FIGURE 5.

GoLoco-insensitivity mutation does not alter the ability of Gα_i to buffer free Gβγ subunits. A-D, superimposed Ca²⁺ current traces evoked with a double-pulse voltage protocol in the absence (open circle) or presence of 10 μm NE (filled circle) from control (A), Gα_i1(N149I, C352G) (B), Gα_i2(N150I, C353G) (C), and Gα_i3(N149I, C352G) (D) expressing SCG neurons. Currents were evoked every 10 s. The dashed lines indicate the zero current level. E, summary graph of Ca²⁺ current inhibition by 10 μm NE from control neurons and neurons expressing Gα_i1(N149I,C352G), Gα_i2(N150I,C353G), or Gα_i3 (N149I,C352G). Ca²⁺ current inhibition was measured 10 ms after initiation of the test pulse (+10 mV) in the absence or presence of 10 μm NE. F, basal facilitation from control neurons or neurons expressing Gα_i1(N149I,C352G), Gα_i2(N150I,C353G), or Gα_i3(N149I,C352G). Basal facilitation was calculated as the ratio of Ca²⁺ current amplitude determined from the test pulse (+10 mV) occurring after and before the +80 mV conditioning pulse. E and F, bars represent mean±S.E.M. Numbers in parentheses indicate the number of neuron tested. The mean for all experimental conditions (colored bars) was different (p < 0.05) from the control condition (open bar) as determined by one-way analysis of variance followed by Neuman-Keuls multiple comparison test. Means among experimental groups were not different.