Figure 2: The components of Ca²⁺-activated AHP currents.

(a) Representative traces of AHP currents after 50 ms of 0 mV depolarizing steps. To distinguish K⁺ and anion components, a 133 mM [K⁺]_in and 60 mM [Cl⁻]_in intrapipette solution was used. Ca²⁺-activated currents were recorded after application of TTX (black), TTX+apamin (blue) and TTX+apamin+NFA (red). Note that the apamin-sensitive K⁺ current is an outward current, and the NFA-sensitive current is inwards. (b) Current densities for each dissected current are shown (n=10 from seven mice). (c,d) Reversal potentials of anion currents at various [Cl⁻]_in concentrations were measured with apamin-containing extracellular buffer. Reversal potentials changed along with [Cl⁻]_in content, indicating that Ca²⁺-activated anion currents are primarily composed of Cl⁻. Error bars represent mean±s.e.