The ineffectiveness of the ‘window field’ in the initiation of muscle contraction

Sten‐Knudsen, O.

doi:10.1113/jphysiol.1954.sp005167

Cited by 48 publications

(32 citation statements)

References 5 publications

(10 reference statements)

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“…Our experiments on the non-propagating muscle give essentially the same result as those of Sten-Knudsen (1954), i.e. that sinusoidal stimulation at 1000 cls, 4 V/cm (r.m.s.)…”

Section: Discussionsupporting

confidence: 80%

“…Gerard & Jenerick, 1953). A similar depolarization can be produced by applying alternating current (Katz & Lou, 1947;Sten-Knudsen, 1954). The advantage of using alternating current is that there is no electrolysis (which damages the muscle), and quite reproducible results are obtained with field strengths up to 6 V/cm (r.m.s.).…”

Section: Local Responsesmentioning

confidence: 87%

“…The advantage of using alternating current is that there is no electrolysis (which damages the muscle), and quite reproducible results are obtained with field strengths up to 6 V/cm (r.m.s.). By using massive electrodes, a large fraction of the muscle can be activated at once in this way, with tension development amounting to 80 % of the tetanic tension (Sten-Knudsen, 1954), in the extensor A. CSAPO AND D. R. WILKIE digiti IV of the frog. In later experiments (private communication, 1955), he gets as much as 92 % under optimal conditions (1000 c/s, 6 V/cm (r.m.s.).…”

Section: Local Responsesmentioning

confidence: 99%

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The dynamics of the effect of potassium on frog's muscle

Csapo¹,

Wilkie²

1956

The Journal of Physiology

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“…Our experiments on the non-propagating muscle give essentially the same result as those of Sten-Knudsen (1954), i.e. that sinusoidal stimulation at 1000 cls, 4 V/cm (r.m.s.)…”

Section: Discussionsupporting

confidence: 80%

Section: Local Responsesmentioning

confidence: 87%

Section: Local Responsesmentioning

confidence: 99%

See 1 more Smart Citation

The dynamics of the effect of potassium on frog's muscle

Csapo¹,

Wilkie²

1956

The Journal of Physiology

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“…It is well established that contraction of skeletal muscle fibres is initiated by fibre depolarization (Kuffler, 1946;Sten-Knudsen, 1954, 1960Hodgkin & Horowicz, 1960) and that to be effective, the depolarization must include membranes of the transverse (T -) tubular system (Huxley & Taylor, 1958;Huxley & Straub, 1958). It is also well established that the myofilaments in skeletal muscle are converted from an inhibited to a disinhibited mechanochemical state by calcium binding to troponin molecules on the thin filaments (cf.…”

Section: Introductionmentioning

confidence: 99%

Contractile activation by voltage clamp depolarization of cut skeletal muscle fibres.

Kovács¹,

Schneider²

1978

The Journal of Physiology

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SUMMARY1. Single frog skeletal muscle fibres bathed in a relaxing solution were cut close to the tendon and mounted across a single Vaseline gap so that a short segment of intact terminated fibre extended beyond one side of the gap.2. A compensating circuit, set with a micro-electrode in the terminated fibre segment, was used both to correct total current for external current crossing the gap and to correct pool voltage for the voltage drop across the fibre segment in the gap.3. The micro-electrode was then removed and the fibre voltage-clamped using the compensating circuit. This allowed movement without damage under controlled voltage.4. Strength-duration curves for contraction thresholds of cut fibres exposed externally to TTX Ringer solution and internally to a predominantly K glutamate solution were similar to strength-duration curves reported for intact fibres.5. The change from TTX Ringer to a predominantly (TEA)2SO4 external solution shifted the strength-duration curve for cut fibre contraction thresholds in the negative direction as reported for intact fibres.6. When studied at 3-4 00, fibres from warm-adapted frogs appeared to have higher contraction thresholds than fibres from cold-adapted frogs.7. Delayed rectifier currents recorded from cut fibres were similar to those reported for intact fibres.

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“…However, little information is at present available about the accommodation of excitation-contraction coupling mechanism within a muscle fibre, though it is generally believed that the first step leading to contraction in muscle is normally a reduction of membrane potential, i.e. depolarization (Kuffler, 1946;Sten-Knudsen, 1954Huxley & Taylor, 1958;Watanabe, 1958; for contrary views see Csapo & Suzuki, 1958;Girardier, Reuben, Brandt & Grundfest, 1963;Reuben, Brandt, Garcia & Grundfest, 1967).…”

Section: Introductionmentioning

confidence: 99%

Local activation of frog muscle fibres with linearly rising currents

Sugi¹

1968

The Journal of Physiology

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SUMMARY1. Single fast muscle fibres isolated from the semitendinosus muscles of the frog were locally activated by applying linearly rising current pulses to a pipette whose tip (diameter, 10-40,u) was in contact with the fibre surface.2. In normal or choline-Ringer solution with 1P8 mM-Ca, the threshold depolarization for producing a just perceptible local contraction was nearly constant over a wide range of the duration of linearly rising currents (0-5-20 sec or more).3. If [Ca]o was reduced to 0-25-0 1 mm, the threshold depolarization increased steeply with the increase in the duration of linearly rising currents, indicating a marked increase in the rate of an accommodation process in excitation-contraction coupling mechanism.

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The ineffectiveness of the ‘window field’ in the initiation of muscle contraction

Cited by 48 publications

References 5 publications

The dynamics of the effect of potassium on frog's muscle

The dynamics of the effect of potassium on frog's muscle

Contractile activation by voltage clamp depolarization of cut skeletal muscle fibres.

Local activation of frog muscle fibres with linearly rising currents

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