Flashcards in 15. Smooth muscle contraction Deck (15)
myosin - light chain kinase
MLCK ( myosin - light chain kinase ) action
myosin + actin --> myosin - P + actin
Smooth muscle cell - vasodilator
Nitric oxide ( NO)
Ca2+ vs No on smooth muscle contraction
Ca2+ --> contraction
NO --> relaxation
NO associated relaxation of smooth muscles - process
No --> activation of Guanylate cyclase --> increased cGMP ( from GTP ) --> activation of MLCP --> Myosin +actin ( no Pi) --> relaxation
mysoin - lught - chain - phosphatase
mLCP ( myosin - light -chain - phosphatase ) action
Myosin - P + actin --> Myosin + actin
MLCP vs MLCK according action and results
MLCP --> MYosin -P actin ---> Myosin +actin --> relaxation
MLCK --> myosin +actin --> myosin -P +actin --> contraction
NO synthase - action
L-argirinine --> NO
• In skeletal muscle, calcium binds ___; in smooth muscle, calcium binds ___
• What are the steps in smooth muscle contraction following calmodulin binding Ca2+?
MLCK is activated, phosphorylating myosin and leading to contraction (relaxation involves MLCP and dephosphorylation of myosin)
• What are the steps to relax smooth muscle after contraction?
NO enters cell, guanylate cyclase stimulated, cGMP increases, cGMP actives MLCP, myosin/actin complex dephosphorylated, unbinding/relaxation
• Calcium leads to muscle ___ (contraction/relaxation). Nitric oxide leads to muscle ___ (contraction/relaxation).
Contraction (Ca2+ = Contraction); relaxation (nitric oxide = relaxation)
• An action potential reaching a smooth muscle cell must activate what type of channel to promote calcium influx into the cell?
L-type voltage gated calcium channels