransmitter. Acetylcholine is an ester of acetic acid and choline. It is made from acetylcholine A by the action of acetylcholine esterase. Acetylcholine is used in a special part of the body known as cholinergic. This pathway is referred to as the cholinergic pathway. Moreover, acetylcholine can be produced from choline which is usually present in the food products such as meat, eggs, dairy, nuts, whole grains, apples, and broccoli.
Figure 02: Acetylcholine
Acetylcholine is released by motor neurons of the nervous system in order to activate muscles. Acetylcholine is also an internal transmitter for the sympathetic nervous system and is the final product released by the parasympathetic nervous system. Furthermore, in the brain, acetylcholine functions as a neurotransmitter and as a neuromodulator.
What are the Similarities Between Catecholamines and Acetylcholine?
- Catecholamines and acetylcholine are two different types of neurotransmitters.
- Both molecules are produced by neurons.
- They can be identified in all animals, including humans.
- Defects in both molecules cause neurodegenerative diseases.
What is the Difference Between Catecholamines and Acetylcholine?
Catecholamines are a type of neurotransmitter derived from amino acid tyrosine, while acetylcholine is a type of neurotransmitter derived from acetylcholine A. Thus, this is the key difference between catecholamines and acetylcholine. Furthermore, catecholamines are made up of catechol and a side-chain amine, while acetylcholine is made up of an ester of acetic acid and choline.
The below infographic presents the differences between catecholamines and acetylcholine in tabular form for side-by-side comparison.
Summary – Catecholamines vs Acetylcholine
A neurotransmitter is a signaling molecule secreted by neurons. A neurotransmitter can be an amino acid, a peptide, a monoamine, a purine, or another molecule. Catecholamines and acetylcholine are two different types of neurotransmitters. Catecholamines are a type of neurotransmitter derived from amino acid tyrosine, while acetylcholine is a type of neurotransmitter derived from acetylcholine A. So, this is the key difference between catecholamines and acetylcholine.
Reference:
1. “Catecholamines: What Are They, and How Do They Function?” Medical News Today, MediLexicon International.
2. “Acetylcholine.” Encyclopædia Britannica, Encyclopædia Britannica, Inc.
Image Courtesy:
1. “Catecholamines biosynthesis” By NEUROtiker – own work (CC BY-SA 3.0) via Commons Wikimedia
2. “Acetylcholine190” By NeuroFall2021 – Own work (CC BY-SA 4.0) via Commons Wikimedia
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