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Membrane Potential Indicators

Introduction

Membrane potential plays a central role in many physiological processes, including nerve-impulse propagation, muscle contraction, and cell signaling. Potentiometric probes are important tools for studying these processes and are generally characterized as slow- or fast-response probes. The fast-response probes change their electronic structure, and consequently their fluorescence properties, in response to changes in the surrounding electric field. The response is fast enough to detect transient (millisecond) potential changes in excitable cells, including single neurons, cardiac cells, and intact brains. However, the magnitude of their potential-dependent fluorescence change is often small (2–10% fluorescence change per 100 mV). The slow-response probes function by entering depolarized cells and binding to proteins or membranes, and exhibit enhanced fluorescence and a red spectral shift.
Fast-response probes are commonly used to image electrical activity from intact heart tissues or measure membrane potential changes in response to pharmacological stimuli. Slow-responding probes are often used to explore mitochondrial function and cell viability.
 

Membrane Potential Indicators Selection Guide

  JC-1 DiOC6(3) Di-4-ANEPPS Di-8-ANEPPS RH 795
Response type Slow-response Slow-response Fast-response Fast-response Fast-response
Readout Fluorescence emission ratio 585/520 nm increases upon menbrane hyperpolarization Fluorescence response to depolarization depends on the staining concentration and detection method Fluorescence excitation ratio 440/505 nm decreases upon membrane hyperpolarization Fluorescence excitation ratio 440/505 nm decreases upon membrane hyperpolarization Fluorescence decreases upon membrane depolarization
Range 1% per 1 mV 1% per 1 mV 2–10% per 100 mV 2–10% per 100 mV 2–10% per 100 mV
Response time 20 ms 20 ms Sub-millisecond Sub-millisecond Sub-millisecond
Ex/Em (nm) 514/529; 585/590 485/500 482/686 467/631 486/689
Cat. No. C045 C050 C265 C266 C267

To order

Buy Cat.No. Product name Ex/Em (nm) Size Price
C045 JC-1 514/529; 585/590 1 mg $100
C050 DiOC6(3) 485/500 25 mg $100
C265 Di-4-ANEPPS  482/686 5 mg $450
C266 Di-8-ANEPPS  467/631 5 mg $450
C267 RH 795  486/689 1 mg $450