Abstract
Radiotracer techniques were used to study the influxes and effluxes of various univalent cations in internally perfused squid giant axons. Membrane currents and conductances were determined by the voltage-clamp technique under analogous internal and external conditions. Both sodium-containing and sodium-free internal and external media were studied. Membrane impedance was measured with an ac impedance bridge to determine the general magnitude and time course of the impedance loss which accompanied the excitation process in both varieties of external media. Maximum transmembrane currents were found to be of comparable magnitude to the charge transfer associated with the peak interdiffusion flux measured under the same conditions. The product of the membrane resistance and the interdiffusion flux remained constant over a wide range of resistance and flux values, both at rest and during activity, both in sodium-containing and sodium-free media. The implications of these findings for excitation theory are discussed.
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Selected References
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- COLE K. S., MOORE J. W. Ionic current measurements in the squid giant axon membrane. J Gen Physiol. 1960 Sep;44:123–167. doi: 10.1085/jgp.44.1.123. [DOI] [PMC free article] [PubMed] [Google Scholar]
- EISENMAN G. THE INFLUENCE OF NA, K LI, RB, AND CS ON CELLULAR POTENTIALS AND RELATED PHENOMENA. Bol Inst Estud Med Biol Univ Nac Auton Mex. 1963 Aug;21:155–183. [PubMed] [Google Scholar]
- FRANKENHAEUSER B., HODGKIN A. L. The action of calcium on the electrical properties of squid axons. J Physiol. 1957 Jul 11;137(2):218–244. doi: 10.1113/jphysiol.1957.sp005808. [DOI] [PMC free article] [PubMed] [Google Scholar]
- HODGKIN A. L., HUXLEY A. F., KATZ B. Measurement of current-voltage relations in the membrane of the giant axon of Loligo. J Physiol. 1952 Apr;116(4):424–448. doi: 10.1113/jphysiol.1952.sp004716. [DOI] [PMC free article] [PubMed] [Google Scholar]
- NARAHASHI T., MOORE J. W., SCOTT W. R. TETRODOTOXIN BLOCKAGE OF SODIUM CONDUCTANCE INCREASE IN LOBSTER GIANT AXONS. J Gen Physiol. 1964 May;47:965–974. doi: 10.1085/jgp.47.5.965. [DOI] [PMC free article] [PubMed] [Google Scholar]
- NIMS L. F. Membranes, tagged components, and membrane transfer coefficient. Yale J Biol Med. 1959 Jun;31:373–386. [PMC free article] [PubMed] [Google Scholar]
- OIKAWA T., SPYROPOULOS C. S., TASAKI I., TEORELL T. Methods for perfusing the giant axon of Loligo pealii. Acta Physiol Scand. 1961 Jun;52:195–196. doi: 10.1111/j.1748-1716.1961.tb02218.x. [DOI] [PubMed] [Google Scholar]
- TASAKI I. Permeability of squid axon membrane to various ions. J Gen Physiol. 1963 Mar;46:755–772. doi: 10.1085/jgp.46.4.755. [DOI] [PMC free article] [PubMed] [Google Scholar]
- TASAKI I., TEORELL T., SPYROPOULOS C. S. Movement of radioactive tracers across squid axon membrane. Am J Physiol. 1961 Jan;200:11–22. doi: 10.1152/ajplegacy.1961.200.1.11. [DOI] [PubMed] [Google Scholar]
- TASAKII, WATANABE A., TAKENAKA T. Resting and action potential of intracellularly perfused squid giant axon. Proc Natl Acad Sci U S A. 1962 Jul 15;48:1177–1184. doi: 10.1073/pnas.48.7.1177. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Tasaki I., Singer I. Membrane macromolecules and nerve excitability: a physico-chemical interpretation of excitation in squid giant axons. Ann N Y Acad Sci. 1966 Jul 14;137(2):792–806. doi: 10.1111/j.1749-6632.1966.tb50200.x. [DOI] [PubMed] [Google Scholar]
- Tasaki I., Singer I., Takenaka T. Effects of internal and external ionic environment on excitability of squid giant axon. A macromolecular approach. J Gen Physiol. 1965 Jul;48(6):1095–1123. doi: 10.1085/jgp.48.6.1095. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Tasaki I., Singer I., Watanabe A. Excitation of internally perfused squid giant axons in sodium-free media. Proc Natl Acad Sci U S A. 1965 Sep;54(3):763–769. doi: 10.1073/pnas.54.3.763. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Tasaki I., Singer I., Watanabe A. Excitation of squid giant axons in sodium-free external media. Am J Physiol. 1966 Sep;211(3):746–754. doi: 10.1152/ajplegacy.1966.211.3.746. [DOI] [PubMed] [Google Scholar]