The Effect And Signaling Mechanism Of UrotensinⅡ On Cardiac Function

AIM To investigate the effect and signaling mechanism of urotensin II on cardiac function in normal and heart failure rats.Methods Hearts were perfused in the Langendorff mode,â‘´UII group: Urotensin II (10-10,10-9,10-8 and 10-7 molï¹’L-1) was given respectively perfusion , then investigated the normal and heart failure rat's cardiac function;⑵KT5720+UII group : perfused UII( IC50 ) on the basis of KT5720 , observed normal and heart failure rat's cardiac function ;⑶KT5720 group : recorded normal and heart failure rat's hemodynamic index after perfused KT5720.Resultsâ‘´UII group: After given UII (10^-10,10^-9,10^-8 and 10^-7 molï¹’L^-1) in the fluid ,â‘ normal rats : +dp/dt_max decreased 16.48%,25.53%,31.53% and 34.47%, -dp/dt_max reduced 22.78%,33.63%,46.09% and 51.73%;â‘¡heart failure rats : +dp/dt_max decreased 19.01%,26.05%,34.36%,37.27%, -dp/dt_max reduced 27.71%,38.72%,53.41%,60.12%, respectively. The heart failure rats'ratio was higher than normal rats'.⑵KT5720+UII group : urotensin II( IC₅₀ ) was given on the basis of KT5720 ,â‘ normal rats : +dp/dt_max reduced 5.37%, -dp/dt_max decreased 7.59%;â‘¡heart failure rats : +dp/dt_max reduced 3.27%, -dp/dt_max decreased 3.15%. There were significantly differences between KT5700+UII and UII group in±dp/dt_max(normal rat and heart failure rat: P<0.01)⑶KT5720 group : after perfused KT5720 ,â‘ normal rats: +dp/dt_max decreased 5.99%, -dp/dt_max decreased 7.63%;â‘¡heart failure rats : +dp/dt_max decreased 2.84%, -dp/dt_max decreased 2.96%. In normal and heart failure rats , there were no significantly differences between KT5720+UII group and KT5720 group in±dp/dt_max, (P>0.05) .Conclusions The inhibitory effect of UII on normal and heart failure rat's cardiac function was dose dependent , KT5720 could inhibit this effect, so the mechanism of UII on normal and heart failure rat's cardiac function was probably mediated by PKA.