Blood-brain-barrier permeable fluorescent astrocyte probes.

The brain's astrocytes play pivotal roles in brain homeostasis, but their contributions to neural circuit function are only beginning to be explored. In order to study astrocytes in their native environment, the field needs imaging probes that are cell-specific, non-toxic, and complementary to existing genetic techniques. We recently described a panel of cationic fluorophores that selectively label rodent and zebrafish astrocytes at low concentrations and short incubation times. Here, we expand on those first-generation astrocyte probes with a new class of brighter and more photostable dyes that allow for imaging across various wavelengths. We demonstrate these probes' subcellular localization to the mitochondria and ability to cross the blood-brain barrier in zebrafish. This new class of astrocyte markers will aid researchers in visualizing and identifying subpopulations of astrocytes in both rodent and zebrafish model systems.