Enhanced neuronal nitric oxide synthase expression is central to cardiac vagal phenotype in exercise-trained mice
Enhanced neuronal nitric oxide synthase expression is central to cardiac vagal phenotype in exercise-trained mice
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DOI：
10.1113/jphysiol.2002.031781
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发表时间：
2003-01-01
影响因子：
5.5
通讯作者：
Paterson, DJ
中科院分区：
文献类型：
--
作者：
Danson, EJF;Paterson, DJ
我们研究了运动训练引起的心脏迷走神经反应性增强是否依赖于神经元一氧化氮合酶（NOS-1），因为 NO-cGMP 途径促进乙酰胆碱释放。右迷走神经支配完整的雄性小鼠（18-22 周龄）在 10 周自愿轮跑后（+EX，n = 27；5 周时达到峰值 9.8 +/- 0.6 km day(-1)）和饲养在无轮笼中的小鼠（-EX，n = 27）中采集具有完整右迷走神经支配的孤立心房。对整个心房进行 NOS-1 免疫染色，鉴定出内在神经元，所有神经元均与胆碱乙酰转移酶阳性神经节共定位。 Western blot分析证实+EX心房中的NOS-1蛋白水平显着高于-EX心房（P < 0.05，未配对t检验）。 +EX 心房的基础心率 (HR) 比 -EX 心房慢（322 +/- 6 与 360 +/- 7 次/min(-1)；P < 0.05，未配对 t 检验）。但是，+EX 心房中，对迷走神经刺激（VNS、3 和 5 Hz）的 HR 反应比 -EX 心房（3 Hz，+EX：-76 +/- 8 次/min(-1)）显着增强。 -EX：-62 +/- 7 次心跳（-1）；+EX：-106 +/- 4 次心跳（-1）对比 -EX：-93 +/- 3 次心跳（-1）；未配对 t 检验）。用乙烯基-(L)-N-5-(1-亚氨基-3-丁烯基)-(L)-鸟氨酸 ((L)-VNIO, 100 mum) 抑制 NOS-1 或用 1H-[1, 2,4] 恶二唑并 [4,3-a] 喹喔啉-1-一 (ODQ, 10 mum) 抑制可溶性鸟苷酸环化酶 (ODQ, 10 mum) 消除了 HR 响应的差异+EX 和 -EX 心房之间的 VNS 以及 L-VNIO 的影响被过量的 L-精氨酸逆转（1 mm；P < 0.01，ANOVA）。 +EX 和 -EX 心房对沐浴应用的乙酰胆碱类似物氯化氨甲酰胆碱的 HR 反应没有差异（IC50 浓度为 5.9 +/- 0.4 mum (-EX) 和 5.7 +/- 0.4 mum (+EX)），表明迷走神经反应性的变化是由突触前神经传递促进引起的。总之，NOS-1 似乎是运动训练引起的心脏迷走神经功能增强的关键蛋白。
We investigated whether enhanced cardiac vagal responsiveness elicited by exercise training is dependent on neuronal nitric oxide synthase (NOS-1), since the NO-cGMP pathway facilitates acetylcholine release. Isolated atria with intact right vagal innervation were taken from male mice (18-22 weeks old) after a period of 10 weeks voluntary wheel-running (+EX, n = 27; peaked 9.8 +/- 0.6 km day(-1) at 5 weeks), and from mice housed in cages without wheels (-EX, n = 27). Immunostaining of whole atria for NOS-1 identified intrinsic neurones, all of which co-localized with choline acetyltransferase-positive ganglia. Western blot analysis confirmed that NOS-1 protein level was significantly greater in +EX compared to -EX atria (P < 0.05, unpaired t test). Basal heart rates (HR) were slower in +EX than in -EX atria (322 +/- 6 versus 360 +/- 7 beats min(-1); P < 0.05, unpaired t test) However, in +EX atria, HR responses to vagal stimulation (VNS, 3 and 5 Hz) were significantly enhanced compared to -EX atria (3 Hz, +EX: -76 +/- 8 beats min(-1) versus -EX: -62 +/- 7 beats min(-1); 5 Hz, +EX: -106 +/- 4 beats min(-1) versus -EX: -93 +/- 3 beats min(-1); P < 0.01, unpaired t test). Inhibition of NOS-1 with vinyl-(L)-N-5-(1-imino-3-butenyl)-(L)-ornithine ((L)-VNIO, 100 mum) or soluble guanylyl cyclase with 1H-[1, 2,4] oxadiazolo [4,3-a] quinoxalin-1-one (ODQ, 10 mum) abolished the difference in HR responses to VNS between +EX and -EX atria, and effects Of L-VNIO were reversed by excess L-arginine (1 mm; P < 0.01, ANOVA). There were no differences between the HR responses to the bath-applied acetylcholine analogue carbamylcholine chloride in +EX and -EX atria (IC50 concentrations were 5.9 +/- 0.4 mum (-EX) and 5.7 +/- 0.4 mum (+EX)), suggesting that the changes in vagal responsiveness resulted from presynaptic facilitation of neurotransmission. In conclusion, NOS-1 appears to be a key protein in generating the cardiac vagal gain of function elicited by exercise training.