Explicit Theoretical Analysis of How the Rate of Exocytosis Depends on Local Control by Ca²⁺ Channels

Figure 4

Relationship between Ca²⁺ influx and exocytosis rate. (a, b) Ca²⁺ current for the different number of non-inactivating (a) and inactivating (b) CaVs. (c, d) Probability of exocytosis, , vs. integral of Ca²⁺ currents, , computed at mV by increasing the integration time, , from 1 to 500 ms, for the granule at distance  nm from k not-inactivating (c) or inactivating (d) CaVs. (e, f) Legends as in (c, d) with  nm. In each panel, the different colors represent different number of CaVs: blue curve for ; magenta for ; cyan for ; and black for . The inserts in (c–f) show a zoom-in of vs. on lower values for the granule coupled with different number k of CaVs: and 8 in (c) and , 2, 4, and 8 in (d–f).

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