Question

When epinephrine is considered as neurotransmitter?

Answer 1

So epinephrine / adrenaline is released by the adrenal gland into the bloodstream as a hormone whereas norepinephrine / noradrenaline is released by neurons in the brain as aneurotransmitter.

Answer 2

Epinephrine is a neurotransmitter in the sense that, within the brain, it help neurons to communicate with one another. However, because epinephrine is mainly produced by the adrenal glands and has functions peripherally, it can also be considered a hormone.