Stretch and
Adaptation
Adaptation
What pump restores calcium into the SR after contraction?
What is SERCA?
What type of contraction occurs in the gut and bladder (phasic or tonic)?
What is phasic?
Which neurotransmitter activates muscarinic receptors in smooth muscle?
What is acetylcholine (ACh)?
Which proteins disassemble during oscillation and reassemble for force generation?
What are myosin filaments?
What ion channel opens to repolarise the membrane after contraction?
What is a delayed rectifier potassium channel (Kv)?
What molecule binds calcium to initiate smooth muscle contraction?
What is calmodulin?
Which protein dephosphorylates myosin to end contraction?
What is MLCP (myosin light chain phosphatase)?
Which second messenger is produced when Gq-coupled receptors are activated?
What is IP3 (inositol triphosphate)?
What cellular mechanism allows force to return after a period of sustained stretch?
What is actin and myosin polymerisation?
Which channel type is open at rest and closes during depolarisation?
What is an inward rectifier potassium channel (Kir)?
Which enzyme does calcium-calmodulin activate to trigger contraction?
What is MLCK (myosin light chain kinase)?
What is the final action of MLCK in initiating contraction?
What is phosphorylating the myosin light chain?
Which receptor type increases cAMP to promote relaxation?
What is a β-adrenergic receptor?
Which drug class blocks L-type calcium channels and inhibits contraction?
What are dihydropyridines (e.g., verapamil, nifedipine)?
Which two messengers promote smooth muscle relaxation by increasing PKA and PKG activity?
What are cAMP and cGMP?
At the end of contraction we see calcium levels decrease, what three mechanisms are responsible
what is
1. SERCA pumps into SR
2. out of cell through PMCA
3. out of sodium antiport
Which enzyme converts ATP to cAMP in smooth muscle signalling?
What is adenylate cyclase?
Which receptor-operated channel is activated by ATP in smooth muscle?
What is the P2X receptor?
Which channel opens when SR calcium stores are depleted?
What are store-operated calcium channels (SOCCs)?
Which two signalling pathways can inhibit MLCP to increase calcium sensitivity?
What are the Rho/ROK and PKC/CPI-17 pathways?
Which intracellular protein is activated by DAG and inhibits MLCP through CPI-17?
A: What is protein kinase C (PKC)?