Effects of Gi/o protein activator mastoparan and AC activator forskolin on electrical synaptic coupling strength. A, Example single traces of coupled neurons before (a), during (b), and after (c) mastoparan application (2 μm, 10 min). Stimulation and response parameters as in Figure 2A. B, Time course measurements of cc and G_C for the pair of neurons shown in A before, during, and after mastoparan application; a–c are the data points corresponding to the traces in A. C, Normalized population time course of cc and G_C before, during, and after mastoparan application (mean ± SE; n = 10 pairs; cc p = 0.02, G_C p = 0.03). D, Example traces of a single pair of coupled TRN neurons before (a), during (b), and after (c) forskolin application (10 μm, 20 min). E, Time course of cc and G_C for the coupled pair shown in D. F, Normalized population time course data for cc and G_C before, during, and after forskolin application (n = 16 pairs; cc p = 0.02, G_C p = 0.01). Arrow shows n = 9 pairs recorded past 36 min. Red boxes indicate regions of analysis, as in Figures 2 and 3.