title: Agonist radioligands for identifying functional neurotransmitter receptors. Introduction.
mesh_terms: D018377:Neurotransmitter Agents; D011869:Radioligand Assay; D017981:Receptors, Neurotransmitter / Q000032:analysis*
chemical_list: D018377:Neurotransmitter Agents; D017981:Receptors, Neurotransmitter