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Electrical fluctuations associated with active transport.

Authors
  • Segal, J R
Type
Published Article
Journal
Biophysical journal
Publication Date
Nov 01, 1972
Volume
12
Issue
11
Pages
1371–1390
Identifiers
PMID: 4642217
Source
Medline
License
Unknown

Abstract

Measurements were made of the spectrum of the voltage fluctuations developed in the 0.025-10 Hz band during active transport by frog abdominal skin with Ringer's solution on both sides. Decreasing the potential across the skin by an external supply of current diminishes the voltage fluctuations, but they do not disappear, reaching a minimum finite value. Thus, fluctuations in both the resistance of the skin and the electric current attendant to the active transport of sodium contribute to the voltage fluctuations. Ouabain eliminates the current fluctuations but not those of the resistance. At 20 degrees C, the spectral intensities of the resistance and current fluctuations are nearly identical, varying as 1/f(a), where f is frequency and a = 1.6-2.0. At 32 degrees C, the spectrum of the voltage fluctuations is sigmoid shaped, evidencing a relaxation process with a time constant of 0.6 sec. The fluctuations can be accounted for by stochastic variations in the concentration of a complex formed between a carrier molecule, fixed or mobile, and the actively transported species, sodium.

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