Fig. 1.
Representative whole-cell Ca currents recorded from HEK293 cells expressing α1A or α1Bchannels, illustrating G-protein-dependent facilitation. Currents were recorded after ≥5 min of intracellular dialysis with GTPγS or GDPβS, as indicated. The voltage protocol is diagrammed at top left. P1, P2, andCP were each 25 msec in duration and were separated by 10 msec intervals. A, α1A with GTPγS, data file 97425003; C = 20 pF;RS = 2.7 MΩ. α1A with GDPβS, data file 97D24008; C = 18 pF;RS = 3.2 MΩ. B, α1B with GTPγS, data file 97403026;C = 16 pF; RS = 4.8 MΩ. α1B with GDPβS, data file 97D19038;C = 23 pF; RS = 2.0 MΩ.