Figure 4.

SR1–GFP cells in the SO respond broadly and over a wide concentration range. A, The SR1 genomic locus and the targeting vectors for generating strains with SR1–IRES–tauGFP and ΔSR1–RFP mutations. B, Image taken under fluorescent illumination of the SO from an SR1–IRES–tauGFP mouse. Scale bar, 5 μm. C, A single SR1–GFP cell responded to all five odorants at 1 μm, and to Mix 1 at 1 μm, under voltage-clamp mode. The gray trace (Ringer) was the mechanical response induced by a Ringer puff that was delivered with the same pressure as the odorant puffs. D, The dose–response curve for amyl acetate was averaged from six SR1–GFP cells. The holding potential was −65 mV for all neurons. Each colored line (and the corresponding symbols) represents the data from a single cell, and the thick black line represents the averaged curve from all six neurons. Error bars indicate SEM. Note that the averaged curve has K_1/2 = 0.11 μm and n = 0.3, which are slightly different from the averaged values from individual curves reported in the text.