Role of calcium ion in the excitability and electrogenic pump activity of theChara corallina membrane: I. Effects of La3+, verapamil, EGTA, W-7, and TFP on the action potential

1987 ◽  
Vol 96 (1) ◽  
pp. 65-73 ◽  
Author(s):  
Izuo Tsutsui ◽  
Taka-aki Ohkawa ◽  
Reiko Nagai ◽  
Uichiro Kishimoto
Keyword(s):  
Action Potential ◽  
Calcium Ion ◽  
Electrogenic Pump ◽  
Pump Activity

A kinetic analysis of the electrogenic pump ofChara corallina: III. Pump activity during action potential

1985 ◽  
Vol 86 (1) ◽  
pp. 27-36 ◽  
Author(s):  
Uichiro Kishimoto ◽  
Yuko Takeuchi ◽  
Taka-aki Ohkawa ◽  
Nobunori Kami-ike
Keyword(s):  
Action Potential ◽  
Kinetic Analysis ◽  
Electrogenic Pump ◽  
Pump Activity

Role of the premature action potential in contractile potentiation: a study of paired stimulation

1972 ◽  
Vol 6 (4) ◽  
pp. 368-374 ◽  
Author(s):  
R. E. EDMANDS ◽  
K. GREENSPAN ◽  
J. C. BAILEY
Keyword(s):  
Action Potential ◽  
Paired Stimulation

Role of the calcium ion and the disulfide bond in the Burkholderia glumae lipase

2003 ◽  
Vol 22 (5-6) ◽  
pp. 329-338 ◽  
Author(s):  
Mohamed El Khattabi ◽  
Patrick Van Gelder ◽  
Wilbert Bitter ◽  
Jan Tommassen
Keyword(s):  
Disulfide Bond ◽  
Calcium Ion ◽  
Burkholderia Glumae

Effect of calcium chelators on heat coagulation and heat-induced changes of concentrated micellar casein solutions: The role of calcium-ion activity and micellar integrity

2012 ◽  
Vol 26 (2) ◽  
pp. 112-119 ◽  
Author(s):  
Esther de Kort ◽  
Marcel Minor ◽  
Thom Snoeren ◽  
Toon van Hooijdonk ◽  
Erik van der Linden
Keyword(s):  
Calcium Ion ◽  
Micellar Casein ◽  
Ion Activity ◽  
Induced Changes

The Na+-K+-ATPase α2-subunit isoform modulates contractility in the perinatal mouse diaphragm

2004 ◽  
Vol 287 (5) ◽  
pp. C1300-C1310 ◽  
Author(s):  
Tatiana L. Radzyukevich ◽  
Amy E. Moseley ◽  
Daniel A. Shelly ◽  
Gregory A. Redden ◽  
Michael M. Behbehani ◽  
...  
Keyword(s):  
Action Potential ◽  
Knockout Mice ◽  
Dominant Mode ◽  
Resting Potential ◽  
Force Frequency ◽  
Cellular Functions ◽  
Tetanic Force ◽  
Potential Threshold ◽  
Rate Of Activation

This study uses genetically altered mice to examine the contribution of the Na+-K+-ATPase α2 catalytic subunit to resting potential, excitability, and contractility of the perinatal diaphragm. The α2 protein is reduced by 38% in α2-heterozygous and absent in α2-knockout mice, and α1-isoform is upregulated 1.9-fold in α2-knockout. Resting potentials are depolarized by 0.8–4.0 mV in heterozygous and knockout mice. Action potential threshold, overshoot, and duration are normal. Spontaneous firing, a developmental function, is impaired in knockout diaphragm, but this does not compromise its ability to fire evoked action potential trains, the dominant mode of activation near birth. Maximum tetanic force, rate of activation, force-frequency and force-voltage relationships, and onset and magnitude of fatigue are not changed. The major phenotypic consequence of reduced α2 content is that relaxation from contraction is 1.7-fold faster. This finding reveals a distinct cellular role of the α2-isoform at a step after membrane excitation, which cannot be restored simply by increasing α1 content. Na+/Ca2+ exchanger expression decreases in parallel with α2-isoform, suggesting that Ca2+ extrusion is affected by the altered α2 genotype. There are no major compensatory changes in expression of sarcoplasmic reticulum Ca2+-ATPase, phospholamban, or plasma membrane Ca2+-ATPase. These results demonstrate that the Na+-K+-ATPase α1-isoform alone is able to maintain equilibrium K+ and Na+ gradients and to substitute for α2-isoform in most cellular functions related to excitability and force. They further indicate that the α2-isoform contributes significantly less at rest than expected from its proportional content but can modulate contractility during muscle contraction.

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