Mutations that suppress the electrophysiological phenotype seen in A307 >GlDN adult flies. (A) Schematic depicting the GF, TTMn and the positioning of the stimulating and recording electrodes to test the function of the GF-TTMn synapse (circled). (B) Traces from individual flies showing the response latency upon a single stimulus and following to 10 stimuli at 250 and 100 Hz. A fly containing A307 alone shows a short response latency and 1:1 following at 250 and 100 Hz. A fly expressing GlDN exhibits a longer latency and gives only a single response or follows poorly at either 100 or 250 Hz. The addition of SG13/+ reduces the response latency back toward that of the control fly and increases following to stimuli at both 250 and 100 Hz. (C) Histograms showing the average response latencies and following to 10 stimuli at the two frequencies for the three suppressors tested. As indicated, responses from A307>GlDN flies were compared to A307-containing flies and all others were compared to A307>GlDN flies. *P < 0.05, **P < 0.01, ***P < 0.001 in unpaired Student's t-test.