Fig. 5.
Effect of G-protein α subunit overexpression on Ca current inhibition by κ receptor activation in cells expressing α1B Ca channels. A–C, Plots of Ca current versus time. Insets show Ca current traces at the points indicated before and during the application of the κ receptor agonist U69593 (200 nm). HEK293 cells were transfected with only the κ receptor (A), κ receptor + Giα1 (B), κ receptor + Goα (C), and κ receptor + Giα3 (D). D, Superimposed control and inhibited (U69593; 200 nm) Ca current traces from a cell expressing the α1B Ca channel, κ receptor, and Giα3. The U69593 inhibition was partially relieved by a prepulse depolarization (see Fig. 2).