Effects of external K concentration on the electrogenicity of the insulin-stimulated Na,K-pump in frog skeletal muscle

Marunaka, Yoshinori

doi:10.1007/bf01925793

Cited by 12 publications

(8 citation statements)

References 25 publications

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“…Insulin has no significant effect on the internal Na and K concentrations and the ratio of Na-permeability to K-permeability at the time when the membrane is hyperpolarized by insulin (30 to 40 min after insulin * Present address: Department of Physiology, Emory University School of Medicine, Atlanta, Georgia 30322. application; Moore & Rabovsky, 1979;Marunaka, 1986). These reports suggest that the insulin-stimulated Na,K-pump is electrogenic.…”

Section: Introductionmentioning

confidence: 86%

“…From these values, the water content in the intracellular space was estimated to be 55% of the wet weight (Marunaka, 1986). a Each value expresses the mean value of six experiments +-SD of the mean value.…”

Section: Estimation Of the Water Content In The Intracellular Spacementioning

confidence: 99%

“…The Na efflux is calculated from the product of the internal Na concentration and the rate coefficient of the 22Na efflux at the steady state (Marunaka, 1986).…”

Section: Calculation Of the Na Effluxmentioning

confidence: 99%

“…These reports suggest that the insulin-stimulated Na,K-pump is electrogenic. In addition, the Na/K coupling ratio of the insulin-stimulated Na,Kpump varies when the ionic environment of the pump is changed (Marunaka, 1986(Marunaka, , 1987aMarunaka, Murayama & Kitasato, 1986).…”

Section: Introductionmentioning

confidence: 98%

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Effects of internal Na and external K concentrations on Na/K coupling of Na,K-pump in frog skeletal muscle

Marunaka

1988

J. Membrain Biol.

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To clarify the dependency of the Na/K coupling of the Na,K-pump on internal Na and external K concentrations in skeletal muscle, the ouabain-induced change in membrane potential, the ouabain-induced change in Na efflux and the membrane resistance were measured at various internal Na and external K concentrations in bullfrog sartorius muscle. Upon raising the internal Na concentration from 6 mmol/kg muscle water to 20 mmol/kg muscle water, the magnitude of the ouabain-induced change in membrane potential increased about eightfold and the magnitude of the ouabain-induced change in Na efflux increased about fivefold while the membrane resistance was not significantly changed. As the external K concentration increased from 1 to 10 mM, the magnitude of the ouabain-induced change in membrane potential decreased (1/5.5 fold), while the magnitude of the ouabain-induced change in Na efflux increased (about 1.5-fold). The membrane resistance decreased upon raising the external K concentration from 1 to 10 mM (1/2-fold). These observations imply that the values of the Na/K coupling of the Na,K-pump increases upon raising the internal Na concentration and decreases upon raising the external K concentration.

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Section: Introductionmentioning

confidence: 86%

Section: Estimation Of the Water Content In The Intracellular Spacementioning

confidence: 99%

“…The Na efflux is calculated from the product of the internal Na concentration and the rate coefficient of the 22Na efflux at the steady state (Marunaka, 1986).…”

Section: Calculation Of the Na Effluxmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 98%

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Effects of internal Na and external K concentrations on Na/K coupling of Na,K-pump in frog skeletal muscle

Marunaka

1988

J. Membrain Biol.

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“…Na',K+-ATPase can also be inhibited by removing potassium from the bath solution (Kernan, 1962;Vyskodil & Illes, 1977;Vizi & Vyskodil, 1979;Marunaka, 1986 Adrenaline and insulin activate Na +,K + -ATPase and the electrogenic Na',K+ pump (cf. Clausen, 1986).…”

Section: Presynaptic Action Ofcarbachol During Inhibition and Activatmentioning

confidence: 99%

Depression of miniature endplate potential frequency by acetylcholine and its analogues in frog

Nikolsky

Bukharaeva

Strunsky

et al. 1991

British J Pharmacology

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of Tatarstan, U.S.S.R.1 Acetylcholine (ACh), 7.5 x 10-5M, and carbachol, 5 x 10-6M (CCh) depressed the frequency of miniature endplate potentials (m.e.p.ps) in the frog (Rana temporaria) sartorious neuromuscular junction with active acetylcholinesterase to about 50-55% of the controls. 2 A similar depression was produced by the nicotinic agonists, nicotine, suberyldicholine and tetramethylammonium. 3 The muscarinic agonists, oxotremorine, methylfurmethide and methacholine were without effect on m.e.p.p. frequency. The muscarinic antagonist, atropine and the nicotinic antagonist, (+)-tubocurarine, had no effect on the depression of m.e.p.p. frequency evoked by CCh. 4 The ganglionic blockers, benzhexonium and IEM-1119, were also without effect on the CCh-evoked depression of m.e.p.p. frequency. 5 Pretreatment of muscles with anticholinesterases did not prevent the CCh-induced drop in m.e.p.p. frequency. 6 The effect of CCh was proportionally the same as in the controls in preparations where the m.e.p.p. frequency was changed by elevation of K+ and in the presence of theophylline, noradrenaline, dibutyryl adenosine 3': 5'-cyclic monophosphate (db cyclic AMP) and db cyclic GMP.7 An inhibitor of Na+,K+-ATPase, ouabain, 5 x 10-5mollP', prevented or reversed the depression of m.e.p.p. frequency by CCh. However, the depression was present in a nominally K+-free medium. Insulin and adrenaline, which are considered to be Na+,K+-ATPase activators, were without effect on depression of m.e.p.p. frequency. 8 The depression of m.e.p.p. frequency by 5 x 10-6 M CCh was the same at temperatures between 5 and 30°C with a Q10 near to 1.0. When threshold amounts of CCh were used (6 x 10-7 and 3 x 10-7 M), the depression was less at higher temperatures. 9 The receptive structures responsible for the CCh (or ACh)-evoked depression of m.e.p.p. frequency differ pharmacologically from muscarinic, nicotinic ganglionic and neuromuscular junction ACh-receptors as well as from the synaptic cholinesterase, in contrast to previous reports (Duncan & Publicover, 1979). The low temperature-dependence points to the possibility that physical rather than biochemical processes are limiting in this presynaptic effect of cholinomimetics.

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Biology Of Sodium‐Absorbing Epithelial Cells: Dawning of a New Era

Schultz¹,

Hudson

1991

Comprehensive Physiology

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Effects of external K concentration on the electrogenicity of the insulin-stimulated Na,K-pump in frog skeletal muscle

Cited by 12 publications

References 25 publications

Effects of internal Na and external K concentrations on Na/K coupling of Na,K-pump in frog skeletal muscle

Effects of internal Na and external K concentrations on Na/K coupling of Na,K-pump in frog skeletal muscle

Depression of miniature endplate potential frequency by acetylcholine and its analogues in frog

Biology Of Sodium‐Absorbing Epithelial Cells: Dawning of a New Era

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