Difference Between Epinephrine and Norepinephrine

Epinephrine Vs Norepinephrine

Epinephrine and norepinephrine are very similar substances. The two are closely related hormones or neurotransmitters that are almost identical chemically and structurally. In layman’s terms, epinephrine is otherwise known as adrenaline while norepinephrine is colloquially known as noradrenaline. Still, the two have some distinct functional differences.

As mentioned, both epinephrine and norepinehprine are quite similar because they are under the same group of neurotransmitters termed as catecholamines. That’s why they are classified as sympathomimetic agents. This means that they mimic the action of the sympathetic nervous system. As a result, they trigger the increase in heart rate, increase the diameter of the bronchial passageway to allow more air to pass through and, at the same time, decreasing most gastric and genitourinary functions once activated.

There’s a slight difference on how the two hormones affect the body during the ‘fight or flight’ response. During such an event, more epinephrine is pumped by the body while only about 20% norepinephrine is released. The major role player, epinephrine serves to restrict the tinier blood vessels situated at the kidneys or liver. Norepinephrine does otherwise by dilating almost all of the body’s blood vessel network so as to supply the skeletal muscles with more blood in times of stress and oxygen depletion at the cellular level.

In terms of pyschoactivity, norepinephrine is used to make psychoactive drugs that are used to control depression. It can also be combined with other chemicals like serotonin to make it an effective mood stabilizer. Epinephrine, as a drug, is more or less used as an emergency recuperative medication that serves to boost one’s vital signs especially when they are very down like when the blood pressure and heart rate drops abruptly to zero. Take note, norepinephrine can also be used in this same way.

Historically speaking, clinical records would tell that epinephrine is the earlier hormone to be discovered than norepinephrine. It was around 1900 when Farbwerke Hoechst managed to isolate the said substance successfully. Norepinephrine waited for several more decades to be discovered.

1. During the ‘flight or fight’ response, more epinephrine is released to the bloodstream as compared to norepinephrine.

2. Epinephrine causes some blood vessels to constrict (narrow down) while norepinephrine generally causes dilation of the majority of blood vessels once released.

3. Epinephrine was discovered much earlier than norepinephrine.

4. Norepinephrine is a more popular drug component used in Psychiatry due to its psychoactive nature.

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