冷冻对心肌合成一氧化氮的影响

目的:观测心肌局部冷冻对心肌合成一氧化氮(NO)的影响,探讨冷冻阻滞心脏传导的机理.方法:采用液氮(-60℃±2℃)冷冻心肌,并用温生理盐水复温,在冷冻时加入L-精氨酸和美兰,观测心肌中NO及一氧化氮合酶(NOS)的含量.结果:心肌冷冻后NO和NOS的含量均下降,但左右房心肌NO的含量未见差异.L-精氨酸组在冷冻时、复温时及冷冻复温时持续滴注L-精氨酸,心肌NO含量分别为(107.4±15.1)、(109.6±15.7 )、(121.8±18.4)nmol/g高于未加L-精氨酸组[(86.8±13.2)nmol/g],且以冷冻前加入并持续滴注组最为明显;美兰组在冷冻时、复温时及冷冻复温时持续滴注美兰,心肌NO分别为(62.3±11.2)、(64.7±11.0)、(42.8±10.6)nmol/g低于未加美兰组[(86.8±13.2)nmol/g],以冷冻前加入并持续滴注组最为明显.冷冻后血液中NO含量未见改变(P>0.05).结论:心肌冷冻后心肌中NO含量减少.

Effect on synthesis of nitric oxide in myocardium by local cryoablation

OBJECTIVE: To study the effect on synthesis of nitric oxide in myocardium by local cryoablation and to investigate its mechanism. METHODS: Myocardium was cryoablated locally by a probe cooled to -60 degrees C and rewarmed by normal salt solution, nitric oxide and its synthesis enzyme were measured before and after cryoablation. L-arginine or methylene blue was added before and during cryoablation and the effect of these drugs on synthesis of nitric oxide was studied. RESULTS: Nitric oxide and its synthesis enzyme decreased after cryoablation; L-arginine preserved the synthesis of nitric oxide and methylene blue inhibited the synthesis of nitric oxide. However, nitric oxide in serum did not change. CONCLUSION: Nitric oxide and its synthesis enzyme in myocardium decrease after cryoablation.