Olfaction signal transduction

The detection of light, smells, and tastes (vision, olfaction, and gustation, respectively) in animals is accomplished by specialized sensory neurons that use signal-transduction mechanisms fundamentally similar to those that detect hormones, neurotransmitters, and growth... 

These are exciting times in the field of chemosensory reception in general and olfaction in particular. In the decade since the landmark identification of a novel class of candidate odorant receptors (ORs) in rats (Buck and Axel, 1991), we have seen an explosion of similar studies involving other vertebrate as well as several insect species. In addition to an ever-increasing wealth of behavioral and physiological studies, insect systems provide arguably the most robust experimental system for the study of olfaction as well as a profound demonstration of the universal conservation of olfactory signal transduction mechanisms. 

Prestwich G. D. and Du G. (1997) Pheromone-binding proteins, pheromone recognition, and signal transduction in moth olfaction. In Insect Pheromone Research, New Directions, eds R. T. Carde and A. K. Minks, pp. 131-143. Chapman and Hall, New York. 

The anosmic phenotypes of mice strains which are deficient in G0if (Belluscio et al., 1998), ACIII (Wong et al., 2000) and functional relevant channel subunits (Brunet et al., 1996 Baker et al., 1999) emphasize the central role of the AC/ cAMP pathway for signal transduction in vertebrate olfactory sensory neurons. These features may be considered as evidence for cAMP as the sole relevant second messenger in vertebrate olfaction. 

How do our sensory systems work How are the initial stimuli detected How are these initial biochemical events transformed into perceptions and experiences We have previously encountered systems that sense and respond to chemical signals—namely, receptors that bind to growth factors and hormones. Our knowledge of these receptors and their associated signal-transduction pathways provides us with concepts and tools for unraveling some of the workings of sensory systems. For example, 7TM receptors (seven-transmembrane receptors, Section 15.1) play key roles in olfaction,... 

Insect Olfaction Receptors, Signal Transduction, and Behavior... 

Tlie second messengers that we have seen recur in many additional signal transduction pathways. For exampile, in a consideration of the sensory systems in Chapter 32, we will see how Ca -based signaling and cyclic nucleotide-based signaling play key roles in vision and olfaction. 

Breer H. (1994). Signal recognition and chemo-electrical transduction in olfaction. Biosensors Bioelectron 9, 625-632. 

Bruch, R. C. and Teeter, I. H., Second-messenger signaling mechanisms in olfaction, in Receptor Events and Transduction in Taste and Olfaction, Brand, I. G., Teeter, J. H., Cagan, R., and Kare, M. R., Eds., Marcel Dekker, New York, 1988, 283. 

This chapter describes the functioning of the five major senses— smell, taste, vision, hearing, and touch—on a molecular level. All are shown to rely on mechanisms involved in transduction of other sorts of signals (hormones, neurotransmitters, etc.). Olfaction, taste, and vision utilize G-protein-linked 7TM receptors. Hearing and touch have different receptors but appear to share ankyrin repeats as part of their structures. 

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