scholarly journals Factors determining the plasma-membrane potential of lymphocytes

1982 ◽  
Vol 204 (2) ◽  
pp. 577-585 ◽  
Author(s):  
S M Felber ◽  
M D Brand

1. Lymphocytes from pig mesenteric lymph node have low permeability to K+ (Rb+), Na+ and Cl-. None of these ions is in Nernst equilibrium with the plasma-membrane potential (delta psi p). 2. delta psi p can be calculated from the transmembrane distribution of the permeant cation methyltriphenylphosphonium (TPMP+) in the presence of the uncoupler carbonyl cyanide p-trifluoromethoxyphenylhydrazone (FCCP) to abolish uptake into intracellular mitochondria. In normal culture medium delta psi p is 56 mV. 3. A similar potential is found in T-enriched pig cells and in mouse thymocytes. 4. The contribution of electrogenic (Na+ + K+)ATPase to delta psi p is about 7 mV. 5. The remainder of the lymphocyte delta psi p is a polyionic potential set up by K+ and Cl- with a permeability coefficient for Cl- of similar magnitude to that for K+.

2019 ◽  
Vol 33 (9) ◽  
pp. 9785-9796 ◽  
Author(s):  
Takuro Numaga‐Tomita ◽  
Tsukasa Shimauchi ◽  
Sayaka Oda ◽  
Tomohiro Tanaka ◽  
Kazuhiro Nishiyama ◽  
...  

1996 ◽  
Vol 314 (2) ◽  
pp. 595-601 ◽  
Author(s):  
Fabienne DEFRISE-QUERTAIN ◽  
Chantal FRASER-L'HOSTIS ◽  
Danièle CORAL ◽  
Jacques DESHUSSES

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.


2019 ◽  
Vol 11 (6) ◽  
pp. 995-1005 ◽  
Author(s):  
Melisa M. Balach ◽  
Cesar H. Casale ◽  
Alexis N. Campetelli

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