Smell

Excerpt

An olfactory enthusiast might plausibly go so far as to state that all biological subsystems are essentially a spin-off of the chemical detector apparatus. Since Buck and Axel first identified a large multigene family of G-protein-coupled receptor genes on rat olfactory sensory neurons (OSNs) (Buck and Axel 1991), it has become apparent that the G-protein-coupled conformation of the olfactory receptor shares much in common with receptors that bind a great many other critical biological ligands, including neurotransmitters, neuromodulators, tastants, light, hormones, growth factors, chemokines, cell adhesion molecules, and chemotactic peptides (Dryer 2000; Fredriksson et al. 2003). Laurence Dryer (2000) has nicely captured the idea that olfaction is a virtual microcosm of the human nervous system: