Nitric oxide synthase inhibition speeds oxygen uptake kinetics in horses during moderate domain running
Nitric oxide synthase inhibition speeds oxygen uptake kinetics in horses during moderate domain running
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DOI：
10.1016/s1569-9048(02)00068-x
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发表时间：
2002-08-30
影响因子：
2.3
通讯作者：
Poole, DC
中科院分区：
文献类型：
--
作者：
Kindig, CA;McDonough, P;Poole, DC
在中等运动强度范围内，向较高代谢率过渡时的摄氧速度(（V) /循环（O2））动力学被认为受到氧化机制惯性的限制。一氧化氮（NO）诱导的电子传递链中O-2消耗的抑制可能有助于这种惯性。本研究验证了一种假设，即通过输注n -omega-硝基- l -精氨酸甲酯（L-NAME；一种NOS抑制剂）来减少或去除任何此类NO效应，将在适度运动开始时加速(V)过圈（O2）动力学。五匹纯种马在马跑步机上进行了四次过渡到7米秒（-1）的跑步速度（2只对照，2只L-NAME [20 mg kg(-1)]），其间使用偏流式系统测定肺气体交换。与中等强度领域的运动一致，在所有过渡中都没有(V) /圈（O2）缓慢成分引起。L- name处理通过降低主振幅时间常数（C, 17.3 +/- 1.7; L- name, 11.8 +/- 1.5秒，P < 0.05）显著加速(V)过环（O2）动力学，同时加快总体动力学（即T-50和T-75均P < 0.05）和减少O-2赤字的趋势（C, 6.4 +/- 0.7; L- name, 4.7 1.2 L， P=0.06）。这些数据支持这样一种观点，即NO对氧化酶惰性有显著的贡献，因此在马中等强度运动开始时(V)超过圆周（O2）动力学的速度。(C) 2002 Elsevier Science B.V.版权所有
Within the moderate exercise intensity domain, the speed of oxygen uptake ((V) over circle (O2)) kinetics at the transition to a higher metabolic rate is thought to be limited by an inertia of the oxidative machinery. Nitric oxide (NO)-induced inhibition of O-2 consumption within the electron transport chain may contribute to this inertia. This investigation tested the hypothesis that a reduction or removal of any such NO effect via infusion of N-omega-nitro-L-arginine methyl ester (L-NAME; a NOS inhibitor) would speed (V) over circle (O2) kinetics at the onset of moderate exercise. Five Thoroughbred geldings underwent four transitions to running speeds of 7 m sec (-1) (two control, C, 2 L-NAME [20 mg kg(-1)]) on an equine treadmill during which pulmonary gas exchange was determined using a bias flow system. Consistent with exercise in the moderate intensity domain, in none of the transitions was a (V) over circle (O2) slow component elicited. The L-NAME treatment significantly accelerated (V) over circle (O2) kinetics via a reduction of the primary amplitude time constant (C, 17.3 +/- 1.7; L-NAME, 11.8 +/- 1.5 sec, P < 0.05) concomitant with faster overall dynamics (i.e. T-50 and T-75 both P < 0.05) and a trend toward a decreased O-2 deficit (C, 6.4 +/- 0.7; L-NAME, 4.7 1.2 L; P=0.06). These data support the notion that NO contributes prominently to the oxidative enzyme inertia and thus the speed of (V) over circle (O2) kinetics at the onset of moderate intensity exercise in the horse. (C) 2002 Elsevier Science B.V. All rights reserved.