notes nervous system: g-proteins and neurotransmitters Flashcards
what type of receptor is fast-acting and a simple ion channel?
ionotropic
in an ionotropic receptor if you put a key in the door ___________
the door opens
what type of receptor is an ionotropic receptor?
ligand-gated
what type of receptor is slow-acting
metabotropic
in a metabotropic receptor if you put a key in the door what are the two things that might occur?
door opens or enzyme is activated
what are the three parts of a g-protein?
alpha, beta, gamma
when are g-proteins inactive?
when GDP is attached
when are g-proteins active?
when GTP is attached
what are the three steps of a g-protein?
hormone binds to receptor
GDP leaves, GTP binds
GTP/alpha leave and bind to a protein
what two things could occur as a result of the binding between GTP and alpha?
opening of an ion channel or activation of secondary messengers (enzymes)
where can g-proteins be found?
cardiac muscle, retina, odor receptors, blood vessel tone
what are the three types of g-protein pathways?
g-alpha s
g-alpha I
g-alpha q
what two g-protein pathways are stimulatory?
g-alpha s and g-alpha q
what g-protein pathway is inhibitory?
g-alpha I
what is the purpose of adenylate cyclase?
converts ATP into cAMP
what is the purpose of cAMP
activates protein kinase A (PKA)
what two g-protein pathways correspond with cAMP?
g-alpha s and g-alpha i
what g-protein pathway corresponds with PLC?
g-alpha q
what does PKA do?
phosphorylates (activates) a protein
what does phospodiesterase (PDE) do?
deactivates cAMP
what is the g alpha s pathway?
ligand binds to a receptor
GDP swapped for GTP leading to the activation of g alpha s
alpha and GTP bind to adenylate cyclase
adenylate cyclase is activated causing ATP to turn into cAMP
cAMP activates PKA
PDE deactivates cAMP
what is the g alpha I pathway?
ligand binds to a g-protein receptor
GDP is swapped for GTP (g alpha protein is activated)
g alpha I and GTP bind with adenylate cyclase
adenylate cyclase is inhibited
ATP is unable to convert into cAMP
reduced amount of PKA is formed
PDE also deactivates cAMP
what is the g alpha q pathway?
a ligand binds to a g-protein receptor
GDP is converted to GTP and g alpha q is activated
GTP and g alpa q bind to PLC
PLC causes PIP2 to breakdown into DAG and IP3
what is the function of DAG?
activates PKC
