VSD Classics

Classic Loew Lab ANEP VSDs

di-4-ANEPPS, di-8-ANEPPS, di-4-ANEPPDHQ, di-3-ANEPPDHQ,  di-2-ANEPEQ, di-1-ANEPEQ

The ANEP class of dyes were originally developed 35 years ago  (1-3) and have stood the test of time by serving to meet the voltage imaging and recording needs of the research community. They respond to voltage changes by an electrochromic mechanism (4-6) that assures the speed needed for high fidelity recording of action potentials (7). This mechanism also lends itself to many different applications, allowing the chromophore to be incorporated into a variety of VSDs with varying solubility and hydrophobicity. While many newer VSDs with improved sensitivity and photostability are available from Potentiometric Probes, we feel it is important to make these “classic” dyes available so that researchers can continue to use them for their established experimental protocols.

di-4-ANEPPS (1-3)

This VSD is arguably the most versatile and widely used fluorescent dye for optical voltage recording and imaging in both cardiac and neuronal systems. It is offered by many specialty suppliers of fluorescent probes, but why not obtain it from the original source? We supply it at highly competitive pricing. In addition, we offer user support to help you design your experiment or assay. Additionally, should this classic VSD prove inadequate for your preparation or assay, we can use the results of your initial studies to offer advice on optimizing your measurement and the best choice of a more advanced VSD.

di-8-ANEPPS (1, 8-10)

This is a more hydrophobic version of di-4-ANEPPS with essentially the same voltage sensitivity. For this reason, di-8-ANEPPS is more resistant to washout. Interestingly, it is also more resistant to internalization and therefore allows for longer term experiments. It has been used for dual wavelength ratio imaging in both excitation and emission modes. Finally, it has become the dye of choice for investigations of membrane dipole potential.

di-4-ANEPPDHQ and di-3-ANEPPDHQ (11-13)

These are more hydrophilic versions of the ANEP class of VSDs and are able to penetrate more deeply into tissue. This has made them good choices for 2-photon imaging of brain slices. They have also been shown to be sensitive to lipid environment and can be used to study membrane domains and lipid rafts.

di-2-ANEPEQ and di-1-ANEPEQ (aka JPW1114 and JPW3028) (14-18)

Short alkyl chains (ethyl and methyl, respectively) render these doubly positively charged VSDs highly water soluble. These VSDs are primarily used for intracellular recording or imaging of single cells in a brain slice or in vivo. This is achieved by allowing them to diffuse out of a patch pipet in the whole cell patch configuration, so that only the patched cell is stained. The high aqueous solubility of the dyes makes it possible to make the staining solution in the patch sufficiently concentrated to stain and then record voltage from long axons, dendritic arbors and dendritic spines. Although di-2-ANEPEQ and di-1-ANEPEQ are routinely used by many labs, we believe the newer fluorinated dye di-2-AN(F)EPPTEA (19, 20) is superior in sensitivity and photochemical stability.