premise: Serotonin induces neuromodulation by binding to receptors.
hypothesis: A receptor antagonist is a type of receptor ligand or drug that blocks or dampens a biological response by binding to a receptor rather than provoking the response like an agonist . Serotonin ( [ ˌsɛrəˈtoʊnᵻn , _ ˌsɪərə - ] ) or 5-hydroxytryptamine ( 5-HT ) is a monoamine neurotransmitter .