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Electromechanical noise in atrial muscle cells of the carp: a possible ionic feed‐back mechanism.
Author(s) -
Akselrod S,
Landau E M,
Lass Y
Publication year - 1979
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1113/jphysiol.1979.sp012777
Subject(s) - mechanism (biology) , carp , ionic bonding , biophysics , chemistry , noise (video) , medicine , anatomy , biology , fish <actinopterygii> , physics , computer science , ion , fishery , organic chemistry , artificial intelligence , image (mathematics) , quantum mechanics
1. Spontaneous electrical fluctuations (+/‐ 0.2‐0.4 mV) were recorded in 'quiescent' atrial fibres of the carp. 2. The noise decreased in acetylcholine, small hyperpolarization and EGTA. 3. The noise increased (to +/‐ 1‐2 mV) and became more synchronous in K+‐free Ringer and in ouabain. 4. Large voltage fluctuations (+/‐ 1‐2 mV) were accompanied by a fine mechanical tremor, indicating intracellular [Ca2+] fluctuations. 5. Spectral analysis showed a clear resonant frequency at about 1 Hz, indicating that the noise cannot result from the random switching of independent ionic channels. 6. We propose that the intracellular [Ca2+] and the membrane K+‐conductance are involved in a feed‐back loop which can oscillate and produce the electromechanical noise. The frequency of oscillation is determined by the relatively slow diffusion of Ca2+ from the intracellular reservoir to the surface membrane.