The effects of chemical properties and nasal air flow patterns on retronasal responses to odorants in the rat. Open Access

Abstract

In this study of orthonasal and retronasal olfaction, electroolfactograms (EOGs)
were measured from the dorsal-medial and lateral regions of the rat olfactory
epithelium. Orthonasal olfaction is the process by which odorants enter the nasal
cavity from the anterior nares, as in sniffing. Retronasal olfaction is the process
of smelling from the mouth, which occurs when odorants from food inside the
mouth travel behind the palate to the posterior nares and enter the nasal cavity.
Sixteen odorants with a range of solubility were tested, and the effects of single
and multiple pulses of odor stimulation were studied. The odorants' molecular
properties are important factors to the distribution of responses on the olfactory
epithelium as well as the magnitude of the orthonasal and retronasal responses.
A set of molecular descriptors related to polarity and solubility, including the
Hansen solubility parameter, the electrotopological state, and Henry's Law
constant, were compared to the peak negative EOG and to the area under the
EOG traces. The multiple pulses provide an initial attempt at simulating the
effect in breathing, chewing and swallowing. The EOG responses to the
odorants were different during orthonasal and retronasal flow. When odorants
travel within the nasal cavity in the orthonasal direction, the responses to the
polar odorants are the greatest in the dorsalâ€medial region of the olfactory
epithelium while the responses to many nonpolar odorants are the greatest in the
lateral region. When odorants travel within the nasal cavity in the retronasal
direction, however, the responses to the polar odorants are greatly reduced at all
recording sites compared to responses of polar odorants flowing in the
orthonasal direction. The single and triple pulse odorant stimulation had similar
relationships with the molecular properties of the odorants. This consistent
relationship between calculated properties and odorant response supports the
hypothesis that odorant sorption is an important contribution to the differences
between orthonasal and retronasal olfaction.

Table of Contents

Table of Contents

Introduction………………………………………………………………………….….1
Methods………………………………………………………………………………....13

Table 1…………………………………………………………………………...14

Figure 1A………………………………………………………………………..15

Figure 1B………………………………………………………………………...15

Figure 1C……………………………………………………………………......15
Results…………………………………………………………………………………...21

Figure 2………………………………………………………………………….25

Figure 3……………………………………………………………………….…26

Figure 4………………………………………………………………………….27

Figure 5………………………………………………………………………….28

Figure 6………………………………………………………………………….29
Discussion……………………………………………………………………………....30
References………………………………………………………………………………37

About this Master's Thesis

Rights statement

• Permission granted by the author to include this thesis or dissertation in this repository. All rights reserved by the author. Please contact the author for information regarding the reproduction and use of this thesis or dissertation.

School	Laney Graduate School
Department	Biological and Biomedical Sciences
Degree	MS
Submission	Master's Thesis
Language	English
Research Field	Health Sciences, Nutrition Biology, Neuroscience Agriculture, Food Science and Technology
Keyword	nasal food odor olfaction retronasal
Committee Chair / Thesis Advisor	Scott, John W, Emory University
Committee Members	Vesper, Hubert, CDC Chen, Ping Helen, Emory University

Last modified

Primary PDF

Thumbnail	Title	Date Uploaded	Actions
	The effects of chemical properties and nasal air flow patterns on retronasal responses to odorants in the rat. ()	2018-08-28 12:14:06 -0400	Press to Select an action Download

Supplemental Files

Thumbnail	Title	Date Uploaded	Actions