Combinatorial receptor codes for odors.

Publication Type:

Journal Article


Cell, Volume 96, Issue 5, p.713-23 (1999)


Amino Acid Sequence, Animals, Brain Mapping, Calcium, Calcium Signaling, Carboxylic Acids, Discrimination (Psychology), gene expression, MICE, Mice, Inbred BALB C, Models, Neurological, Models, Psychological, Molecular Sequence Data, Multigene Family, Odors, Olfactory Bulb, Olfactory Receptor Neurons, Protein Isoforms, Receptors, Odorant, Reverse Transcriptase Polymerase Chain Reaction, RNA, Messenger, Sequence Alignment, Sequence Homology, Amino Acid, Structure-Activity Relationship


The discriminatory capacity of the mammalian olfactory system is such that thousands of volatile chemicals are perceived as having distinct odors. Here we used a combination of calcium imaging and single-cell RT-PCR to identify odorant receptors (ORs) for odorants with related structures but varied odors. We found that one OR recognizes multiple odorants and that one odorant is recognized by multiple ORs, but that different odorants are recognized by different combinations of ORs. Thus, the olfactory system uses a combinatorial receptor coding scheme to encode odor identities. Our studies also indicate that slight alterations in an odorant, or a change in its concentration, can change its "code," potentially explaining how such changes can alter perceived odor quality.