Low mobility of the Ca2+ buffers in axons of cultured Aplysia neurons

Moshe Gabso*, Erwin Neher, Micha E. Spira

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

116 Scopus citations

Abstract

Cellular Ca2+ buffers determine amplitude and diffusional spread of neuronal Ca2+ signals. Fixed Ca2+ buffers tend to retard the signal and to lower the apparent diffusion coefficient (D(app)) of Ca2+, whereas mobile buffers contribute to Ca2+ redistribution. To estimate the impact of the expression of specific Ca2+-binding proteins or the errors in Ca2+ measurement introduced by indicator dyes, the diffusion coefficient D(e) and the Ca2+-binding ratio κ(e) of endogenous Ca2+ buffers must be known. In this study, we obtain upper bounds to these quantities (D(e) < 16 μm2/s; κ(e) < 60) for axoplasm of metacerebral cells of Aplysia california. Due to these very low values, even minute concentrations of indicator dyes will interfere with the spatiotemporal pattern of Ca2+ signals and will conceal changes in the expression of specific Ca2+-binding proteins, which in the native neuron are expected to have significant effects on Ca2+ signals.

Original languageEnglish
Pages (from-to)473-481
Number of pages9
JournalNeuron
Volume18
Issue number3
DOIs
StatePublished - Mar 1997

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