The involvement of Rho-associated kinases in agonist-dependent contractions of human maternal and placental arteries at term gestation.
OBJECTIVE
The purpose of this study was to assess the involvement of rho kinase (ROK) in agonist-dependent contraction of omental, myometrial, and placental arteries of pregnant women at term.


METHODS
Wire myography was used to assess if contractions of intact or alpha-toxin-permeabilized arteries obtained from women at elective cesarean section were influenced by the ROK inhibitor Y-27632.


RESULTS
Western blotting indicated the presence of ROKalpha in each of the 3 tissue types. In intact human omental, myometrial, or placental arteries, Y-27632 dose-dependently reduced constrictions to the thromboxane-mimetic U46619. In permeabilized vessels, U46619 induced substantial Ca(2+)-sensitization of contraction that was inhibited by Y27632. The phosphatase inhibitor calyculin A induced a Ca(2+)sensitization of contraction similar to that of U46619 in permeabilized omental arteries that was unaffected by Y-27632, suggesting that ROK may signal via myosin phosphatase in these vessels.


CONCLUSIONS
These results are the first report of the involvement of ROK in the receptor-coupled constriction of intact and permeabilized arteries from pregnant women.
Wareing
Mark
M
Maternal and Fetal Health Research Centre, St Mary's Hospital, USA.
O'Hara
Maureen
M
Seghier
Fella
F
Baker
Philip N
PN
Taggart
Michael J
MJ
D000577:Amides / Q000494:pharmacology; D001158:Arteries; D015153:Blotting, Western; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D008387:Marine Toxins; D009125:Muscle Relaxants, Central / Q000494:pharmacology; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000502:physiology; D009215:Myometrium / Q000098:blood supply; D009852:Omentum / Q000098:blood supply; D010080:Oxazoles / Q000494:pharmacology; D010749:Phosphoprotein Phosphatases / Q000037:antagonists & inhibitors; D010920:Placenta / Q000098:blood supply; D011247:Pregnancy; D011263:Pregnancy Trimester, Third / Q000502:physiology*; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism / Q000502:physiology*; D011725:Pyridines / Q000494:pharmacology; D014661:Vasoconstriction / Q000187:drug effects / Q000502:physiology*; D054460:rho-Associated Kinases
D000577:Amides; D047908:Intracellular Signaling Peptides and Proteins; D008387:Marine Toxins; D009125:Muscle Relaxants, Central; D010080:Oxazoles; D011725:Pyridines; C108830:Y 27632; C059041:calyculin A; D017346:Protein Serine-Threonine Kinases; D054460:rho-Associated Kinases; D010749:Phosphoprotein Phosphatases