Figure 2.

(A) Noxious stimuli trigger calcium transients in ASH. Shown are typical calcium transients in ASH evoked by the noxious stimuli 10 mM Cu²⁺, 1 M glycerol, 0.1% SDS, 10 mM quinine and 10 mM denatonium; by nose touch with and without 2.5 mM serotonin, in wild type; by nose touch in the presence of 2.5 mM serotonin in unc-13 (synaptic transmission defective) backgrounds; and by the innocuous stimuli of extracellular saline buffer and 50 mM NaCl. Response is plotted as fractional fluorescence ratio change over baseline. Black bars indicate duration of application of each stimulus. (B) Quantification of ASH responses to selected noxious stimuli in N2 and unc-13 backgrounds, and in N2 in the presence of 2.5 mM serotonin. Small diamonds indicate the amplitude of YFP/CFP ratio change during a single application of a repellent (black bar). Horizontal lines indicate mean±s.e.m. The asterisk indicates a significant decrease in Cu²⁺ response compared to N2 without serotonin (P<0.01). N2 sample sizes (n=number of animals): Cu²⁺ (n=19); glycerol (n=12); SDS (n=15); quinine (n=11); unc-13 sample sizes: Cu²⁺ (n=10); glycerol (n=7); 5-HT sample sizes: Cu²⁺ (n=5); glycerol (n=6).