Microsecond response of a voltage-sensitive merocyanine dye: fast voltage-clamp measurements on squid giant axon.
Extrinsic absorption changes exhibited by squid giant axons stained with the voltage-sensitive merocyanine-oxazolone dye NK 2367 were measured during brief voltage-clamp steps. Experiments that employed an optical recording system having a sub-microsecond response time constant demonstrate that this dye responds to step changes in membrane voltage in less than 2 microseconds at room temperature. The optical response is independent of ionic currents and is unlikely to depend upon cytoskeletal or cytoplasmic events.
Salzberg
B M
BM
Department of Neuroscience, University of Pennsylvania School of Medicine, Philadelphia 19104-6074.
Obaid
A L
AL
Bezanilla
F
F
D000818:Animals; D001369:Axons / Q000502:physiology*; D002462:Cell Membrane / Q000502:physiology; D004396:Coloring Agents; D003593:Cytoplasm / Q000502:physiology; D003599:Cytoskeleton / Q000502:physiology; D049832:Decapodiformes; D004594:Electrophysiology; D066298:In Vitro Techniques; D008564:Membrane Potentials / Q000502:physiology; D010081:Oxazolone / Q000031:analogs & derivatives*; D011199:Potentiometry
D004396:Coloring Agents; D010081:Oxazolone; C025144:NK 2367