Figure 4.
Effect of the Nature of the External Monovalent Cation on ZmK2.1 Conductance and Activity.
(A) and (B) Currents mediated by ZmK2.1 in COS cells were recorded in bath solutions successively containing KCl, RbCl, LiCl, NaCl, and NH4Cl at a concentration of 50 mM.
(A) Current-voltage relationships at steady state. Currents were normalized for each cell by current level in the presence of K+ at −160 mV. Values shown are means ± se (n = 5).
(B) Examples of deactivation currents recorded at 0 mV after activation steps at voltages ranging from −40 to −160 mV. The recordings shown were obtained from the same cell.
(C) and (D) Comparison of currents in oocytes expressing either ZmK2.1 or KAT1 in bath solutions containing 100 mM KCl or 100 mM NaCl.
(C) Current-voltage relationships at steady state.
(D) Deactivation currents recorded at −40 mV after activation steps at voltages ranging from +10 to −160 mV in a bath containing NaCl. The steady state and deactivation currents shown for each channel are from the same oocyte.