Ca2+ current versus Ca2+ channel cooperativity of exocytosis (Matveev et al. 2009)

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"... While varying extracellular or intracellular Ca2+ concentration assesses the intrinsic biochemical Ca2+ cooperativity of neurotransmitter release, varying the number of open Ca2+ channels using pharmacological channel block or the tail current titration probes the cooperativity between individual Ca2+ channels in triggering exocytosis. ... Here we provide a detailed analysis of the Ca2+ sensitivity measures probed by these experimental protocols, present simple expressions for special cases, and demonstrate the distinction between the Ca2+ current cooperativity, defined by the relationship between exocytosis rate and the whole-terminal Ca2+ current magnitude, and the underlying Ca2+ channel cooperativity, defined as the average number of channels involved in the release of a single vesicle. ... Further, we use three-dimensional computational modeling of buffered Ca2+ diffusion to analyze these distinct Ca2+ cooperativity measures, and demonstrate the role of endogenous Ca2+ buffers on such measures. We show that buffers can either increase or decrease the Ca2+ current cooperativity of exocytosis, depending on their concentration and the single-channel Ca2+ current."
1 . Matveev V, Bertram R, Sherman A (2009) Ca2+ current versus Ca2+ channel cooperativity of exocytosis. J Neurosci 29:12196-209 [PubMed]
Model Information (Click on a link to find other models with that property)
Model Type: Channel/Receptor;
Brain Region(s)/Organism:
Cell Type(s):
Gap Junctions:
Simulation Environment: CalC Calcium Calculator (web link to model);
Model Concept(s): Calcium dynamics;
Implementer(s): Matveev, Victor V. [m a t v e e v at n j i t . e d u ];
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