Figure 5.

GABA_A receptors contribute to odor-evoked chloride responses in PNs. A, left, Schematic illustrating expression site of Clomeleon. Middle, AL map viewed from the angle that was used for imaging. Glomeruli indicated in green could reliably be identified. Right, Contralateral AL including reliably identified glomeruli. ALT, AL tract. B, Pseudocolor rendering of representative Cl^- responses to different odors and mineral oil in PN dendrites in the AL. Images represent ΔR/R (%) superimposed onto raw fluorescence images according to the scale on the right. Numbers in each image give the individual fluorescence minimum. Glomerular positions are shown in the first image; individual glomeruli revealing highest Cl^- increase are indicated in each image. C, False color pictures of averaged odor-evoked Cl^- signals for 12 identified glomeruli (40% of all glomeruli labeled by GH146-Gal4) over time across 9–11 animals. Clomeleon responses were normalized to highest Cl^- influx in each animal over all odors before averaging. Black bar indicates the odor application. D, Quantification of Cl^- influx to ethyl-3-hydroxybutyrate in PNs before, during and after applying of picrotoxin. The GABA_A receptor blocker significantly reduces odor-evoked Cl^- responses (**p < 0.01, repeated measures ANOVA, n = 9).