PROBLEM TO BE SOLVED: To provide a P2X4 receptor antagonist.SOLUTION: A diazepine derivative represented by a representative compound expressed by formula (wherein each of R1 to R4 represents a hydrogen atom, and A represents an N-containing heterocyclic group) or a pharmacologically acceptable salt thereof is used as a P2X4 receptor antagonist.COPYRIGHT: (C)2014,JPO&INPIT【課題】P2X4受容体拮抗剤を提供する。【解決手段】代表化合物例(式中、R1からR4は水素原子、AはN含有複素環基を表す。)で表されるジアゼピン誘導体又はその薬理学的に許容される塩をP2X4受容体拮抗剤として使用する。【選択図】なし