The effect of depolarization and calcium ion influx on synaptosomal microtubules

1983 ◽  
Vol 11 (1) ◽  
pp. 86-87 ◽  
Author(s):  
RICHARD CUMMING ◽  
ROBERT D. BURGOYNE ◽  
E. GEORGE GRAY
Keyword(s):  
Calcium Ion ◽  
Ion Influx

Are capacitation or calcium ion influx required for the human sperm acrosome reaction?

1994 ◽  
Vol 62 (6) ◽  
pp. 1255-1261 ◽  
Author(s):  
Peter Bielfeld ◽  
Robert A. Anderson ◽  
Steven R. Mack ◽  
Christopher J. De Jonge ◽  
Lourens J.D. Zaneveld
Keyword(s):  
Calcium Ion ◽  
Acrosome Reaction ◽  
Human Sperm ◽  
Ion Influx ◽  
Sperm Acrosome Reaction ◽  
Sperm Acrosome

scholarly journals Increased calcium-ion influx is a component of capacitation of spermatozoa

1978 ◽  
Vol 172 (3) ◽  
pp. 549-556 ◽  
Author(s):  
J P Singh ◽  
D F Babcock ◽  
H A Lardy
Keyword(s):  
Calcium Ion ◽  
Time Course ◽  
Acrosome Reaction ◽  
Local Anaesthetics ◽  
Defined Medium ◽  
Ionophore A23187 ◽  
Net Uptake ◽  
Ion Influx ◽  
Triton X

Capacitation (modifications required for gamete fusion) is produced by incubating guinea-pig spermatozoa in vitro in a chemically defined medium. It is shown that during such incubation a net uptake of Ca2+ by the sperm occurs in two distinguishable phases. An initial loose association of Ca2+, possibly to surface sites, is unaffected by agents (Mg2+, inhibitors of mitochondiral function) that prevent or delay the exocytotic spermatozoal acrosome reaction. The time course of a secondary Ca2+ uptake parallels or slightly precedes the time course of the acrosome reaction. This parallelism is maintained during a variety of treatments that either expedite (local anaesthetics, ionophore A23187, Triton X-100) or delay (Mg2+, low external Ca2+) the acrosome reaction. We conclude that the secondary Ca2+ influx described herein apparently serves to link alterations of the spermatozoal membrane to subsequent contractile and secretory components of the capacitation sequence.

scholarly journals High Doses of Dexamethasone Induce Endoplasmic Reticulum Stress-Mediated Apoptosis by Promoting Calcium Ion Influx-Dependent CHOP Expression in Osteoblasts

2021 ◽  
Author(s):  
Yunshan Guo ◽  
Dingjun Hao
Keyword(s):  
Endoplasmic Reticulum ◽  
Endoplasmic Reticulum Stress ◽  
Cell Apoptosis ◽  
Calcium Ion ◽  
Caspase 3 ◽  
Combined Treatment ◽  
Caspase 12 ◽  
Ion Influx ◽  
High Doses ◽  
In Cells

Abstract Background: The molecular mechanisms by which dexamethasone (Dex) induces apoptosis in osteoblasts remain unclear.Materials and Methods: MC3T3-E1 cells were treated with 0, 10-8, 10-6, and 10-4 M Dex for 24 h. The expression of ATF6, and phosphorylated PERK and IRE1, cell apoptosis, and the activity of caspase-12 and caspase-3 were measured. The expression of CHOP and the rate of influx of calcium ions were also measured in cells treated with 0 and 10-4 M Dex for 24 h. The effect of 2-APB treatment was assessed in cells treated with 0 or 10-4 M Dex.Results: The levels of ATF6 and phosphorylated PERK and IRE1 increased in a dose-dependent manner in MC3T3-E1 cells treated with 10-8, 10-6, and 10-4 M Dex, compared to in cells treated with 0 M Dex (P <0.05). Cells treated with 10-6 and 10-4 M Dex had significantly increased cell apoptosis rates and caspase-12 and caspase-3 activity compared to the control (P <0.05). Cells treated with 10-4 M Dex had significantly increased levels of CHOP and calcium ion influx rates compared to in the control (P <0.05). Combined treatment with 10-4 M Dex and 2-APB abrogated the observed increases in cell apoptosis and the activity of caspase-12 and caspase-3 (P>0.05). Conclusion: High doses of Dex induce endoplasmic reticulum stress-mediated apoptosis by promoting calcium ion influx-dependent expression of CHOP, and the activation of caspase-12 and caspase-3 in osteoblasts. Combined treatment with 2-APB protects the cells from the effects of Dex, preventing endoplasmic reticulum stress-mediated apoptosis.

Calcium Transients and Transmitter Secretion in Different Parts of Frog Nerve Endings in Different Conditions of Calcium Ion Influx

2020 ◽  
Vol 50 (7) ◽  
pp. 914-919
Author(s):  
E. F. Khaziev ◽  
D. V. Balashova ◽  
A. N. Tsentsevitsky ◽  
E. A. Bukharaeva ◽  
D. V. Samigullin
Keyword(s):  
Calcium Ion ◽  
Calcium Transients ◽  
Nerve Endings ◽  
Transmitter Secretion ◽  
Ion Influx ◽  
Different Parts

Improvement of tissue perfusion with inhibitors of calcium ion influx

1980 ◽  
Vol 29 (4) ◽  
pp. 479-481 ◽  
Author(s):  
J.M. Van Nueten ◽  
P.M. Vanhoutte
Keyword(s):  
Calcium Ion ◽  
Tissue Perfusion ◽  
Ion Influx

scholarly journals Calcium ion influx during mitogenic stimulation of lymphocytes.

1987 ◽  
Vol 12 (4) ◽  
pp. 345-355 ◽  
Author(s):  
Hiroshi Komada ◽  
Hiroshi Nakabayashi ◽  
Hiroshi Nakano ◽  
Hideki Takanari ◽  
Takao Takahashi ◽  
...  
Keyword(s):  
Calcium Ion ◽  
Mitogenic Stimulation ◽  
Ion Influx ◽  
Stimulation Of
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