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Sci. Signal., 11 January 2011
Vol. 4, Issue 155, p. ra1
Heightened Sense of Smell?
Smells are detected through the stimulation of members of the G protein–coupled receptor family called odorant receptors (ORs) found on olfactory sensory neurons (OSNs) within the olfactory epithelium of the nose. This region is innervated by sympathetic nerve endings, which produce norepinephrine, and parasympathetic nerve endings, which produce acetylcholine (see the Perspective by Hall). Although regulation of signaling in the visual system by these neurotransmitters has been well studied, less is known about their role in other sensory organs. Li and Matsunami found that the M3 member of the muscarinic acetylcholine receptor family enhanced the responses of multiple ORs. Furthermore, the M3-R, which is found in OSNs, physically associated with ORs in transfected cells. Whereas M3-R agonists enhanced OR responses, M3-R antagonists inhibited odorant signaling, leading the authors to suggest that crosstalk between the M3-R and the ORs is required for efficient odorant signaling.
Citation: Y. R. Li, H. Matsunami, Activation State of the M3 Muscarinic Acetylcholine Receptor Modulates Mammalian Odorant Receptor Signaling. Sci. Signal.4, ra1 (2011).