title: Combined behavioral and c-Fos studies elucidate the vital role of sodium for odor detection.
abstract: Salt, known as taste quality, is generally neglected in olfaction, although the olfactory sensory neurons stretch into the salty nasal mucus covering the olfactory epithelium (OE). Using a psychophysical approach, we directly and functionally demonstrate in the awake rat for a variety of structurally diverse odorants that sodium is a critical factor for olfactory perception and sensitivity, both very important components of mammalian communication and sexual behavior. Bathing the olfactory mucus with an iso-osmotic sodium-free buffer solution results in severe deficits in odorant detection. However, sensitivity returns fully within a few hours, indicating continuous mucus production. In the presence of sodium in the mucus covering the OE, all odorants induce odorant-specific c-Fos expression in the olfactory bulb. Yet, if sodium is absent in the mucus, no c-Fos expression is induced as demonstrated for n-octanal. Our noninvasive approach to induce anosmia in mammals here presented--which is fully reversible within hours--opens new possibilities to study the functions of olfactory communication in awake animals.
authors.affiliation: Department of Neurophysiology, Faculty of Medicine, Institute of Physiology, Ruhr-University Bochum, D-44780 Bochum, Germany.
authors.forename: Elke
authors.initials: E
authors.lastname: Weiler
authors.forename: Swetlana
authors.initials: S
authors.lastname: Deutsch
authors.forename: Raimund
authors.initials: R
authors.lastname: Apfelbach
mesh_terms: D000085:Acetates / Q000494:pharmacology; D000447:Aldehydes / Q000494:pharmacology; D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects; D003216:Conditioning, Operant; D053138:Cyclohexenes; D004192:Discrimination, Psychological / Q000187:drug effects / Q000502:physiology; D015870:Gene Expression / Q000187:drug effects; D007150:Immunohistochemistry; D000077222:Limonene; D008297:Male; D009830:Olfactory Bulb / Q000378:metabolism* / Q000648:ultrastructure; D016760:Proto-Oncogene Proteins c-fos / Q000235:genetics / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D012903:Smell / Q000187:drug effects / Q000502:physiology*; D012964:Sodium / Q000494:pharmacology / Q000502:physiology*; D013729:Terpenes / Q000494:pharmacology
chemical_list: D000085:Acetates; D000447:Aldehydes; D053138:Cyclohexenes; D016760:Proto-Oncogene Proteins c-fos; D013729:Terpenes; C007650:ethyl acetate; D000077222:Limonene; D012964:Sodium; C031639:caprylic aldehyde