Related Experiment Videos
Time course-dependent evolution of nitric oxide-mediated arterial hyporeactivity to phenylephrine in rats with
M Kimpel1, I C Folz, E Hanisch
1Dept. of Surgery, Faculty of Medicine, Johann Wolfgang Goethe University, Frankfurt am Main, Germany.
Background:
Nitric oxide (NO) may be heavily involved the phenomenon of arterial vasodilation in cirrhosis. However, the subject is still controversial.
Aim:
This study therefore characterizes the dynamic role of the NO system during development of experimental cirrhosis.
Methods:
The contractile response to phenylephrine of thoracic rat aortic rings was studied in vitro before and after nitric oxide blockade. Experiments were performed 1, 2, 3, and 4 weeks after induction of cirrhosis via bile duct ligation with an appropriate control group.
Results:
In bile duct-ligated rats reduction of the maximum contractile response to phenylephrine was 4.4 +/- 7.3% after 1 week, 22.7 +/- 8.7% after 2 weeks, 48.4 +/- 8.3% after 3 weeks, and 64.6 +/- 8.9% after 4 weeks, in comparison with the control group. This reduction in contractility to phenylephrine was completely reversed by blocking NO synthesis.
Conclusion:
The data presented indicate a dynamic decrease in contractile response to phenylephrine even at an early stage of secondary cirrhosis. Reversibility of the effect after NO synthesis blockade suggests that increased NO synthesis is a major factor in vascular hyporeactivity to vasoconstrictors in cirrhosis.