Insect Odorant Receptors: Channeling Scent Tal Soo Ha, Dean P. Smith  Cell  Volume 133, Issue 5, Pages 761-763 (May 2008) DOI: 10.1016/j.cell.2008.05.007 Copyright © 2008 Elsevier Inc. Terms and Conditions

Figure 1 Two Models for Odor-Activated Cation Channels in Fly Olfactory Neurons (A) Dual mode activation of a heterodimeric complex between the odorant receptor (OR) and Or83b (Wicher et al., 2008). At low odorant concentrations, OR activation triggers a relatively slow increase in cyclic nucleotide production that activates Or83b and allows the inward flow of current (increased membrane potential). At high odor concentrations, OR activation triggers rapid and direct ligand gating of the Or83b channel. (B) Direct ligand-gated cation channel (Sato et al., 2008). Odor molecules activate the OR-Or83b complex directly without the need for a second messenger system. (Gα, stimulatory G protein α subunit; AC, adenylyl cyclase.) Cell 2008 133, 761-763DOI: (10.1016/j.cell.2008.05.007) Copyright © 2008 Elsevier Inc. Terms and Conditions