Lecture 2: Olfaction and Gustation Flashcards
What are the 4 principles for odour discrimination?
Large number of operant receptor genes for olfaction
Olfactory sensory neutron usually express a single receptor or distinct ligand profile
OSNs expressing same receptor extend axons that converge on same glomerulus in the brain
One door can activate multiple OR or each OR can respond to multiple odor
Describe mammalian and c.elegan odorant receptors?
OSNs are 7 transmembrane G protein coupled receptors
Binding of odor to OR results in GPCR signalling and neuronal depolarisation
Describe insect errant receptors?
At atomically similar to mammals but evolutionary different.
How many ORs do drosophila have?
62
Where does fly olfaction take place?
antenna and maxillary pulp
What are the ORS in the drosophila antenna?
Basiconic sensilla
Trichoia sensilla
coeloconic sensilla
What are the ORS in the drosophila palp?
Basiconic sensilla
What are the ORS in the drosophila larva?
Dorsal organ dome
Where are the ordorant binding protein in Drosophila found?
Wings, adult carcass, torsi, eyes , maxillary palps and so on
Axons of the same OR coverage onto the same what?
Glomeruli
What happens in the decoder stage?
Processing
What happens in the encoder stage?
Order what happens in the brain
What is the order of the olfactory circuits in mammals?
Olfactory epithelium (olfactory receptor neutron) Olfactory bulb (primary centre) Piriform cortex, olfactory tubercle, Entorhinal cortex (secondary centre)
What is the order of the olfactory circuits in insects?
antenna maxillary pulp (olfactory receptor neutron)
antennal lobe (primary centre)
MB calyx, lateral horn (secondary centre)
How many gustatory organs do mammals have in the head?
1
Where are the gustation organ distributed in insects?
All over the body
What does pickpocket28 detect in flies?
Water
What does inotropic receptors in flies?
Amines, salt, acid detection
What does gustatory receptors in flies?
Sweet and bitter detection
Where does detection of food occur in the fly?
On the legs
What does each taste bud contain in a mammal?
Four types of cells
3 types of TRCs
Basal cells
How many types of TRC are there?
3
Whats type 1 TRC?
Low salt concentration
Whats type 2 TRC?
Sweet, biter
Whats type 3 TRC?
Sour, acids
