Usefulness and limitations of linear approximations to the understanding of Ca++ signals.
Simple approximations to some limiting cases of Ca++ signalling provide insight into the complex problems of buffered diffusion and of Ca++ homeostasis in the presence of buffers. Three cases are presented, where the influence of Ca++ buffers can readily be understood in the limit of small signals: the return of global cellular [Ca++] following a short stimulus in a 'Single Compartment', buffered diffusion along a cylindrical axon in the 'Rapid Buffer Approximation', and nonequilibrium microdomains of elevated [Ca++] in the immediate vicinity of open Ca++ channels.
Neher
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Max-Planck-Institut für biophysikalische Chemie, Göttingen, Germany. eneher@gwdg.de
D000818:Animals; D020013:Calcium Signaling / Q000502:physiology*; D004058:Diffusion; D016014:Linear Models; D008958:Models, Molecular