Sodium current inhibition following stimulation of exchange protein directly activated by cyclic-3',5'-adenosine monophosphate (Epac) in murine skeletal muscle.

We investigated effects of pharmacological triggering of exchange protein directly activated by cyclic-3',5'-adenosine monophosphate (Epac) on Nav1.4 currents from intact murine (C67BL6) skeletal muscle fibres for the first time. This employed a loose patch clamp technique which examined ionic currents in response to superimposed 10-ms V steps to varying degrees of depolarisation, followed by V steps to a fixed, +100 mV depolarisation relative to resting membrane potential following 40 mV hyperpolarising prepulses of 50 ms duration.