Figure 3.

Repetitive AP firing in RCCs is abolished by 0 Ca²⁺. (A1) Action potentials were elicited by constant-current injection in identified BK_i (upper) and BK_s (lower) RCCs using perforated-patch recording with normal extracellular (1.8 mM Ca²⁺) saline. (A2) Traces were recorded in 0 Ca²⁺ normal saline (with 2 mM Mg²⁺). In all cases, the extracellular saline contained 200 nM apamin. (B1) Action potentials activated by constant-current injection were simulated in BK_i (upper) and BK_s (lower) model cells. SK current was inactive. (B2) The traces were obtained from model simulations in which only Ca²⁺ current was removed from the simulation.