Minimum Odorant Concentrations Detectable by the Dog and Their Implications for Olfactory Receptor Sensitivity

  • David G. Moulton


In the absence of other cues, the sooner an animal detects, recognizes and responds to certain odorants entering its environment, the better will be its chances of survival. Faced with such evolutionary pressures, the ability to detect odorants, in some species at least, may well have approached or reached absolute theoretical limits. This seems to be true of the silk moth, Bombyx mori. The male will respond, behaviorally, to the female sex attractant, Bombykol, when 104 molecules/cm3 are present in air currents flowing at 60cm3/s over 2 s. Experiments with tritiated Bombykol suggest that this corresponds to about one molecule per sense cell (Schneider, et al., 1968; Schneider, 1969). In mammals, however, delivery of odorant molecules to the receptors depends on the flow of air through respiratory airways and across extensive mucous surfaces. These and other variables compound the difficulty of assessing the sensitivity of individual receptors or sites. It is nevertheless valuable to attempt such an estimate not only for its intrinsic interest but also for the light it may throw on olfactory mechanisms, and for the framework it provides in defining the nature and diversity of events that limit access of odorant molecules to receptor sites. Ultimately such information may also assist in evaluating whether, in a specific context, a given odorant is present in sufficient concentration to elicit a pattern of behavior.


Olfactory Receptor Receptor Site Olfactory Epithelium Caprylic Acid Odorant Molecule 
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  1. Altner, H., and I. Kolnberger (1975). The application of transmission microscopy to the study of the olfactory epithelium of vertebrates. In Moulton, D.G., Turk, A., and Johnson, J.W., Jr. (eds.) Methods in Olfactory Research. Academic Press, London, 163–190.Google Scholar
  2. Becker, R.F., and J.E. King (1957). Delineation of the nasal air streams in the living dog. A.M.A. Archiv. Otolaryngol. 65: 428–436.CrossRefGoogle Scholar
  3. Calalano, G.B., and S. Biondi (1969). Aspetti ultrastrutturali del recettore olfattivo nella cavia. La Clinica Otorinolaringoiatrica 23: 166–201.Google Scholar
  4. De Vries, H., and M. Stuiver (1960). The absolute sensitivity of the human sense of smell. In Sensory Communication, W.A. Rosenblith (ed.) Wiley & Sons, New York. 159–167.Google Scholar
  5. Gage, P.W. (1976). Generation of end-plate potentials. Physiol. Rev. 56: 177–247.PubMedGoogle Scholar
  6. Hornung, D.E., R.D. Lansing, and M.M. Mozell (1975). Distribution of butanol molecules along bull frog olfactory mucosa. Nature 254: 617–618.PubMedCrossRefGoogle Scholar
  7. Hornung, D.E., and M.M. Mozell (1976). Removal of odorants from the olfactory sac. Neurosci. Abstr. 1: 4.Google Scholar
  8. Kauer, J.S., and D.G. Moulton (1974). Responses of olfactory bulb neurones to odour stimulation of small nasal areas in the salamander. J. Physiol. 243: 717–737.PubMedGoogle Scholar
  9. Lauruschkus, G. (1942). Uber Riechfeldgrösse und Riechfeldkoeffizient bei einigen Hundrassen und der Katze. Arch. Tierheilk. 7: 473–497.Google Scholar
  10. Lucas, A.M., and L.C. Douglas (1934). Principles underlying ciliary activity in the respiratory tract II. A comparison of nasal clearance in man, monkey, and other mammals. Arch. Otolaryng. 20: 518–541.CrossRefGoogle Scholar
  11. Moulton, D.G. (1976). Spatial patterning of response to odors in nthe peripheral olfactory system. Physiol. Rev. 56: 578–593.PubMedGoogle Scholar
  12. Moulton, D.G., E.H. Ashton, and J.T. Eayrs (1960). Studies in olfactory acuity 4. Relative detectability of n-aliphatic acids by the dog. Anim. Behav. 8: 117–128.CrossRefGoogle Scholar
  13. Moulton, D.G, and D.A. Marshall (1976). The performance of dogs in detecting a-ionone in the vapor phase. J. Comp. Physiol. 110: 287–306.CrossRefGoogle Scholar
  14. Neuhaus, W. (1953). Ober die Riechschärfe des Hundes für Fettsäuren. Zeitschr. f. Vergl. Physiol. 35: 527–552.Google Scholar
  15. Okano, M., A.F. Weber, and S.P. Frommes (1967). Electron microscopic studies of the distal border of the canine olfactory epithelium. J. Ultrastructure Res. 17: 487–502.CrossRefGoogle Scholar
  16. Schneider, D. (1969). Insect olfaction: deciphering system for chemical messages. Science 163: 1031–1037.PubMedCrossRefGoogle Scholar
  17. Schneider, D., G. Kasang, and K.E. Kaissling (1968). Bestimmung der Riechschwelle von Bombyx mori mit Tritium-markiertem Bombykol. Naturwissenschaften 55: 395.PubMedCrossRefGoogle Scholar

Copyright information

© Plenum Press, New York 1977

Authors and Affiliations

  • David G. Moulton
    • 1
  1. 1.Monell Chemical Senses Center & Department of Physiology, School of MedicineUniversity of Pennsylvania, and V. A. HospitalPhiladelphiaUSA

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