Premium
Assessment of conduction properties and thermal noise in cell membranes by admittance spectroscopy
Author(s) -
Fishman Harvey M.
Publication year - 1992
Publication title -
bioelectromagnetics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.435
H-Index - 81
eISSN - 1521-186X
pISSN - 0197-8462
DOI - 10.1002/bem.2250130709
Subject(s) - admittance , electrical impedance , thermal conduction , time constant , membrane , chemistry , materials science , physics , biological system , analytical chemistry (journal) , electrical engineering , engineering , thermodynamics , biochemistry , chromatography , quantum mechanics , biology
Advances in the speed of signal processing enable application of a Fourier‐synthesized function as a small perturbation (1 mV) superposed on voltage clamp steps to rapidly (<1 sec) acquire cell membrane complex driving‐point functions (impedance or admittance) in several frequency bands ranging from 1 Hz to 10 kHz. Curve fits of admittance models to these data yield a complete quantitative linear description of membrane conduction systems and their kinetics. Furthermore, the rate constants between microscopic states of an ion channel can be calculated from conductance parameters derived from model curve fits of membrane admittances. Additionally, the power spectrum of membrane thermal noise is obtainable from impedance determinations by use of the Nyquist relation. Consequently, rapid driving‐point function determinations provide the most complete macroscopic assessment of membrane conduction properties presently available. Admittance determinations of the potassium conduction system in squid giant axon and the potassium conducting “inward rectifier” in snail neuron are used to illustrate the above points. 1992 Wiley‐Liss, Inc.