Singas E, Lesser M, Spungen A M, Bauman W A, Almenoff P L
Pulmonary Section, Bronx (NY) Veterans Affairs Medical Center 10468, USA.
Chest. 1996 Oct;110(4):911-5. doi: 10.1378/chest.110.4.911.
Previously, we found that never-smokers with quadriplegia were hyperresponsive to aerosolized methacholine. To further explore the phenomenon, we compared responsiveness to methacholine in never-smokers with that of smokers and ex-smokers. We also evaluated responsiveness in subjects with high paraplegia (lesions at T-1 to T-6) or low paraplegia (lesions at T-7 and below). We found that smokers and ex-smokers with quadriplegia were hyperresponsive to methacholine (provocative concentration causing a 20% fall in FEV1 = 1.9 mg/mL), and that the response was comparable to that found in never-smokers, revealing that hyperresponsiveness among never-smokers cannot be attributed to preinjury airway hyperreactivity that precluded cigarette use. In contrast, subjects with low paraplegia were not hyperresponsive to methacholine. Among subjects with high paraplegia, the three subjects demonstrating airway hyperresponsiveness had significantly lower FEV1 (percent predicted). The findings support the hypothesis that airway hyperresponsiveness in subjects with quadriplegia represents loss of sympathetic innervation of the lung, thereby leaving intact unopposed bronchoconstrictor cholinergic activity. However, reduced lung volumes in these subjects also suggest the possibility that airway hyperresponsiveness is due to loss of ability to stretch airway smooth muscle by deep breathing.
此前，我们发现四肢瘫痪的非吸烟者对雾化乙酰甲胆碱反应过度。为了进一步探究这一现象，我们比较了非吸烟者与吸烟者及已戒烟者对乙酰甲胆碱的反应性。我们还评估了高位截瘫（损伤位于T-1至T-6）或低位截瘫（损伤位于T-7及以下）患者的反应性。我们发现，四肢瘫痪的吸烟者和已戒烟者对乙酰甲胆碱反应过度（引起第一秒用力呼气量下降20%的激发浓度 = 1.9毫克/毫升），且该反应与非吸烟者的反应相当，这表明非吸烟者的反应过度不能归因于损伤前的气道高反应性而导致无法吸烟。相比之下，低位截瘫患者对乙酰甲胆碱没有反应过度。在高位截瘫患者中，表现出气道高反应性的三名患者的第一秒用力呼气量（预测百分比）显著更低。这些发现支持了这样一种假说，即四肢瘫痪患者的气道高反应性代表肺交感神经支配丧失，从而使支气管收缩性胆碱能活动未受抑制。然而，这些患者肺容量降低也提示气道高反应性可能是由于深呼吸拉伸气道平滑肌的能力丧失所致。
