scholarly journals Electrical Properties and Excitation-Contraction Coupling in Skeletal Muscle Treated with Ethylene Glycol

1972 ◽  
Vol 60 (2) ◽  
pp. 221-236 ◽  
Author(s):  
Carlos Sevcik ◽  
Toshio Narahashi
Keyword(s):  
Membrane Potential ◽  
Ethylene Glycol ◽  
Control Level ◽  
Membrane Resistance ◽  
Ringer Solution ◽  
Resting Membrane Potential ◽  
Sartorius Muscle ◽  
Frog Sartorius ◽  
Specific Membrane ◽  
Normal Ringer

The contractility of the frog sartorius muscle was suppressed after treatment with a Ringer solution added with ethylene glycol (EGR). No contraction was elicited by nerve stimulation when the muscle was brought back to normal Ringer solution after having been soaked in 876 mM EGR for 4 hr or in 1095 mM EGR for 2 hr. However, the action potential of normal amplitude was generated and followed by a depolarizing afterpotential. The resting membrane potential was slightly decreased from the mean normal value of –91.1 mv to –78.8 mv when 1095 mM EGR was used, and to –82.3 mv when 876 mM EGR was used, but remained almost constant for as long as 2 hr. The afterpotential that follows a train of impulses and a slow change in membrane potential produced by a step hyperpolarizing current (so-called "creep") were suppressed after treatment with ethylene glycol. The specific membrane capacity decreased to about 50% of the control values while the specific membrane resistance increased to about twice the control values Therefore, the membrane time constant remained essentially unchanged. The water content of the muscle decreased by about 30% during a 2 hr immersion in 1095 mM EGR, and increased by about 30% beyond the original control level after bringing the muscle back to normal Ringer. The intracellular potassium content did not change significantly during these procedures. Some differences between the present results and those obtained with glycerol are discussed.

scholarly journals Potassium Exchange and Afterpotentials in Frog Sartorius Muscles Treated with Glycerol

1970 ◽  
Vol 56 (6) ◽  
pp. 692-715 ◽  
Author(s):  
Edward G. Henderson
Keyword(s):  
Membrane Potential ◽  
Action Potentials ◽  
Ringer Solution ◽  
Resting Membrane Potential ◽  
Extracellular Potassium ◽  
Glycerol Treatment ◽  
Treatment Action ◽  
Net Flux ◽  
Potassium Exchange ◽  
Frog Sartorius

The potassium exchange properties of glycerol-treated sartorius muscles of the frog were determined. Potassium (42K) uptake, efflux, and net flux were measured in the presence of glycerol and at various times after exposure to glycerol and return to isotonic Ringer solution. Potassium uptake was not altered by the presence of glycerol but was reduced on the average 53% after glycerol treatment. Efflux transiently increased in the presence of glycerol and was reduced 37% after glycerol removal. Consequently, there was a net loss of intracellular potassium as well as a gain of sodium. In contrast to the irreversible alterations of potassium exchange induced by glycerol treatment, action potentials with normal negative afterpotentials (N.A.P.) were elicited 4–5 hr after glycerol removal. The reappearance of the N.A.P. was associated with a return of the membrane potential to normal values (90 ± 2 mv). However, the response of these muscles to reduced extracellular potassium was anomalous. In K+-free Ringer solution the average resting membrane potential was 74 ± 3 mv and a positive afterpotential of 11 ± 3 mv was associated with the action potential.

Effects of amphotericin B on the electrical properties and electrolyte content of frog sartorius muscle

1980 ◽  
Vol 58 (9) ◽  
pp. 1138-1141 ◽  
Author(s):  
A. Coulombe ◽  
O. F. Schanne ◽  
I. Reisin ◽  
E. Ruiz-Ceretti
Keyword(s):  
Membrane Potential ◽  
Amphotericin B ◽  
Membrane Resistance ◽  
Equilibrium Potential ◽  
Sartorius Muscle ◽  
Sodium Permeability ◽  
A Value ◽  
Goldman Equation ◽  
Frog Sartorius ◽  
B 52

We studied the effect of amphotericin B (52 μM) on the membrane potential, membrane resistance, and intracellular Na+ and K+ concentrations in isolated frog sartorius muscles to characterize further the nature of the ionic conductance induced by the antibiotic. After 5 h of exposure to amphotericin B, the membrane depolarized from −89.9 to −51.0 mV, the membrane resistance decreased from 4537 to 907 Ωcm2, [K]i decreased from 122 to 31.2 mmol/L fiber H2O, and [Na]i increased from 30.9 to 88.7 mmol/L fiber H2O. The relative sodium permeability, PNa/PK, calculated with the Goldman equation remained apparently constant at a value of 0.01 in treated and untreated muscles. We hypothesize that amphotericin B creates either a nonselective cation channel or a completely nonselective ionic leak channel whose equilibrium potential is equal or close to the membrane potential.

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.

Cardiac Ganglion of Limulus: Intracellular Activity in the Unipolar Cells

1970 ◽  
Vol 53 (2) ◽  
pp. 411-423
Author(s):  
VINCENT J. PALESE ◽  
JANE L. BECKER ◽  
RALPH A. PAX
Keyword(s):  
Functional Relationship ◽  
Membrane Resistance ◽  
Recovery Phase ◽  
Resting Membrane Potential ◽  
Cardiac Ganglion ◽  
External Stimulation ◽  
A Value ◽  
Number Of Factors ◽  
Soma Membrane ◽  
Specific Membrane

1. The electrical activity of unipolar cells of the cardiac ganglion of Limulus has been examined with microelectrodes to determine the electrical properties and the functional relationship between unipolar cells. 2. Resting membrane potential in these cell averages -43 mV. 3. Correlated with each contraction of the heart there occurs a burst of activity which consists of a sustained depolarization of several seconds on which is superimposed a series of small 2-5 mV spikes. 4. Activity which occurs during the initial phase appears to be the result of pre-synaptic inputs to these cells. Spike activity during the recovery phase is probably endogenous to the cell from which we are recording. 5. The specific membrane resistance for the soma membrane averages 12700Ω.cm2. The time constant has a value of 19.6ms. The specific membrane capacitance measures endogenous to the cell from which we are recording. 6. External stimulation produces a number of different responses in the unipolar cells which are dependent upon a number of factors. These responses can be classified into at least three types: (a) a driven response similar to a spontaneous burst; (b) slowly rising potentials which may be antidromic spikes.

Electrical and Mechanical Properties of the Red and White Muscles in the Silver Carp

1972 ◽  
Vol 57 (2) ◽  
pp. 551-567
Author(s):  
T. YAMAMOTO
Keyword(s):  
Mechanical Properties ◽  
White Muscle ◽  
Silver Carp ◽  
Membrane Resistance ◽  
Resting Potential ◽  
Resting Membrane Potential ◽  
Mechanical Responses ◽  
Red Muscle ◽  
Red And White Muscles ◽  
Specific Membrane

1. Electrical and mechanical properties of the red muscle (M. levator pinnae pectoralis) and white muscle (M. levator pinnae lateralis abdominis) in the silver carp (Carassius auratus Linné) were investigated by using caffeine and thymol. 2. A complete tetanus could be produced in the red muscle. But in the white muscle no tetanus was produced and there was a gradual decrease in tension during continuous stimulation, even at a frequency of 1 c/s or less. 3. Caffeine (0.5-1 mM) and thymol (0.25-0.5 mM) potentiated the twitch tension in both muscles without an increase in the resting tension; they produced a contracture in both muscles when the concentration was increased further. 4. The falling phase of the active state of contraction was nearly the same in both muscles and was prolonged by caffeine (0.5 mmM) and by thymol (0.25 mM). 5. The resting membrane potential of the red muscle was scarcely affected by caffeine (0.5-5 mM), whereas in the white muscles a depolarization of 10 mV was observed with caffeine of more than 2 mM. The resting potential of both muscles was little changed by o.25 mm thymol. However, at a concentration of more than 0.5mM thymol depolarized the membrane in both muscles to the same extent. 6. In caffeine (2-3 mM) solution the mean specific membrane resistance was reduced from 8.8 kΩ cm2 to 6.0 kΩ cm2 in the red muscle, and from 5.0 kΩ cm2 to 2.7 kΩ cm2 in the white muscle. In thymol (0.5-1 mM) solution it was reduced from 11.2 kΩcm2 to 6.5 kΩ cm2 in the red muscle, and from 5.4kΩ cm2 to 3.1 kΩ) cm2 in the white muscle. The specific membrane capacitance, calculated from the time constant and the membrane resistance, remained more or less the same in both muscles after a treatment with these agents. 7. Electrical properties of the muscles and the effects of caffeine and thymol on mechanical responses suggest that there are no fundamental differences between red and white muscles except for the excitation-contraction coupling. A lack of summation of twitch, a successive decline of twitch, and inability to produce potassium contracture in the white muscle may be due to the fact that the Ca-releasing mechanism is easily inactivated by depolarization of the membrane.

Intracellular pH recovery from lactic acidosis of single skeletal muscle fibres

1988 ◽  
Vol 66 (12) ◽  
pp. 1560-1564 ◽  
Author(s):  
Y. E. Allard
Keyword(s):  
Skeletal Muscle ◽  
Lactic Acid ◽  
Intracellular Ph ◽  
Buffer Capacity ◽  
Ringer Solution ◽  
Sartorius Muscle ◽  
Muscle Fibres ◽  
Diffusion Limited ◽  
Skeletal Muscle Fibres ◽  
Frog Sartorius

Intracellular pH (pHi, measured with H+-selective microelectrodes, in quiescent frog sartorius muscle fibres was 7.29 ± 0.09 (n = 13). Frog muscle fibres were superfused with a modified Ringer solution containing 30 mM HEPES buffer, at extracellular pH (pHo) 7.35. Intracellular pH decreased to 6.45 ± 0.14 (n = 13) following replacement of 30 mM NaCl with sodium lactate (30 mM MES, pHo 6.20). Intracellular pH recovery, upon removal of external lactic acid, depended on the buffer concentration of the modified Ringer solution. The measured values of the pHi recovery rates was 0.06 ± 0.01 ΔpHi/min (n = 5) in 3 mM HEPES and was 0.18 ± 0.06 ΔpHi/min (n = 13) in 30 mM HEPES, pHo 7.35. The Na+–H+ exchange inhibitor amiloride (2 mM) slightly reduced pHi recovery rate. The results indicate that the net proton efflux from lactic acidotic frog skeletal muscle is mainly by lactic acid efflux and is limited by the transmembrane pH gradient which, in turn, depends on the extracellular buffer capacity in the diffusion limited space around the muscle fibres.

Action of acetylcholine, choline and D-tubocurarine on the membrane of frog sartorius muscle fibers

1959 ◽  
Vol 196 (6) ◽  
pp. 1191-1196 ◽  
Author(s):  
S. Ochs ◽  
A. K. Mukherjee
Keyword(s):  
Membrane Potential ◽  
Mechanical Stimulation ◽  
Muscle Fibers ◽  
Potential Drop ◽  
Sartorius Muscle ◽  
End Plate ◽  
Frog Sartorius Muscle ◽  
Before And After ◽  
The Mean ◽  
Frog Sartorius

Resting potentials of frog sartorius muscle fibers were taken with microelectrodes at different distances along the length of muscles before and after adding acetylcholine or choline. The mean membrane potential drop and scatter of the potentials recorded in the relatively nerve-free, and in the more densely innervated parts of the muscle, were similar. The loss of direct excitability to electrical and mechanical stimulation was correlated with the concentration of choline or acetylcholine presented. d-tubocurarine added beforehand protected against the depolarizing effect of acetylcholine and choline everywhere along the length of the muscle. A generalized action of acetylcholine and choline and also of d-tubocurarine all along the muscle fibers was inferred. This generalized action at higher concentrations of acetylcholine and choline is believed to be additional to a more specific end plate action.

Sign in / Sign up

Export Citation Format

Share Document