Fuller S D, Freed A N
Department of Environmental Health Sciences, Johns Hopkins University, Baltimore, Maryland 21205, USA.
J Appl Physiol (1985). 1995 Apr;78(4):1242-9. doi: 10.1152/jappl.1995.78.4.1242.
Our goal was to partition whole lung resistance (RL) and cholinergic reactivity in rabbits into central airway, peripheral airway, and alveolar tissue (Rt) resistances by using forced oscillation (2 Hz), a retrograde catheter, and an alveolar capsule. Central and peripheral airway resistances accounted for approximately 80% of the baseline RL. However, immediately after acetylcholine challenge, Rt was negative. Bilateral vagal stimulation made Rt negative when the capsule was located on the left lung and not on the right lung. Stimulating either vagus produced a negative Rt in the lung ipsilateral to the stimulated nerve. Partial occlusion of the right main-stem bronchus with a balloon also made Rt negative. These results suggest that heterogeneous airflow exists at the level of the alveolar capsule during bronchoconstriction. Phase relationships between tracheal flow and retrograde catheter pressure suggest that flow at the level of the catheter was homogeneous. Thus, using only tracheal and retrograde catheter pressures, we repartitioned RL into its central airway and peripheral lung components. We conclude that cholinergic reactivity resides predominantly in the peripheral lung and that its peripheral location may be due largely to the development of heterogeneous airflow in peripheral airways.
我们的目标是通过使用强迫振荡（2赫兹）、逆行导管和肺泡囊，将兔的全肺阻力（RL）和胆碱能反应性划分为中央气道、外周气道和肺泡组织（Rt）阻力。中央气道和外周气道阻力约占基线RL的80%。然而，乙酰胆碱激发后立即出现Rt为负值。当囊位于左肺而非右肺时，双侧迷走神经刺激使Rt为负值。刺激任何一侧迷走神经均使受刺激神经同侧肺的Rt为负值。用球囊部分阻塞右主支气管也使Rt为负值。这些结果表明，支气管收缩期间肺泡囊水平存在气流不均一性。气管流量与逆行导管压力之间的相位关系表明导管水平的气流是均匀的。因此，仅使用气管和逆行导管压力，我们将RL重新划分为其中央气道和外周肺成分。我们得出结论，胆碱能反应性主要存在于外周肺，其在外周的位置可能很大程度上归因于外周气道气流不均一性的发展。
