Shapland J E, Garner H E, Hatfield D G
J Vet Pharmacol Ther. 1981 Mar;4(1):43-50. doi: 10.1111/j.1365-2885.1981.tb00709.x.
Clenbuterol, a bronchospasmolytic agent (beta 2 agonist) was studied in terms of its hemodynamic and airflow response in eight, healthy horses. Four animals were instrumented to record intrapleural pressure and air flow, these were used to compute pulmonary resistance, peak flow rates, and tidal volumes. Four animals were instrumented to record pulmonary arterial pressure, carotid arterial pressure, cardiac output, and arterial gas tensions. After control values were recorded, clenbuterol (0.8 microgram/kg) was intravenously administered to each horse in each experiment group. Following clenbuterol administration, non-elastic resistance of the lung or pulmonary resistance significantly decreased, 33.6% reduction at 10 min post-clenbuterol. Pulmonary resistance remained lowered during the entire procedure and showed no tendency of returning toward control values by 3 h post-clenbuterol. Within 30 sec following clenbuterol injection carotid arterial pressure decreased (mean pressure decrease 28.2%). Accompanying the change in arterial pressure, the heart rate drastically increased, 99.0%. Both changes were transient and returned to control ranges within 2 min. Clenbuterol appears to be effective in reducing non-elastic resistance of the lung, however intravenous administration to an animal with pre-existing cardiovascular or cardiopulmonary disease should be avoided.
克仑特罗是一种支气管解痉剂（β2 激动剂），研究人员对其在八匹健康马匹中的血流动力学和气流反应进行了研究。四匹马被安装仪器以记录胸膜腔内压和气流，这些数据用于计算肺阻力、峰值流速和潮气量。另外四匹马被安装仪器以记录肺动脉压、颈动脉压、心输出量和动脉血气张力。记录对照值后，在每个实验组中给每匹马静脉注射克仑特罗（0.8 微克/千克）。注射克仑特罗后，肺的非弹性阻力或肺阻力显著降低，注射后 10 分钟降低了 33.6%。在整个过程中肺阻力一直保持降低状态，到注射克仑特罗后 3 小时也没有恢复到对照值的趋势。注射克仑特罗后 30 秒内颈动脉压下降（平均压力下降 28.2%）。伴随着动脉压的变化，心率急剧增加，增加了 99.0%。这两种变化都是短暂的，在 2 分钟内恢复到对照范围。克仑特罗似乎对降低肺的非弹性阻力有效，然而应避免对已有心血管或心肺疾病的动物静脉注射。
