Potassium and sodium current noise from squid axon membranes.

Current noise under voltage clamp has been measured from the giant axon of Loligo vulgaris. Relatively large areas (up to 0.4 cm2) were used for these measurements, under standard space clamped conditions. Current noise spectral densities were studied in the range of 0 to 20 C, -100 to -40 mV and in normal, tetrodotoxin, and tetraethylammonium ion solutions. Three components of current noise were found, l/f-noise, and a K and a Na component.