Making for Sensitive Smelling

Science's STKE  28 Jun 2005:
Vol. 2005, Issue 290, pp. tw237
DOI: 10.1126/stke.2902005tw237

Receptors that couple to a heterotrimeric guanosine triphosphate (GTP)-binding protein (G protein) are thought to stimulate a large number of G protein molecules. This model of signal amplification is based primarily on quantitative studies of phototransduction in vertebrate retinal cells. Bhandawat et al. have examined signal transduction by olfactory receptors in frog olfactory neurons. Quantal analysis of receptor responses to odorant ligands suggests that an activated odorant receptor, probably due to an extremely brief dwell time of odorant-receptor interaction, has a low probability of stimulating a single G protein molecule. High sensitivity to odorants might still be achieved with repetitive odorant binding and by signal convergence in the olfactory bulb.

V. Bhandawat, J. Reisert, K.-W. Yau, Elementary response of olfactory receptor neurons to odorants. Science 308, 1931-1934 (2005). [Abstract] [Full Text]