---
_id: '3472'
abstract:
- lang: eng
text: A novel potassium-selective channel which is active at membrane potentials
between -100 mV and +40 mV has been identified in peripheral myelinated axons
of Xenopus laevis using the patch-clamp technique. At negative potentials with
105 mM-K on both sides of the membrane, the channel at 1 kHz resolution showed
a series of brief openings and closings interrupted by longer closings, resulting
in a flickery bursting activity. Measurements with resolution up to 10 kHz revealed
a single-channel conductance of 49 pS with 105 mM-K and 17 pS with 2.5 mM-K on
the outer side of the membrane. The channel was selective for K ions over Na ions
(PNa/PK = 0.033). The probability of being within a burst in outside-out patches
varied from patch to patch (> 0.2, but often > 0.9), and was independent
of membrane potential. Open-time histograms were satisfactorily described with
a single exponential (tau o = 0.09 msec), closed times with the sum of three exponentials
(tau c = 0.13, 5.9, and 36.6 msec). Sensitivity to external tetraethylammonium
was comparatively low (IC50 = 19.0 mM). External Cs ions reduced the apparent
unitary conductance for inward currents at Em = -90 mV (IC50 = 1.1 mM). Ba and,
more potently, Zn ions lowered not only the apparent single-channel conductance
but also open probability. The local anesthetic bupivacaine with high potency
reduced probability of being within a burst (IC50 = 165 nM). The flickering K
channel is clearly different from the other five types of K channels identified
so far in the same preparation. We suggest that this channel may form the molecular
basis of the resting potential in vertebrate myelinated axons.
acknowledgement: A grant from the Konrad-Adenauer-Stiftung to D.-S.K. is gratefully
acknowledged, and this paper constitutes a part of his dissertation. We thank Drs.
H. Bostock, B. Neumcke, D. Siemen and Mr. G. Reid for reading the manuscript and
Mrs. Elke Schmidt for technical assistance. Financial support was received from
the Deutsche Forschungsgemeinschaft (Vol88/13-2).
article_processing_charge: No
article_type: original
author:
- first_name: Duk
full_name: Koh, Duk
last_name: Koh
- first_name: Peter M
full_name: Jonas, Peter M
id: 353C1B58-F248-11E8-B48F-1D18A9856A87
last_name: Jonas
orcid: 0000-0001-5001-4804
- first_name: Michael
full_name: Bräu, Michael
last_name: Bräu
- first_name: Werner
full_name: Vogel, Werner
last_name: Vogel
citation:
ama: Koh D, Jonas PM, Bräu M, Vogel W. A TEA-insensitive flickering potassium channel
active around the resting potential in myelinated nerve. Journal of Membrane
Biology. 1992;130:149-162. doi:10.1007/BF00231893
apa: Koh, D., Jonas, P. M., Bräu, M., & Vogel, W. (1992). A TEA-insensitive
flickering potassium channel active around the resting potential in myelinated
nerve. Journal of Membrane Biology. Springer. https://doi.org/10.1007/BF00231893
chicago: Koh, Duk, Peter M Jonas, Michael Bräu, and Werner Vogel. “A TEA-Insensitive
Flickering Potassium Channel Active around the Resting Potential in Myelinated
Nerve.” Journal of Membrane Biology. Springer, 1992. https://doi.org/10.1007/BF00231893.
ieee: D. Koh, P. M. Jonas, M. Bräu, and W. Vogel, “A TEA-insensitive flickering
potassium channel active around the resting potential in myelinated nerve,” Journal
of Membrane Biology, vol. 130. Springer, pp. 149–162, 1992.
ista: Koh D, Jonas PM, Bräu M, Vogel W. 1992. A TEA-insensitive flickering potassium
channel active around the resting potential in myelinated nerve. Journal of Membrane
Biology. 130, 149–162.
mla: Koh, Duk, et al. “A TEA-Insensitive Flickering Potassium Channel Active around
the Resting Potential in Myelinated Nerve.” Journal of Membrane Biology,
vol. 130, Springer, 1992, pp. 149–62, doi:10.1007/BF00231893.
short: D. Koh, P.M. Jonas, M. Bräu, W. Vogel, Journal of Membrane Biology 130 (1992)
149–162.
date_created: 2018-12-11T12:03:30Z
date_published: 1992-01-01T00:00:00Z
date_updated: 2022-03-16T11:15:02Z
day: '01'
doi: 10.1007/BF00231893
extern: '1'
external_id:
pmid:
- '1291683 '
intvolume: ' 130'
language:
- iso: eng
main_file_link:
- url: https://link.springer.com/article/10.1007/BF00231893
month: '01'
oa_version: None
page: 149 - 162
pmid: 1
publication: Journal of Membrane Biology
publication_identifier:
issn:
- 0022-2631
publication_status: published
publisher: Springer
publist_id: '2915'
quality_controlled: '1'
scopus_import: '1'
status: public
title: A TEA-insensitive flickering potassium channel active around the resting potential
in myelinated nerve
type: journal_article
user_id: ea97e931-d5af-11eb-85d4-e6957dddbf17
volume: 130
year: '1992'
...
---
_id: '2528'
abstract:
- lang: eng
text: We previously reported a novel rat membrane protein that exhibits a voltage-dependent
potassium channel activity on the basis of molecular cloning combined with an
electrophysiological assay. This protein, termed I(sK) protein, is small and different
from the conventional potassium channel proteins but induces selective permeation
of potassium ions on its expression in Xenopus oocytes. In this investigation,
we examined cellular localization of rat I(sK) protein by preparing three different
types of antibody that specifically reacts with a distinct part of rat I(sK) protein.
Immunohistochemical analysis using these antibody preparations demonstrated that
rat I(sK) protein is confined to the apical membrane portion of epithelial cells
in the proximal tubule of the kidney, the submandibular duct and the uterine endometrium.
The observed tissue distribution of rat I(sK) protein was consistent with that
of the I(sK) protein mRNA determined by blot hybridization analysis. In epithelial
cells, the sodium, potassium-ATPase pump in the basolateral membrane generates
a sodium gradient across the epithelial cell and allows sodium ions to enter the
cell through the apical membrane. Thus, taking into account the cellular localization
of the I(sK) protein, together with its electrophysiological properties, we discussed
a possible function of the I(sK) protein, namely that this protein is involved
in potassium permeation in the apical membrane of epithelial cells through the
depolarizing effect of sodium entry.
article_processing_charge: No
article_type: original
author:
- first_name: Tetsuo
full_name: Sugimoto, Tetsuo
last_name: Sugimoto
- first_name: Yasuto
full_name: Tanabe, Yasuto
last_name: Tanabe
- first_name: Ryuichi
full_name: Shigemoto, Ryuichi
id: 499F3ABC-F248-11E8-B48F-1D18A9856A87
last_name: Shigemoto
orcid: 0000-0001-8761-9444
- first_name: Masazumi
full_name: Iwai, Masazumi
last_name: Iwai
- first_name: Toru
full_name: Takumi, Toru
last_name: Takumi
- first_name: Hiroaki
full_name: Ohkubo, Hiroaki
last_name: Ohkubo
- first_name: Shigetada
full_name: Nakanishi, Shigetada
last_name: Nakanishi
citation:
ama: 'Sugimoto T, Tanabe Y, Shigemoto R, et al. Immunohistochemical study of a rat
membrane protein which induces a selective potassium permeation: Its localization
in the apical membrane portion of epithelial cells. Journal of Membrane Biology.
1990;113(1):39-47. doi:10.1007/BF01869604'
apa: 'Sugimoto, T., Tanabe, Y., Shigemoto, R., Iwai, M., Takumi, T., Ohkubo, H.,
& Nakanishi, S. (1990). Immunohistochemical study of a rat membrane protein
which induces a selective potassium permeation: Its localization in the apical
membrane portion of epithelial cells. Journal of Membrane Biology. Springer.
https://doi.org/10.1007/BF01869604'
chicago: 'Sugimoto, Tetsuo, Yasuto Tanabe, Ryuichi Shigemoto, Masazumi Iwai, Toru
Takumi, Hiroaki Ohkubo, and Shigetada Nakanishi. “Immunohistochemical Study of
a Rat Membrane Protein Which Induces a Selective Potassium Permeation: Its Localization
in the Apical Membrane Portion of Epithelial Cells.” Journal of Membrane Biology.
Springer, 1990. https://doi.org/10.1007/BF01869604.'
ieee: 'T. Sugimoto et al., “Immunohistochemical study of a rat membrane protein
which induces a selective potassium permeation: Its localization in the apical
membrane portion of epithelial cells,” Journal of Membrane Biology, vol.
113, no. 1. Springer, pp. 39–47, 1990.'
ista: 'Sugimoto T, Tanabe Y, Shigemoto R, Iwai M, Takumi T, Ohkubo H, Nakanishi
S. 1990. Immunohistochemical study of a rat membrane protein which induces a selective
potassium permeation: Its localization in the apical membrane portion of epithelial
cells. Journal of Membrane Biology. 113(1), 39–47.'
mla: 'Sugimoto, Tetsuo, et al. “Immunohistochemical Study of a Rat Membrane Protein
Which Induces a Selective Potassium Permeation: Its Localization in the Apical
Membrane Portion of Epithelial Cells.” Journal of Membrane Biology, vol.
113, no. 1, Springer, 1990, pp. 39–47, doi:10.1007/BF01869604.'
short: T. Sugimoto, Y. Tanabe, R. Shigemoto, M. Iwai, T. Takumi, H. Ohkubo, S. Nakanishi,
Journal of Membrane Biology 113 (1990) 39–47.
date_created: 2018-12-11T11:58:12Z
date_published: 1990-01-01T00:00:00Z
date_updated: 2022-02-24T09:55:39Z
day: '01'
doi: 10.1007/BF01869604
extern: '1'
external_id:
pmid:
- '2154581'
intvolume: ' 113'
issue: '1'
language:
- iso: eng
main_file_link:
- url: https://link.springer.com/article/10.1007/BF01869604
month: '01'
oa_version: None
page: 39 - 47
pmid: 1
publication: Journal of Membrane Biology
publication_identifier:
eissn:
- 1432-1424
issn:
- 0022-2631
publication_status: published
publisher: Springer
publist_id: '4371'
quality_controlled: '1'
scopus_import: '1'
status: public
title: 'Immunohistochemical study of a rat membrane protein which induces a selective
potassium permeation: Its localization in the apical membrane portion of epithelial
cells'
type: journal_article
user_id: ea97e931-d5af-11eb-85d4-e6957dddbf17
volume: 113
year: '1990'
...
---
_id: '3465'
abstract:
- lang: eng
text: Asymmetrical displacement currents and Na currents of single myelinated nerve
fibers of Xenopus laevis were studied in the temperature range from 5 to 24 degrees
C. The time constant of the on-response at E = 4 mV, tau on, was strongly temperature
dependent, whereas the amount of displaced charge at E = 39 mV, Qon, was only
slightly temperature dependent. The mean Q10 for tau on-1 was 2.54, the mean Q10
for Qon was 1.07. The time constant of charge immobilization, tau i, at E = 4
mV varied significantly (alpha = 0.001) with temperature. The mean Q10 for tau
i-1 was 2.71 +/- 0.38. The time constants of immobilization of gating charge and
of fast inactivation of Na permeability were similar in the temperature range
from 6 to 22 degrees C. The Qoff/Qon ratio for E = 4 mV pulses of 0.5 msec duration
decreased with increasing temperature. The temperature dependence of the time
constant of the off-response could not be described by a single Q10 value, since
the Q10 depended on the duration of the test pulse. Increasing temperature shifted
Qon (E) curves to more negative potentials by 0.51 mV K-1, but shifted PNa (E)
curves and h infinity (E) curves to more positive potentials by 0.43 and 0.57
mV K-1, respectively. h infinity (E = -70 mV) increased monotonously with increasing
temperature. The present data indicate that considerable entropy changes may occur
when the Na channel molecule passes from closed through open to inactivated states.
article_processing_charge: No
article_type: original
author:
- first_name: Peter M
full_name: Jonas, Peter M
id: 353C1B58-F248-11E8-B48F-1D18A9856A87
last_name: Jonas
orcid: 0000-0001-5001-4804
citation:
ama: Jonas PM. Temperature dependence of gating current in myelinated nerve fibers.
Journal of Membrane Biology. 1989;112(3):277-289. doi:10.1007/BF01870958
apa: Jonas, P. M. (1989). Temperature dependence of gating current in myelinated
nerve fibers. Journal of Membrane Biology. Springer. https://doi.org/10.1007/BF01870958
chicago: Jonas, Peter M. “Temperature Dependence of Gating Current in Myelinated
Nerve Fibers.” Journal of Membrane Biology. Springer, 1989. https://doi.org/10.1007/BF01870958.
ieee: P. M. Jonas, “Temperature dependence of gating current in myelinated nerve
fibers,” Journal of Membrane Biology, vol. 112, no. 3. Springer, pp. 277–289,
1989.
ista: Jonas PM. 1989. Temperature dependence of gating current in myelinated nerve
fibers. Journal of Membrane Biology. 112(3), 277–289.
mla: Jonas, Peter M. “Temperature Dependence of Gating Current in Myelinated Nerve
Fibers.” Journal of Membrane Biology, vol. 112, no. 3, Springer, 1989,
pp. 277–89, doi:10.1007/BF01870958.
short: P.M. Jonas, Journal of Membrane Biology 112 (1989) 277–289.
date_created: 2018-12-11T12:03:28Z
date_published: 1989-12-01T00:00:00Z
date_updated: 2022-02-15T08:59:02Z
day: '01'
doi: 10.1007/BF01870958
extern: '1'
external_id:
pmid:
- '2559205 '
intvolume: ' 112'
issue: '3'
language:
- iso: eng
main_file_link:
- url: https://link.springer.com/article/10.1007/BF01870958
month: '12'
oa_version: None
page: 277 - 289
pmid: 1
publication: Journal of Membrane Biology
publication_identifier:
eissn:
- 1432-1424
issn:
- 0022-2631
publication_status: published
publisher: Springer
publist_id: '2922'
quality_controlled: '1'
scopus_import: '1'
status: public
title: Temperature dependence of gating current in myelinated nerve fibers
type: journal_article
user_id: ea97e931-d5af-11eb-85d4-e6957dddbf17
volume: 112
year: '1989'
...