The relationship between voltage noise at constant current and current noise at constant voltage across a linear electrical system is emphasized. In systems like the nerve membrane near its resting state, which show a complicated dependence of impedance on frequency in the range 1–1000 hertz, current noise and voltage noise are completely different. Two different preparations of the axon at rest are used, resulting in small area (∼ 0.04 cm2) and large area (∼ 0.4 cm2) membranes, and in different intracellular compositions. These are shown to give the same results when membrane impedance is accounted for. A distinct hump exists in the voltage spectrum, which is absent in the current spectrum. This structure depends on temperature and voltage, and may be understood when membrane impedance is taken into account. This result is in contrast with previously published work of voltage noise from squid axon. It is argued here that voltageclamp/current-noise data is most likely to give significant kinetic information about conductance changes in membranes.
This is a preview of subscription content, log in to check access.
Buy single article
Instant access to the full article PDF.
Price includes VAT for USA
Subscribe to journal
Immediate online access to all issues from 2019. Subscription will auto renew annually.
This is the net price. Taxes to be calculated in checkout.
Anderson, C. R., Stevens, C. F.: Voltage clamp analysis of acetylcholine produced conductance fluctuations at frog neuromuscular junction. J. Physiol. (Lond.) (in press)
Conti, F.: Nerve membrane electrical characteristics near the resting state. Biophysik6, 257–270 (1970)
Conti, F., Palmieri, G.: Nerve fiber behavior in heavy water under voltage-clamp. Biophysik5, 71–81 (1968)
Cole, K. S.: Rectification and inductance in the squid giant axon. J. gen. Physiol.25, 29–51 (1941)
DeFelice, L. J., Firth, D. R.: Spontaneous voltage fluctuations in glass microelectrodes. IEEE Trans. Bio-med. Eng.18, 339–351 (1970)
DeFelice, L. J., Michalides, J. P. L. M.: Electrical noise from synthetic membranes. J. membr. Biol.9, 261–290 (1972)
Fishman, H. M.: Relaxation spectra of potassium channel noise from squid axon membranes. Proc. nat. Acad. Sci. (Wash.)70, 876–879 (1973)
Hill, T. L., Chen, Y.: On the theory of ion transport across the nerve membrane. IV. Noise from the open-close kinetics of K+ channels. Biophys. J.12, 948–959 (1972)
Hodgkin, A. L., Huxley, A. F.: A quantitative description of membrane current and its application to conduction and excitation in nerve. J. Physiol. (Lond.)117, 500–544 (1952)
Hooge, F. N., Gaal, J. L. M.: Fluctuations with a 1/f spectrum in the conductance of ionic solutions and in the voltage of concentration cells. Phillips Res. Rep.26, 77–90 (1970)
Katz, B., Miledi, R.: The statistical nature of the acetylcholine potential and its molecular components. J. Physiol. (Lond.)224, 665–699 (1972)
Lecar, H., Nossal, R.: Theory of threshold fluctuations in nerves, I and II. Biophys. J.11, 1048–1067, 1068–1084 (1971)
Mauro, A., Conti, F., Dodge, F., Schor, R.: Subthreshold behavior and phenomenological impedance of the squid giant axon. J. gen. Physiol.55, 497–523 (1970)
Narahashi, T., Moore, J. W., Scott, W. R.: Tetrodotoxin blockage of sodium conductance increase in lobster giant axons. J. gen. Physiol.47, 965–974 (1964)
Poussart, D. J. M.: Membrane current noise in lobster axon under voltage clamp. Biophys. J.11, 211–234 (1971)
Siebenga, E., Meyer, A., Verveen, A. A.: Membrane shot-noise in electrically depolarized nodes of Ranvier. Pflügers Arch.341, 97–104 (1973)
Stevens, C. F.: Inferences about membrane properties from electrical noise measurements. Biophys. J.12, 1028–1047 (1972)
Tasaki, I., Watanabe, A., Takenaka, T.: Resting and action potential of intracellularly perfused squid giant axon. Proc. nat. Acad. Sci. (Wash.)48, 1177–1184 (1962)
Verveen, A. A., Derksen, H. E.: Fluctuation phenomena in nerve membrane. Proc. IEEE56, 906–916 (1968)
Supported by the CNR and the NSF.
About this article
Cite this article
Wanke, E., DeFelice, L.J. & Conti, F. Voltage noise, current noise and impedance in space clamped squid giant axon. Pflugers Arch. 347, 63–74 (1974). https://doi.org/10.1007/BF00587055
- Current Noise
- Voltage Noise
- Squid Axon