Effects And Mechanism Of Adenosine And AMP579 On Isolated Rat Aortas

OBJECTIVE The study was designed to compare the effects of adenosine and AMP579 on the potassium chloride-induced contraction of isolated rat aortas and mechanism.METHODS The preparation of isolated rat aortas stips. The artery strips were suspended from tension energy transducer(Powerlab/4SP, ADInstruments)and were observed with Chart5.2 computer system. The dose-response curves of adenosine and AMP579 on potassium chloride-induced contraction of isolated rat aortas were done. The result of maximum contractile reponse induced by 20mmol/l potassium chloride was regarded as 100%. Then we calculate the percentage of relaxation response induced by adenosine and AMP579 of each concentration.RESULT 1.In isolated rat aortas precontracted with KCl20mmol/L,Adenosine 10μmol/L-1mmol/L and AMP579 100nmmol/L-30μmmol/L induced relaxation in a concentration-dependent manner; Pretreatment with 10μmol/L,30μmol/L,100μmol/L,300μmol/L,1mmol/L adenosine produced the role that inhibited the vasoconstriction induced by 20mmol/L KCl were 4.4±3.7%,17.0±9.9%,32.0±11.3%,66.3±8.7%,94.8±4.1%; Pretreatment with 100nmol/L,300nmol/L,1μmol/L,3μmol/L,10μmol/L,30μmol/L AMP579 produced the role that inhibited the vasoconstriction induced by 20mmol/L KCl were 2.8±3.7%,14.9±7.0%,29.2±7.0%,51.3±15.1%,66.8±14.6%,86.1±12.0%. 2. Adenosine group: After pretreated with L-NAME,Glyburide and DMPX, adenosine produced the role that inhibited the vasoconstriction induced by 20mmol/L KCl were 7.3±0.7%(P<0.01),5.3±3.6%(P<0.01),6.1±5.1%(P<0.01). AMP579 group: After pretreated with the removal of endothelium,L-NAME and GF109203X, AMP579 produced the role that inhibited the vasoconstriction induced by 20mmol/L KCl were 5.3±5.1%(P<0.01),24.5±8.6%(P<0.01),12.5±22.5%(P<0.01). 3. In the solution contained Ca²⁺, AMP579 produced the role that inhibited the vasoconstriction induced by 20mmol/L KCl was 46.5±6.6%. In the solution freed Ca²⁺, AMP579 produced the role that inhibited the vasoconstriction induced by 20mmol/L KCl was 12.3±3.0%(P<0.01).CONCLUSION: 1. Adenosine and AMP579 induced relaxation of isolated rat aortas precontracted with KCl in a concentration-dependent manner. 2. The vasodilation induced by adenosine were involved A2 receptor,activation of KATP channel and NO-path. The removal of endothelium can't affect vasodilation of adenosine, it proved the adenosi...