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A fixable red fluorescent nerve terminal probe that is spectrally identical to SynaptoRed™ C2 (also called FM®4-64).

Product Attributes

Probe cellular localization


For live or fixed cells

For live/intact cells

Assay type/options

Real-time imaging

Fixation options

Fix after staining (formaldehyde), Permeabilize after staining




510/750 nm (see product description)

Catalog #
1 mg
Clear selection
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Product Description

AM4-66 is a fixable red fluorescent nerve terminal probe. The dye is spectrally identical to SynaptoRed™ C2 (also called FM®4-64), but it has an additional amine group at the hydrophilic end of the molecule, making the dye fixable with formaldehyde or gluteraldehyde. The long emission wavelength makes the dye suitable to be used with GFP in two-color imaging.

  • Red fluorescent nerve terminal probe that is fixable with formaldehyde or gluteraldehyde
  • λExEm (membranes) = ~510/750 nm*
  • Dark purple solid soluble in water
  • MW: 872.85

* Excitation/emission settings of 515/640 nm have been used for detection of yeast vacuole staining with SynaptoRed™ C2 (FM®4-64), and should be applicable to AM4-66.

Nerve Terminal Dyes and Kits

ProductCatalog No.Features
SynaptoGreen™ Dyes
(Ex/Em ~480/660 nm in membranes)
70020... 70053View full list of SynaptoGreen™ Dyes
SynaptoRed Dyes™
(Ex/Em ~510/750 nm in membranes)
70021... 70050View full list of SynaptoRed™ Dyes
Background Reducers
ADVASEP-770029Sulfonated cyclodextrin that aids in removal of free dye during washes
SCAS70037Quenches extracellular fluorescences with fewer wash steps than ADVASEP-7
Sulforhodamine 10180101Red fluorescent dye that quenches extracellular fluorescence of SynaptoGreen™ dyes
Nerve Terminal Staining Kits
Nerve Terminal Staining Kit I70030Includes SynaptoGreen™ C4 and ADVASEP-7
Nerve Terminal Staining Kit II (A)70031Includes AM1-43 and ADVASEP-7
Nerve Terminal Staining Kit II (B)70031-1Includes AM1-43 and SCAS
Nerve Terminal Staining Kit III70032Includes SynaptoGreen™ C4 and Sulforhodamine 101
Nerve Terminal Staining Kit V70034Includes SynaptoRed™ C2 and ADVASEP-7
m is the number of carbons in the lipophilic tail and n is the number of double bonds linking the two aromatic rings in the dye.
**The positively-charged end of SynaptoRed C2M is a trimethylammonium group.
FM is a registered trademark of Thermo Fisher Scientific.

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