One neuron--multiple receptors: increased complexity in olfactory coding?
Olfaction--the sense of smell--is responsible for detecting molecules of immense structural variety. Precise recognition of such diverse stimuli requires a massive receptor repertoire. This functional challenge has been met by simultaneous expression of a multitude of odor-detecting receptors that all belong to the superfamily of heterotrimeric GTP-binding protein (G protein)-coupled receptors. Studies conducted over the past decade have led to the assumption that an individual olfactory sensory neuron expresses only a single odorant receptor, consequently giving rise to the "one receptor-one neuron" hypothesis. This idea is attractive because of its simplicity and has served as the basis for models of olfactory coding. However, recent reports regarding Drosophila have found exceptions to the rule that could have important implications for the logic of olfactory coding.
Spehr
Marc
M
Department of Anatomy and Neurobiology, University of Maryland School of Medicine, 20 Penn Street, Baltimore, MD 21201, USA.
Leinders-Zufall
Trese
T
D000818:Animals; D017173:Caenorhabditis elegans / Q000502:physiology; D002628:Chemoreceptor Cells / Q000502:physiology*; D029721:Drosophila Proteins / Q000235:genetics / Q000502:physiology; D004331:Drosophila melanogaster / Q000502:physiology; D019143:Evolution, Molecular; D005786:Gene Expression Regulation; D020962:Heterotrimeric GTP-Binding Proteins / Q000502:physiology*; D007313:Insecta / Q000235:genetics / Q000502:physiology; D051379:Mice / Q000502:physiology; D008959:Models, Neurological; D018034:Olfactory Receptor Neurons / Q000502:physiology*; D043562:Receptors, G-Protein-Coupled / Q000235:genetics / Q000502:physiology; D018035:Receptors, Odorant / Q000235:genetics / Q000502:physiology*; D012689:Sequence Homology, Nucleic Acid; D012903:Smell / Q000502:physiology*; D013045:Species Specificity
D029721:Drosophila Proteins; C492465:Orco protein, Drosophila; D043562:Receptors, G-Protein-Coupled; D018035:Receptors, Odorant; C431926:taste receptors, type 1; D020962:Heterotrimeric GTP-Binding Proteins