Di-2-ANEPEQ

Neuronal voltage-sensitive dye imaging detects membrane-potential-dependent optical changes from dyes associated with neuronal membranes, enabling optical recording of electrical activity from single neurons, dendrites, axons, spines, or neuronal populations in brain slices and cultured neurons. VSD signals are typically reported as fractional fluorescence or absorbance changes over baseline, such as ΔF/F or ΔI/I, and published protocols use high-speed cameras or photodiode arrays because neuronal voltage signals occur on millisecond time scales. Fast VSD imaging can be applied at two common scales: bulk staining of brain slices to measure circuit-level spatiotemporal activity, and single-cell loading or biolistic delivery to record membrane-potential transients from individual neuronal compartments. Optical signals should be interpreted as membrane-potential-related readouts, and validation by simultaneous electrophysiology or pharmacological controls is recommended when the experimen

Fluorescent plasma-membrane potential dye assays measure changes in cell membrane potential using voltage-sensitive dyes whose fluorescence changes when cells depolarize or hyperpolarize. Anionic bis-oxonol dyes such as DiBAC4(3) enter depolarized cells more readily and show increased fluorescence after intracellular binding, while hyperpolarization reduces dye accumulation and fluorescence. FMP/FLIPR membrane-potential dyes are used for faster, homogeneous microplate assays of ion-channel or receptor-mediated membrane-potential changes.