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On the permeability of end‐plate membrane during the action of transmitter
Author(s) -
Takeuchi A.,
Takeuchi N.
Publication year - 1960
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.1960.sp006564
Subject(s) - citation , transmitter , membrane permeability , computer science , action (physics) , library science , chemistry , membrane , telecommunications , physics , biochemistry , channel (broadcasting) , quantum mechanics
Movements of specific ions in excitable tissues have been emphasized by a number of recent experiments. In particular, there have been many quantitative experiments which show that the rising phase of the nerve impulse in invertebrate giant axons is associated with an inflow of sodium and the falling phase with an outflow of potassium (Hodgkin, Huxley & Katz, 1952; Hodgkin & Huxley, 1952) and similar selective permeability changes have been observed accompanying the propagated action potential in muscle fibres and in myelinated nerve fibres (Dodge & Frankenhaeuser, 1959; Hodgkin & Horowicz, 1959a). In addition, the inhibitory potentials observed in some nerve cells (Coombs, Eccles & Fatt, 1955; Edwards & Hagiwara, 1959), heart muscle fibres (Burgen & Terroux, 1953; Hutter & Trautwein, 1956; Trautwein & Dudel, 1958), and crustacean muscle (Fatt & Katz, 1953; Boistel & Fatt, 1958) have been shown to be produced by changes in permeability of the post-synaptic membrane to potassium and/or chloride ions. On the other hand, it has been considered that at the end-plate the transmitter produces a rapid simultaneous transfer of sodium and potassium, and possibly also of all other free ions on either side of the membrane (Fatt & Katz, 1951; del Castillo & Katz, 1954, 1955, 1956). An approximately linear relationship has been observed between the amplitude of the end-plate potential (e.p.p.) and the membrane potential, the equilibrium potential being about -15 mV (Fatt & Katz, 1951). A similar relationship has also been observed in the amplitude of end-plate current (e.p.c.) obtained when the membrane was clamped at a constant potential during neuromuscular transmission (Takeuchi & Takeuchi, 1959). The membrane potential at which e.p.c. becomes zero may be called provisionally 'e.p.c. equilibrium potential'. In the present experiment, the e.p.c. equilibrium potential was measured in solutions of various ionic composition and the ions which contributed to the e.p.c. were determined. It will be shown