Selective depression of 2,4-dinitrophenol depolarized canine Purkinje fibers by lidocaine.

Concentrations of lidocaine which minimally decrease conduction and excitability of normal canine Purkinje fibers markedly decrease these parameters in fibers depolarized by metabolic depression (DNP superfusion). The decrease in Vmax and the slowing of the post-stimulation recovery of Vmax by lidocaine are also more marked during DNP superfusion than during superfusion with a DNP-free salt solution. Since these effects could be reversed by a lidocaine-free DNP superfusion, it is concluded that lidocaine selectivity depresses the electrical activity of tissue depolarized by the metabolic inhibitor DNP. This selective depressive action of lidocaine is similar to that observed in cardiac tissues depolarized by other means.