The main difference between catecholamines and acetylcholine is that catecholamines are a type of neurotransmitter derived from the amino acid tyrosine, whereas acetylcholine is a type of neurotransmitter derived from acetylcholine A.
Neurotransmitters are chemicals that carry chemical signals from one neuron to the next nerve cell, a muscle cell, or a gland. In fact, neurotransmitters are functionally associated with the nervous system. A synaptic clef is a small gap between neurons where communication between two neurons occurs. Here, the electrical signals that have travelled along the axon get converted to chemical signals via the release of neurotransmitters. This causes a response to be generated in the receiving neuron. Therefore, this is the function of the neurotransmitters.
There are three different ways that a neurotransmitter influence a neuron: excitatory, inhibitory, or modulatory. Furthermore, there are many different types of neurotransmitters. Some examples are dopamine, serotonin, epinephrine, norepinephrine, catecholamines, and acetylcholine.
Key Areas Covered
1. What are Catecholamines
– Definition, Composition, Function
2. What is Acetylcholine
– Definition, Composition, Function
3. Similarities Between Catecholamines and Acetylcholine
– Outline of Common Features
4. Difference Between Catecholamines and Acetylcholine
– Comparison of Key Differences
Key Terms
Acetylcholine, Catecholamines, Neurotransmitter
What is Catecholamine
Catecholamine is a type of neurotransmitter. This molecule contains catechol and a side chain amine. Dopamine, norepinephrine, and epinephrine are some types of catecholamines. Catecholamines also act as hormones that maintain homeostasis through the autonomic nervous system. Moreover, the adrenal glands and the nerve endings present throughout the body produce these neurotransmitters. Besides, phenylalanine hydroxylase is the enzyme necessary for the synthesis of catecholamines.
Figure 1: Catecholamines Biosynthesis
A complex system involving the pituitary gland, hypothalamus, and adrenal glands produces and regulates catecholamines. Hypothalamus releases a corticotrophin-releasing hormone (CRH) when it encounters a stressor or a threat. This hormone stimulates the pituitary to release adrenocorticotropic hormone (ACTH). The hormone released then travels to the adrenal gland to stimulate the release of catecholamines into the bloodstream. Hence, we can say that catecholamines are responsible for the fight-or-flight responses of the body.
Catecholamines dopamine and norepinephrine perform the function of neuromodulation in the central nervous system (they perform the functions of memory processing, emotion, cognition, and motor control). Eepinephrine is also associated with attention, focus and excitement, and metabolism.
The presence of higher or lower levels of catecholamines (than the normal level) may result in certain medical issues such as ADHD, depression, Schizophrenia, and Parkinson’s disease.
What is Acetylcholine
Acetylcholine is a neurotransmitter. It is an ester of acetic acid and choline. The constituent of this molecule is acetylcholine A. The enzyme associated with this reaction is acetylcholine esterase. Acetylcholine can also be produced from choline which is present in foods such as eggs, nuts, and meat.
Figure 1: Acetylcholine
Acetylcholine acts as an internal transmitter for the sympathetic nervous system. In fact, this molecule acts as a neurotransmitter and a neuromodulator in the brain. It also activates muscles. Moreover, the diseases associated with acetylcholine defects are Alzheimer’s disease and Parkinson’s disease.
Similarities Between Catecholamine and Acetylcholine
- Catecholamines and acetylcholine are both neurotransmitters.
- In fact, they are present in all animals (including humans).
- Additionally, both types of molecules cause neurodegenerative diseases.
Difference Between Catecholamines and Acetylcholine
Definition
Catecholamines are a type of neurotransmitter derived from the amino acid tyrosine, whereas acetylcholine is a type of neurotransmitter derived from a type of neurotransmitter that is derived from acetylcholine A.
Enzyme Needed for Synthesis
The enzyme necessary for the synthesis of catecholamines is phenylalanine hydroxylase, whereas the enzyme necessary for the synthesis of acetylcholine is acetylcholine esterase.
Composition
Catecholamines are made up of catechol and a side chain amine, whereas acetylcholine is made up of an ester of acetic acid and choline.
Function
Catecholamines act as neuromodulators in the central nervous system, act as hormones in blood circulation, and play a role in metabolism, attention, excitement, and focus, while acetylcholine acts as an internal transmitter for the sympathetic nervous system and functions as a neurotransmitter and a neuromodulator.
Diseases Due to the Defects
Diseases due to catecholamine defects are Schizophrenia, depression, AHDH, and Parkinson’s disease, whereas diseases due to the defects in acetylcholine are Alzheimer’s disease and Parkinson’s disease.
Conclusion
In brief, neurotransmitters are the chemicals that carry chemical signals from one neuron to the next nerve cell, muscle cell, or gland. Catecholamines and acetylcholine are two such neurotransmitters. There are both similarities and differences between them. The main difference between catecholamines and acetylcholine is that catecholamines are a type of neurotransmitter that originate from the amino acid tyrosine, whereas acetylcholine is a type of neurotransmitter that originate from acetylcholine A.
Reference:
1. “Acetylcholine (ACh).” Cleaveland Clinic.
2. “What are catecholamines, and what do they do?” Medical News Today.
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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