�ber die Ursache spontaner Fibrillationen denervierter Skeletmuskulatur

Effect of denervation on the resting membrane potential of healthy and dystrophic muscle.

“…This effect of denervation on the resting membrane potential is in agreement with the observations of Ware et al (1954) and Lullmann and Pracht (1957). The similar findings of Ware et al are of interest in that the technique employed differed in important respects from that of the present study.…”

“…Li et al (1957) did not find any difference in the mean values for resting potential in the fibres of rat skeletal muscle before and after denervation but they noted considerable fluctuations in membrane potential and observed that fibrillation potentials were frequently preceded by a slow fall in the resting potential towards the depolarization threshold. Lullmann reported similar excursions in resting potential in the rat diaphragm and regards these as a significant factor in initiating the fibrillation potential (Lullmann, 1960). In our limited number of observations of spontaneously occurring action potentials in denervated dystrophic muscle prepotentials have been a conspicuous finding (Fig.…”

“…In our experience insertion of the electrode deeply into the muscle is liable to give rise to tip potentials, a possible source of error (Adrian, 1956), and we have therefore confined our observations to superficial fibres and included all measurements where the criterion of an abrupt fall in potential has been fulfilled. Lullmann and Pracht (1957), in addition to finding a fall in membrane potential in the fibres of the rat diaphragm after denervation, found that the potential reverted to normal as reinnervation took place.…”

“…Moreover it is doubtful whether any significant change in intracellular potassium concentration occurs following denervation (Drahota, 1962). It is more likely, therefore, that the changes are to be explained in terms of alterations in membrane conductance, and Lullmann (1960) has reported a lowering of the potassium permeability of the cells of the rat diaphragn after denervation.…”

The electrical properties of muscle fiber membranes in dystrophia myotonica and myotonia congenita.

“…If the resting membrane potential is lower than this, because the Na: K permeability ratio is abnormally high, the membrane potential will subsequently decline to the resting value; this depolarization may activate the regenerative sodium conductance mechanism responsible for the action potential. Such a mechanism has been advanced to explain the genesis of fibrillation potentials in denervated muscle (Lullmann, 1960) and the autorhythmicity of cardiac muscle fibres (Dudel and Trautwein, 1958). However, the available evidence suggests that it is unlikely to be involved in myotonia.…”