Figure 1.

mtt was not required for l-canavanine-induced action potentials or for behavioral avoidance. A, Representative traces of l-canavanine triggered nerve firings from w¹¹¹⁸ and mtt^f06268 flies. The tip recordings were performed in S3 sensilla using 25 mM l-canavanine. B, Mean number of action potentials in response to 25 mM l-canavanine recorded from S3, S5, and S10 sensilla. The genotypes are indicated. Df stands for Df(2R)Exel7096. n=10-12. C, Tip recordings surveying nerve firings in GRNs from w¹¹¹⁸ labellar sensilla in response to 25 mM l-canavanine. Shown are the mean action potentials. n=10-18. D, Effects of red and blue food dyes on two-way choice assays. The flies were given a choice between 1 mM sucrose and 5 mM sucrose (plus or minus 30 mM l-canavanine). The red and blue bars indicate the color of the food dye added to the 1 mM or 5 mM sucrose. The dashed line indicates a P.I.=0.5, which results if there is no preference. n=5. Unless indicated otherwise, the two-way choice tests were performed with the 0.125 mg/ml brilliant blue FCF and 0.2 mg/ml sulforhodamine B. E, Effects of different concentrations of l-canavanine on the selection of 5 mM versus 1 mM sucrose. n=4-10 for each concentration. Shown are means ±SEMs. F, Two-way choice tests in the presence or absence of 30 mM NMA. G, Two-way choice tests using 5 mM sucrose plus 5 mg/ml erioglaucine (with or without 30 mM l-canavanine) versus 5 mM sucrose plus 20 mg/ml sulforhodamine B.