Bursting firing of action potentials in central snail neurons elicited by d-amphetamine: Role of the intracellular calcium ions

1996 ◽  
Vol 115 (3) ◽  
pp. 195-205 ◽  
Author(s):  
Y.-H. Chen ◽  
M.-C. Tsai
Keyword(s):  
Intracellular Calcium ◽  
Calcium Ions ◽  
Action Potentials ◽  
Snail Neurons

Role of intracellular calcium ions and reactive oxygen species in apoptosis induced by ultrasound

2004 ◽  
Vol 30 (5) ◽  
pp. 683-692 ◽  
Author(s):  
Hidemi Honda ◽  
Takashi Kondo ◽  
Qing-Li Zhao ◽  
Loreto B Feril ◽  
Hiroshi Kitagawa
Keyword(s):  
Reactive Oxygen Species ◽  
Intracellular Calcium ◽  
Calcium Ions ◽  
Reactive Oxygen ◽  
Oxygen Species

scholarly journals The role of calcium ions in the process of acetyltransferase activation during the formation of platelet-activating factor (PAF-acether)

1984 ◽  
Vol 219 (2) ◽  
pp. 419-424 ◽  
Author(s):  
J Gómez-Cambronero ◽  
P Iñarrea ◽  
F Alonso ◽  
M Sánchez Crespo
Keyword(s):  
Intracellular Calcium ◽  
Significant Role ◽  
Calcium Ions ◽  
Calcium Transport ◽  
Platelet Activating Factor ◽  
Peritoneal Macrophages ◽  
Threshold Concentration ◽  
Ionophore A23187 ◽  
Different Doses

The role of Ca2+ in the activation of the enzyme lyso-(platelet-activating factor): acetyl-CoA acetyltransferase was studied in rat peritoneal macrophages in response to complement-coated zymosan particles and ionophore A23187. By using Ca2+-containing buffers, a threshold concentration of extracellular Ca2+ above 1 microM was found to be necessary to observe the activation of the enzyme in response to zymosan. By contrast, a significant role of intracellular Ca2+ in this process could be ruled out, since the putative intracellular calcium-transport antagonist TMB-8 [8-(NN-diethylamino)octyl-3,4,5-trimethoxybenzoate] did not inhibit the activation of the acetyltransferase induced by zymosan in the presence of extracellular Ca+. The link between acetyltransferase activation and extracellular Ca2+ transport was studied by measuring Ca2+ uptake in response to the stimuli. Zymosan particles induced a rapid increment in cell-associated Ca2+ which correlated well with the extent of acetyltransferase activation (r = 0.91) and with the release of platelet-activating factor (r = 0.95) in response to different doses of zymosan. Cellular Ca2+ efflux in response to zymosan particles was also measured and found to be increased, as compared with controls, when the activation of the acetyltransferase declined. In short, the data suggest that the entry of extracellular Ca2+ into the cell is a crucial event in the activation of acetyltransferase and, thereby, in the formation of platelet-activating factor in rat peritoneal macrophages.

Mitochondrial matrix calcium ions regulate energy production in myocardium: A cytochemical study

1990 ◽  
Vol 48 (2) ◽  
pp. 166-167
Author(s):  
W.A. Jacob ◽  
R. Hertsens ◽  
A. Van Bogaert ◽  
M. De Smet
Keyword(s):  
Energy Metabolism ◽  
Calcium Ions ◽  
Energy Production ◽  
Regulation Of Respiration ◽  
Free Calcium ◽  
Mitochondrial Matrix ◽  
Cytochemical Study ◽  
Nmr Techniques

In the past most studies of the control of energy metabolism focus on the role of the phosphorylation potential ATP/ADP.Pi on the regulation of respiration. Studies using NMR techniques have demonstrated that the concentrations of these compounds for oxidation phosphorylation do not change appreciably throughout the cardiac cycle and during increases in cardiac work. Hence regulation of energy production by calcium ions, present in the mitochondrial matrix, has been the object of a number of recent studies.Three exclusively intramitochondnal dehydrogenases are key enzymes for the regulation of oxidative metabolism. They are activated by calcium ions in the low micromolar range. Since, however, earlier estimates of the intramitochondnal calcium, based on equilibrium thermodynamic considerations, were in the millimolar range, a physiological correlation was not evident. The introduction of calcium-sensitive probes fura-2 and indo-1 made monitoring of free calcium during changing energy metabolism possible. These studies were performed on isolated mitochondria and extrapolation to the in vivo situation is more or less speculative.

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