[Slow asymmetric currents and ultrastructure of tubulo-reticular contacts in the muscle fibers of the crayfish].

Asymmetric membrane currents were studied in isolated muscle fibres of the crayfish Astacus fluviatilis under conditions of voltage clamp and controlled composition of both the external and internal environment. In addition to fast asymmetric currents, probably associated with the opening of calcium channels in the superficial membrane, slow asymmetric currents could be also observed in this type of muscle fibre; the time course of the latter currents was almost by one order slower than that of the fast muscle fibres of the frog. The value of the displaced charge was related to the number of feet in the tubulo-reticular (TR) junction.

[Ionic conductivity of muscle fiber membranes of Locusta migratoria].

On muscle fibers from m. flexor tibiae of the locust studies have been made of the effect of rapid changes in potassium and chloride concentrations on the membrane potential (MP). The MP constituted 56.