Contraction of frog stomach muscle and frog heart in electrolyte-free solutions

1967 ◽  
Vol 23 (12) ◽  
pp. 996-996 ◽  
Author(s):  
I. Singh ◽  
S. I. Singh
Keyword(s):  
Frog Heart ◽  
Stomach Muscle ◽  
Frog Stomach ◽  
Frog Stomach Muscle

Effect of external sodium on net potassium uptake by frog muscle

1965 ◽  
Vol 208 (1) ◽  
pp. 61-67 ◽  
Author(s):  
W. McD. Armstrong
Keyword(s):  
Room Temperature ◽  
Ringer Solution ◽  
Frog Muscle ◽  
Potassium Uptake ◽  
Partial Replacement ◽  
Stomach Muscle ◽  
K Uptake ◽  
Frog Stomach ◽  
Frog Sartorius ◽  
Frog Stomach Muscle

When longitudinal strips of frog stomach muscle or frog sartorius muscles, previously depleted of K by overnight immersion in the cold in K-free Ringer solution containing 116 mEq Na/liter, were reimmersed at room temperature in solutions containing K, replacement of Na in the recovery fluid by Li or choline inhibited net K uptake by the fibers. Stomach muscles soaked overnight in Na-free solutions containing Li or choline lost K and most of their Na, the Na being replaced by Li and, inferentially, by choline. When these muscles were reimmersed in Na-Ringer solution they accumulated K from the medium. On reimmersion in Na-free Li or choline-Ringer solution no net K uptake occurred. Partial replacement of Li or choline by Na resulted in net K accumulation. Stomach muscles soaked in K-free Na-Ringer solution and subsequently transferred to Na-free solutions containing Cs and K did not accumulate K. Partial replacement of Cs by Na did not affect the inhibition of K uptake by Cs. K accumulation by frog stomach muscle was not affected by cyanide (2 mmoles/liter). These results are compatible with a specific stimulating effect of external Na on K accumulation in frog muscle.

scholarly journals THE EFFECT OF POTASSIUM ON FROG STOMACH MUSCLE

1979 ◽  
Vol 66 (2) ◽  
pp. 303-306 ◽  
Author(s):  
F. BAYSAL ◽  
S. ÖNDER ◽  
M. ÖZGÜL ◽  
A. TOYGAR
Keyword(s):  
Stomach Muscle ◽  
Frog Stomach ◽  
Frog Stomach Muscle

Sodium, potassium, and chloride in frog stomach muscle

1964 ◽  
Vol 206 (3) ◽  
pp. 469-475 ◽  
Author(s):  
William McD. Armstrong
Keyword(s):  
Sharp Increase ◽  
Room Temperature ◽  
Rana Temporaria ◽  
Stomach Muscle ◽  
Total Water ◽  
Sodium Potassium ◽  
Inulin Space ◽  
Frog Stomach ◽  
Total Muscle ◽  
Frog Stomach Muscle

In freshly excised stomach muscles of Rana temporaria total Na was found to be 40.2 ± 6.1 mEq/kg wet wt. Total K was 66.5 ± 4.8 and total Cl was 33.9 ± 3.9 mEq/kg. Total water content was 805 ± 16 g/kg and inulin space was 341 ± 52 ml/kg. The average intrafiber concentrations calculated from these data were 10 mEq Na, 141.5 mEq K, and 18 mEq Cl/ liter fiber water. In muscles immersed overnight at 5 C in Ringer's solutions containing various amounts of KCl, total muscle Cl was a direct linear function of external KCl. When the external KCl concentration was less than 20 mm/liter, muscle K decreased on immersion. Increasing the external KCl from 20 to 40 mm/liter resulted in a sharp increase in muscle K. Further increasing external KCl from 40 to 80 mm/liter had relatively little effect on total muscle K. The Na content of these muscles was in all cases greater than that of freshly excised muscles. Muscles immersed overnight in the cold in K-free solutions gained Na and lost K. On reimmersion at room temperature in solutions containing KCl there was a net loss of Na from and a net gain of K by the fibers. The amount of K taken up was a function of the external KCl concentration. Na loss and K accumulation were inhibited by ouabain and by iodoacetate.

scholarly journals Sodium Flux in the Smooth Muscle of Frog Stomach

1969 ◽  
Vol 54 (1) ◽  
pp. 53-75 ◽  
Author(s):  
Elizabeth W. Stephenson
Keyword(s):  
Normal Solution ◽  
High Rate ◽  
Rate Coefficients ◽  
Stomach Muscle ◽  
Transport Mechanisms ◽  
Normal Muscle ◽  
Simple Diffusion ◽  
Sodium Efflux ◽  
Na Efflux ◽  
Frog Stomach

Sodium efflux from rings of frog stomach muscle was measured at 5° and 15°C in three different steady states. After incubation in normal, K-free, or ouabain (10-4 M) solutions, intracellular cations stabilized at markedly differing levels. At 5°C, inhibition of Na extrusion was shown in the rate coefficients for 22Na efflux, which were slightly smaller in K-free than in normal solutions, and much smaller in ouabain. Due to the intracellular Na concentration differences, total Na efflux was similar in K-free and ouabain solutions, and only ⅕ as large in normal solution. At 15°C, normal total Na flux was only 1/7;–1/10 inhibitors, and may be underestimated. The total flux differences may involve dependence of the Na pump and Na permeation on internal Na concentration. The Q10 of the steady-state fluxes was 3.7 in ouabain, 2.8 in K-free solution, and 1.9 in normal solution. The high temperature dependence of influx as well as efflux suggests transport mechanisms other than simple diffusion. Sodium turnover in the cell water was 46–66 mM/hr in inhibitors at 15°C, and a high rate of Na extrusion in normal muscle is suggested. However, cell volume:surface ratio is only 1.6 µ and all estimates of Na flux were under 3 pmoles/cm2 per sec, indicating low Na permeability.

Potassium flux in smooth muscle of frog stomach

1976 ◽  
Vol 230 (3) ◽  
pp. 743-753
Author(s):  
EW Stephenson
Keyword(s):  
Steady State ◽  
Ethacrynic Acid ◽  
Normal Operation ◽  
Stomach Muscle ◽  
Pump Operation ◽  
Delay Effects ◽  
Saturation Kinetics ◽  
Quasilinear Function ◽  
Frog Stomach ◽  
Low K

In frog stomach muscle fibers, normal steady-state K flux, estimated directly from 42K uptake, was 0.17 pmol/cm2 per s at 5 degrees C and 0.63 pmol/cm2 per s at 15 degrees C. Influx characteristics were studied at 5 degrees C, where backflux and diffusional delay effects are minimized. Steady-state K influx was a saturating function of external [K] over the range 0.25-11 mM [K]o; influx at normal and higher [K]o did not differ significantly. Na loading (in K-free or low K solution) strongly stimulated influx, which showed altered saturation kinetics; maximal K influx was a quasilinear function of internal [Na]. Ouabain (10(-4) M) reduced normal and stimulated K influx markedly. Ethacrynic acid (10(-3) M) caused net K loss and Na gain, but increased K influx fourfold; ouabain inhibited the stimulated influx by 50%. These results indicate that K influx depends mainly on cycling of the Na-K pump and is normally limited by Na efflux. Ethacrynic acid may stimulate another mode of pump operation, K-K exchange, and uncouple the normal operation.

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