Comparison of isotropic calcium signals from intact frog muscle fibers injected with Arsenazo III or Antipyrylazo III.
Intact single skeletal muscle fibers were micro-injected with either of the metallochromic indicator dyes Arsenazo III or Antipyrylazo III, and dye-related Ca2+ signals from each were measured during a twitch. In comparison with the Arsenazo III Ca2+ signal, the signal from Antipyrylazo III had three favorable features: (a) it was temporally faster, (b) its spectral dependence agreed with a cuvette calibration, and (c) its kinetic behavior was consistent with a single Ca2+ -dye stoichiometry. It is therefore suggested that the Antipyrylazo III Ca2+ signal is a more accurate monitor of the time course of the underlying myoplasmic free Ca2+ transient and one that may be more reliably calibrated.
D000818:Animals; D001150:Arsenazo III / Q000494:pharmacology*; D001391:Azo Compounds / Q000494:pharmacology*; D002118:Calcium / Q000378:metabolism*; D009132:Muscles / Q000187:drug effects / Q000502:physiology*; D009282:Naphthalenesulfonates / Q000494:pharmacology*; D011896:Rana temporaria
D001391:Azo Compounds; D009282:Naphthalenesulfonates; D001150:Arsenazo III; C016238:antipyrylazo III; D002118:Calcium