The screening method for a compound or a salt thereof that alters the binding property between Neuromedin U or a salt thereof and TGR-1 or a salt thereof, characterized by using Neuromedin U, a derivative thereof or a salt thereof and TGR-1 or a salt thereof, can be useful for screening a therapeutic and/or prophylactic agent for hypertension and stress-related diseases, etc. A TGR-1 antagonist can be useful as a therapeutic and/or prophylactic agent for hypertension and stress-related diseases, etc.