Fig. 2

A schema for the NKCC model and current–voltage relationship of the KIR model. a A schema for the NKCC model of Markov-type simplified from Benjamin’s model [36, 37]. E1 and E2 in the model represent the states having their ion-binding sites on the extracellular and intracellular sides, respectively. Each of E1 and E2 state consists of five states according to the sequential binding of Na⁺, Cl⁻, K⁺ and Cl⁻. The translocation between E1 and E2 can happen only between the fully occupied states (E ₁NaClkCl and E ₂NaClKCl) or between empty states (E ₁ and E ₂), and b the current–voltage relationship of I _KIR in the KIR model. The current–voltage relationship with Eq. (29) (solid line) is shown with the experimental I _KIR in astrocytes (circle) [41]