Dendritic Ca~2+ Dynamics in the Presence of Immobile Buffers and of Dyes

摘要

We present a reaction-diffusion model of [Ca~2+]regulation in neuronal dendrites, in the presence of high-affinity indicator and endogenous buffers. We investigate the applicability of equilibration assumptions for a slow. NMDAR-like source, present an analytical soultion to the system in linear approximation, and discuss a possible scheme for extending this approximation's applicability. We obtain data on spatial Ca~2+spread that suggest that dendritic Ca~2+ signals of NMDAR origin can be localized to 2 - 3 #mu#m with no need for differential buffering or spines. Finally, we show that the difficulties presented by dye saturation may be circumvented by using fluorescence tails as a probe of [Ca~2+] peaks.