ABSTRACT
Objective To construct a recombinant plasmid vector containing the distal fragment of the distal C-terminus (dDCT) of the Cav 1.2 channel,and express,extract,and purify dDCT protein and characterize its biological activity.Methods dDCT cDNA was ligated into the pGEX-6p-1 vector to create a recombinant plasmid that was subsequently transformed into Escherichia coli BL21 competent cells.Expression of GST-dDCT fusion protein from this plasmid was induced with isopropy-β-D-thiogalactoside,and the resulting protein was purified using glutathione-sepharose 4B beads.The biological activity of dDCT was analyzed by GST pull-down assay.Results The recombinant plasmid was verified by restriction enzyme digestion and sequencing.The concentration and purity of the dDCT protein,which was extracted by ultrasonication,were high enough to detect dDCT activity.The binding of dDCT to CT1 was determined to be concentration-dependent.Conclusion The recombinant dDCT plasmid was successfully constructed,providing the fundamental basis for future studies on mechanisms of Cav 1.2 channel autoregulation.
ABSTRACT
Objective To investigate the the molecular mechanism of telmisartan for myocardial remodeling in rats with renovascular hypertention. Methods The renovascular hypertensive myocardial hypertrophy model of rats were established by narrowing the left renal artery.The total of 45 mature male SD rats were divided into sham-operated group(n= 15),model control (n = 15 ) and telmisartan group ( n = 15 ) randomly. The rats in telmisartan group were treated with telmisartan (10 mg?kg-1?d-1 ) while those in the sham-operated and model control were reated with the same amounts of distilled water by intragastrical administration . At 8th week of administration, the myocardial structure and function were detected by ultrasonography.The blood pressure was measured by arterial catheterization and calculating the left ventricular mass index (LVMI) .The level of serum calcium and nerve phosphatase ( CaN) and the expression of β-myosin heavy chain ( β-MHC) mRNA were detected. Results The thickness of left ventricular,ejection fraction[(69.23± 1.09)% vs(73.77± 3.00)%], fractional shortening [(30.21±2.02)% vs(35.29±0.90)%],LVMI[(2.83±0.14) mg?g-1 vs(2.32±0.11) mg?g-1 ] were decreased,and the differences were statistically significant (P<0.05).The level of serum calcium and nerve phosphatase (CaN) and the expression of β-myosin heavy chain (β-MHC) mRNA were decreased in telmisartan treated rats,and the differences were statistically significant (P< 0.05) when compared with the model control group. Conclusion Telmisartan can improve the myocardial hypertrophy of renovascular hypertensive rats,and it may downregulate the expression of β-MHC by inactivating of the start signal CaN and its downstream signal pathway.