Figure 3.
Effect of APETx2 on homomeric ASIC3 current. (A) Concentration–response curve for APETx2 effects on ASIC3 channels expressed in Xenopus oocytes (▴) and in COS cells (•). Holding potential: −50 mV, pH drop from 7.4 to 6. APETx2 was perfused for 30 s before the pH drop. Data were fitted by the Hill equation (nH=1) giving an IC50 value of 63 nM. Each point is the mean±s.e.m. (3–6 cells). (B) APETx2 (3 μM) totally inhibits the ASIC3 current. (C) Effect of 100 nM APETx2 on ASIC3 currents, and reversibility. (D) Upon stimulation of ASIC3 at pH4, APETx2 (3 μM) inhibits the peak, but not the plateau phase of the current.