Changes in intra- and extracellular potassium and intracellular sodium activities induced by repetitive stimulation and their relation to membrane potential in guinea-pig papillary muscle.

Hotokebuchi, Nobuo; Yano, Toshiyuki; Nishizono, Yasufumi; Nishi, Katsuhide

doi:10.2170/jjphysiol.37.797

Cited by 6 publications

(6 citation statements)

References 27 publications

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“…The method of preparing K+-selective microelectrodes (KISEs) was essentially the same as that described by HOTOKEBUCHI et al (1987). In brief, two capillaries (Narishige, GD-1) were mounted in parallel on a horizontal micropipette puller (Narishige, PW-77), and heat was applied.…”

Section: Methodsmentioning

confidence: 99%

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Unaffected electrogenic Na-K pump activity in "diseased" human atrial fibers, as assessed by intracellular K+ activity.

Sako

Imanishi²,

Arita

et al. 1989

Jpn.J.Physiol

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To investigate the role of the electrogenic Na-K pump in the resting membrane of "diseased" or "depolarized" human atrial muscles, intracellular K+ activity (ak) and resting membrane potential (Vm) were simultaneously measured using double-barreled K+-selective microelectrodes. Under perfusion with normal Tyrode's solution (37°C) containing 5.4 mM [K]0, Vm averaged -43.9 + 1.4 mV, and aK was 99.7 + 1.3 mM (mean + S.E., n = 33). The aK was comparable to that of atrial muscles obtained from other intact mammalian species. In 5.4 mM [K]0, dihydro-ouabain (DHO) at concentrations of 10 -6 and 10 -5 M significantly decreased aK and depolarized Vm. Similar decreases in aK were observed when [K]0 was decreased from 5.4 to 0.5 mM or when the temperature of the perfusing solution was decreased from 37 to 22°C. Upon returning [K]0 from 0.5 to 5.4 mM at 37°C, aK increased, Vm hyperpolarized markedly for about 3 min, and this was followed by less marked levels of hyperpolarization in the steady state. The high [K]0-induced increases in aK were inhibited in the presence of DHO, and at low temperature (22°C). Isoproterenol (10-' M) increased aK and hyperpolarized Vm. Acetylcholine (10 -5M) hyperpolarized Vm with no change in aK. The rate of reduction of Na+-efflux during application of DHO (10 -5 M) was calculated based on the change in aK and surface-to-volume ratio of the cell measured electronmicroscopically in the same tissue, and estimated to be 2.6 to 3.8 pmol/(cm2 . s), close to the value reported for Purkinje fibers excised from intact animals. We conclude that the Na-K pump functions normally even in "diseased" human atrial muscles, thereby keeping aK within a physiological range.

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Section: Methodsmentioning

confidence: 99%

“…The DC-resistance of the K+-selective barrel and the reference barrel were 10-100 GSA and 20-60 MS2, respectively. The KISE, thus prepared, was stable for more than 12 h. The "response time" (HOTOKEBUCHI et al, 1987) of the Vol. 39, No.…”

Section: Methodsmentioning

confidence: 99%

Unaffected electrogenic Na-K pump activity in "diseased" human atrial fibers, as assessed by intracellular K+ activity.

Sako

Imanishi²,

Arita

et al. 1989

Jpn.J.Physiol

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“…The methods used to fabricate the ion-sensitive, double-barreled electrodes were reported previously [16], and are described briefly here. Two glass capillary tubes with a glass fiber inside were mounted in parallel on a horizontal micropippet puller (PD-5; Narishige, Tokyo, Japan).…”

Section: Measurement Of Monovalent Ions In the Endolymph And Epmentioning

confidence: 99%

Development of Monovalent Ions in the Endolymph in Mouse Cochlea

Yamasaki

Komune²,

Shimozono³

et al. 2000

ORL

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The present study was designed to clarify the chronological developmental process of monovalent ions (Na⁺, K⁺, Cl^–) in the endolymph of the mouse in relation to the development of the endocochlear potential (EP). The EP and ionic concentrations were measured simultaneously with the ion-sensitive double-barreled microelectrodes from the scala media of the basal turn. The EP increased abruptly 7 days after birth (DAB) and reached approximately 80 mV 14 DAB. In the earliest postnatal days, the endolymphatic Na⁺ concentration was significantly higher than that in adult mice, however, the K⁺ and the Cl^– concentrations were lower. The concentrations of all the monovalent ions in endolymph reached adult levels at 7 DAB when the EP was still under 20 mV. These data strongly suggest the presence of a different mechanism between the production of monovalent ions, especially of high K⁺ in the endolymph and that of EP.

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“…WPI IE-190 for K* and WPI IE-170 for Cl") according to the method reported by Hotokebuchi et al [16], and it was used for penetration of the stria vascularis. Two glass capillary tubes were mounted in parallel on a horizontal micropipette puller (Narishige.…”

Section: Introductionmentioning

confidence: 99%

Movement of Monovalent Ions across the Membranes of Marginal Cells of the Stria vascularis in the Guinea Pig Cochlea

Komune¹,

Nakagawa²,

Hisashi³

et al. 1993

ORL

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The resting potential and monovalent ions in the marginal cells and scala media were measured before and 20 min after the onset of anoxia using ionsensitive microelectrodes. The resting potential of the marginal cells decreased from 62.7 to ––2.4 mV. The K⁺ activity decreased from 77.7 to 53.2 mEq/l, while the Na⁺ activity increased from 2.6 to 24.7 mEq/l. The Cl^–– activity did not change significantly. In the scala media, the endocochlear potential decreased rapidly from 80.9 to ––28.0 mV after the onset of anoxia. The K⁺ activity decreased from 119.0 to 96.5 mEq/l, the Na⁺ activity increased from 1.3 to 9.5 mEq/l and that of Cl^–– decreased from 127.0 to 115.1 mEq/l. The electrochemical gradients determined for each ion based on the ionic changes in the scala media and marginal cells, suggested the existence of an Na/K pump and Na-K-2Cl cotransport at the basolateral membrane of the marginal cells, and a rheogenic K pump and Na-K-2Cl transport at the luminal membrane of the marginal cells. The Na⁺ and K⁺ must be recycled at the basolateral membrane and luminal membrane of marginal cells, respectively.

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Changes in intra- and extracellular potassium and intracellular sodium activities induced by repetitive stimulation and their relation to membrane potential in guinea-pig papillary muscle.

Cited by 6 publications

References 27 publications

Unaffected electrogenic Na-K pump activity in "diseased" human atrial fibers, as assessed by intracellular K+ activity.

Unaffected electrogenic Na-K pump activity in "diseased" human atrial fibers, as assessed by intracellular K+ activity.

Development of Monovalent Ions in the Endolymph in Mouse Cochlea

Movement of Monovalent Ions across the Membranes of Marginal Cells of the Stria vascularis in the Guinea Pig Cochlea

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