Summary
A special recording chamber has been constructed which allows for the perfusion of the fragile protoplasmic droplets from Nitella cells while making electrical measurements on the preparation.
Measurements were made of the potential of the interior of the droplet relative to the bathing medium, under resting conditions and during electrical stimulation. In a bathing medium whose cationic concentration resembled the natural vacuolar sap, a small resting potential of between 0 and −30 mV was observed. Stimulation with depolarizing current shocks of 100 μs in duration and of up to 0.28 mA/cm2 elicited active responses of up to 130 mV which outlasted the stimulus artifacts. The responses were graded but they resembled nerve action potentials in shape and duration.
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Koppenhöfer, E., Schramm, M. A method for electrical measurements on isolated protoplasmic droplets from Nitella. Pflugers Arch. 350, 341–346 (1974). https://doi.org/10.1007/BF00592642
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DOI: https://doi.org/10.1007/BF00592642