The study of potassium outflow from muscle with the aid of a contact ion selective electrode
Fiziologicheskii Zhurnal SSSR Imeni I M Sechenova 76(11): 1550-1556
With the aid of a contact K+-sensitive electrode, potassium levels were measured near the surface of the frog resting and twitching isolated m. gastrocnemius. Increasing extracellular K+ in case of indirect repetitive stimulation of the muscle or the blocking of K+-Na+-pump can lead to a depression of the muscle twitches. Transition from repetitive to a single-shock stimulation of the muscle restored the twitches. Elevated extracellular potassium seems to be able to cause a presynaptic blockade in the motor axons.