Effects of Plasmalemmal V-ATPase Activity on Plasma Membrane Potential of Resident Alveolar Macrophages

Lung ◽  
2003 ◽  
Vol 181 (3) ◽  
pp. 121-135 ◽  
Author(s):  
T. A. Heming ◽  
A. Bidani
Keyword(s):  
Plasma Membrane ◽  
Membrane Potential ◽  
Atpase Activity ◽  
Alveolar Macrophages ◽  
Plasma Membrane Potential

scholarly journals Silica Induces Changes in Cytosolic Free Calcium, Cytosolic pH, and Plasma Membrane Potential in Bovine Alveolar Macrophages

1997 ◽  
Vol 15 (2) ◽  
pp. 61-72 ◽  
Author(s):  
Attila Tárnok ◽  
Thomas Schlüter ◽  
Ingeborg Berg ◽  
Günther Gercken
Keyword(s):  
Plasma Membrane ◽  
Membrane Potential ◽  
Alveolar Macrophages ◽  
Specific Inhibitor ◽  
Dust Particles ◽  
Calcium Signal ◽  
Free Calcium ◽  
Cytosolic Free Calcium ◽  
Extracellular Medium ◽  
Plasma Membrane Potential

The mineral‐dust induced activation of pulmonary phagocytes is thought to be involved in the induction of severe lung diseases. The activation of bovine alveolar macrophages (BAM) by silica was investigated by flow cytometry. Short‐term incubation (10 min) of BAM with silica gel and quartz dust particles induced increases in the cytosolic free calcium concentration ([Ca2+]i), decreases in intracellular pH (pHi), and increases in plasma membrane potential (PMP). The extent of these changes was concentration dependent, related to the type of dust and was due to Ca2+influx from the extracellular medium. An increase in [Ca2+]iwas inhibited, when extracellular Ca2+was removed. Furthermore the calcium signal was quenched by Mn2+and diminished by the calcium channel blocker verapamil. The protein kinase C specific inhibitor bisindolylmaleimide II (GF 109203 X) did not inhibit the silica‐induced [Ca2+]irise. In contrast, silica‐induced cytosolic acidification and depolarization were inhibited by GF 109203 X but not by removal of extracellular calcium. Addition of TiO2particles or heavy metal‐containing dusts had no effect on any of the three parameters. Our data suggest the existence of silica‐activated transmembrane ion exchange mechanisms in BAM, which might be involved in the specific cytotoxicity of silica by Ca2+‐dependent and independent pathways.

scholarly journals TRPC6 regulates phenotypic switching of vascular smooth muscle cells through plasma membrane potential‐dependent coupling with PTEN

2019 ◽  
Vol 33 (9) ◽  
pp. 9785-9796 ◽  
Author(s):  
Takuro Numaga‐Tomita ◽  
Tsukasa Shimauchi ◽  
Sayaka Oda ◽  
Tomohiro Tanaka ◽  
Kazuhiro Nishiyama ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Plasma Membrane ◽  
Membrane Potential ◽  
Vascular Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Vascular Smooth Muscle Cells ◽  
Muscle Cells ◽  
Phenotypic Switching ◽  
Plasma Membrane Potential

scholarly journals Kinetic study of the plasma-membrane potential in procyclic and bloodstream forms of Trypanosoma brucei brucei using the fluorescent probe bisoxonol

1996 ◽  
Vol 314 (2) ◽  
pp. 595-601 ◽  
Author(s):  
Fabienne DEFRISE-QUERTAIN ◽  
Chantal FRASER-L'HOSTIS ◽  
Danièle CORAL ◽  
Jacques DESHUSSES
Keyword(s):  
Plasma Membrane ◽  
Membrane Potential ◽  
Trypanosoma Brucei ◽  
Cultured Cells ◽  
Bloodstream Form ◽  
Metabolic Inhibitors ◽  
Trypanosoma Brucei Brucei ◽  
Plasma Membrane Potential ◽  
Regulation Mechanisms ◽  
K Concentration

The characteristics of the plasma-membrane potential of procyclic and bloodstream forms of Trypanosoma brucei brucei (cultured cells) were investigated using the fluorescent anionic probe bisoxonol. Observation of a stable and representative plasma-membrane potential in the resting state required careful washing, centrifugation and maintenance of the cells at room temperature before measurement. Bloodstream forms were more prone to depolarization during washing at 4 °C than procyclic cells. The higher fluorescence observed in the presence of long slender cells than in the presence of procyclic cells shows that the plasma-membrane potential is more negative in the insect form. Healthy dilute cells can sustain their plasma-membrane potential for hours in the presence of external glucose. The presence of a high K+ concentration in the medium did not promote by itself the depolarization of either type of cell. Study of bisoxonol fluorescence as a function of time allowed us to follow the kinetics of the action of metabolic inhibitors in the presence of various ions. o-Vanadate (1 mM) was found to depolarize bloodstream-form cells rapidly but only in a phosphate-free NaCl buffer. Omeprazole and strophanthidin also specifically depolarized bloodstream-form trypanosomes. However, NN´-dicyclohexylcarbodi-imide depolarized both types of cell, but more rapidly for bloodstream-form cells. Bloodstream-form trypanosomes appear to use mainly a vanadate-sensitive Na+ pump to maintain their Na+-diffusion gradient. However, most of the ATPase inhibitors tested had little or no effect on the plasma-membrane potential of procyclics suggesting that this form of trypanosome may rely on several regulation mechanisms.

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