Cell Communication Flashcards
Order of bonds from weakest to strongest :
Hydrogen, Ionic, Van der Waals, Covalent, Hydrophobic
- Van der Waals
- Hydrophobic
- Hydrogen
- Ionic
- Covalent
Order of GCPR signaling (5)
- first messenger (ligand)
- GCPR
- Effector
- Second messenger
- Cellular response
What does Adenylyl Cyclase stimulate/inhibit?
Cyclic AMP (cAMP)
What does Phospholipase C stimulate?
Inositol Triphosphate (IP3)
& Diacylglycerol (DAG)
What is the function of adenylyl cyclase?
to convert ATP to cAMP
What GCPR turns on adenylyl cyclase?
Gs
What GCPR turns off adenylyl cyclase?
Gi
Stimulatory GCPRs
Gs & Gq
Inhibitory GCPR
Gi
What GCPR stimulates more cAMP?
Gs
What GPCR inhibits the release of cAMP?
Gi
What is the function of Phospholipase C?
Converts PIP2 to IP3 & DAG
PIP2 - phospha-tidyl-inositol, 4-5 biphosphate
IP3 - Inositol triphosphate
DAG - Diacylglycerol
What GPCR stimulates Phospholipase C?
Gq (G11)
What enzyme liberates arachidonic acid from the cell membrane?
Phospholipase A2
What does increased cAMP in cardiac monocytes result in?
Enhanced contractility (beta-1 effect)
What does increased cAMP in the smooth muscle of the airways and vessels cause?
Relaxation & Dilation (beta-2 effect)
What does increased cAMP in platelets result in?
Increased platelet aggregation
What does increased cAMP do in the principal cells of the nephron?
increase in aquaporin-2 water channels
What enzyme produces IP3 and DAG from PIP2?
Phospholiapase C
What is the primary NT in the peripheral efferent (motor) neural pathway?
Acetylcholine
What does Acetylcholine control peripherally vs centrally?
peripherally- motor function
centrally - sleep, wakefulness (RAS), learning and memory
How is Acetylcholine eliminated?
By Acetylcholinesterase (AChE) in the synaptic cleft
-it hydrolyzes ACh into acetate and choline
-Choline is taken back up to the pre-synaptic terminal for recycling
Why can magnesium cause muscle weakness or potentiate neuromuscular blockade?
Because magnesium antagonizes calcium at the presynaptic nerve terminal. Without calcium going into the presynaptic nerve terminal, acetylcholine can’t be released from the vesicles.
-No ACh release, decrease in skeletal muscle contraction
Which cholinergic receptor is the ion-gated one?
Nicotinic
Which cholinergic receptor is the GPCR?
Muscarinic
What must happen for the nicotinic ion channel to open?
Acetylcholine must bind simultaneously to the two alpha subunits on the receptor
Which cholinergic receptor type is inhibitory and which is excitatory?
Excitatory: Nicotinic (N1/N2, Nm/Nn), M1, M3, M5
Inhibitory: M2, M4