Scheuermann B W, Kowalchuk J M, Paterson D H, Cunningham D A
Centre for Activity and Ageing, School of Kinesiology, The University of Western Ontario, London, Ontario, Canada N6A 3K7.
J Appl Physiol (1985). 2000 Feb;88(2):713-21. doi: 10.1152/jappl.2000.88.2.713.
The effect of carbonic anhydrase (CA) inhibition with acetazolamide (Acz, 10 mg/kg body wt iv) on exercise performance and the ventilatory (VET) and lactate (LaT) thresholds was studied in seven men during ramp exercise (25 W/min) to exhaustion. Breath-by-breath measurements of gas exchange were obtained. Arterialized venous blood was sampled from a dorsal hand vein and analyzed for plasma pH, PCO(2), and lactate concentration (La(-)). VET [expressed as O(2) uptake (VO(2)), ml/min] was determined using the V-slope method. LaT (expressed as VO(2), ml/min) was determined from the work rate (WR) at which La(-) increased 1.0 mM above rest levels. Peak WR was higher in control (Con) than in Acz sutdies [339 +/- 14 vs. 315 +/- 14 (SE) W]. Submaximal exercise VO(2) was similar in Acz and Con; the lower VO(2) at exhaustion in Acz than in Con (3.824 +/- 0. 150 vs. 4.283 +/- 0.148 l/min) was appropriate for the lower WR. CO(2) output (VCO(2)) was lower in Acz than in Con at exercise intensities >/=125 W and at exhaustion (4.375 +/- 0.158 vs. 5.235 +/- 0.148 l/min). La(-) was lower in Acz than in Con during submaximal exercise >/=150 W and at exhaustion (7.5 +/- 1.1 vs. 11.5 +/- 1.1 mmol/l). VET was similar in Acz and Con (2.483 +/- 0.086 and 2.362 +/- 0.110 l/min, respectively), whereas the LaT occurred at a higher VO(2) in Acz than in Con (2.738 +/- 0.223 vs. 2.190 +/- 0.235 l/min). CA inhibition with Acz is associated with impaired elimination of CO(2) during the non-steady-state condition of ramp exercise. The similarity in VET in Con and Acz suggests that La(-) production is similar between conditions but La(-) appearance in plasma is reduced and/or La(-) uptake by other tissues is enhanced after the Acz treatment.
研究了在七名男性进行递增运动（25瓦/分钟）至力竭过程中，静脉注射乙酰唑胺（Acz，10毫克/千克体重）抑制碳酸酐酶（CA）对运动能力、通气阈值（VET）和乳酸阈值（LaT）的影响。逐次呼吸测量气体交换情况。从手背静脉采集动脉化静脉血，分析血浆pH值、PCO₂和乳酸浓度（La⁻）。使用V斜率法测定VET[以摄氧量（VO₂）表示，毫升/分钟]。根据La⁻比静息水平升高1.0毫摩尔/升时的工作率（WR）确定LaT（以VO₂表示，毫升/分钟）。对照组（Con）的峰值WR高于乙酰唑胺组[339±14对315±14（标准误）瓦]。亚极量运动时的VO₂在乙酰唑胺组和对照组相似；乙酰唑胺组力竭时的VO₂低于对照组（3.824±0.150对4.283±0.148升/分钟），这与较低的WR相适应。在运动强度≥125瓦时以及力竭时，乙酰唑胺组的二氧化碳排出量（VCO₂）低于对照组（4.375±0.158对5.235±0.148升/分钟）。在亚极量运动≥150瓦时以及力竭时，乙酰唑胺组的La⁻低于对照组（7.5±1.1对11.5±1.1毫摩尔/升）。乙酰唑胺组和对照组的VET相似（分别为2.483±0.086和2.362±0.110升/分钟），而乙酰唑胺组的LaT出现在比对照组更高的VO₂时（2.738±0.223对2.190±0.235升/分钟）。在递增运动的非稳态条件下，用乙酰唑胺抑制CA与二氧化碳清除受损有关。对照组和乙酰唑胺组VET相似表明，两种情况下乳酸生成相似，但乙酰唑胺处理后血浆中乳酸的出现减少和/或其他组织对乳酸的摄取增加。
