Muscle metabolism during heavy-intensity exercise after acute acetazolamide administration

• Published in: Journal of applied physiology (1985) 2000-02, Vol.88 (2), p.722-729
• Main Authors: Scheuermann, Barry W, Kowalchuk, John M, Paterson, Donald H, Taylor, Albert W, Green, Howard J
• Format: Article
• Language: English
• Subjects: Acetazolamide - administration & dosage; Acetazolamide - pharmacology; Acid-Base Equilibrium; Acids - blood; Adenosine Triphosphate - metabolism; Adult; Alkalies - blood; Biological and medical sciences; Carbonic Anhydrase Inhibitors - administration & dosage; Carbonic Anhydrase Inhibitors - pharmacology; Diphosphates - metabolism; Enzymes; Exercise; Exercise - physiology; Fundamental and applied biological sciences. Psychology; Glycogen - metabolism; Heart Rate - drug effects; Humans; Infusions, Intravenous; Lactates - blood; Lactates - metabolism; Male; Metabolism; Muscle, Skeletal - drug effects; Muscle, Skeletal - metabolism; Muscular system; Oxygen Consumption - drug effects; Phosphates - metabolism; Phosphocreatine - drug effects; Phosphocreatine - metabolism; Pulmonary Gas Exchange - drug effects; Space life sciences; Striated muscle. Tendons; Vertebrates: osteoarticular system, musculoskeletal system
• ISSN: 8750-7587; 1522-1601
• DOI: 10.1152/jappl.2000.88.2.722

1  Centre for Activity and Ageing, School of Kinesiology, and 2  Department of Physiology, The University of Western Ontario, London, Ontario N6A 3K7; and 3  Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1 Carbonic anhydrase (CA) inhibition is associated with a lower plasma lactate concentration ([La ] pl ), but the mechanism for this association is not known. The effect of CA inhibition on muscle high-energy phosphates [ATP and phosphocreatine (PCr)], lactate ([La ] m ), and glycogen was examined in seven men [28 ± 3 (SE) yr] during cycling exercise under control (Con) and acute CA inhibition with acetazolamide (Acz; 10 mg/kg body wt iv). Subjects performed 6-min step transitions in work rate from 0 W to a work rate corresponding to ~50% of the difference between the O 2 uptake at the ventilatory threshold and peak O 2 uptake. Muscle biopsies were taken from the vastus lateralis at rest, at 30 min postinfusion, at end exercise (EE), and at 5 and 30 min postexercise. Arterialized venous blood was sampled from a dorsal hand vein and analyzed for [La ] pl . ATP was unchanged from rest values; no difference between Con and Acz was observed. The fall in PCr from rest [72 ± 3 and 73 ± 3.6 (SE) mmol/kg dry wt for Con and Acz, respectively] to EE (51 ± 4 and 46 ± 5 mmol/kg dry wt for Con and Acz, respectively) was similar in Con and Acz. At EE, glycogen (mmol glucosyl units/kg dry wt) decreased to similar values in Con and Acz (307 ± 16 and 300 ± 19, respectively). At EE, no difference was observed in [La ] m between conditions (46 ± 6 and 43 ± 5 mmol/kg dry wt for Con and Acz, respectively). EE [La ] pl was higher during Con than during Acz (11.4 ± 1.0 vs. 8.2   ± 0.6 mmol/l). The similar [La ] m but lower [La ] pl suggests that the uptake of La by other tissues is enhanced after CA inhibition. muscle lactate; plasma lactate; high-energy phosphates; carbonic anhydrase