Adrenaline vs Noradrenaline
There are number of things that are known by different names but are more or less the same. The most confusing thing is that what the world knows as adrenaline is known as epinephrine by most people in the US. Noradrenalin is known as norepinephrine in the US. What is the difference between the two? Lets us find out:
For starters, adrenalin and Noradrenalin are different from each other chemically. Adrenalin is actually produced by the body when the body modifies noradrenalin. This is what makes it chemically different.
The two substances are used in different areas of the body. The post ganglionic neurons of the nervous system use the Noradrenalin. It is basically used as a neurotransmitter, that is, it is generated by the neurons in the brain.
Adrenaline on the other hand, is mainly produced by the adrenal medulla. Though this structure also produces some Noradrenalin, the main output of the gland is actually adrenaline.
Adrenaline and Noradrenalin also differ in their functions. There are number of receptors for adrenaline. For example, the α1 receptors are found in the blood vessels and when stimulated, result in a constriction. However, the β1 receptors located in the heart result in a rise in the force and the rate of the heart contractions.
Noradrenalin on the other hand, has a dominant α effect. It always acts as a stimulator on the brain and increases arousal and alertness.
Noradrenalin and adrenaline are called catecholamine because they have a catechol group. They are derived from the amino acid called tyrosine.
When Noradrenaline acts as a drug, it increases the blood pressure by increasing upon its vascular tone. However, it does not have a direct stimulatory effect on the heart.
A major difference between adrenaline and Noradrenalin is that adrenaline or epinephrine contains a methyl group that is attached to the nitrogen. This is replaced by a hydrogen atom where norepinephrine or Noradrenalin is concerned.
Both adrenaline and noradrenalin are an important part of the fight or flight syndrome in the body that is activated when a person is either too angry or too excited. It prepares the body for a rush of blood through the system. Unfortunately, both these substances are under the direct control of the central nervous system and is therefore not under voluntary control.
Summary:
1. Adrenaline and Noradrenalin are chemically different from each other.
2. They are also used by different parts of the body.
3. Adrenaline has a very weak beta effect, but a strong α effect. NorAdrenaline on the other hand has a less sensitive α effect.
4. Adrenaline has a methyl group attached to the nitrogen. In Noradrenalin, it is replaced by a hydrogen atom.