Effect of transmembrane potential on the manifestations of ouabain toxicity in sheep cardiac Purkinje fibres.

The effect of membrane potential on the manifestations of ouabain-induced alterations in the electrical activity of shortened sheep cardiac Purkinje fibres was studied by a microelectrode technique. The level of membrane potential was modulated by passing intracellular polarizing current. It was found that the toxic electrical effects induced by exposure to ouabain vary according to the level of membrane potential.