GPCR 2 and calcium homeostasis Flashcards
Name 4 effector enzymes and what reactions they catalyse.
adenylyl cyclase ATP==> cAMP
phospholipase C PIP2==> DAG+ IP3
phosphoinositide 3- kinase PIP2==>PIP3
cGMP phosphodiesterase cGMP==>5’- GMP
Name two ion channels that GPCRs act on.
voltage operated ca channels (VOCC)
G-protein regulated inwardly rectifying K+ channels (GIRKs)
Name the adenylyl cyclase activating subunit
alpha s
Name three receptors that activate AC
beta adrenoreceptor
D1- dopamine receptor
H1- histamine receptor
What does cAMP activate?
PKA
cyclic AMP dependent protein kinase A
Name the adenylyl cyclase inhibitory subunit
alpha i
Name three receptors that inhibit AC.
alpha 2 adreno receptor
D2 dopamine receptor
u opioid receptor
name three receptors that activate phospholipase C
alpha 1 adrenorecpetor
m1 muscarinic receptor
h1 histamine receptor
Name the phospholipase C activating subunit
alpha q
What does the activation of phospholipase C cause
pip2 to DAG and ip3
ip3 to ca on sr/er released ca in to cytoplasm
Explain signal amplification
allows small extracellular signals to elicit significant changes in cellular behaviour
Explain how heart inotropy can be increased
adrenaline + noradrenaline to beta 1 receptor
g alpha s to ac to camp to pka
vocc phosphorylated
Ca influx
How is vasoconstriction caused by GPCR’s?
noradrenaline to alpha 1 to vasocontriction via Gq-phospholipase c pathway
How is bronchoconstriction caused by GPCR’s?
ACh to M3 to bronchoconstriction via Gq-phospholipase C pathway
How can modulation of NS release via GPCR’s allow pain relief?
morphine to u-opioid receptor g-protein activated
beta gamma subunit inhibits VOCC
prevent NT release
Why is Ca homeostasis important?
changes in intracellular Ca responsible for or regulate a wide range of physiological and pathological pathways
How are the Ca concentration gradients set up?
pm relatively impermeable to ca
pumps and transporters
Ca buffer proteins
Name 4 pumps involved with the regulation of the Ca gradient.
serca
pmca
mt uniport
ncx (na-ca exchanger)
Name three mechanisms that increase intracellular calcium
VOCC
Ligand gated ion channels
Ca induced ca release
Name the types of channel involved with ca induced ca release
ryanodine receptors
ip3 receptors
