Analysis of endothelin receptor and its subtypes in the left ventricle of rats with dilated cardiomyopathy / 中国临床药理学与治疗学

ABSTRACT

Aim To observe the changes of endothelin receptors and their subtypes of left ventricules in normal SD rats and dilated cardiomyopathy rats. Methods To establish the best conditions of the binding experiment, different protein concentrations, incubation temperature ?and?incubating?time?were?tested? with 125 I-ET-1 ligand respectively. With the selected conditions, saturation binding experiments were performed to determine the amount of endothelin receptor and its subtypes in normal SD rats and in dilated cardiomyopathy ones. Results (1) The optimal incubating temperature was 37 ℃. Under this condition, the binding amount of 125 I-ET-1 increased rapidly in 0～30 minutes, and reached to saturation point at 60 minutes, and there was a linear correlation between 125 I-ET-1 binding amount and cell membrane protein concentration. (2) Endothelin-1, bosentan,BQ123,BQ788 etc. could competitively suppress the bound of 125 I-ET-1 to endothelin receptors. (3) The amount of endothelin receptor in left ventricle of dilated cardiomyopathy rats was ( 92.21? 34.34) nmol?kg -1 protein, which was significantly low than that in normal SD ones. There was no change on the ratio of endothelin receptor subtypes A and B. Conclusion 125I-ET-1 can be used to determine the amount of endothelin receptor and its subtypes in varied tissues specifically. The amount of endothelin receptor in left ventricle of dilated cardiomyopathy rats is down regulated, but the ratio of endothelin receptor subtype A vs B remains to be 21.