Lecture 2: Olfaction and Gustation

Question 1

What are the 4 principles for odour discrimination?

Answer 1

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

Question 2

Describe mammalian and c.elegan odorant receptors?

Answer 2

OSNs are 7 transmembrane G protein coupled receptors

Binding of odor to OR results in GPCR signalling and neuronal depolarisation

Question 3

Describe insect errant receptors?

Answer 3

At atomically similar to mammals but evolutionary different.

Question 4

How many ORs do drosophila have?

Answer 4

62

Question 5

Where does fly olfaction take place?

Answer 5

antenna and maxillary pulp

Question 6

What are the ORS in the drosophila antenna?

Answer 6

Basiconic sensilla
Trichoia sensilla
coeloconic sensilla

Question 7

What are the ORS in the drosophila palp?

Answer 7

Basiconic sensilla

Question 8

What are the ORS in the drosophila larva?

Answer 8

Dorsal organ dome

Question 9

Where are the ordorant binding protein in Drosophila found?

Answer 9

Wings, adult carcass, torsi, eyes , maxillary palps and so on

Question 10

Axons of the same OR coverage onto the same what?

Answer 10

Glomeruli

Question 11

What happens in the decoder stage?

Answer 11

Processing

Question 12

What happens in the encoder stage?

Answer 12

Order what happens in the brain

Question 13

What is the order of the olfactory circuits in mammals?

Answer 13

Olfactory epithelium  (olfactory receptor neutron)
Olfactory bulb (primary centre)
Piriform cortex, olfactory tubercle, Entorhinal cortex (secondary centre)

Question 14

What is the order of the olfactory circuits in insects?

Answer 14

antenna maxillary pulp (olfactory receptor neutron)
antennal lobe (primary centre)
MB calyx, lateral horn (secondary centre)

Question 15

How many gustatory organs do mammals have in the head?

Answer 15

1

Question 16

Where are the gustation organ distributed in insects?

Answer 16

All over the body

Question 17

What does pickpocket28 detect in flies?

Answer 17

Water

Question 18

What does inotropic receptors in flies?

Answer 18

Amines, salt, acid detection

Question 19

What does gustatory receptors in flies?

Answer 19

Sweet and bitter detection

Question 20

Where does detection of food occur in the fly?

Answer 20

On the legs

Question 21

What does each taste bud contain in a mammal?

Answer 21

Four types of cells
3 types of TRCs
Basal cells

Question 22

How many types of TRC are there?

Answer 22

3

Question 23

Whats type 1 TRC?

Answer 23

Low salt concentration

Question 24

Whats type 2 TRC?

Answer 24

Sweet, biter

Question 25

Whats type 3 TRC?

Answer 25

Sour, acids