Volume 18, Issue 3
September 1943, pages 53-71
pp 53-57 September 1943
The similarity of the effects of ions on the protoplasmic viscosity of simple organisms and that on unstriated muscle suggest that the latter consists of a viscous protoplasmic non-contractile element. The similarity of the reactions of isolated myosin strips and isolated muscle suggests that it contains a contractile element. This view is supported by (a) the differential action of drugs, (b) viscous elastic properties of plain muscle, and by its histological picture.
Similarity of the responses of isolated muscle and isolated myosin suggests that plain muscle can contract without the use of oxygen.
pp 58-71 September 1943
As shown by the effect of death, resistance of the muscle to alternating current of low frequency is a measure of the permeability of the cell.
Permeability is high at low and high temperatures; frog muscle if heated beyond 35°C. and mammalian muscle beyond 40°C, is irreparably damaged, the resistance being permanently lowered.
Cations such as potassium, calcium, ammonium, magnesium increase the resistance of the muscle in small concentrations.
Anions such as Cl, Br, I, NO3, SCN, CN increase the resistance of the muscle in small concentrations.
Drugs and narcotics such as adrenaline, caffeine, novocaine, chloral hydrate, ether, chloroform, ethyl alcohol, butyl alcohol, octyl alcohol increase the resistance in small and decrease it in large concentrations.
Inhibition and narcosis are associated with increased resistance or decreased permeability. Increased excitability to ions without is associated with an opposite change. Excitability to electric current is increased with diminished permeability.
For excitation an optimum permeability is necessary.
The resistance of frog skin is higher than that of muscle.