Hypokalemic periodic paralysis: In vitro investigation of muscle fiber membrane parameters

@article{Rudel1984HypokalemicPP,
  title={Hypokalemic periodic paralysis: In vitro investigation of muscle fiber membrane parameters},
  author={Reinhardt Rüdel and Frank Lehmann-Horn and Kenneth Ricker and Gerald K{\"u}ther},
  journal={Muscle \& Nerve},
  year={1984},
  volume={7}
}
To study the mechanism of attacks in familial hypokalemic paralysis, we recorded resting membrane potentials, action potentials, current–voltage relationships, and isometric forces in intercostal muscle fibers from three patients. In normal extracellular medium, the resting potential was reduced, but membrane conductance was not different from control. Excitability was reduced and the action potentials had no overshoot. On exposure to a 1‐mM potassium solution, with or without insulin, the… 

Insulin acts in hypokalemic periodic paralysis by reducing inward rectifier K+ current.

  • R. Ruff
  • Biology, Medicine
    Neurology
  • 1999
Insulin potentiates depolarization of hypokalemic periodic paralysis (HypoPP) fibers by reducing inward rectifier K+ conductance and indirectly derange membrane excitability by altering the function of other membrane channels.

Membrane defects in paramyotonia congenita (eulenburg)

The previous conclusion that the Cl conductance at 27°C was also increased when TTX was present was not confirmed and the Cl permeability was shown to be normal even in the cold.

Adynamia episodica hereditaria with myotonia: A non‐inactivating sodium current and the effect of extracellular pH

Lowering of the extracellular pH did not influence the resting potential, but it effectively antagonized or prevented the paralytic effect of high [K]e by changing the inactivation characteristics of the sodium channels.

Membrane currents in human intercostal muscle at varied extracellular potassium

Hyperpolarizing and depolarizing square steps were imposed on the membrane potential of excised human intercostal muscle fibers by means of a 3‐microelectrode voltage clamp, and the results were qualitatively similar to those reported for rat skeletal muscle.

Schwartz–Jampel syndrome: II. Na+ channel defect causes myotonia

It is hypothesized that altered membrane conductances are responsible for the hyperexcitability and the associated slowed relaxation in skeletal muscle fibers from a patient with Schwartz–Jampel syndrome.

Skeletal muscle sodium current is reduced in hypokalemic periodic paralysis.

  • R. Ruff
  • Biology
    Proceedings of the National Academy of Sciences of the United States of America
  • 2000
This issue defined some of the abnormalities in surface membrane ionic currents that are responsible for the phenotype of HypoPP and described five families, each of which had one of two mutations Arg-672→His or Arg-674→Gly.

An important piece has been placed in the puzzle of hypokalemic periodic paralysis

A common mechanism causing the depolarization in HypoPP—though not the paramyotonia—for all the known NaV1.4 channel mutations associated with Hypo PP is established.

Paradoxical depolarization of BA2+‐ treated muscle exposed to low extracellular K+: Insights into resting potential abnormalities in hypokalemic paralysis

A quantitative computer model of resting ionic conductances was constructed, and simulations demonstrated that small alterations to resting conductances, such as adding a low‐amplitude aberrant inward current flowing through “gating pores” in mutant Na+ channels causing HypoPP‐2, can promote paradoxical depolarization in low K+.

Transient weakness and altered membrane characteristic in recessive generalized myotonia (Becker)

The electrical instability of the membrane and the transient weakness can be explained on the basis of the N‐shaped membrane characteristic.

Enhancement of K+ conductance improves in vitro the contraction force of skeletal muscle in hypokalemic periodic paralysis

Recordings of intracellular K+ and Cl− activities in human muscle and isolated rat soleus muscle support the view that cromakalim enhances the membrane K+ conductance (gK+), indicating that K+ channel openers may have a beneficial effect in primary hypokalemic periodic paralysis.
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References

SHOWING 1-10 OF 45 REFERENCES

Two cases of adynamia episodica hereditaria: In vitro investigation of muscle cell membrane and contraction parameters

Membrane potentials, current–voltage relationships, and contractile parameters were studied in intact muscle cell bundles obtained from two patients with adynamia episodica hereditaria, finding that the reason for this paralysis was a reduced excitability.

Membrane currents in human intercostal muscle at varied extracellular potassium

Hyperpolarizing and depolarizing square steps were imposed on the membrane potential of excised human intercostal muscle fibers by means of a 3‐microelectrode voltage clamp, and the results were qualitatively similar to those reported for rat skeletal muscle.

Calcium activation of electrically inexcitable muscle fibers in primary hypokalemic periodic paralysis

The electrical inexcitability of muscle fibers in periodic paralysis could be due to one or more of the following derangements in the currently accepted scheme of events of excitation-contraction coupling: failure of synaptic transmission to generate an end-plate potential which can give rise to a propagated action potential, failure of action-potential propagation by the surface membrane, and failure of transverse impulse conduction.

Membrane defects in paramyotonia congenita with and without myotonia in a warm environment

Analysis of the membrane current densities using voltage clamps with 3 microelectrodes revealed that in paramyotonic patients at 37°C all component conductances were normal, except for a decreased CI conductance in the patient who had myotonia in a warm environment, which explains the clinical symptoms of weakness and paralysis.

The resting membrane parameters of human intercostal muscle at low, normal, and high extracellular potassium

Membrane parameters at the respective resting potentials in low, normal, and high extracellular potassium solutions were determined in intercostal muscle fibers from 15 patients with no known neuromuscular disease, following the predictions by the constant field theory.

MUSCLE MEMBRANE POTENTIALS IN EPISODIC ADYNAMIA.

Barium‐treated mammalian skeletal muscle: similarities to hypokalaemic periodic paralysis.

  • E. Gallant
  • Biology, Medicine
    The Journal of physiology
  • 1983
It is concluded that Ba2+ acts relatively slowly to block K+ channels, to decrease K+ fluxes and to induce depolarization, and may provide an appropriate means for evaluating K+ channel function in other muscle disorders.

Effects of potassium on frog skeletal muscle in a chloride-deficient medium.

Muscle fibers give prolonged action potentials with a characteristic plateau in a medium in which chloride has been replaced by anions which do not carry charge across the membrane, which can substitute for sodium in the prolonged response.

The relationship of insulin receptors to hypokalemic periodic paralysis

The hypothesis proposed is that increased amount or affinity of insulin binding on the HOPP muscles causes continual depolarization in the presence of normally subthreshold concentrations of circulating insulin.

Effects of potassium depletion and insulin on resting and stimulated skeletal rat muscle.

The K-depleted rat does not seem to be an entirely satisfactory model of the human disease hypokalaemic periodic paralysis.