Role of Rho-kinase in contractions of ureters from rabbits with unilateral ureteric obstruction.
OBJECTIVE
To investigate the expression of two isoforms of Rho-kinase (ROCK) and its functional role in the pathophysiological control of smooth muscle contraction in rabbits with unilateral ureteric obstruction (UUO).


METHODS
Left UUO was created in 14 rabbits and eight other rabbits (controls) had sham operations. After 2 weeks all the rabbits were killed. Ureteric strips suspended in an organ bath were used for functional studies and the effects of Y-27632, a specific inhibitor of Rho-kinase, on spontaneous contractions and electrical field stimulation (EFS; 50 V, 1 ms, 16 Hz, for 20 s), carbachol- (10(-7)-10(-4)m), phenylephrine- (10(-7)-10(-4)m) and KCl- (50 mm) induced contractions were analysed. Western blotting was used to determine expression levels of Rho-kinase protein in the ureters of UUO and control rabbits.


RESULTS
In the functional analysis, the contractions induced by EFS, KCl, phenylephrine and carbachol in the ureteric strips from rabbits with UUO were significantly greater than those from the control rabbits. Y-27632 considerably suppressed the ureter contractile responses in both UUO and control rabbits. Western blot analysis showed that both ROCK-1 and ROCK-2 proteins were expressed in the rabbit ureter. In accordance with the functional studies, the expression levels of both ROCK-1 and ROCK-2 were significantly greater in the ureters of UUO rabbits than in the controls.


CONCLUSIONS
Y-27632 suppressed ureteric contractions in the rabbits with UUO. Western blot analysis also confirmed greater expression levels of ROCK-1 and ROCK-2 in the ureters of UUO rabbits. It is important to elucidate by which mechanisms the Rho-kinase pathway affects ureteric function after obstruction.
Turna
Burak
B
Department of Urology, Ege University School of Medicine, Izmir, Turkey. burakturna@gmail.com
Cinar
Mehtap G
MG
Canda
Abdullah E
AE
Orhan
Elif C
EC
Tiftik
Nalan R
NR
Nazli
Oktay
O
Buyukafsar
Kansu
K
D000704:Analysis of Variance; D000818:Animals; D015153:Blotting, Western; D009119:Muscle Contraction / Q000502:physiology*; D009130:Muscle, Smooth / Q000502:physiology*; D011817:Rabbits; D014513:Ureter / Q000503:physiopathology*; D014517:Ureteral Obstruction / Q000503:physiopathology*; D054460:rho-Associated Kinases / Q000378:metabolism / Q000502:physiology
D054460:rho-Associated Kinases