Intracellular ion concentrations in the frog cornea epithelium during stimulation and inhibition of Cl secretion

1987 ◽  
Vol 95 (3) ◽  
pp. 229-240 ◽  
Author(s):  
Roger Rick ◽  
Franz X. Beck ◽  
Adolf Dörge ◽  
Klaus Thurau
Keyword(s):  
Ion Concentrations ◽  
Cl Secretion ◽  
Intracellular Ion Concentrations ◽  
Cornea Epithelium ◽  
Frog Cornea

X-ray microanalysis of intracellular ions in the anaerobic halophilic eubacterium Haloanaerobium praevalens

1997 ◽  
Vol 43 (6) ◽  
pp. 588-592 ◽  
Author(s):  
Aharon Oren ◽  
Mikal Heldal ◽  
Svein Norland
Keyword(s):  
Electron Microscope ◽  
High Variability ◽  
Sodium Potassium ◽  
X Ray ◽  
Ion Concentrations ◽  
Major Cation ◽  
Transmission Electron ◽  
Intracellular Ion Concentrations ◽  
Intracellular Ions ◽  
Chloride Concentrations

The intracellular concentrations of Na+, K+, and Cl− of the anaerobic halophilic eubacterium Haloanaerobium praevalens were assayed by means of X-ray microanalysis with the transmission electron microscope. Apparent intracellular cation concentrations between 1.22 and 1.91 M and chloride concentrations of 0.93–1.57 M were measured in cells growing exponentially in 2.6 M total salts. In exponentially growing cells, K+ was the major cation (70% of the cation sum). Stationary phase cells showed a high variability among individual cells, some of the cells containing higher Na+ than K+ concentrations.Key words: Haloanaerobium praevalens, intracellular ion concentrations, sodium, potassium, X-ray microanalysis.

Characterization in vitro of H+ secretion and H+:Na+ exchange by an organism normally inhabiting a CO2-rich environment: Hymenolepis diminuta (Cestoda) in the rat intestine

1978 ◽  
Vol 56 (11) ◽  
pp. 2344-2354 ◽  
Author(s):  
R. B. Podesta
Keyword(s):  
Metabolic Pathways ◽  
Intestinal Parasite ◽  
Hymenolepis Diminuta ◽  
Ambient Fluid ◽  
Rat Intestine ◽  
Ion Concentrations ◽  
Intracellular Ion Concentrations ◽  
Metabolic Reactions ◽  
Stimulation Of

H+ and Na+ transport by the intestinal parasite Hymenolepis diminuta were studied in vitro. The flatworms acidified the ambient fluid by secreting H+ and the acidification could not be correlated with organic acid excretion. Ambient CO2-independent H+ secretion was attributed to protons of metabolic origin: dephosphorylation reactions and ionization of organic acids within the tissues. Ambient CO2-dependent H+ secretion was attributed to protons produced as a result of the hydration of CO2 within the tissue and to the stimulation of anaerobic metabolic pathways by CO2 acting as a cosubstrate in energy metabolism. Studies in which Na+ uptake was stimulated by CO2 or glucose and inhibited by ouabain, amiloride, or Na+ replacement suggested a partial direct coupling of Na+ absorption and H+ secretion but the different activation energies and the effect of buffer anions other than HCO3− suggested an indirect interaction. Various interactions were considered, including the effect of CO2 and intracellular ion concentrations on metabolic reactions leading to the supply of protons for H+ secretion and energy for ion transport.

The effects of thiocyanate on the intracellular ion concentrations of branchial epithelial cells of brown trout

1995 ◽  
Vol 198 (5) ◽  
pp. 1229-1232 ◽  
Author(s):  
I J Morgan ◽  
W T W Potts
Keyword(s):  
Epithelial Cells ◽  
Brown Trout ◽  
Salmo Trutta ◽  
Sodium Concentration ◽  
Phosphorus Concentration ◽  
Similar Amount ◽  
Ion Concentrations ◽  
Chloride Uptake ◽  
Intracellular Ion Concentrations ◽  
Brown Trout Salmo Trutta

Exposure of brown trout (Salmo trutta) in fresh water to 0.15 mmol l-1 external thiocyanate for 1 h resulted in a significant decrease in chlorine concentration in the branchial mitochondria-rich (MR) cells from 37 mmol l-1 to 22 mmol l-1. The intracellular sodium concentration in these cells decreased by a similar amount, whilst the intracellular phosphorus concentration increased significantly. In contrast to the MR cells, 0.15 mmol l-1 external thiocyanate had no effect on the intracellular ion concentrations in the pavement epithelial cells. Thiocyanate is known to inhibit chloride uptake in a number of freshwater animals and therefore these data suggest that it is only the MR cells that are involved in the uptake of Cl- in brown trout.

scholarly journals A four-electrode method to study dynamics of ion activity and transport in skeletal muscle fibers

2019 ◽  
Vol 151 (9) ◽  
pp. 1146-1155 ◽  
Author(s):  
Judith A. Heiny ◽  
Stephen C. Cannon ◽  
Marino DiFranco
Keyword(s):  
Skeletal Muscle ◽  
Muscle Fibers ◽  
Ionic Current ◽  
Transport Mechanisms ◽  
Electrical Stability ◽  
Ion Concentrations ◽  
Cell Functions ◽  
Skeletal Muscle Fibers ◽  
Intracellular Ion Concentrations ◽  
Ion Movements

Ion movements across biological membranes, driven by electrochemical gradients or active transport mechanisms, control essential cell functions. Membrane ion movements can manifest as electrogenic currents or electroneutral fluxes, and either process can alter the extracellular and/or intracellular concentration of the transported ions. Classic electrophysiological methods allow accurate measurement of membrane ion movements when the transport mechanism produces a net ionic current; however, they cannot directly measure electroneutral fluxes and do not detect any accompanying change in intracellular ion concentrations. Here, we developed a method for simultaneously measuring ion movements and the accompanying dynamic changes in intracellular ion concentrations in intact skeletal muscle fibers under voltage or current clamp in real time. The method combines a two-microelectrode voltage clamp with ion-selective and reference microelectrodes (four-electrode system). We validate the electrical stability of the system and the viability of the preparation for periods of ∼1 h. We demonstrate the power of this method with measurements of intracellular Cl−, H+, and Na+ to show (a) voltage-dependent redistribution of Cl− ions; (b) intracellular pH changes induced by changes in extracellular pCO2; and (c) electroneutral and electrogenic Na+ movements controlled by the Na,K-ATPase. The method is useful for studying a range of transport mechanisms in many cell types, particularly when the transmembrane ion movements are electrically silent and/or when the transport activity measurably changes the intracellular activity of a transported ion.

Effect of melittin on the apical membrane Na+ and C1- conductances of frog cornea epithelium

1997 ◽  
Vol 75 (3) ◽  
pp. 199-204
Author(s):  
G. Carrasquer ◽  
S. Yang ◽  
M. Schwartz ◽  
M.A. Dinno
Keyword(s):  
Apical Membrane ◽  
Cornea Epithelium ◽  
Frog Cornea
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