Biology Reference
In-Depth Information
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B
Fluo-3 and Di-4-ANEPPS
Rhod-2 and RH-237
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Wavelength (nm)
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Wavelength (nm)
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C
Fluo-3 and RH-237
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Wavelength (nm)
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Fig. 11 Single-photon emission spectra of voltage-sensitive Di-4-ANEPPS and RH-237, and Ca 2 þ -
sensitive Fluo-3 and Rhod-2 dyes. The following emission spectra were obtained by spectrophotometry
after simultaneously loading cardiac muscle cells in a high Ca 2 þ solution (60 m M) with Ca 2 þ - and
voltage-sensitive dyes and exciting at 488 nm. The presence of intact excitable cells in a Ca 2 þ -rich
environment provides substrate for both Ca 2 þ - and voltage-sensitive dyes. (A) Fluo-3 (Ca 2 þ ; first peak)
and Di-4-ANEPPS (voltage; second peak). (B) Rhod-2 (Ca 2 þ ; first peak) and RH-237 (voltage; second
peak). (C) Fluo-3 (Ca 2 þ ; first peak) and RH-237 (voltage; second peak).
be avoided as the Ca 2 þ and voltage signals are spatially separated between intra-
cellular and membrane compartments of the cell, though in muscle cells this may
turn out to be di
cult because of the dense network of plasma membrane trans-
verse tubules that penetrate into the interior of the cell. The same overlap problem
exists with the voltage-sensitive RH-237 and the Ca 2 þ -sensitive Rhod-2 dyes, with
emission peaks occurring at
Y
660 nm, respectively, but with especially
the RH-237 emission spectrum being very broad ( Fig. 11 B). In contrast, Fluo-3
and RH-237 are more distinctly separated from one another. Both Fluo-3 and
RH-237 dyes may be excited by the same single-photon excitation wavelength at
580 and
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