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Signal transduction WS 09/10
Olfaction
Signal transduction
Emotions and behaviour
memory
orientation in environment
quality ofnutrients / food
social behaviour
choosing a partner
Signal transduction
Axel, R. (1995) Spektrum der Wissenschaft, Dezember 1995
Olfaction
OlfactionSignal transduction
Signal transduction
Olfactory thesholds
Signal transduction
Decline in olfactory sensitivity
Signal transduction
Quelle: Kleene + Gesteland (1981) Brain Res. 229: 536
olfactory neuron
supportingcell
olfactoryepitheliumbasal
cell
Anholt, R.R (1987) Trends in Biochemical Science 12, 58ff
The olfactory epithelium
Signaltransduktion
olfactory neuron
supportingcell
Anholt, R.R (1987) Trends in Biochemical Science 12, 58ff
mammals5 - 120 million
olfactory neurons
humansapprox. 10 million
life timeapprox. 4 – 8 weeks
basalcell
Signal transduction
c = ciliafunction: detect odorants; chemo-electrical signal transduction
s = somafunction: energy production,protein biosynthesis
a = axonfunction: generate and conductaction potentials
d = dendrite
Signal transduction
Odorants excite olfactory neurons
depolarisation
odorant
Signal transduction
depolarisation hyperpolarisation
Duftstoff
Signal transduction
Signal transduction
in olfaction
Signal transduction
receptorsspecificty
sensitivityenzyme cascade
electrical responseion channel(s)
Olfaction
Signal transduction
odorantreceptor
Olfaction
Signal transduction
G-protein: Golf
Olfaction
Signal transduction
Adenylyl cyclase
Olfaction
Signal transduction
CNG channel
Olfaction
Signal transduction
amplification
Cl- channel
Olfaction
Is the signalling cascade
supported by
chloride efflux?
Signal transduction
OlfactionSignal transduction
Ion distribution (vertebrate)
outside inside
Na+ 140 mM 3-30 mMK+ 5 mM 140 mMCa2+ 2 mM < 1 µMMg2+ 2 mM einige mM Cl- 140 mM 10 mM
OlfactionSignal transduction
high [Cl-] in the neuron
⇒ amplification
Signal transduction
Properties of the
molecular components
of the signalling cascade
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