Monoamine neurotransmitter
Monoamine neurotransmitters are neurotransmitters and neuromodulators that contain one amino group connected to an aromatic ring by a two-carbon chain (such as -CH2-CH2-). Examples are dopamine, norepinephrine and serotonin.
Source: Wikipedia — Monoamine neurotransmitter (CC BY-SA 4.0)