Figure 10.

Support cells that are depolarized can suppress automaticity in an excitable cell sharing a diffusion-limited cleft. (A) Cell 1 is excitable and shares a cleft with inexcitable cell 2 (g_Na = 0). Minimal membrane potential of cell 2 (yellow trace) is depolarized relative to cell 1 (blue trace). Cells are coupled via a shared cleft domain with nominal w_f = 1 and high fractional potassium cleft current $F_{IK}^1$= 0.8 in cell 1. $F_{IK}^2$in cell 2 is varied as the independent variable and ranges from 0 to 0.01. Automaticity is supported for 0 < $F_{IK}^2$ < 0.005 in cell 2. (B) Relationship between extracellular cleft potassium [K]_cl and fractional. (C) Cleft potassium current I_K,cl for cell 1. (D) Cleft potassium current I_K,cl for $F_{IK}^2$ in cell 2.