Miniature responses under ‘voltage-clamp’

¹ Laboratory of Neurophysiology, National Institute of Neurological Diseases and Blindness, National Institutes of Health, Bethesda, Maryland

A number of the properties of the giant axon membrane of Loligo pealii were studied under ‘voltage-clamp.’ Inward surges of current of such properties as are characteristic of the action potential were demonstrated following short depolarizing pulses. With an exploring microelectrode inserted into the ‘clamped’ portion of the membrane, evidence was obtained showing that this inward surge was the result of activity restricted in a small area of membrane. The inward surges of current were demonstrated to add quantally. The experiments described are consistent with the concept of the existence in the membrane of two stable potential states. Such states are also encountered in metals in contact with oxidizing agents.