Electrical activity and intracellular sodium concentration in frog muscle

Desmedt, Jean Edouard

doi:10.1113/jphysiol.1953.sp004940

Cited by 162 publications

(125 citation statements)

References 20 publications

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“…This may be compared with the much faster loss of sodium from Na-loaded muscles allowed to recover in an identical solution. Desmedt's (1953) results correspond to an initial rate constant for sodium loss of about 1-2 hr-' (see Keynes, 1954). The outward movement of lithium was thus over ten times slower than the outward movement of sodium under similar conditions.…”

Section: Resultsmentioning

confidence: 99%

“…When Li-loaded muscles were soaked in a sodium recovery medium containing 10 mM-K they lost their Li with a rate constant just under 0.1 hr-1, this figure being about one tenth of that observed by Desmedt (1953) for the extrusion of Na into the same solution. 3.…”

mentioning

confidence: 89%

“…In order to load the muscles with Na or Li, they were sometimes soaked at a low temperature in the low-K 4soaking-in' solution shown in Table 1, and sometimes for a shorter period in a similar solution from which the potassium phosphate was omitted. The 'sodium recovery' solution was similar to the medium devised by Boyle & Conway (1941) to imitate closely the inorganic composition of frog plasma, except that (following Desmedt, 1953), it contained 10 mM-K. On some occasions a K-free modification of it was used, the KCI being omitted, but the other components left unchanged. The 'lithium recovery' solution had Li substituted for all the Na except the 0-9 mM added as gluconate; since LiHCO3 was not available as such, it was made up by taking appropriate quantities of 'Specpure' Li2CO3 and HCI A.R.…”

Section: Solutionmmentioning

confidence: 99%

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The permeability of frog muscle fibres to lithium ions

Keynes¹,

Swan²

1959

The Journal of Physiology

239

107

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Section: Resultsmentioning

confidence: 99%

mentioning

confidence: 89%

Section: Solutionmmentioning

confidence: 99%

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The permeability of frog muscle fibres to lithium ions

Keynes¹,

Swan²

1959

The Journal of Physiology

239

107

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“…According to Sato, Akaike & Nishi (1967), who employed similar experimental methods and materials to those of Desmedt (1953), the alteration of [K]i from about 120 to 70 m-mole/l. fibre water did not result in the membrane potential expected from the ionic theory, but rather hyperpolarized the fibres beyond the steady-state value.…”

Section: Introductionmentioning

confidence: 99%

Contribution of an electrogenic sodium pump to membrane potential in mammalian skeletal muscle fibres.

Akaike¹

1975

The Journal of Physiology

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SUMMARY1. Relationship between the resting membrane potential and the changes in the intracellular Na and K concentrations ([Na]i and [K]1) was studied in 'Na-loaded' and 'K-depleted' soleus (SOL) muscles of rats which had fed a K-free diet for 40 and more days.2. The extracellular space of the muscles was not significantly different between normal and K-deficient rats. The inulin space in both the 'fresh' and 'Na-rich' muscles can be determined by the same function relating the space to the muscle weight.3. Presence of 2-5-15 mm-K in the recovery solution hyperpolarized the 'Na-rich' muscle fibres at the beginning of recovery. The hyperpolarized membrane potential exceeded, beyond the measured potential of 'fresh' muscle fibres, the theoretical potential derived from the ionic theory, or even beyond Ek. Then, the measured membrane potential declined progressively during the immersion in a recovery solution and returned to the steady-state value. When a considerable Na extrusion and K uptake took place, the measured membrane potential became equal to Ek. 6. The membrane potential obtained after inhibition of the electrogenic Na-pump with cooling or ouabain agrees well with that predicted by the 'constant-field' equation.7. The external Cl ions had a short-circuiting effect on the electrogenic Na-pumping activated on adding K ions.22-2 8. The replacement of Na ions in a recovery solution with Li ions resulted in a faster rate of depolarization from the maximal hyperpolarization.9. It is concluded that the resting membrane potential of 'Na-loaded' and 'K-depleted' SOL muscle fibres is the sum of an ionic diffusion potential predicted by either the Nernst equation or the constant-field equation and of the potential produced by an electrogenic Na-pump.

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“…At the start of expenments, rats were stunned and bled, the duodenum (2 cm caudal to the pylorus) was isolated and emptied of contents by flushing with 0.9% saline, and longitudinal segments (1 cm) were prepared. (Desmedt, 1953;Akaike, 1975a).…”

Section: Methodsmentioning

confidence: 99%

The electrogenic Na‐pump and spontaneous contraction of the hypokalemic rat duodenum

Akaike

Wakita

1986

British J Pharmacology

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1 The effects of the electrogenic Na-pump on spontaneous contraction in the isolated, longitudinal muscle of the duodenum of rats which had been on a potassium-deficient diet for 7 weeks, have been investigated. Intracellular levels of Na+ are increased by this diet. 2 The spontaneous contraction of the duodenal muscle was stopped, transiently, by 0.5 to 120 mM-KC Krebs solution. The period of decrease of tone and amplitude occurring immediately after adding KC was shortened when the external K+ concentration ([K]b) was increased from 0.5 to 120 mM.3 The decrease in tone and amplitude induced by KC was abolished by exposure ofthe tissue to 0 mM [K]b, by exposure to a temperature below 14C, and in the presence of ouabain (3 x 10-5_10-4 M).4 The spontaneous contraction of'Na-rich' duodenum in bathing medium containing 15mM K and following inhibition ofthe electrogenic Na-pump with cooling or ouabain was much the same as in the duodenum from rats fed balanced diets: i.e., increase of contractile tone immediately after adding KV.

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Electrical activity and intracellular sodium concentration in frog muscle

Cited by 162 publications

References 20 publications

The permeability of frog muscle fibres to lithium ions

The permeability of frog muscle fibres to lithium ions

Contribution of an electrogenic sodium pump to membrane potential in mammalian skeletal muscle fibres.

The electrogenic Na‐pump and spontaneous contraction of the hypokalemic rat duodenum

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