Fig. 2

The amount of Ca²⁺ transmitted by a firing channel increases with the number of pores for evenly spaced pores, until it saturates. White panel (left): maximum Ca²⁺ concentration measured at a reference point P _N, in response to single channel C release. P _N and C are located in different sides of the NE, and example Ca²⁺ paths are depicted in red. The pores are distributed evenly across the surface. In general, a larger transmission is achieved for a larger number of pores. For the numbers and positions of pores represented, larger diffusion constants lead to larger transmissions. In the firing event, the channel releases σ=2.0× 10⁻²⁰ mol of Ca²⁺. Ca²⁺ levels are given as a fraction of the released amount σ. For comparison, in the shaded right panels we consider a point at the same distance from C as P _N, but on the same side as the release channel on a NE without pores. We consider three pairs of values for the diffusion coefficient D, and for each D, the larger value corresponds to the same release amount as in the non-shaded panel, σ=2.0×10⁻²⁰ mol and the lowest to half that value, σ=1.0×10⁻²⁰ mol. As in the other panel, we also rescale the calcium units by dividing by 20.0. Other parameter: α=0.15