Calcium, the two-faced messenger of olfactory transduction and adaptation.
Exposure of olfactory receptor cells to odour stimulates the influx of Ca(2+) through cyclic nucleotide-gated channels into the small volume within the cilia, the site of olfactory transduction. The consequent rise in intraciliary Ca(2+) concentration has two opposing effects: activation of an unusual excitatory Cl(-) conductance, and negative feedback actions on various stages of the odour transduction mechanism. Recent studies are beginning to unravel how Ca(2+) performs this dual function, and how the spatial and temporal dynamics of Ca(2+) modulate the odour response. The feedback actions of Ca(2+) on different elements of the transduction cascade seem to occur on different timescales, and are therefore responsible for shaping different parts of the receptor current response to odour stimulation.
Matthews
Hugh R
HR
Physiological Laboratory, University of Cambridge, Downing Street, Cambridge CB2 3EG, UK. hrm1@cam.ac.uk
Reisert
Johannes
J
D000222:Adaptation, Physiological / Q000502:physiology*; D000818:Animals; D002118:Calcium / Q000502:physiology*; D006801:Humans; D040542:Mechanotransduction, Cellular / Q000502:physiology*; D015290:Second Messenger Systems / Q000502:physiology*; D012903:Smell / Q000502:physiology*
D002118:Calcium