Wood, Philip Howard (1985) Biochemical sensing mechansims in olfaction. PhD thesis, University of Warwick.

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Abstract

The present work, employing biochemical, biophysical and
electrophysiological techniques, attempted to identify specific
receptor sites in the vertebrate olfactory system for heterocyclic
odorants.
An in vitro rat preparation was developed and characterised
for use in vapour-phase chemical modification experiments; the EOG
responses obtained from this preparation were stable for up to
5 hours after the death of the animal. The signals to various
compounds were differentially reduced when brominated odorants were
employed as vapour-phase labelling reagents; the responses obtained
to these derivatives and to their non-reactive analogues were
preferentially diminished.
The effect of concanavalin A on ECGs obtained from an in vivo
frog preparation was examined. This lectin was found to preferentially
inhibit the signals elicited by small, sweaty-smelling carboxylic
acids; the responses to most of the non-carboxylic acid odorants
tested were not significantly inhibited.
The failure to identify specific receptor sites by electrophysiological
techniques prompted the performance of odorant binding
studies. Examinations of the interaction of [3H] 2-isobutyl-3-
methoxypyrazine with 13,000 x g supernatant fractions of sheep
olfactory epithelium showed that a component of the homogenate
fraction exhibited high affinity saturable binding of this odorant (KD-10-8M). However, the presence of large amounts of non-specific
binding, substantially decreased the sensitivity and accuracy of the
assay. Non-specific binding was observed with tissue fractions of
sheep respiratory epithelium, brain and liver. An investigation of binding specificity showed that other bell pepper odorants competed for the 2-iscbutyl-3-methoxypyrazine binding site.
The steno requirements for the protein binding of various
substituted heterocyclic odorants were examined using nuclear magnetic
relaxation techniques. Model studies performed with bovine serum
albumin showed that particular side chains of the odorants tested
were primarily involved in the binding interaction. The methoxy group
of 2-isopropyl-3-methoxypyrazine was found to be responsible for
primary recognition by 13,000 x g supernatant fractions of sheep
olfactory epithelium.

Item Type:	Thesis or Dissertation (PhD)
Subjects:	Q Science > QH Natural history Q Science > QP Physiology
Library of Congress Subject Headings (LCSH):	Olfactory receptors, Heterocyclic compounds, Odors
Official Date:	December 1985
Dates:	Date Event December 1985 Submitted
Institution:	University of Warwick
Theses Department:	Department of Chemistry
Thesis Type:	PhD
Publication Status:	Unpublished
Supervisor(s)/Advisor:	Dodd, G. H.
Sponsors:	Medical Research Council (Great Britain) (MRC) ; Royal Society (Great Britain)
Extent:	xxii, 394 p.
Language:	eng

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