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Proc Natl Acad Sci U S A. 2016 Feb 16;113(7):E902-11. doi: 10.1073/pnas.1518329113. Epub 2016 Feb 1.

Distinct signaling of Drosophila chemoreceptors in olfactory sensory neurons.

Author information

1
State Key Laboratory of Membrane Biology, College of Life Sciences, Peking University, Beijing 100871, China; Center for Quantitative Biology, Peking University, Beijing 100871, China; McGovern Institute for Brain Research, Peking University, Beijing 100871, China; Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China;
2
Department of Neurobiology, Zhejiang University School of Medicine, Hangzhou 310058, China;
3
Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147;
4
IBM T. J. Watson Research Center, Yorktown Heights, NY 10598.
5
State Key Laboratory of Membrane Biology, College of Life Sciences, Peking University, Beijing 100871, China; Center for Quantitative Biology, Peking University, Beijing 100871, China; McGovern Institute for Brain Research, Peking University, Beijing 100871, China; Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China; dgluo@pku.edu.cn.

Abstract

In Drosophila, olfactory sensory neurons (OSNs) rely primarily on two types of chemoreceptors, odorant receptors (Ors) and ionotropic receptors (Irs), to convert odor stimuli into neural activity. The cellular signaling of these receptors in their native OSNs remains unclear because of the difficulty of obtaining intracellular recordings from Drosophila OSNs. Here, we developed an antennal preparation that enabled the first recordings (to our knowledge) from targeted Drosophila OSNs through a patch-clamp technique. We found that brief odor pulses triggered graded inward receptor currents with distinct response kinetics and current-voltage relationships between Or- and Ir-driven responses. When stimulated with long-step odors, the receptor current of Ir-expressing OSNs did not adapt. In contrast, Or-expressing OSNs showed a strong Ca(2+)-dependent adaptation. The adaptation-induced changes in odor sensitivity obeyed the Weber-Fechner relation; however, surprisingly, the incremental sensitivity was reduced at low odor backgrounds but increased at high odor backgrounds. Our model for odor adaptation revealed two opposing effects of adaptation, desensitization and prevention of saturation, in dynamically adjusting odor sensitivity and extending the sensory operating range.

KEYWORDS:

Drosophila; OSN; chemoreceptor; olfaction; sensory adaptation

PMID:
26831094
PMCID:
PMC4763727
DOI:
10.1073/pnas.1518329113
[Indexed for MEDLINE]
Free PMC Article

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