ASIC and ENaC properties

Data are from many different studies and reviews (Sutherland et al., 2001; Hesselager et al., 2004; Poirot et al., 2004; Blanchard and Kellenberger, 2011; Alijevic and Kellenberger, 2012; Wemmie et al., 2013). pH dependence and kinetics of ASICs vary between subtypes and also between orthologs of the same subtypes. Typical values are indicated here. For more information, see the relevant chapters.

IC50 Amiloride InhibitionaNa+/K+ Permeability RatiopH50 ActivationpHD50 Steady-State DesensitizationDesensitization Time Constant (at pH Close to pH50)Most Important Sites of Expression
ASIC1a106–136.2–6.6∼7.2∼0.4CNS, PNS
ASIC2a28∼104.0–4.9∼5.6∼1.4CNS, PNS
ENaCαβγ0.1≥100N.A.N.A.N.A.Kidney, colon, lung
  • N.A., not applicable; pHD50, pH of half-maximal desensitization.

  • a For transient ASIC current component.