Fig. 6. Real-time measurement of the [Ca²⁺]_i response by A. stephensi leucokinin receptor. S2 cells were co-transfected with the A. stephensi leucokinin receptor ORF and apoaequorin ORF constructs, and expression induced. Peptide was injected at 15 s. Samples were stimulated with either Anopheles leucokinin I (A), II (B) or III (C) peptide at a concentration of 10^–7 mol l^–1. (D) Comparison of the responses to the three Anopheles leucokinin peptides applied at a concentration of 10^–7 mol l^–1. Data are expressed as [Ca²⁺]_i (nmol l^–1) against time (s); measurements were taken at 0.1 s intervals. The traces shown are average responses ± S.E.M. (N=8). Error bars are negligible for all panels.