title: Fura-2 diffusion and its use as an indicator of transient free calcium changes in single striated muscle cells.
abstract: Two questions bearing on the use of fura-2 to measure transient changes in intracellular Ca2+ concentration have been addressed. To investigate fura-2 intracellular binding, the amounts of fura-2 and [14C]glycine in Balanus nubilus myofibrillar bundles after loading were determined and their intracellular apparent diffusion constants measured. No significant fura-2 immobilisation occurs under the conditions used. The apparent diffusion constant for fura-2 in aqueous solution was determined. The relationship between half-time for relaxation of force and fura-2 fluorescence transients, and intracellular fura-2 concentration, in voltage-clamped single muscle fibres was examined. Significant buffering of the Ca2+ transient occurred at fura-2 concentrations above approximately 6 microM.
mesh_terms: D000818:Animals; D001572:Benzofurans; D002118:Calcium / Q000378:metabolism*; D004058:Diffusion; D005456:Fluorescent Dyes; D016257:Fura-2; D007700:Kinetics; D009132:Muscles / Q000378:metabolism*; D009210:Myofibrils / Q000378:metabolism / Q000648:ultrastructure; D001468:Thoracica
chemical_list: D001572:Benzofurans; D005456:Fluorescent Dyes; D002118:Calcium; D016257:Fura-2