L-Type Ca2+ Channel Responses to Bay K 8644 in Stem Cell-Derived Cardiomyocytes Are Unusually Dependent on Holding Potential and Charge Carrier

Junzhi Ji; Jiesheng Kang; David Rampe

doi:10.1089/adt.2014.596

Modulation of Single Channels Underlying Hippocampal L-Type Current Enhancement by Agonists Depends on the Permeant Ion

Journal of Neurophysiology ◽

10.1152/jn.00700.2003 ◽

2004 ◽

Vol 92 (2) ◽

pp. 824-837 ◽

Cited By ~ 10

Author(s):

Steven J. Tavalin ◽

Dawn Shepherd ◽

Robin K. Cloues ◽

Sarah E. H. Bowden ◽

Neil V. Marrion

Keyword(s):

Charge Carrier ◽

Hippocampal Neurons ◽

Single Channel ◽

Bay K 8644 ◽

Diagnostic Tools ◽

Single Channels ◽

Cellular Processes ◽

Long Duration ◽

Current Activation ◽

Channel Open Time

The influx of calcium (Ca2+) ions through L-type channels underlies many cellular processes, ranging from initiation of gene transcription to activation of Ca2+-activated potassium channels. L-type channels possess a diagnostic pharmacology, being enhanced by the dihydropyridine BAY K 8644 and benzoylpyrrole FPL 64176. It is assumed that the action of these compounds is independent of the ion conducted through the channel. In contrast to this assumption, modulation of L-type channel activity in acutely dissociated rat CA1 hippocampal neurons depended on the divalent ion identity. BAY K 8644 and FPL 64176 substantially increased single-channel open time only when barium (Ba2+) was the permeant ion. BAY K 8644 increased single-channel conductance when either Ba2+ or Ca2+ ions were the charge carrier, an effect not observed with FPL 64176. BAY K 8644 enhanced the whole cell L-type channel Ca2+- or Ba2+-carried current without a change in deactivation tail kinetics. In contrast, enhancement by FPL 64176 was associated with a dramatic slowing of deactivation kinetics only when Ba2+ and not Ca2+ was the charge carrier. Current activation was slowed by FPL 64176 with either charge carrier, an effect arising from a clustering of agonist-modified long-duration openings toward the end of the voltage step. These data indicate that agonists enhanced L-type current by distinct mechanisms dependent on the permeant ion, indicating that care must be considered when used as diagnostic tools.

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Author response for "Inhibition of neural stem cell aging through the transient induction of reprogramming factors"

10.1002/cne.24967/v2/response1 ◽

2020 ◽

Author(s):

Min Ji Han ◽

Won Ji Lee ◽

Joonhyuk Choi ◽

Yean Ju Hong ◽

Sang Jun Uhm ◽

...

Keyword(s):

Stem Cell ◽

Neural Stem Cell ◽

Author Response ◽

Cell Aging ◽

Stem Cell Aging ◽

Reprogramming Factors

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Decision letter for "Inhibition of neural stem cell aging through the transient induction of reprogramming factors"

10.1002/cne.24967/v2/decision1 ◽

2020 ◽

Keyword(s):

Stem Cell ◽

Neural Stem Cell ◽

Cell Aging ◽

Stem Cell Aging ◽

Reprogramming Factors

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The Response of Testes Cells to Low Level, Single dose Helium Particle Irradiation

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100053929 ◽

1982 ◽

Vol 40 ◽

pp. 252-253

Author(s):

D.E. Philpott ◽

W. Sapp ◽

C. Williams ◽

J. Stevenson ◽

S. Black ◽

...

Keyword(s):

Stem Cell ◽

Single Dose ◽

B Cell ◽

Cell Survival ◽

Spermatogonial Stem Cell ◽

Low Doses ◽

Particle Irradiation ◽

Stem Cell Survival ◽

Irradiation Injury ◽

Radio Sensitivity

Spermatogonial stem-cell survival after irradiation injury has been studied in rodents by histological counts of surviving cells. Many studies, including previous work from our laboratory, show that the spermatogonial population demonstrates a heterogeneous response to irradiation. The spermatogonia increase in radio-sensitivity as differentiation proceeds through the sequence As - Apr - A1 - A2 - A3 - A4 - In - B. The stem (As) cell is the most resistant and the B cell is the most sensitive. The purpose of this work is to investigate the response of spermatogonial cell to low doses (less than 10 0 rads) of helium particle irradiation.

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The Response of Testis Cells to Low Dose X-Irradiation

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100099155 ◽

1981 ◽

Vol 39 ◽

pp. 542-543

Author(s):

D. E. Philpott ◽

W. Sapp ◽

C. Williams ◽

Joann Stevenson ◽

S. Black

Keyword(s):

Electron Microscopy ◽

Stem Cell ◽

Light Microscopy ◽

Dose Level ◽

Cross Sections ◽

Low Dose ◽

Light And Electron Microscopy ◽

Cellular Responses ◽

Post Irradiation ◽

X Irradiation

The response of spermatogonial cells to X-irradiation is well documented. It has been shown that there is a radiation resistent stem cell (As) which, after irradiation, replenishes the seminiferous epithelium. Most investigations in this area have dealt with radiation dosages of 100R or more. This study was undertaken to observe cellular responses at doses less than 100R of X-irradiation utilizing a system in which the tissue can be used for light and electron microscopy.Brown B6D2F1 mice aged 16 weeks were exposed to X-irradiation (225KeV; 15mA; filter 0.35 Cu; 50-60 R/min). Four mice were irradiated at each dose level between 1 and 100 rads. Testes were removed 3 days post-irradiation, fixed, and embedded. Sections were cut at 2 microns for light microscopy. After staining, surviving spermatogonia were identified and counted in tubule cross sections. The surviving fraction of spermatogonia compared to control, S/S0, was plotted against dose to give the curve shown in Fig. 1.

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The early development of antenna and antennal sensilla in the noctuid moth, Agrotis segetum (Insecta: Lepidoptera)

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100160066 ◽

1990 ◽

Vol 48 (3) ◽

pp. 502-503

Author(s):

Eric Hallberg ◽

Lina Hansén

Keyword(s):

Cell Death ◽

Stem Cell ◽

Early Development ◽

Larval Stage ◽

Pupal Stage ◽

Agrotis Segetum ◽

Antennal Sensilla ◽

Noctuid Moth ◽

Standard Procedures

The antennal rudiments in lepidopterous insects are present as disks during the larval stage. The tubular double-walled antennal disk is present beneath the larval antenna, and its inner layer gives rise to the adult antenna during the pupal stage. The sensilla develop from a cluster of cells that are derived from one stem cell, which gives rise to both sensory and enveloping cells. During the morphogenesis of the sensillum these cells undergo major transformations, including cell death. In the moth Agrotis segetum the pupal stage lasts about 14 days (temperature, 25°C). The antennae, clearly seen from the exterior, were dissected and fixed according to standard procedures (3 % glutaraldehyde in 0.15 M cacaodylate buffer, followed by 1 % osmiumtetroxide in the same buffer). Pupae from day 1 to day 8, of both sexes were studied.

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