The temperature dependence of the movement of potassium and chloride ions associated with nerve impulses.

Landowne, David; Scruggs, V.

doi:10.1113/jphysiol.1976.sp011458

Cited by 16 publications

(14 citation statements)

References 20 publications

(23 reference statements)

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“…We now need an estimate of the probable efflux. For the brief (< 1 ms) action potential of squid giant axon, Landowne & Scruggs (1976) measured a K+ efflux of 3-7 pmol cm-2 at 26 'C. For temperatures below 26°C, they measured a temperature coefficient, Qlo, of 1/1-52, but, since there is a physical limit to the 406 K+ IN RAT SUPRAOPTIC NUCLEUS minimum efflux, this Qlo must tend to 1 at higher temperatures.…”

Section: Synchronization Of Bursts Of Firingmentioning

confidence: 99%

Extracellular K+ in the supraoptic nucleus of the rat during reflex bursting activity by oxytocin neurones.

Coles

Poulain

1991

The Journal of Physiology

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SUMMARY1. We have investigated changes in extracellular potassium concentration [K+]o in the supraoptic nucleus of lactating rats and in particular those that occur during the intense burst of firing by the oxytocin neurones involved in the milk ejection reflex.2. Double-barrelled K+-selective microelectrodes containing a highly selective sensor based on valinomycin were lowered through the exposed cortex towards the supraoptic nucleus (SON) of female rats anaesthetized with urethane. The mean resting [K+]o in the hypothalami of five rats was 2-4 mM, S.D. = 0-3 mM.

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Section: Synchronization Of Bursts Of Firingmentioning

confidence: 99%

Extracellular K+ in the supraoptic nucleus of the rat during reflex bursting activity by oxytocin neurones.

Coles

Poulain

1991

The Journal of Physiology

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“…Recent experiments on the temperature dependence of sodium and potassium fluxes associated with nerve impulses have underlined these contradictions between observed and predicted tracer fluxes (Cohen & Landowne, 1974;Landowne & Scruggs, 1976) and have shown again the need for a more direct comparison between currents and fluxes. It is possible to measure the efflux of radioactive sodium from relatively intact squid axons while voltage clamping the membrane and measuring the associated currents (Mullins, Adelman & Sjodin, 1962).…”

Section: Introductionmentioning

confidence: 99%

Sodium efflux from voltage clamped squid giant axons.

Landowne¹

1977

The Journal of Physiology

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“…The results are compared with the tracer flux data obtained from cephalopod giant axons at various temperatures between 70 and 270 (2). We find the data to be consistent with a model channel containing three ion sites.…”

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confidence: 52%

“…The exchange of K+ across the nerve membrane during nerve impulses is considerably less than that predicted from the Hodgkin-Huxley equations, assuming independent movement of ions (1,2). One explanation of this discrepancy may be that K+ interact with one another within the membrane.…”

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confidence: 63%

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Random walk analysis of potassium fluxes associated with nerve impulses.

Clay¹,

Shlesinger²

1977

Proc. Natl. Acad. Sci. U.S.A.

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We present a novel recursion method for obtaining theoretical expressions for unidirectional single-file fluxes of ions through narrow membrane channels containing an arbitrary number of ion sites. The theory is applied to experimental tracer fluxes associated with nerve impulses from cephalopod giant axon membranes at various temperatures between 70 and 270. The comparison between the theoretical and experimental one-way fluxes suggests that the potassium channel in nerve membrane contains three ion sites, which is consistent with the deduction by Hodgkin and Keynes that the potassium channel contains two or three sites on the basis of the ratio of tracer influx to tracer efflux. The analytical results in this paper provide a further test of the single-file model for nerve and other membrane preparations.The exchange of K+ across the nerve membrane during nerve impulses is considerably less than that predicted from the Hodgkin-Huxley equations, assuming independent movement of ions (1, 2). One explanation of this discrepancy may be that K+ interact with one another within the membrane. For example, Hodgkin and Keynes (3) demonstrated that the voltage-dependence of the ratio of passive fluxes in resting membrane is consistent with a single-file model in which ions move via "knock-cn" collisions through a narrow channel containing two or three ion sites. A problem with comparing the single-file model to flux data associated with nerve activity has been the lack of theoretical expressions for the one-way fluxes.In this paper we present such expressions for a channel containing an arbitrary number of sites which we use to calculate the unidirectional fluxes during a Hodgkin-Huxley model action potential. The results are compared with the tracer flux data obtained from cephalopod giant axons at various temperatures between 70 and 270 (2). We find the data to be consistent with a model channel containing three ion sites. Description of the model A detailed description of our model of ion translocation has been given in our theoretical work on K+ current noise in nerve membrane (4, 5). We start with the model of Hodgkin and Keynes (3) which consists of a channel having s (s > 1) fully occupied K-selective sites along which K+ move in single file. The ion row moves only when a K+ from the internal or external bathing solution strikes the corresponding end of the channel with sufficient energy to overcome static forces that tend to keep the ions in place. We separate the motion of the channel ions into its temporal and spatial components by describing successful collisions from either side of the membrane with a single probability density function ,6(t). That is, ,t(t)dt is the probability of a successful collision from either side of the membrane within the infinitesimal time interval (t, t + dt).The process represented by f(t) is in general semi-Markovian.The motion of the channel row in response to a successful collision is described by the probability p(/), in which IlI is the distance that the row moves and...

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The temperature dependence of the movement of potassium and chloride ions associated with nerve impulses.

Cited by 16 publications

References 20 publications

Extracellular K+ in the supraoptic nucleus of the rat during reflex bursting activity by oxytocin neurones.

Extracellular K+ in the supraoptic nucleus of the rat during reflex bursting activity by oxytocin neurones.

Sodium efflux from voltage clamped squid giant axons.

Random walk analysis of potassium fluxes associated with nerve impulses.

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