[Relation between inter- and intracellular action potentials of frog isolates muscle fiber at various temperatures]

Extra- and intracellular action potentials (AP) of isolated muscle fibres plunged into volume conductor were studied at different temperatures. Changes of the first and second AP derivatives and their temperature dependence were described. The changes are explained by temperature effect on the density of input and output ion currents. Changes of the shape of extracellular potential with temperature increase were described. They were concerned with the changes of the first and second AP derivatives and are due to the peculiar distribution of the potential field in the volume conductor around an excitable fibre of the finite length.