Scheuermann B W, Kowalchuk J M, Paterson D H, Cunningham D A
The Centre for Activity and Ageing, School of Kinesiology, The University of Western Ontario, London, Ontario, Canada N6A 3K7.
J Appl Physiol (1985). 1999 May;86(5):1534-43. doi: 10.1152/jappl.1999.86.5.1534.
The effect of carbonic anhydrase inhibition with acetazolamide (Acz) on CO2 output (VCO2) and ventilation (VE) kinetics was examined during moderate- and heavy-intensity exercise. Seven men [24 +/- 1 (SE) yr] performed cycling exercise during control (Con) and Acz (10 mg/kg body wt iv) sessions. Each subject performed step transitions (6 min) in work rate from 0 to 100 W [below ventilatory threshold (<VET)] and to an O2 uptake corresponding to approximately 50% of the difference between the work rate at VET and peak O2 uptake [above ventilatory threshold (>VET)]. VE and gas exchange were measured breath by breath. The time constant (tau) was determined for exercise <VET by using a single-exponential model (fit between 20 s and end-exercise); the mean response time (MRT) was determined for exercise >VET by using a three-component model (fit from the start of exercise). VCO2 kinetics were slower in Acz (<VET, tau = 45 +/- 6 s; >VET, MRT = 75 +/- 10 s) than Con (<VET, tau = 34 +/- 6 s; >VET, MRT = 54 +/- 7 s). During <VET exercise, VE kinetics were slower in Acz (tau = 48 +/- 6 s) than Con (tau = 34 +/- 6 s), but >VET kinetics were faster in Acz (MRT = 85 +/- 17 s) than Con (MRT = 106 +/- 16 s). Carbonic anhydrase inhibition slowed VCO2 kinetics during both moderate- and heavy-intensity exercise, demonstrating impaired CO2 elimination in the nonsteady state of exercise. The slowed VE kinetics in Acz during exercise <VET is consistent with a mechanism coupling VE kinetics with the flow of CO2 to the lungs.
在中等强度和高强度运动期间，研究了乙酰唑胺（Acz）抑制碳酸酐酶对二氧化碳排出量（VCO2）和通气（VE）动力学的影响。七名男性[24±1（SE）岁]在对照（Con）和Acz（静脉注射10mg/kg体重）期间进行了自行车运动。每个受试者进行工作率从0到100W的阶跃转换（6分钟）[低于通气阈值（<VET）]，并达到与通气阈值时工作率和峰值摄氧量之间差值的约50%相对应的摄氧量[高于通气阈值（>VET）]。逐次呼吸测量VE和气体交换。通过使用单指数模型（在运动开始20秒至运动结束之间拟合）确定运动<VET时的时间常数（tau）；通过使用三成分模型（从运动开始拟合）确定运动>VET时的平均反应时间（MRT）。与Con相比，Acz组的VCO2动力学较慢（<VET，tau = 45±6秒；>VET，MRT = 75±10秒）（Con组：<VET，tau = 3C±6秒；>VET，MRT = 54±7秒）。在<VET运动期间，Acz组的VE动力学比Con组慢（tau = 48±6秒）（Con组：tau = 34±6秒），但在>VET时，Acz组的动力学比Con组快（MRT = 85±17秒）（Con组：MRT = 106±16秒）。在中等强度和高强度运动期间，碳酸酐酶抑制均减缓了VCO2动力学，表明在运动的非稳定状态下二氧化碳清除受损。运动<VET期间Acz组VE动力学减慢与将VE动力学与二氧化碳向肺部流动相耦合的机制一致。
