0310 Flashcards
What two genes cause the perception of sweet
T1r2 & t1r3
What genes code for Unami
T1r1 & t1r3
What receptors for taste use GCPR‘s and TRP channels
Sweet Unami and bitter TRCs use GCPRs whereas all three also used TRP channels
What GCPR‘s use the G inhibitory proteins in the gustatory system
Type 2 taste receptor cells use gustducin which is a GQ and the receptors on type two TRC‘s (TR ones and TR twos) are gcprs
What is a GCPRthe activates GS is the means to affect intracellular events?
Olfactory receptor proteins golf is a GS
What 2 receptors use members of the TRP family of channels
Type 2 taste receptor cells (TRPM5) and type 3 taste receptor cells
What are the two features in the response of a neuronal population that make up an intensive code for any sensory system
The number of neurons firing action potentials and the number of action potentials each neuron fires make up an intensive coat
If the narrow neurons are saturated, what activity in other populations of olfactory sensory neurons allows us to detect higher concentrations of the same odorant?
Olfactory sensory neurons more broadly to to odorant molecules – one with lower affinity for the specific odorant molecule
What type of tastant does the class of type two TRC‘s respond to
Sweet bitter and Unami
How can we be sure that the activation of PLC and the production of IP three releasing calcium from the smooth endoplasmic reticulum is not sufficient for the drive of the release of ATP?
Knock out the key RPM5 channel and a mouse cannot taste sweet bitter or Unami
What gene is missing when sweet cannot be tasted
The Gene for T1 R2
What are two channels that are absolutely necessary for an olfactory sensory neuron to be able to send information to neurons in the olfactory bulb and where do we find these channels?
Calcium regulated chlorine channel (ANO2) in the cilia and voltage gated sodium channels of the axon hillock/initial segment
What type of taste receptor cell is silence as a result of the knockout of the TPM 5 gene
Class two taste receptor cells
What type of receptor proteins do class 2 taste receptor cells use?
T1rs (R 1–3) and T2ts are all GCPRS
What two other genes when deleted would have the same effect as the deletion of the TPM 5 gene
PLC beta two and gustducin and CALHM1 (knocking out the IP3 receptor and P2 X would have a much bigger effect than simply shutting down the class 2 taste receptor cells)
What intracellular messenger molecule is necessary for the proper guidance of olfactory sensory neurons
Calcium
What is the general sensory transduction pathway
Receptor cells two receptor molecule to transduction channel 2 receptor potential to spike train to transmitter release
Which receptors can generate action potentials and which receptors cannot generate action potential
Short receptors like taste receptor cells cannot generate action potentials but they signal neurons closer to them. Olfactory sensory neurons are long and they can generate action potential‘s. 
What are the two functions of the gustatory system?z
One. Stimulate eating a fish that provide a source of energy, protein, and salt. Two. Drive an animal to avoid items that might be poisonous or contaminated by bacteria
What are the three types of Papile
Fungi.form, foliate, and circumvallate
What are the three cell types of a taste but
Taste receptor cell, supporting cells, and basal cells
What is a taste receptor cell and what does he do?
They stick micro villi into the only opening of the bud, called a taste pore, which is the route by which saliva and molecules dissolved in it can reach the taste receptor cells
What do supporting cells of the taste bud do
They form an outer envelope for the bud
What do basil cells of the taste bud do
They serve as progenitors for taste receptor cells, which are short-lived and easily damaged due to various insults
What chain allows us to taste bitter phenylthiourea?
T2R-38;
What high population of pappillae allows for super tasting
Fungiform
Why do super tasters die young
They are only attracted to sweet things and repel by bitter things like healthy foods for example broccoli
What are type one cells
They respond selectively to sodium concentration therefore they are salty taste receptors
How are Type 1 cells like astrocytes glial lik
They extract K+ from extracellular fluid by expressing GLAST
What are the three sub types of type number 2 taste receptor cells
One has receptors for suite one has receptors for Unami and a third binds to bitter
What do you type three taste receptor cells do
They can detect the hydronium concentration so they are sour taste receptors
What phase determines which functional type a taste receptor cell becomes
It depends on the local environment during the terminal S phase
When does the basal cell populations stop growing in decline by 1%
35
What happens after type two cells find a molecule
It stimulates the gustatory inhibitory gustducin and the beta gamma subunit turns on PLC beta two in generates I P3 to open calcium channels on the smooth endoplasmic reticulum which opens T RPMs
The opening of what channel leads to depolarization in action potential generation and type to taste receptor cells
TRPM5
Oh what is released as the result of type number to action potentials
ATP
Where does ATP release from
It releases from the base of the taste receptor cell
What channel is required for ATP release
Voltage gated sodium channels are required to bring the potential to or above +10 mV
Where are the ATP channels that allow ATP to move out from a taste receptor cell
Voltage gated CALHM1 channels
How can you block sodium channels
Tetrodotoxin is a sodium antagonist
What happens to ATP release if sodium channels are blocked
Atp release is also blocked
What happens if there is a C aLHM one null mutation
A mouse will be insensitive to Sweet Unami or bitter but shower and salty will stay intact
What is the general taste transduction pathway in type number to taste receptor cells
Receptors to G- routine (GUSTDUC IN) goes to PLC beta two goes to TRP M5
What is the Janne tropic receptor that ATP buns to
P2 X
What reaction does the enzyme PLC beta to catalyze
The breakdown of PIP 2 and two DAG and IP3
 What class of GCPrs are t1rs
Class three
What genes do unami taste receptor cells Xpress
T1R1 and T1R3
What neurotransmitter do tsunami taste receptor cells blind with the hetero timer
Glutamate
Oh what jeans do sweet taste receptor cells express
T1r2 and t1r3
What does the sweet taste receptors cell heteodimer bind
Carbohydrates
What class of GCPR‘s do T2R use
Class one
Where are the receptors for bitter taste
Tw4
Why do we have a high affinity of t2rs
Since there is a high affinity it allows the binding of trace amounts of bitter tasting food without damage to the person if the food turns out to be poisonous
What are the two groups that bind on bitter receptors
Alkaloids or nitrogen rich groups
What do the expression of a lot of t2rs permits
Permits bitter taste receptor cells to respond to a very broad range of very different compounds
What is the consequence of all of the taste receptor cells expressing so many t2rs
Since they express multiple you cannot tell one bitter compact from another. You can easily detect better but you can poorly discriminate bitter
How does soda trigger a response in type three TCR‘s
The carbon dioxide in water for carbonic acid. Then the enzyme carbonic hydrates allows the response to it as it disociates into bicarbonate and hydronium
What happens if the OTOP one gene gets knocked out
Chord tympani nerve (cranial nerve seven) loses response to acidics stimuli
What does the dimer of OTOP11
A proton channel
What taste receptor cell is OTOP1 expressed in
Type three
How is sour taste processed
Hydronium entrance the taste receptor cell through the OTOP one channel, which lowers intercellular pH. Low pH leads to the close of potassium channels, which causes to polarization and subsequent action potentials
What happens when you delete both ENAC Alpha genes in mutant mice
The mice cannot distinguish between salt and pure water so they like both equally
What evidence does the mic is leaking pure water and salt equally provide
It provides half of the evidence for a label line theory because ENAC is necessary but it doesn’t provide evidence that is sufficient to code for salty taste
How was enac tested in Reese‘s monkeys
They are only responsible for a fraction of the sodium protection. Amilo ride treatment doesn’t affect their licking, so there must be another channel
Where are ENAC ion channels express
They are expressed and taser so sales I do not express receptors for other tastes and this occurs through release of neuroactive peptides
What is the concentration of salt and saliva
20 nm
What is the range of salt from least attractive to aversive for our detection
60 - 300
What happens if ENAC ion channels are knocked out
The mice have a selective abolishment of the attractive taste of sodium chloride but it does not affect any other taste responses
What channels are crucial for salt detection and how
Sodium enters to open voltage gated calcium channels
What taste processing model is mowt support
Label line
What is the label line model
The label line model is that everything is separate for the taste reception cells and it combines later
How is the label line model supported
Functional studies and Mayas have demonstrated that different taste receptor cells define the different taste modalities, and the activation of a single type of taste receptor cell is sufficient to encode taste quality 
What is the Cross fiber model of taste processing
The crossfire model says that the proud tune neurons either insert arrange a receptors or single cells in contacts to more than one receptor
What happens if T2 R5 gene is knocked out
There is a selective elimination in the response to cycloheximide which is a bitter compound
What happens if the taste receptor cells that express PDk2L1 knockout
There is no response to hydronium
What happens if you knockout plc beta or TRPM5
There is no sweet unami or bitter
What do the knock out tell us about genes and behavior
Genes code for proteins not behavior
What Jean allows for cromolyn detection in humans
T2 R 49
What is the reaction of the elimination of PKD2L1 and PKD1L3
Eliminated all response to acids
What is the type three taste receptor cell toxin
Diphtheria toxin a
What expression does diphtheria toxin a remove
PKD2L1 expression
How can we make mice respond to cromolyn sweet
Add t2r49 to T1r2 and T1 are three and they were perceive crumbling a sweet
What high concentration of ions does olfactory sensory neurons need
Chlorine
And why do olfactory sensory neurons need high intracellular chlorine concentration
The outward driving force allows for an inward current to cause a depolarization of the neuron
How much deplorization does the chlorine account for
90
What code transporter insurers hi chlorine concentration and how
NKCC one insures high intrusellular chlorine concentration and the movement of sodium and potassium down there gradient allows for this
What Jane is turned on an immature neuron that makes the intercellular chlorine low
KCC to
What transports odorant molecules
Obps
What happens if Celia can’t fail to develop
Loss of smell, anosmia
BArdet-biedl syndrome
 How do you olfactory sensory neurons compared to other axons of the nervous system
They are the smallest and most solely conducting accents
Past what age do you start losing one percent of your osns
40
What is the three layers of olfactory epithelium from top to bottom
At the top there is one layer of supporting cells. At the bottom there is one or two layers of basal cells. In the middle there are olfactory sensory neurons
What is the site of odorant detection
Cilia
 What do the olfactory progenitor cells do
The OSN‘s are a place throughout life
What receptor channels are important for the calcium entry
Calcium gated chlorine channels
What type of receptor proteins are olfactory receptor proteins
Class one GCPRs
What feature of olfactory receptor proteins allows it to respond to a Y range of odorants
They have hyper variable binding regions
Since odorant receptors are the largest Jean family with more than 1000 jeans in most mammals, how many are intact and are expressed in humans
350… 5%
How many odorant receptor proteins does each olfactory sensory neuron have
1
How does one receptor come to be expressed and a mouse
The LCR limits transcriptions to 40 and then more limitation comes from the commitment of olfactory sensory neuron to one
What type of antagonist are some odorants
Competitive antagonist
How is a given odorant recognized by a unique set of olfactory receptors
Different olfactory receptors recognize different sets of odorants and different odorants activate different sets of olfactory receptors
And what happens when there is a high concentration of odorant
There is a high spike rate and there are an increase number of old factory sensory neuronsbound
How do low sulfur bearing compounds smell
Plesant eg coffee
How do high bearing sulfur content smell
Awful like rotten eggs
What happens when the CNG channel a two subunit is mutated or deleted
There is no ability to smell
What G protein is in all olfactory sensory neurons
Golf
What is the olfactory transduction pathway
Orderant to odorant receptor to golf to a C3 to camp to CNG to calcium to a in 02 depolarization
What inhibits camp
PDE1C
What diminishes calcium in the olfactory transduction pathway
NCKX four
What does adaptation allow you to do in olfactory sensation
Adaptation allows an olfactory sensory neuron to respond to a broad range of outer intensity. Adaptation decreases in olfactory sensory neuron sensitivity to low concentration but increases olfactory sensory neurons relative sensitivity to high concentration
How can you remove adaptation
One. Eliminate extracellular calcium concentration or to baPTA cheerleader prevent calcium rise intracellular
What are three negative calcium feedback loops with calmodulin olfactory adaptation
One desensitize CNG to camp
two enhance PDE 1C to degrad camp
three inhibit AC three by phosphorating it with cam K2 to decrease synthesis
