%0 Journal Article %T Eperisone Hydrochloride, a Muscle Relaxant, Is a Potent P2X7 Receptor Antagonist. %A Okada M %A Nose T %J Chem Pharm Bull (Tokyo) %V 72 %N 3 %D 2024 %M 38556262 %F 1.903 %R 10.1248/cpb.c24-00032 %X Eperisone Hydrochloride was launched in Japan in 1983 and has been used to improve muscle tone and treat spastic paralysis (Originator: Eisai Co., Ltd.). However, its biochemical mechanism of action is unknown. SB Drug Discovery was used to evaluate purinergic P2X (P2X) receptor antagonism using fluorescence. In this study, we discovered that its target protein is the P2X7 receptor. Also, P2X receptor subtype selectivity was high. This finding demonstrates the (Eperisone-P2X7-pain linkage), the validity of P2X7 as a drug target, and the possibility of drug repositioning of Eperisone Hydrochloride.