scholarly journals Carbon dioxide, membrane potential and intracellular potassium activity in frog skeletal muscle.

1980 ◽  
Vol 303 (1) ◽  
pp. 139-152 ◽  
Author(s):  
F Huguenin ◽  
W Reber ◽  
T Zeuthen
Keyword(s):  
Carbon Dioxide ◽  
Skeletal Muscle ◽  
Membrane Potential ◽  
Frog Skeletal Muscle ◽  
Intracellular Potassium ◽  
Intracellular Potassium Activity

Intracellular potassium activities in Amphiuma small intestine

1976 ◽  
Vol 231 (4) ◽  
pp. 1214-1219 ◽  
Author(s):  
JF White
Keyword(s):  
Small Intestine ◽  
Membrane Potential ◽  
Activity Coefficient ◽  
Potassium Concentration ◽  
Equilibrium Potential ◽  
Absorptive Cell ◽  
Buffer Solution ◽  
Intracellular Potassium ◽  
Intracellular Potassium Activity ◽  
Liquid Ion Exchanger

Intracellular potassium activity (aKi) has been determined in absorptive cells lining the villi of isolated, stripped proximal segments of Amphiuma small intestine. With single-barreled liquid ion-exchanger microelectrodes aKi = 41.6 +/- 1.5 mM in normal chloride buffer; with double-barreled microelectrodes constructed by a new method aKi = 38.5 +/- 2.4 mM. Also, by the latter approach aKi = 41.1 +/- 2.1 mM in buffer in which potassium was elevated to 5 meq/liter and aKi = 44.2 +/- 1.3 mM in sulfate buffer with the same bath potassium concentration. Since the calculated potassium equilibrium potential exceeds the membrane potential this ion is accumulated by the intestinal absorptive cell. A major portion of cellular potassium is bound or compartmentalized since the intracellular potassium activity coefficient is very low. A layer exists near the villi in which the potassium activity exceeds that in the bath buffer solution.

scholarly journals Strophanthidin-sensitive sodium fluxes in metabolically poisoned frog skeletal muscle.

1976 ◽  
Vol 68 (4) ◽  
pp. 405-420 ◽  
Author(s):  
B G Kennedy ◽  
P De Weer
Keyword(s):  
Skeletal Muscle ◽  
Membrane Potential ◽  
Human Erythrocyte ◽  
Sodium Pump ◽  
Giant Axon ◽  
Squid Giant Axon ◽  
Frog Skeletal Muscle ◽  
Na Efflux ◽  
Unidirectional Fluxes ◽  
External K

Strophanthidin-sensitive and insensitive unidirectional fluxes of Na were measured in fog sartorius muscles whose internal Na levels were elevated by overnight storage in the cold. ATP levels were lowered, and ADP levels raised, by metabolic poisoning with either 2,4-dinitrofluorobenzene or iodoacetamide. Strophanthidin-sensitive Na efflux and influx both increased after poisoning, while strophanthidin-insensitives fluxes did not. The increase in efflux did not require the presence of external K but was greatly attenuated when Li replaced Na as the major external cation. Membrane potential was not markedly altered by 2,4-dinitrofluorobenzene. These observations indicate that the sodium pump of frog skeletal muscle resembles that of squid giant axon and human erythrocyte in its ability to catalyze Na-Na exchange to an extent determined by intracellular ATP/ADP levels.

Effects of abamectin on intracellular potassium ion activity and membrane potential in dipteran skeletal muscle

1993 ◽  
Vol 37 (1) ◽  
pp. 49-55
Author(s):  
Elizabeth M. Fitzgerald ◽  
Jason Curry ◽  
Mustafa B. A. Djamgoz
Keyword(s):  
Skeletal Muscle ◽  
Membrane Potential ◽  
Potassium Ion ◽  
Intracellular Potassium ◽  
Ion Activity
Sign in / Sign up

Export Citation Format

Share Document