Ion transport across sodium channels in biological membranes

Chizmadjev, Yu.A.; Ait'yan, S. Kh

doi:10.1016/0022-5193(77)90281-8

Cited by 32 publications

(11 citation statements)

References 15 publications

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“…The steady-state open probability of the channel (s) was determined by the diagrammatic method (King & Altman, 1956;Hill, 1966;Chizmadjev & Aityan, 1977;Hille & Schwarz, 1978) (4) Equation (4) is equivalent to the experimentally-derived formula (3) in every respects. The time constant of inactivation (Zs) (A8) is calculated from a second order differential equation for s (A6), as follows:…”

Section: Discussionmentioning

confidence: 99%

Dual effects of K ions upon the inactivation of the anomalous rectifier of the tunicate egg cell membrane

Ohmori

1980

J. Membrain Biol.

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Summary. Inactivation of the K inward currentthrough the anomalous rectifier channel of the egg cell membrane of a tunicate, Halocynthia roretzi Drashe, was studied under voltage-clamp. The noise spectrum of the steady-state current recorded at hyperpolarized potentials was measured in solutions in which Na, Cs, Hydrazine, or Sr caused inactivation of the current. The unitary conductance estimated was independent of which cation caused inactivation. From the relation between the concentration of cations which caused inactivation and the extent of inactivation at fixed potentials, the binding of one inactivator to a channel was found to cause inactivation, and the potency of inactivation was Cs+>Hydrazine+>Na+>Li +, and Ba2+>Sr 2+. The inactivation caused by Na + was increased by K + when [K]o was lower than 20raM, but was decreased by K + in higher K-ASW (artificial sea water). One K + was found to inactivate the channel cooperatively with one Na +. Increase of inactivation by K + was a dominant effect, in Cs-ASW. The inactivation was explained quantitatively by a model assuming cooperative plugging by a monovalent inactivator and a K +.Key words: anomalous rectifier, inactivation, K inward current.The inward K current through the anomalous rectifier in the cell membrane of starfish eggs and of frog skeletal muscle is inactivated in a solution containing small amounts of Cs or Ba ions (Hagiwara,

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Section: Discussionmentioning

confidence: 99%

Dual effects of K ions upon the inactivation of the anomalous rectifier of the tunicate egg cell membrane

Ohmori

1980

J. Membrain Biol.

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“…It is well known that a dynamic system which can make transitions between a finite number of discrete states can be represented by a state diagram (cf Heckmann, 1965a, b;Chizmadjev & Aityan, 1977;Hille & Schwarz, 1978). Usually such a diagram describes each loading state explicitly where the molecular mechanism underlying the transitions between states (e.g., vacancy diffusion or correlated "knock-off" jumps) will determine how the lines, representing the various transition paths, will connect the different states.…”

Section: Vectorial Representationmentioning

confidence: 99%

Multioccupancy models for single filing ionic channels: Theoretical behavior of a four-site channel with three barriers separating the sites

1983

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A procedure is developed for dealing with multioccupancy in single-filing channels having any number of sites internal to the barriers at the channel ends but having the outermost sites in equilibrium with the bathing solutions. Using this procedure, a general theory is developed for a single-filing channel having three barriers and four sites, the outermost of which are in equilibrium with the bathing solutions. By introducing a vectorial representation, it is shown that the four-site model can be reduced to an equivalent two-site model with respect to the number of possible transitions, thereby simplifying the algebraic steps required to solve transport equations for the system. The transport coefficients are derived and expressed in terms of the energy levels of the peaks and the wells for the different occupancy configurations. An explicit solution to the transport equations is given in a comprised form for a single permeable species. The solution allows some important properties for the system to be deduced, specifically with regard to the conductance at zero current, the correlation factor between electrical conductance and tracer flux, and the current-voltage relationship. Examples are given for the use of the present results in a physical interpretation of the data from the gramicidin A channel.

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“…The model is a general case of models considered by Chizmadjev, Khodorov & Aityan (1974) and Chizmadjev & Aityan (1977). It is the same as one used by Hille & Schwarz (1978) but the matrix method described here for obtaining solutions is faster than the graph theory technique used by Hille & Schwarz (1978) (see also Heckmann, Vollmerhaus, Kutschera & Vollmerhaus, 1969;Hill, 1966;Lam & Priest, 1972).…”

Section: Appendixmentioning

confidence: 99%

Sodium channel permeation in squid axons. I: Reversal potential experiments.

Begenisich¹,

Cahalan²

1980

The Journal of Physiology

119

118

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SUMMARY1. Na channel reversal potentials were studied in perfused voltage clamped squid giant axons. The concentration dependence of ion selectivity was determined with both external and internal changes in Na and ammonium concentrations.2. A tenfold change in the internal ammonium activity results in a 42 mV shift in the reversal potential, rather than the 56 mV shift expected from the Goldman, Hodgkin, Katz equation for a constant PNa/P~N 14 ratio. However, changing [Na]0 tenfold at constant internal [NH4] gives approximately the expected 56 mV shift. Therefore, the apparent channel selectivity depends upon the internal ammonium concentration but not the external Na concentration.3. With ammonium outside and Na inside, the calculated permeability ratio is nearly constant, regardless of the permeant ion concentration.4. Internal Cs ions can alter the Na/K permeability ratio. 5. The results are considered in terms of a three-barrier, two-site ionic permeation model.

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Ion transport across sodium channels in biological membranes

Cited by 32 publications

References 15 publications

Dual effects of K ions upon the inactivation of the anomalous rectifier of the tunicate egg cell membrane

Dual effects of K ions upon the inactivation of the anomalous rectifier of the tunicate egg cell membrane

Multioccupancy models for single filing ionic channels: Theoretical behavior of a four-site channel with three barriers separating the sites

Sodium channel permeation in squid axons. I: Reversal potential experiments.

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