Olfaction and Perception

7/24/2019 Olfaction and Perception

http://slidepdf.com/reader/full/olfaction-and-perception 1/27

Olfac ! on & Percep! on

Olfac ! on & Percep! on



"Press Release: The 2004 Nobel Prize in Physiology or Medicine".

Nobelprize.org. 19 Oct 2012 http://www.nobelprize.org/

nobel_prizes/medicine/laureates/2004/press.html

http://www.nobelprize.org/nobel_prizes/medicine/laureates/2004/press.html



Odor molecules are generally:

Detectable ! Volatile!

< 300 g/mol

Hydrophobic/Hydrophilic



The Cell Surface

Hydrophillicend

Hydrophobic end

O

O

O

O

OP

O

OO

N

phosphatidylcholine

HO

NH2

OHsphingosine

HO

HN

OH

O

ceramide

O

HN

OH

O

P

O

O ON

sphingomyelin

HO

H

HH

cholesterol



Phospholipid Bilayer

H2O

H2O

Cellular contents are isolatedfrom extracellular environment



Olfactory Receptors

and the

7-Transmembrane G-protein coupled receptor proteins (GCPR)

Extracellular Hydrophillic Region

Intracellular Hydrophillic Region

Receptorprotein

Lipid bilayer Cholesterol

Hydrophobic Region



G-protein-coupled receptors (7-TM receptors)

Structure - Single protein with 7 transmembrane regions

Transmembranehelix

C -Terminal chain

G-Protein

binding region

Extracellular

loops

Intracellular loops

N -Terminal chain

HO2C

NH2

VII VI V IV III II IMembrane





O O

Molecular Weight: 258.40

O O

ot ~ 0.001 ppb

ot ~ 0.44 ppb

ot ~ 0.00063 ppb

ot ~ 0.13 ppb

O

ot ~ 223 ppb

O

ot ~ 61 ppb

Molecular Weight: 238.41



O

(S)-Carvone

O

(R)-Carvone

caraway spearmint



Olfactory Receptorsand the

7!Transmembrane G!protein coupled receptor proteins "GCPR #



ß

!

"

GDP GTP

Ligand

binding

Inducedfit

G-protein

binds

Induced

fit for

G-protein

ß

!

"

Ligand

Receptor

G Protein

Cell membrane

ß

!

"

Binding site for G-protein opens

= GDP

Interaction of receptor with G!protein

Guanosine diphosphate Guanosine triphosphate

The cAMP Transduction Cascade



ß

!

"

Binding site recognizes GTP

GTP binds

Induced fit

G-protein alters !-subunit shape

Complex destabilized

Fragmentationand release

ß

!

"ß

!

"



Interaction of !!subunit with adenylate cyclase

Active site"closed#

Binding site

for!!

subunit

cyclic AMPATP

Binding

Inducedfit

Active site"open #

!!subunit

Adenylate cyclase

GTPGDP

cAMP acts as hormone thatactivates Ca 2+ ion channels

Signal transduction via axons



Summary

Sound Like ALOT to Remember?

ß

!

"

GDP GTP1. Odorant " ligand # binds receptor, which then binds G!protein

2. GDP leaves and GTP binds, resulting in destabilizing complex

3. !!Subunit binds adenylate cyclase where ATP is converted to cAMP

4. cAMP activates Ca2+ ion channels resulting in signal transduction

cyclic AMPATP



Receptorcells

Olfactory bulb

Olfactory cortex

Hypothalamusemotion and memory



Fragrance Perception

Humans use 350 ! 400 di$ erent types of olfactory receptors! variations among individuals

Statistically, each individual may detect odor with di$ erent combination of receptors

Odor ! Emotion, each individual response may depend on previous experiences

Market Research - understanding your customers

Sensory Analysis - using humans as measuring tool

Can you discriminate between odors?

Can you recognize odors (vocabulary)?



Sensory AnalysisOdor Threshold

O O

O

O

Floral!musk, 200 ppb " in water #

O

O

O

O Classical musky odor, 0.7 ng/L " in air #

O Powerful musk odor, 0.00063 ppb " in air #

1 ppb " part per billion # = 1 microgram/L = 0.000001 g/L = 0.0000001 %

1,000,000 microgram = 1 gram

1 ng = 0.000000001 g



Sensory AnalysisOdor Threshold

O

H

(-) ambrox

ot ~ 1 ppb

O

O

OH

maltol

ot ~ 35,000 ppb

vp ~ 0.01 mm Hg @ 25 C vp = 0.0005 mm Hg @ 25 C

mp = 75 C mp = 162 C



Sensory AnalysisOdor Profiling

Animal: Refers to the warm, sensual and heady base notes once associated with the natural odor of musk, ambergris, civet, andcastoreum, now produced by some vegetable materials and aroma chemicals.

Herbaceous: Aromatic and sharp, deriving from the plant kingdom, these are closely linked to the green notes, whilst at the same time taking on more complex characteristics. They are particularly

aromatic and in general have a scent similar to that of the earth, therefore grass and roots.

Amber: Rich, spicy, warm, sweet and sensual. Smooth, rich and intoxicating, amber is one of the hardest fragrances to describe.

Balsamic: Pungent, fresh. A heavy scent that calls to mind sticky sap. " balsamic vinegar, mint, pine #

Green: Penetrating and spontaneous, this derives above all from leaves, stalks or freshly cut grass.Lively and bubbly, it can be traced back to certain flowers such as Violet, or fruits, such as Watermelon.




Spicy: Lively or pungent notes such as clove oil, cinnamon; characteristic of notes of carnation, ginger, lavender or thechemical spicy notes of eugenol or isoeugenol.

Woody: An odor which is linked to the aroma of freshly cut, dry wood or fibrous root such as sandalwood or vetiver.

Musky: Intense and persistent, typically masculine. In most cases, the smell reminds us of wood, resin and earth.

Marine/Ozone: Lively and e$ ervescent, fresh and agreeable, these notes remind us of water, the sea and the ozone.




Pane llist: ________________________________________ Date : _______________________

Sample

ID Flo ral Fru ity Citr us Herba l Gree n Mint Marine Sweet Spicy Woo dy Fres h




0

5

10

15

20

Floral Fruity Citrus Herbal Mint Sweet Woody Fresh




O

raspberry ketoneHO

O

CO2Mehedione

O

Pharaone

A B C




Top note " 15!25%#

Middle note " 30!40%#

Base/bottom note " 45!55%#



Sensory AnalysisOdor Profiling - Multidimensional scaling map




Olfaction and Perception

Documents