Figure 2. Expression of G-protein β₁γ₂ dimers reduces L-type calcium current density in skeletal muscle fibres.

A, representative sets of Ca²⁺ current traces recorded from a control (left panel) and from a Gβ₁γ₂ dimer-expressing fibre (right panel) in response to 1 s depolarizing steps to values ranging between −50 mV and +80 mV from a holding potential of −80 mV. B, corresponding mean voltage dependence of the peak Ca²⁺ current density. Inset presents the mean half-maximal activation potential for control and Gβ₁γ₂-expressing fibres. C, corresponding mean values for the voltage dependence of Ca²⁺ conductance in the two populations. Inset presents the mean maximal conductance for control and Gβ₁γ₂-expressing fibres. The maximal conductance was reduced by 35% (P= 0.001) in the Gβ₁γ₂-expressing fibres.