The effect of reserpine and chlorpromazine on the resting potential and the membrane resistance of the frog sartorius muscle after potassium depolarisation

1970 ◽  
Vol 266 (4-5) ◽  
pp. 352-352 ◽  
Keyword(s):  
Membrane Resistance ◽  
Resting Potential ◽  
Sartorius Muscle ◽  
Frog Sartorius Muscle ◽  
Frog Sartorius

The interactive effects of fatigue and pH on the ionic conductance of frog sartorius muscle fibers

1985 ◽  
Vol 63 (11) ◽  
pp. 1444-1453 ◽  
Author(s):  
J. M. Renaud ◽  
G. W. Mainwood
Keyword(s):  
Action Potential ◽  
Normal Values ◽  
Muscle Fibers ◽  
Membrane Conductance ◽  
Interactive Effects ◽  
Resting Potential ◽  
Sartorius Muscle ◽  
Ionic Conductance ◽  
Frog Sartorius Muscle ◽  
Frog Sartorius

The effects of fatigue on the membrane conductance of frog sartorius muscle at the resting potential and during an action potential were studied. When muscles were exposed to an extracellular pH of 8.0 the membrane conductance at the resting potential increased during fatigue by about 20% and returned to prefatigue level in about 20 min. The membrane conductance of muscle fibers exposed to pH 6.4 was about three times less than that of pH 8.0 and decreased further during fatigue. Furthermore, the recovery of a normal membrane conductance was slow at pH 6.4. Both the inward, depolarizing and the outward, repolarizing currents during the action potential are reduced in fatigue. In each case the effect is greater at pH 6.4 than at 8.0 and recovery towards normal values is slower at pH 6.4. It is concluded that the ionic conductance of the sareolemmal membrane at the resting potential and during an action potential are modified by fatigue and that these changes are modulated by pHo.

Effect of dinitrophenol on phosphorylation and bioelectric phenomena of excitable tissues

1961 ◽  
Vol 200 (3) ◽  
pp. 431-436 ◽  
Author(s):  
L. G. Abood ◽  
K. Koketsu ◽  
K. Noda
Keyword(s):  
Energy Metabolism ◽  
Muscle Fibers ◽  
Resting Potential ◽  
Sartorius Muscle ◽  
Nerve Roots ◽  
Intracellular Potassium ◽  
Frog Sartorius Muscle ◽  
Anodal Polarization ◽  
Frog Sartorius

The effect of 2, 4-dinitrophenol (DNP) was investigated on the phosphorylation of frog sartorius muscle and ventral nerve roots, using P32 as a tracer. It was possible almost completely to inhibit phosphorylation without significantly altering excitability, although the resting potential and intracellular potassium decreased over 30%. The addition of 0.01 mm DNP to a sodium-free hydrazinium system completely blocked excitability, despite the fact that this concentration of DNP produced no further inhibition of phosphorylation. It was possible to restore the excitability of frog sartorius muscle fibers by anodal polarization after the fibers were rendered inexcitable by immersion in 1 mm DNP. The results were discussed in terms of the role of energy metabolism in excitability and other bioelectric phenomena of muscle and nerve.

Potassium movements in denervated frog sartorius muscle

1985 ◽  
Vol 248 (3) ◽  
pp. C217-C227 ◽  
Author(s):  
Roque A. Venosa ◽  
Basilio A. Kotsias
Keyword(s):  
Driving Forces ◽  
Resting Potential ◽  
Equilibrium Potential ◽  
Resting Membrane Potential ◽  
Sartorius Muscle ◽  
Experimental Conditions ◽  
Frog Sartorius Muscle ◽  
The Difference ◽  
Denervated Muscles ◽  
Frog Sartorius

The movement of42K+across the sarcolemma and the resting membrane potential ( VM) of normal and denervated frog sartorius muscle were studied under several experimental conditions in preparations initially equilibrated in 100 mM K+and 219 mM Cl-. The results can be summarized as follows. 1) In the absence of any driving force on K+, i.e., when the difference between VMand the K+equilibrium potential ( EK) is zero ( VM- EK= 0), the K+conductance ( gK) was 368 ΜS·cm-2in control and 282 ΜS·cm-2in denervated muscle. 2) The reduced gK of denervated muscles results from the addition of the opposite changes in the conductances of a Rb+-sensitive inward rectifying pathway ( gIR), which decreases, and a Rb+-insensitive linear channel ( gL), which increases. Thus in control muscles gK(368 ΜS·cm-2) equals gIR(359 ΜS·cm-2) plus gL(9 ΜS·cm-2), while in denervated muscles gK(282 ΜS·cm-2) equals gIR(198 ΜS·cm-2) plus gL(84 ΜS·cm-2). 3) Denervation significantly reduces the inward rectifying properties of the resting K+permeability system. In the presence of outward driving forces on K+( VM- EK> 0) of 35-50 mV, the Rb+-sensitive inward rectifier channel appears to close completely in both control and denervated muscles. In the latter, however, the effect was not as well maintained as in the former, suggesting that its closing mechanism might be altered by denervation. 4) No changes were observed during the first 2 wk after denervation.sarcolemma; resting potential; K+equilibrium potential; K+conductanceSubmitted on July 25, 1983Accepted on July 11, 1984

scholarly journals A Study on the Electrical Resistance of the Frog Sartorius Muscle

1966 ◽  
Vol 49 (5) ◽  
pp. 897-912 ◽  
Author(s):  
Otto Schanne ◽  
Hiroshi Kawata ◽  
Bärbel Schäfer ◽  
Marc Lavallée
Keyword(s):  
Muscle Fiber ◽  
Potassium Concentration ◽  
Membrane Resistance ◽  
Ringer Solution ◽  
Effective Resistance ◽  
Sartorius Muscle ◽  
Cable Model ◽  
Frog Sartorius Muscle ◽  
Electrode Resistance ◽  
Frog Sartorius

Four different methods of measuring the resistance of a muscle fiber have been applied to the frog sartorius muscle. The methods, in which the resistance of the microelectrode entered the calculation of the effective resistance of the fiber, resulted in values which were 8 times higher than the resistance values obtained with methods independent of the electrode resistance. A simple cable model of a muscle fiber could not account for the discrepancy in the effective resistance found in these measurements; therefore, an enlarged cable model for a muscle fiber has been proposed, and its biological implications have been discussed. The effective resistance (measured with the two different groups of methods) decreased when the potassium concentration in the bath increased. Using the proposed enlarged cable model for the interpretation of these results, it is shown that not only the membrane resistance but also the myoplasmic resistance decreases with an increasing potassium concentration in the Ringer solution.

Influence of Ouabain, Strophanthidin and Dihydrostrophanthidin on Sodium and Potassium Transport in Frog Sartorii

1956 ◽  
Vol 187 (2) ◽  
pp. 328-332 ◽  
Author(s):  
John A. Johnson
Keyword(s):  
Inhibitory Action ◽  
Potassium Transport ◽  
Resting Potential ◽  
Sartorius Muscle ◽  
Frog Sartorius Muscle ◽  
Frog Sartorius ◽  
Sodium And Potassium

Ouabain and strophanthidin at a concentration of about 10–6 molar appear to inhibit the net transport of sodium out of and of potassium into the cells of the frog sartorius muscle under conditions where transport would otherwise occur. This inhibition occurs without significant effect on the resting potential. Dihydrostrophanthidin, also at a concentration of 10–6 m, failed to show the inhibitory action displayed by ouabain and strophanthidin.

Constancy of Axial Spacings in Frog Sartorius Muscle during Contraction

Nature ◽  
1965 ◽  
Vol 206 (4991) ◽  
pp. 1358-1358 ◽  
Author(s):  
H. E. HUXLEY ◽  
W. BROWN ◽  
K. C. HOLMES
Keyword(s):  
Sartorius Muscle ◽  
Frog Sartorius Muscle ◽  
Frog Sartorius
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