Year: 2011
Type: article
Abstract: Olfaction begins with the detection of odorants by olfactory receptor neurons (ORNs) in the nasal cavity.Olfactory transduction is mediated by a G protein-coupled transduction cascade culminating in the opening of the two olfactory transduction ion channels, the olfactory CNG channel and the Ca 2+ -activated Cl channel anoctamin 2 (Ano2), and ultimately action potential (AP) generation.The mechanisms that activate olfactory transduction have been understood quite well over the last two decades.Mechanisms of response adaptation, however, have actually become much less clear, with mechanisms previously thought to be important now suggested to play less significant roles, raising the question of which transduction components are the target of adaptational feedback.Because ORNs are often stimulated rhythmically by the inhalation of odorants, fast response termination should be a prerequisite to adequately resolve the temporal aspect of the stimulus.Recent progress suggests that mechanisms that regulate ciliary Ca 2+ transients dictate kinetics of transduction termination.Ultimately, the question to answer is how ORNs code for "natural" stimuli in the behaving animal. Activation and amplification of olfactory transductionORNs are embedded in the olfactory epithelium that covers the olfactory turbinates, a convoluted bone structure, located in the posterior nasal cavity in most mammals.These primary sensory neurons, like touch-sensitive neurons but unlike photoreceptors (see accompanying Perspectives by Bautista and Lumpkin, 2011, andSchwartz andRieke, 2011) generate APs upon stimulation and send axons to the olfactory bulb, where they communicate with mitral and tufted (second-order) neurons.Odorants are carried to ORNs via the inhaled air in a rhythmic fashion, the frequency of which depends on the breathing frequency that can vary from 2 to 3 Hz at rest to up to 10 Hz during sniffing in rodents
Authors: Johannes Reisert, Haiqing Zhao
Institutions: Monell Chemical Senses Center, Johns Hopkins University
Language: English
Subfield: Sensory Systems
Field: Neuroscience
Domain: Life Sciences
Open Access status: bronze
OpenAlex ID: W2012083840