Abstract: Objective: To investigate the mechanism of pulmonary hypertension, the effect of ET-1 receptors in pulmonary hypertension due to left to right shunt was studied. Methods: Thirtyfour 150-200g male Wistar rats were randomly selected and divided into three groups: experiment groupⅠ(n=15), experiment groupⅡ (n=9) and control group (n=10). A cervical left to right shunt pulmonary hypertension model was established by the cuff technique in the experiment groups. After four weeks, the rats of experiment group Ⅱ underwent a 12-week intravenous administration of BQ123 ［cyclopropane (Trp-Asp-Pro-Val-Leu)］. The systolic pulmonary artery pressures (sPAPs), ET-1 concentrations and the expressions of the prepro ET-1(PPET-1) mRNA, ETA receptor mRNA and ETB receptor mRNA of pulmonary tissues in the three groups were measured. Results: The sPAP and ET-1 concentrations were significantly higher in the experiment groups than in the control group (P＜0.01), and they were higher in experiment groupⅠthan in experiment groupⅡ. The mRNA expression of ET-1 and ETA receptors were distinctly elevated in the experiment groups (P＜0.01), and they were higher in experiment groupⅠthan in experiment groupⅡ(P＜0.05). ETB receptors changed inversely. Conclusions: The above results indicate that different ET receptors may exhibit different effects on pulmonary hypertension progression due to left to right shunt.

Key words: Endothelin-1, Receptor, Left to right shunt, Hypertension, pulmonary, Rats, Wistar