title: Nafamostat mesilate reversibly blocks acid-sensing ion channel currents.
abstract: We electrophysiologically investigated the effects of nafamostat mesilate (NM: 6-amidino-2-naphthyl p-guanidinobenzoate dimethanesulfonate) and its two metabolites, 6-amidino-2-naphthol (AN) and p-guanidinobenzoic acid (PGBA), on three distinct types of human acid-sensing ion channels (ASICs). Acid-evoked inward currents at a holding potential of -60mV in ASIC1a- and ASIC2a-expressing oocytes were decreased by extracellular application of NM in a concentration-dependent manner with IC(50) (inhibition constant) values of approximately 13.5 and 70.6microM, respectively. The NM application also produced concentration-dependent inhibition of the initial-phase transient component of biphasic ASIC3 currents with an IC(50) value of approximately 2.5microM. Application of AN showed weak blocking effects on the ASIC1a, ASIC2a, and transient ASIC3 currents with IC(50) values of approximately 1.2, 1.3, and 0.14mM, respectively, whereas PGBA was insensitive to their currents.
authors.affiliation: Department of Neurobiology and Anatomy, Graduate School of Medical Sciences, Nagoya City University, 1 Kawasumi, Mizuho-cho, Mizuho-ku, Nagoya 467-8601, Japan.
authors.forename: Shinya
authors.initials: S
authors.lastname: Ugawa
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Ishida
authors.forename: Takashi
authors.initials: T
authors.lastname: Ueda
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Inoue
authors.forename: Masataka
authors.initials: M
authors.lastname: Nagao
authors.forename: Shoichi
authors.initials: S
authors.lastname: Shimada
mesh_terms: D062565:Acid Sensing Ion Channels; D000818:Animals; D001550:Benzamidines; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D006146:Guanidines / Q000008:administration & dosage*; D015640:Ion Channel Gating / Q000187:drug effects / Q000502:physiology*; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology*; D008565:Membrane Proteins / Q000187:drug effects / Q000502:physiology*; D009419:Nerve Tissue Proteins / Q000187:drug effects / Q000502:physiology*; D009865:Oocytes / Q000187:drug effects / Q000502:physiology*; D015222:Sodium Channels / Q000187:drug effects / Q000502:physiology*; D014982:Xenopus laevis