s&m

• where are taste buds located?


  taste papillae
• what are taste buds made out of?

  many different taste cells
• what are the two taste system pathways?

  1) insular cortex to amygdala

  2) amygdala and hypothalamus - NST
• what cranial nerve is the facial nerve?


  CN VII
• what cranial nerve is the glossopharyngeal nerve?


  CN IX
• what cranial nerve affects the vagus nerves?

  CN X
• what are the five categories of tastants?

  1) sour/acid

  2) bitter

  3) salty

  4) sweet

  5) umami/amino acid
• what categories are dimers?

  umami and sweet
• what does umami use?


  T1R1 and T1R3
• what does sweet use?


  T1R2 and T1R3
• what must dimers use as a subunit?

  T1R3
• what are T2Rs?


  bitter R
• what is salty transduced from?


  amiloride-sensitive sodium channels
• what is sour (acid) taste transduced from?


  H+ sensitive TRP channels
• what is umami/aa taste transduced from?

  GPCR
• what is sweet taste transduced through?


  GPCR
• what is the MOA for sweet taste?


  1) GBy activated

  2) PLC

  3) IP3

  4) Ca2+ release from stores

  5) TRPM5 opening

  6) depolarization
• what did genetic deletion of T1R3 do?


  eliminated the ability to detect artificial sweet
• what controls did they use?


  1) WT

  2) Sac mutant

  3) Sac mutant with transgene
• results?


  -sac mutant needs increased concentration of sucrose water to prefer it better

  -sac mutant with transgene showed preference right away
• to ensure caloric sufficiency what was found?


  having cells detect glucose independent of T1R3 - mice still have preference for starchy foods
• what happened with the KO mice that lacked T1R2 and T1R3 ?

  they could still detect carbohydrates - possible moa in which sweet taste is potentiated by Na+
• what is bitter taste transduced by?


  GPCR
• what does PTC do?


  -detects bitter compounds

  -individuals differ in expression

  -tasters v non tasters

  -detects bitter compounds through range of tasty vs not
• what are the three models of taste signaling?


  1) each taste cell is capable of detecting all tastes

  2) have taste cells specialized but all go to same neurons

  3) taste buds have taste cells that are best at distinguishing certain tastes - send info along dedicated axons
• what backs up the labeled line hypothesis?


  T2Rs are co-expressed in same cells, but not with T1R cells
• what were the controls for the experiment that that sweet and bitter activate separate pathways?


  -hT2R16 expressed from T1R2 promotor

  -control (no hT2R16)

  -hT2R16 expressed from T2R promoter
• when hT2R16 was expressed in sweet promotor (T1R2) what happened?


  taste PDG as sweet
• when hT2R16 was expressed in bitter promotor (T2R) what happened?


  taste PDG as bitter
• what else supports labeled line hypothesis?


  specificity in peripheral taste coding
• what is the layout of gustatory maps in the insular cortex?


  specificity in central coding - segregated
• what happens within taste cells?


  signal transduction that forms chemical synapses onto primary sensory afferents
• where are taste buds located?


  taste papillae
• what are taste buds made out of?

  many different taste cells
• what are the two taste system pathways?

  1) insular cortex to amygdala

  2) amygdala and hypothalamus - NST
• what cranial nerve is the facial nerve?


  CN VII
• what cranial nerve is the glossopharyngeal nerve?


  CN IX
• what cranial nerve affects the vagus nerves?

  CN X
• what are the five categories of tastants?

  1) sour/acid

  2) bitter

  3) salty

  4) sweet

  5) umami/amino acid
• what categories are dimers?

  umami and sweet