Biology Reference
In-Depth Information
A
B
Fluo-3 and Di-4-ANEPPS
Rhod-2 and RH-237
800
600
700
500
600
400
500
400
300
200
100
300
200
100
0
0
500
700
Wavelength (nm)
600
800
500
700
Wavelength (nm)
600
800
C
Fluo-3 and RH-237
700
600
500
400
300
200
100
0
500
700
Wavelength (nm)
600
800
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