Effects of extracellular calcium on fASIC1 currents

Academic Article


  • Fish ASIC1 (fASIC1) cloned from Opsanus tau, unlike the rat ASICs, requires Ca2+ in the extracellular preconditioning solution (pH 7.4) to be activated. Here we show that fASIC1 is interacting with Ca2+ in the same way as mammalian ASICs: extracellular Ca2+ is increasing the proportion of channels available for activation by stabilizing the closed state of the channel; in the activation process Ca2+ is released; H + compete for the binding site of Ca2+ making the gating mechanism both Ca2+ and H+ dependent; H+ stabilizes the desensitized state; Ca2+ blocks the fASIC1 channel; and the affinity of the block is also modulated by H+. The "Ca2+ activation requirement" of fASIC1 reflects its greater affinity for steady-state desensitization by H+ compared to mammalian ASIC1. © 2005 New York Academy of Sciences.
  • Digital Object Identifier (doi)

    Pubmed Id

  • 12078856
  • Author List

  • Todorović N; Ćorić T; Zhang P; Canessa C
  • Start Page

  • 331
  • End Page

  • 336
  • Volume

  • 1048