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一氧化氮参与了缺血预处理后5′-核苷酸酶的延迟升高(PDF)

《心脏杂志》[ISSN:1009-7236/CN:61-1268/R]

期数:
2002年第3期
页码:
189-191,194
栏目:
实验研究
出版日期:
2002-05-01

文章信息/Info

Title:
Nitric oxide is involved in the delayed elevation of myocardial 5-nucleotidase activity after ischemic preconditioning in rabbits
作者:
李伟杰;  贾国良;  郭文怡;  王海昌
第四军医大学西京医院心血管内科, 陕西 西安 710032
Author(s):
LI Wei-jie;  JIA Guo-liang ;  GUO Wen-yi;  WANG Hai-chang
Departmet of Cardiology, Xijing Hospital, Fourth Military Medical University, Xi’an, Shaanxi 710032, China
关键词:
一氧化氮;  5′- 核苷酸酶;  缺血预处理
Keywords:
nitric oxide;  5’-nucleotidase;  ischemicp reconditioning
分类号:
R363
DOI:
-
文献标识码:
A
摘要:
目的 观察在缺血预处理期间抑制一氧化氮合酶对24 h后5′-核苷酸酶活性的影响和对缺血预处理第二保护窗的影响。方法 阻断兔冠脉5 min,再灌注10 min,重复4次,造成缺血预处理。在缺血预处理期间静脉注射一氧化氮合酶抑制剂NG-硝基-L-精氨酸甲酯(L-NAME),缺血预处理后24 h,提取心肌标本测量5′-核苷酸酶活性, 或阻断冠脉30 min再灌注120 min,测量心肌梗死面积。结果 缺血预处理24 h后,心肌细胞膜和胞浆5′-核苷酸酶活性均较假手术对照组明显升高。静脉注射L-NAME阻断了缺血预处理所致的细胞膜和胞浆5′-核苷酸酶活性的升高。缺血预处理组心梗面积明显小于对照组,而L-NAME阻断了这种保护作用。结论 一氧化氮参与了缺血 预处理所致的5′-核苷酸酶活性的延迟升高。延迟升高的5′-核苷酸酶活性可能参与了缺血预处理的第二保护窗。
Abstract:
AIM To examine the inhibition of nitric oxide (NO) synthesis during ischemic preconditioning (IP) on the activity of myocardial 5' -nucleotidase (5' -N) 24 h after IP and infarct sizelimiting effect of the second window of cardioprotection of IP.METHODS Rabbits were subjected to 4 cycles of 5-min of coronary artery occlusion separated by 10-min reperfusion, or received a sham operation. During this procedure, we injected 10 mg·kg-1of NG-nitro-L-arginine methyl ester (L-NAME, an inhibitor of NO synthase) intravenously 5 min before IP followed by its continuous infusion (1.5 mg·kg-1·min-1). 24 h after IP or the sham operation, the hearts were rapidly excised for measuring myocardial 5' -N activity or were subjected to 30-min coronary artery occlusion followed by 120-min reperfusion and then measured infarct size (IS).RESULTS 24 h after IP or the sham operation, there was no difference in heart rate and mean arterial pressure between groups. Both ectosolic-5' -N activity [80.8±7.0 nmol·(mg protein)-1·min-1]and cytosolic-5' -N activity [12.2±0.9 nmol·(mg protein)-1·min-1] increased, compared with that in sham-operated control group [54.6±4.0 and 8.4±0.6 nmol·(mg protein)-1·min-1,respectively,P<0.01], which was blocked by L-NAME [57.2±6.2 and 8.8±0.5 nmol·(mg protein)-1·min-1]. Pretreatment with L-NAME alone did not change the activity of ecto-and cytosolic 5' -N [53.1±4.9 and 8.7±0.5 nmol·(mg protein)-1·min-1], In the IP rabbits, IS was reduced compared with sham-operated control rabbits [ (30.3±3.3)%vs(50.4±4.4)%,P<0.01], and which was blunted by L-NAME [ (49.8±5.0)% ]. L-NAME alone did not affect IS [ (48.8±4.6)% ].CONCLUSION NO is involved in the delayed activation of 5' -N, which may be attributable to the second window of cardioprotection of IP.

参考文献/References

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备注/Memo

备注/Memo:
收稿日期：2001-11-14.
更新日期/Last Update: 2005-05-01