[The potential-dependent incoming ionic currents of myoblasts from the frog Rana temporaria developing in culture].

Voltage-dependent inward ionic currents in 1-6-day cultured skeletal myoblasts have been studied using whole-cell patch clamp technique. Sodium (INa) and two types of calcium (ICa) currents were recorded at all stages. INa did not differ from that described in frog striated muscle fibres. Both types of ICa were found to be DHP-sensitive. They differ in their activation time. It is suggested that two types of ICa correspond to ICa of twitch and tonic muscle fibres.