Applicability of available ion-selective liquid-membrane microelectrodes to intracellular ion-activity measurements

Meier, P C; Lanter, F.; Ammann, D.; Steiner, R. A.; Simon, W.

doi:10.1007/bf00582386

Cited by 30 publications

(15 citation statements)

References 33 publications

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“…Also hyperpolarizing actions of GABA did not change aka, which can be seen in the recording illustrated in Fig. 5B (Meier, Lanter, Ammann, Steiner & Simon, 1982) reveals that a voltage change of only 1-2 mV would result from a carbachol-induced increase in the intracellular free Ca2+ concentration from 0 4 to 1 /LM (see Fig. 6; background 120 mM-K+; 10 mM-Na+).…”

Section: General Obfervation8mentioning

confidence: 55%

An intracellular analysis of gamma‐aminobutyric‐acid‐associated ion movements in rat sympathetic neurones.

Ballanyi¹,

Grafe²

1985

The Journal of Physiology

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SUMMARY1. Double-barfelled ion-sensitive micro-electrodes were used to measure the changes of the intracellular activities of Cl-, K+, and Na+ (at1, ak, aka) in neurons of isolated rat sympathetic ganglia during the action of y-aminobutyric acid (GABA).2. The membrane potential of some of the neurones was manually 'voltage clamped' by passing current through the reference barrel of the ion-sensitive micro-electrode. This enabled us to convert the normal depolarizing action of GABA into a hyperpolarization.3. A GABA-induced membrane depolarization was accompanied by a decrease of at1, ai and no change in ai whereas a GABA-induced membrane hyperpolarization noK Na' a A resulted in an increase of ati, ak and also no change in aka.4. GABA did not change the free intracellular Ca2+ concentration, as measured with a Ca2+-sensitive micro-electrode, whereas such an effect was seen during the action of carbachol. pH-sensitive electrodes, on the other hand, revealed a small GABA-induced extracellular acidification.5. The inward pumping of Cl-following the normal, depolarizing action of GABA required the presence of extracellular K+ as well as Na+, whereas C02/HCO3--free solutions did not influence the uptake process. Furosemide, but not DIDS, blocked the inward pumping of Cl-.6. In conclusion, our data show that only changes in intracellular activities of K+ and Cl-are associated with the action of GABA. Furthermore, they indicate that a K+/Cl-co-transport, and not a Cl-/HCO3-counter-transport, may be involved in the homoeostatic mechanism which operates to restore the normal transmembrane Cl-distribution after the action of GABA.

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Section: General Obfervation8mentioning

confidence: 55%

An intracellular analysis of gamma‐aminobutyric‐acid‐associated ion movements in rat sympathetic neurones.

Ballanyi¹,

Grafe²

1985

The Journal of Physiology

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“…Our Na+ electrodes were calibrated under the assumption of an intraglial free Ca2+ concentration of 10-v M (see Methods). This Ca2+ background level might be too low since, very recently, Morris, Krnjevic & MacDonald (1985) as well as Coles & Orkand (1985) have determined free intraglial Ca2+ concentrations ([Ca2+],) between 10-6 and IO--M. If [Ca2+], would be 10-5 M, a calculation reveals that the voltage reading of our Na+ electrodes would indicate an a'a of 20 mm instead of25 mm (calculation based on a selectivity ratio for Ca2+ Na+:K+ = 2-5:1: 0-025, background 90 mM-K+, 25 mM-Na+; Meier, Lanter, Ammann, Steiner & Simon, 1982). Such a result would not change the conclusion about a relatively high aia in the glial cells.…”

Section: Discussionmentioning

confidence: 99%

Ion activities and potassium uptake mechanisms of glial cells in guinea‐pig olfactory cortex slices.

Ballanyi¹,

Grafe²,

Bruggencate³

1987

The Journal of Physiology

297

233

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SUMMARY1. Double-barrelled ion-sensitive micro-electrodes were used to measure changes in the intracellular activities of K+, Na+ and Cl-(aK, aNa, acl) in glial cells of slices from guinea-pig olfactory cortex during repetitive stimulation of the lateral olfactory tract.2. Base-line levels of aj , aia and ai1 were about 66, 25 and 6 mm, respectively, for cells with resting potentials higher than -80 mV. During stimulation, intraglial aj and ai1 increased, whereas aia decreased. Within about 2 min after stimulation the ion activities returned to their base-line levels.3. The Cl-equilibrium potential was found to be close to the membrane potential (Em). There was also a strong correlation between changes of Em and aC1. These observations indicate a high Cl-conductance of the glial cell membrane. 4. In the presence of Ba2+, the usual depolarizing response of the glial cells to a rise of the extracellular K+ activity (a4) reversed into a membrane hyperpolarization. Furthermore, Ba2+ strongly reduced the stimulus-related rise of intraglial a4. An additional application of ouabain blocked both the membrane hyperpolarization as well as the remaining rise of a.5. In conclusion, our data show that glial cells in guinea-pig olfactory cortex slices possess at least two mechanisms of K+ accumulation. One mechanism is sensitive to the K+ channel blocker Ba2+ and might be a passive KCl influx. The other appears to be the electrogenic Na+/K+ pump, which can be activated by excess extracellular K+.

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“…For the Cl--sensitive microelectrodes a liquid membrane (WPI-IE 170) was used. A slope constant of 54.9 _+ 0.2 mV/decade in CI--activity was found (n = 30), while the selectivity coefficients were Kci.HCO3 = 0.16 -+ 0.01 (n = 12), KcI.gl ..... te = 0.04 -+ 0.01 (n = 12) and KcLnPO4 < 0.10 [3,34].…”

Section: Ion-sensitive Microelectrodesmentioning

confidence: 99%

Cellular and transepithelial responses of goldfish intestinal epithelium to chloride substitutions

1985

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Summary. In goldfish intestine chloride was substituted by large inorganic anions (gluconate or glucuronate) either mucosally, serosally or bilaterally. Changes in intracellular activities of chloride (aiCl), sodium (aiNa +) and potassium (a/K+), pHi, relative volume, membrane and transepithelial potentials, transepithelial resistance and voltage divider ratio were measured. Control values were: aiCI-= 35 meq/liter, aiNa + = I 1 meq/liter and alK + = 95 meq/liter. During bilateral substitution the latter two did not change while aiCI dropped to virtually zero.Mucosal membrane potentials (~bmc) were: control, -53 mV; serosal substitution, -51 mV; bilateral substitution, -66 mV; while during mucosal substitution a transient depolarization occurred and the final steady state ~]/mc was -66 inV.During control and bilateral substitution the transepithelial potentials (qJm~) did not differ from zero. During unilateral substitutions qJm.~ was small, in the order of magnitude of the errors in the liquid junction potentials near the measuring salt bridges 9During bilateral substitution phi increased 0.4 pH units 9 Cellular volume decreased during mucosal substitution to 88% in 40 min; after serosal substitution it transiently increased, but the new steady-state value was not significantly above its control value.Three minutes after mucosal substitution an a~CI of approx. 10 meq/liter was measured.Chemical concentrations of Na, K and C1 were determined under control conditions and bilateral substitution. CI concentrations were also measured as a function of time after unilateral substitutions.The data indicate an electrically silent chloride influx mechanism in the brush border membrane and an electrodiffusional chloride efftux in the basolateral membrane. A substantial bicarbonate permeability is present in the basolateral membrane. The results are in agreement with the observed changes in membrane resistances, volume changes and pH changes.

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Applicability of available ion-selective liquid-membrane microelectrodes to intracellular ion-activity measurements

Cited by 30 publications

References 33 publications

An intracellular analysis of gamma‐aminobutyric‐acid‐associated ion movements in rat sympathetic neurones.

An intracellular analysis of gamma‐aminobutyric‐acid‐associated ion movements in rat sympathetic neurones.

Ion activities and potassium uptake mechanisms of glial cells in guinea‐pig olfactory cortex slices.

Cellular and transepithelial responses of goldfish intestinal epithelium to chloride substitutions

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