Electrophysiology of Cells and Organelles: Studies with Optical Potentiometric Indicators

Freedman, Jeffrey C.; Laris, Philip C.

doi:10.1016/b978-0-12-364373-5.50015-9

Cited by 45 publications

(40 citation statements)

References 281 publications

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“…We conclude that Ap is kept remarkably constant at zip = -123 mV + 16°70 over a wide range of pHext values. Its magnitude is distinctly higher than that of other mycoplasmal species [7][8][9].…”

Section: Determination Of Aphmentioning

confidence: 87%

“…The membrane potential zi¢ was determined using a potential-sensitive fluorescent carbocyanine dye [6][7][8][9]. With this method the membrane potential is compared with a K + diffusion potential induced by addition of the K+-specific ionophore valinomycin.…”

Section: R Tziph]/f = Zi~ -(Z-ziph)mentioning

confidence: 99%

“…External [K +] and buffer compositions are varied until, after addition of valinomycin, no changes in fluorescence intensity or internal [K ÷] occur thus indicating that [K +] is in Donnan equilibrium. At this very special [K +] (the 'null point' [7]; 'critical K + concentration' [[K+]crit } [10,11]) the membrane potential equals the K + diffusion potential induced by valinomycin, and is calculated according to…”

Section: R Tziph]/f = Zi~ -(Z-ziph)mentioning

confidence: 99%

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Transmembrane proton‐motive potential of Spiroplasma foricola

Schummer

Schiefer

1987

FEBS Letters

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In Spiroplasma.floricola, the transmembrane proton-motive potential zip was studied. It is composed of a transmembrane electric potential difference, ziq;, and a transmembrane proton gradient, zipH, according to zip = 3~9 -(Z.ZIpH). Using a potential-sensitive carbocyanine dye and 5,5'-dimethyl[2-14C]oxazolidine -2,4-dione as probes, zi~ and zipH were measured at different [H +] of the medium, and zip was calculated to be remarkably constant at 123 mV + 16% over a wide range of external pH values. Inhibition experiments indicated that it is generated by a membrane-bound, electrogenic, proton-translocating ATPase.

show abstract

Section: Determination Of Aphmentioning

confidence: 87%

Section: R Tziph]/f = Zi~ -(Z-ziph)mentioning

confidence: 99%

Section: R Tziph]/f = Zi~ -(Z-ziph)mentioning

confidence: 99%

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Transmembrane proton‐motive potential of Spiroplasma foricola

Schummer

Schiefer

1987

FEBS Letters

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“…This minireview, however, does not treat the vast literature on the "optical probes of the membrane potential," which is adequately covered by other excellent reviews [14,22,23,30,52].When the nerve fiber is excited, it transiently changes many of its physical properties. From the biological point of view, the most significant is the change in membrane potential, since the transmission of information along the nerve fiber is mediated by the electric local current.…”

mentioning

confidence: 99%

“…This minireview, however, does not treat the vast literature on the "optical probes of the membrane potential," which is adequately covered by other excellent reviews [14,22,23,30,52].…”

mentioning

confidence: 99%

Mechanical, thermal, and optical changes of the nerve membrane associated with excitation.

Watanabe

1986

Jpn.J.Physiol

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In this minireview, some of the recent experimental findings on the excitable membranes of nerve fibers obtained by nonelectrophysiological means are discussed. This minireview, however, does not treat the vast literature on the "optical probes of the membrane potential," which is adequately covered by other excellent reviews [14,22,23,30,52].When the nerve fiber is excited, it transiently changes many of its physical properties. From the biological point of view, the most significant is the change in membrane potential, since the transmission of information along the nerve fiber is mediated by the electric local current. Other physical changes are significant mainly because they contain information on the molecular mechanism of the excitation process. They are usually very small for an easy detection, but progress in the techniques of extracting small signals from noise allowed us to discover and examine some of these signals. In this minireview, several recent findings on mechanical, thermal, and optical signals will be discussed.

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Determination of the membrane potential of cultured mammalian schwann cells and its sensitivity to potassium using a thiocarbocyanine fluorescent dye

Hargittai¹,

Youmans²,

Lieberman³

1991

Glia

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The membrane potential of cultured rat sciatic nerve Schwann cells was determined with conventional microelectrode and voltage-sensitive fluorescent dye, Di-S-C3(5), optical techniques. The value for membrane potential obtained with microelectrodes was -42.1 +/- 4.7 mV (n = 8). Using optically determined fluorescent intensity changes caused by changes in external potassium ion concentration, in the presence or absence of valinomycin (null point method), the membrane potential was estimated at -45.7 +/- 6.2 mV (n = 7); with a gramicidin and valinomycin double ionophore method it was -52.2 +/- 9.1 (n = 4). The membrane potential of Schwann cells was found to be potassium sensitive at and above the physiological range of [K+] at 27.5 mV/10x delta[K+], which is approximately half the Nernstian value. This result suggests that other ion permeabilities strongly influence the resting membrane potential of cultured Schwann cells. Since Na+ had little effect on the membrane potential, it is concluded that Cl- is a likely candidate for the other permeant ionic species. The optical method has been shown to be a useful tool for the systematic study of the membrane potential of Schwann cells in culture and for the characterization of its ionic basis and regulation.

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Electrophysiology of Cells and Organelles: Studies with Optical Potentiometric Indicators

Cited by 45 publications

References 281 publications

Transmembrane proton‐motive potential of Spiroplasma foricola

Transmembrane proton‐motive potential of Spiroplasma foricola

Mechanical, thermal, and optical changes of the nerve membrane associated with excitation.

Determination of the membrane potential of cultured mammalian schwann cells and its sensitivity to potassium using a thiocarbocyanine fluorescent dye

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