Complex sentence: Similarly to α-MT, α-ET is a releasing agent of serotonin, norepinephrine and dopamine (with serotonin being the primary neurotransmitter affected); in addition, it acts as a non-selective serotonin receptor agonist.
Split into simpler sentences: Similarly to α-MT, α-ET is a releasing agent of serotonin, norepinephrine and dopamine, with serotonin being the primary neurotransmitter affected. In addition, it acts as a non-selective serotonin receptor agonist.