Some effects of Ca‐free choline—Ringer solution on frog skeletal muscle

Curtis, Brian

doi:10.1113/jphysiol.1963.sp007091

Cited by 51 publications

(34 citation statements)

References 23 publications

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“…Frank (1958), using a paraffin-gap recording technique, reported that the depolarization produced by potassium chloride, and by implication the resting potential, was not affected by calcium depletion in the toe muscle of the frog. It is possible that the toe muscle is different in this respect to the frog sartorius muscle, in which the fall is now well documented (Bulbring et al 1956;Ishiko & Sato, 1957;Edman & Grieve, 1961;Koketsu & Noda, 1962); however, Curtis (1963) has also described a fall of resting potential in the toe muscle, using intracellular microelectrodes.…”

Section: Resultsmentioning

confidence: 99%

“…There are no reports in the literature regarding the influence of calcium on the membrane potential at which inactivation of the excitation-contraction coupling system occurs. Increased calcium concentration causes an increase in the mechanical threshold potential of roughly the same size as the change in critical potential at which a spike arises in nerve (Hodgkin & Horowicz, unpublished); however, a decreased calcium concentration has been reported to leave the mechanical threshold potential unaffected (Curtis, 1963). While further work on this point is obviously required, it is worth noting that an effect of calcium on the mechanical inactivation potential, analogous to that produced on the inactivation potential in nerve, provides a satisfactory explanation of the results presented here.…”

Section: Resultsmentioning

confidence: 99%

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The role of resting potential changes in the contractile failure of frog sartorius muscles during calcium deprivation

Jenden¹,

Reger²

1963

The Journal of Physiology

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

The role of resting potential changes in the contractile failure of frog sartorius muscles during calcium deprivation

Jenden¹,

Reger²

1963

The Journal of Physiology

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“…Hodgkin & Horowicz (1960) showed that a second contracture could only be produced after the coupling process had been 'primed' by repolarization of the membrane in a solution of relatively low potassium-ion concentration for a sufficient time. Potassium contractures in frog toe muscles, which are composed mainly of twitch fibres, are abolished by treatment of the muscle with calcium-free solutions (Frank, 1960), but Curtis (1963) showed that, under these conditions, contractions in response to depolarizing pulses applied through an intracellular electrode could be restored by passing hyperpolarizing current through the membrane. Jenden & Reger (1963) suggested that the contractile failure of frog sartorius muscles in calcium-free solutions was due to two processes: (i) the fall in resting potential which occurred, and (ii) a rise in the potential at which the coupling process could be 'primed'.…”

Section: Calcium Ions and Insect Musclementioning

confidence: 99%

The effect of calcium ions on potassium contracture in a locust leg muscle

Aidley¹

1965

The Journal of Physiology

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It seems very probable that movement of calcium ions is involved in the excitation-contraction coupling process in vertebrate muscle. The presence of calcium ions in the extracellular fluid appears to be necessary for the production of potassium contractures in vertebrate skeletal (Frank, 1960; Liittgau, 1963), heart (Niedergerke, 1956) and smooth muscle (Edman & Schild, 1962). In contrast to these observations, Hoyle (1961) found that potassium contractures of a locust spiracular muscle were maintained for as long as 17 hr in isotonic solutions of potassium chloride or sulphate in the absence of calcium. These results raised the possibility that excitationcontraction coupling in insect muscles does not involve calcium ions.This paper reports the results of experiments on the effect of calcium ions on isometric potassium contractures in a locust leg muscle. A preliminary report of some of this work has appeared elsewhere (Aidley, 1963). METHODSThe experiments were performed on the extensor tibialis of the mesothoracic leg of the locust Schistocerca gregaria.Tension recording. After light carbon dioxide anaesthesia, the head, abdomen, wings and gut of the insect were removed. The thorax was placed in a T-shaped Perspex chamber with the right mesothoracic leg projecting into the 'stem' of the T (Fig. 1). The leg was thus contained in an isolated cell through which physiological saline could be circulated. The femur was attached to the floor of the cell with Eastman 910 adhesive, and the coxa and base of the femur were firmly fixed with dental cement in the slot in the wall dividing the two sections of the chamber. A silk thread was tied round the tibia (the knot being cemented with Eastman 910 adhesive) and its other end was tied to a 5-link length of fine chain. A movable brass hook engaged the distal link of this chain and served to hold the tibia in the extended position during the dissection. The ventral cuticle and flexor tibialis muscle were removed from the femur and the femoro-tibial joint was then dissected so that contraction of the muscle caused the tibia to move horizontally along its axis. The ventral cuticle of the thorax was removed so as to expose the motor nerves; these could be stimulated by square pulses applied through chlorided silver wire electrodes.Tension was recorded by means of an RCA type 5734 transducer valve. The anode peg was extended by a short length of hypodermic tubing and a stainless-steel hook; the * Present address: Department of Zoology, University of Oxford.

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“…When the ionic composition of this solution was varied, the tonicity was held constant by adjusting appropriately the concentration of the NaCl. Since solutions deficient in both Ca and Mg are deleterious to nerve and muscle (Biilbring, Hollman & Liillman, 1956;Curtis, 1963;Jenden & Reger, 1963;Frankenhauser, 1957), we added Mg to all the low-Ca solutions. In our initial experiments 4 mM-Mg was used since this concentration of Mg has roughly the same effect on nerve excitability as does the Ringer concentration of Ca (Frankenhauser & Meves, 1958).…”

Section: Methodsmentioning

confidence: 99%

Effects of calcium and magnesium on the frequency of miniature end‐plate potentials during prolonged tetanization

Hurlbut¹,

Longenecker²,

Mauro³

1971

The Journal of Physiology

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1. End‐plate potentials (e.p.p.s) and miniature end‐plate potentials (min.e.p.p.s) were recorded intracellularly from the cutaneous pectoris nerve‐muscle preparation of the frog during prolonged stimulation at low frequencies (5/sec—50/sec). 2. When Ca was present in the bathing solution, the quantum content of the e.p.p. and the frequency of occurrence of the min.e.p.p.s gradually increased during the period of stimulation. During the first few minutes of stimulation, the min.e.p.p. frequency increased linearly with time, and the rate of increase was dependent on the Ca concentration of the bathing solution. However, Mg had no effect on this Ca‐dependent increase in min.e.p.p. frequency. 3. A large maintained increase in min.e.p.p. frequency also occurred during prolonged stimulation in solutions that contained no added Ca and 1‐2 m M‐EGTA. Under these conditions the increase in min.e.p.p. frequency was dependent on the Mg concentration of the bathing solution and was exponential in time. 4. It is suggested that the rise in min.e.p.p. frequency is caused by an accumulation of Ca or Mg ions in the nerve terminal, and it is suggested that these ions enter the terminal at relatively non‐specific sites distinct from the Ca‐specific sites that trigger the ‘phasic’ release of transmitter.

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Some effects of Ca‐free choline—Ringer solution on frog skeletal muscle

Cited by 51 publications

References 23 publications

The role of resting potential changes in the contractile failure of frog sartorius muscles during calcium deprivation

The role of resting potential changes in the contractile failure of frog sartorius muscles during calcium deprivation

The effect of calcium ions on potassium contracture in a locust leg muscle

Effects of calcium and magnesium on the frequency of miniature end‐plate potentials during prolonged tetanization

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