Symposium Overview

The nasal cavity is innervated by two cranial nerves: the olfactory (Cr. N. I) and the trigeminal (Cr. N. V). These structures together convey the sense of smell (I) and nasal pungency (V). These percepts are normally integrated in everyday life, as is implicit in references to, for example, “pungent odors.” Nasal pungency (often referred to as “irritation”) is an essential component of our response to foods, selected medications and cosmetics, and many air pollutants. Despite its obvious functional importance, however, nasal trigeminal function has commanded relatively modest scientific attention and resources, particularly when compared to its companion senses of smell and taste.1 The distinction between olfaction and nasal trigeminal chemoreception dates at least back to 1912, when Parker coined the term “common chemical sense” to describe the nonolfactory, nontaste chemical responsiveness of mucous membranes in vertebrates.2 Despite confusion regarding the word “common” (did it refer to the sensory apparatus or the nature of the stimuli?), the term continued to be used without serious debate at least until the 1960s. In 1964, Keele and Armstrong proposed the term “chemalgia,” highlighting the nociceptive nature of the sense.3 However, in 1990 Green