Figure 6. VSNs are highly selective.
(A) Raster plot of one VSN's firing responses to a panel of 31 sulfated steroids. The compounds were at 100 μM, except for A2534 (50 μM), E4105 (50 μM), P2135 (50 μM), C5075 (10 μM), C6905 (50 μM), Q4765 (50 μM). Each row represents a single trial (shown grouped by stimulus, but trials to different stimuli were interleaved; 5 trials total). For this neuron, only one synthetic compound excited a reliable spiking response. The black bar represents the stimulus timing.
(B) 12 single unit response profiles to 31 sulfated steroids as in (A). Normalized responses (see methods) shown as a colorscale. The tenth neuron is shown in (A).
(C-E) and (G-J) Dose/response profiles of seven single units to a set of 8 structurally-related compounds. Most units responded to only one of these ligands, with EC50 typically in the micromolar range. The points in (C) marked with asterisks underestimate the real Δr because at those ligand concentrations the spike amplitude decreased during prolonged high firing rates to the point they could not be sorted.
(F) The percentage of electrodes that respond to cort21S increased as the concentration of cort21S rises. The arrow indicates the estimated concentration of cort21S in female mouse urine.