scholarly journals Effects of Various Ions on the Resting and Active Membrane of the Somatic Muscle of the Earthworm

1969 ◽  
Vol 50 (2) ◽  
pp. 405-415
Author(s):  
T. HIDAKA ◽  
Y. ITO ◽  
H. KURIYAMA ◽  
N. TASHIRO
Keyword(s):  
Calcium Concentration ◽  
Longitudinal Muscle ◽  
Potassium Concentration ◽  
Resting Potential ◽  
Somatic Muscle ◽  
Membrane Potential Change ◽  
Maximum Slope ◽  
External Potassium ◽  
Maximum Rate Of Rise ◽  
External Calcium

1. The properties of the membrane, in both the resting and the active state, of the longitudinal muscle of the earthworm were studied under various ionic environments. 2. The maximum slope of the membrane potential change against a tenfold change in the external potassium concentration was 27 mV. in the presence of external sodium and 42 mV. in the absence of external sodium. 3. In the normal external potassium concentration the removal of sodium hyper-polarized the membrane from a normal resting potential of -36 to -58 mV. 4. Reduction of the external calcium concentration to a tenth of its normal value depolarized the membrane by about 16 mV. 5. In excess of external potassium the spike height and the after-hyperpolarization were decreased and the duration of the spike was prolonged. 6. In sodium-free solution spikes with an overshoot potential were generated both spontaneously and under the stimulus of an intracellularly depolarizing current. 7. The amplitude and the maximum rate of rise of the spike were dependent on the external calcium concentration, whether or not sodium was present externally. 8. Manganese modified the membrane activity by competition with calcium.

Calcium Spike in the Longitudinal Muscle of the Lobworm, Tylorrynchus Heterochaetus, (Nereidae)

1970 ◽  
Vol 53 (3) ◽  
pp. 597-609
Author(s):  
Y. ITO ◽  
N. TASHIRO
Keyword(s):  
Electrical Stimulation ◽  
Membrane Potential ◽  
Longitudinal Muscle ◽  
Spike Generation ◽  
Somatic Muscle ◽  
Membrane Potential Change ◽  
Maximum Slope ◽  
Phasic Contraction ◽  
Sustained Contraction ◽  
Electrical Activities

1. The mechanical and electrical activities of the longitudinal somatic muscle of the nereid Tylorrynchus heterochaetus were studied by intra- and extracellular stimulating methods. 2. The contraction elicited by electrical stimulation under isometric conditions consisted of two components, i.e. early phasic contraction and sustained contraction. The sustained contraction lasted more than 1 min after the cessation of the tetanic stimulation. 3. The membrane potential was 62.8 mV, and spontaneous discharges with overshoot (mean 18 mV) were recorded. A similar amplitude of the spike could be recorded by the intra-cellular polarizing method. 4. The maximum slope of the membrane potential change against a tenfold change in [K]o was 39 mV in the presence of Na+ and 48 mV in the absence of Na+. 5. The membrane was hyperpolarized by reduction of [Na]o but not by reduction of [Cl]o. 6. Tetrodotoxin (10-5 g/ml) blocked neither spontaneous spike generation nor spikes evoked by electrical stimulation. 7. The spike amplitude (overshoot) was proportionally increased with increased [Ca]o in the absence of Na+. The electrical threshold and the membrane potential remained the same in the ranges of 2 and 200 mM [Ca]o in the absence of Na+. 8. Sr2+ and Ba2+ could produce spike generation in the absence of Na+ and Ca2+. Prolongation of the spike (plateau) was observed when 20 mM Ba2+ was added to the solution containing no Na2+ and Ca2+. 9. The electrical and mechanical properties of the muscle were discussed in comparison with those observed of the longitudinal muscle of the earthworm.

Miniature Excitatory Junction Potentials in the Somatic Muscle of the Earthworm, Pheretima Communissima, in Sodium Free Solution

1969 ◽  
Vol 51 (1) ◽  
pp. 107-118
Author(s):  
Y. ITO ◽  
H. KURIYAMA ◽  
N. TASHIRO
Keyword(s):  
Reversal Potential ◽  
Muscle Layer ◽  
Physiological Solution ◽  
Free Solution ◽  
Somatic Muscle ◽  
Longitudinal Muscle Layer ◽  
High Calcium ◽  
Excitatory Junction Potentials ◽  
External Potassium ◽  
External Calcium

1. Miniature excitatory junction potentials (m.e.j.p.s) could be recorded from the longitudinal muscle layer of earthworm in sodium-free solution. 2. The amplitude and frequency of the m.e.j.p.s indicated the diffuse innervation and random release of the chemical transmitter from the nerve terminals. 3. Generation of the m.e.j.p.s was prevented by treatment with D-tubocurarine, but not by atropine and picrotoxin. 4. Hyperpolarizations of the membrane by applications of inward current increased the frequency and amplitude of the m.e.j.p.s in sodium-free solution. 5. The reversal potential level for the m.e.j.p.s in sodium-free solution was -;20 mV., and this value was 20 mV. negative to that measured in physiological solution. Low-potassium solution shifted the reversal potential levels in a more negative and high-calcium in a less negative direction. 6. The change of the reversal potential produced by a tenfold change of the external potassium concentration was 24.5 mV., and that by change of the external calcium concentration was 17 mV.

scholarly journals Relative Ion Permeabilities in the Crayfish Giant Axon Determined from Rapid External Ion Changes

1967 ◽  
Vol 50 (7) ◽  
pp. 1929-1953 ◽  
Author(s):  
Alfred Strickholm ◽  
B. Gunnar Wallin
Keyword(s):  
Membrane Potential ◽  
Potassium Level ◽  
Potassium Concentration ◽  
Giant Axon ◽  
Resting Potential ◽  
Resting Membrane Potential ◽  
Constant Field ◽  
Appreciable Effect ◽  
Ion Concentrations ◽  
External Potassium

The changes in membrane potential of isolated, single crayfish giant axons following rapid shifts in external ion concentrations have been studied. At normal resting potential the immediate change in membrane potential after a variation in external potassium concentration is quite marked compared to the effect of an equivalent chloride change. If the membrane is depolarized by a maintained potassium elevation, the immediate potential change due to a chloride variation becomes comparable to that of an equivalent potassium change. There is no appreciable effect on membrane potential when external sodium is varied, at normal or at a depolarized membrane potential. Starting from the constant field equation, expressions for the permeability ratios PCl/PK, PNa/PK, and for intracellular potassium and chloride concentrations are derived. At normal resting membrane potential, PCl/PK is 0.13 but at a membrane potential of -53 mv (external potassium level increased about five times) it is 0.85. The intracellular concentrations of potassium and chloride are estimated to be 233 and 34 mM, respectively, and it is pointed out that this is not compatible with ions distributed in a Nernst equilibrium across the membrane. It is also stressed that the information given by a plot of membrane potential vs. the logarithm of external potassium concentrations is very limited and rests upon several important assumptions.

Cation Contributions To Potentiometric Dye Responses In Human Platelets

1981 ◽  
Author(s):  
Jonathan L Miller ◽  
Theodore M Mazer
Keyword(s):  
Potassium Concentration ◽  
Calcium Ionophore ◽  
Human Platelets ◽  
Calcium Ionophore A23187 ◽  
Ionophore A23187 ◽  
Electrochemical Gradient ◽  
Activated State ◽  
External Potassium ◽  
Low Levels ◽  
External Calcium

The potentiometric dye, Di-S-C3(5) (0.9μM) was incubated with stirred suspensions of-3washed human platelets (5-6 × 104μl) in buffer containing 137mM NaCl, 2.7mM KCl, 0.2% dextrose, and 25mM Tris-HCl, pH 7.4 in an Ami neo-Bowman fluorometer, with excitation λ 620nm and emmision λ 680nm. Equilibrium levels of fluorescence (F) nearly doubled as external potassium concentration (K °) was increased from 2.7mM to 105.6mM. Addition of°2mM CaCl2 always produced immediate transient increases in F, regardless of K0 , in contrast to the increases or decreases produced by the potassium ionophore, valino- mycin (VAL) (5μM) in adherance to the electrochemical gradient determined by the choice of K°. Equilibrium F was also relatively insensitive to external calcium (Ca°) at either high or low levels of K . However, add?tion of the calcium ionophore, A23187 (10μM) produced immediate increases in F, with peak values (F-A23peak) increasing sharply with increasing Ca°. At a given Ca the F-A23peak was insensitve to K ° however, with the prior addition of VAL, F-A23peak became sensitive to K , particularly so at the lowest values of K° , where the F-A23peak was significantly lower in tne presence than in the absence of VAL. Replacement of sodium by choline had no significant effect on equilibrium F or on responses to VAL or to A23187- Platelet agglutination induced by ristocetin plus cryoprecipitate was not accompanied by similar increases in F.These findings suggest that Di – S–C3 F reflects a strong contribution of potassium permeability in the resting state, with relatively little contribution by calcium. Production of an activated state in platelets by A23187, in contrast, results in an increase in F that appears to reflect a major contribution by calcium.

scholarly journals EFFECTS OF EXTERNAL IONS ON MEMBRANE POTENTIALS OF A CRAYFISH GIANT AXON

1959 ◽  
Vol 42 (5) ◽  
pp. 971-982 ◽  
Author(s):  
John C. Dalton ◽  
Keyword(s):  
Action Potential ◽  
Inverse Function ◽  
Giant Axon ◽  
Sodium Concentration ◽  
Resting Potential ◽  
Transmembrane Potentials ◽  
External Potassium ◽  
Ionic Effects ◽  
External Calcium ◽  
Good Agreement

Transmembrane potentials in the crayfish giant axon have been investigated as a function of the concentration of normally occurring external cations. Results have been compared with data already available for the lobster and squid giant axons. The magnitude of the action potential was shown to be a linear function of the log of the external sodium concentration, as would be predicted for an ideal sodium electrode. The resting potential is an inverse function of the external potassium concentration, but behaves as an ideal potassium electrode only at the higher external concentrations of potassium. Decrease in external calcium results in a decrease in both resting potential and action potential; an increase in external calcium above normal has no effect on magnitude of transmembrane potentials. Magnesium can partially substitute for calcium in the maintenance of normal action potential magnitude, but appears to have very little effect on resting potential. All ionic effects studied are completely reversible. The results are in generally good agreement with data presently available for the lobster giant axon and for the squid giant axon.

Resting potential dependency on external potassium in Amphioxus muscle

1965 ◽  
Vol 208 (5) ◽  
pp. 852-854 ◽  
Author(s):  
Donald S. Geduldig
Keyword(s):  
Membrane Potential ◽  
Relative Permeability ◽  
Resting State ◽  
Potential Versus ◽  
Potassium Concentration ◽  
Structural Features ◽  
Resting Potential ◽  
Semilogarithmic Plot ◽  
External Potassium

The resting potential of Amphioxus muscle was determined by using an internal micropipet electrode. The effect of external potassium concentration was studied. From the curvature of the semilogarithmic plot of membrane potential versus external potassium concentration, an estimate can be made of the relative permeability of the membrane (in the resting state) to Na+ and K+. The permeability to sodium is 0.03 of the permeability to potassium. Structural features which may be responsible for this permeability difference are noted.

Contractile repriming of single muscle fibers: inactivation and tubular diffusion

1975 ◽  
Vol 229 (6) ◽  
pp. 1498-1504 ◽  
Author(s):  
SC Stuesse ◽  
BD Lindley
Keyword(s):  
Calcium Concentration ◽  
Potassium Concentration ◽  
Recovery Period ◽  
Transverse Tubular System ◽  
Significant Difference ◽  
Maximal Tension ◽  
Tubular System ◽  
The Times ◽  
Fiber Radius ◽  
External Calcium

Following maximal potassium contractures of isolated single fibers from Rana pipiens, a brief recovery period is required to restore the ability to produce maximal tension by subsequent depolarization. At normal potassium concentration (2.5 mM), there is a minimal lag time of 5 s before any tension is produced by a second exposure to elevated K+; half-maximal tension can be produced in 13 s. The rate of repriming is directly related to the square of the fiber radius and is slowed by lowering external calcium concentration (1.5-0.4 mM). There is no significant difference in any of these respects between normal fibers and fibers dissected from semitendinosus muscles which had been chronically denervated for periods of up to 8 wk. Increased potassium concentration (5-20 mM) in the recovery solution decreased the steady-state repriming level, affecting denervated fibers more than controls. No repriming occurred at concentrations above 20 mM (-48 mV membrane potential.) At these intermediate concentrations, repriming was less complete in denervated muscle, reflecting the increased speed of delayed contractile inactivation. From the times to 50% repriming, which were proportional to the square of fiber radius, we estimated an upper limit for the diffusion coefficient for K+ in the transverse tubular system of 0.3 X 10(-6) cm2/s for both control and chronically denervated fibers.

scholarly journals Some Relations between Action Potential and Resting Potential of the Lobster Giant Axon

1960 ◽  
Vol 43 (3) ◽  
pp. 597-607 ◽  
Author(s):  
J. C. Dalton ◽  
W. J. Adelman
Keyword(s):  
Action Potential ◽  
Initial Conditions ◽  
Giant Axon ◽  
Analog Computer ◽  
Resting Potential ◽  
Quantitative Relation ◽  
High Potassium ◽  
Axon Membrane ◽  
External Potassium ◽  
External Calcium

Experiments were performed to determine the quantitative relation existing between action potential and resting potential of the lobster giant axon. Resting potential changes were induced by either increasing the external potassium concentration or by reducing the external calcium concentration. For either treatment the action potential amplitude is proportional to the logarithm of the resting potential minus a constant. This constant is equivalent to the minimum resting potential at which a propagated spike is possible, and is larger for depolarization in low calcium than in high potassium. Thus the change in action potential per unit change in resting potential is greater in low external calcium than in high external potassium. Analog computer solutions to the Hodgkin-Huxley equations for squid axon membrane potentials show that, if the initial conditions are properly specified, the action potential is proportional to the logarithm of the potassium potential minus a constant. The experimental results and the analog computations suggest that reducing external calcium produces changes in the invertebrate axon that cannot be accounted for solely on the basis of alterations in the potassium potential.

scholarly journals Expressed Na channel clones differ in their sensitivity to external calcium concentration

1992 ◽  
Vol 62 (1) ◽  
pp. 37-40 ◽  
Author(s):  
M. Chahine ◽  
L.Q. Chen ◽  
R.G. Kallen ◽  
R.L. Barchi ◽  
R. Horn
Keyword(s):  
Calcium Concentration ◽  
Na Channel ◽  
External Calcium

Studies on the mechanism of fluid secretion by isolated salivary glands of Calliphora

1976 ◽  
Vol 64 (2) ◽  
pp. 311-322
Author(s):  
M. J. Berridge ◽  
B. D. Lindley ◽  
W. T. Prince
Keyword(s):  
Salivary Glands ◽  
Apical Membrane ◽  
Potassium Concentration ◽  
Basal Membrane ◽  
Fluid Secretion ◽  
Sodium Permeability ◽  
Bathing Medium ◽  
Major Cation ◽  
Diuretic Agent ◽  
External Potassium

1. Potassium is the major cation in the secretion of the salivary glands of Calliphora and is necessary for full secretory rates. 2. Other ions (rubidium and sodium) can support secretion in the absence of potassium. 39. During stimulation with 5-HT a Nernst plot of the basal membrane potential has a slope of 53 mV for a tenfold change in external potassium concentration and the slope at rest deviates from this over the range I-20 mM external potassium. 4. Hyperpolarization of the basal membrane by 5-HT is abolished if the chloride in the bathing medium is replaced by isethionate. 5. The diuretic agent amiloride inhibits fluid secretion by a mechanism which may include a reduction in calcium entry in addition to its recognized effect on sodium permeability. 6. A model is proposed in which fluid secretion is driven by the active transport of potassium across the apical membrane with chloride following passively.

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