Iscoe S, Gordon S P
Department of Physiology, Queen's University, Kingston, Ontario, Canada.
J Appl Physiol (1985). 1992 Oct;73(4):1619-25. doi: 10.1152/jappl.1992.73.4.1619.
We assessed the effects of chest wall distortion, changes in lung volume, and abolition of airway smooth muscle tone on the discharge patterns of 92 pulmonary slowly adapting receptors (SAR) in decerebrate, spontaneously breathing cats. Distortion resulted from their inspiratory efforts against an occluded airway at functional residual capacity and at increased end-expiratory lung volumes. Approximately 40% of SAR increased discharge frequencies during occlusions. Modulation of SAR discharge during occlusions persisted after administration of atropine to eliminate airway smooth muscle tone. Phasic modulation of SAR discharge was eliminated during no-inflation tests after paralyzing the cats and ventilating them on a cycle-triggered pump. We conclude 1) parasympathetic modulation of airway smooth muscle tone makes no obvious contribution to SAR discharge in spontaneously breathing cats; 2) the no-inflation test (withholding of lung inflation during neural inspiration) in paralyzed and ventilated cats is a valid test for the presence of projections from SAR to medullary respiratory neurons; and 3) in the absence of tidal volume changes, distortion stimulates some SAR. Sensory feedback from receptors in the lung, not just those in the chest wall, may therefore provide information about abnormal chest wall configurations.
我们评估了胸壁变形、肺容积变化以及气道平滑肌张力消除对92只去大脑、自主呼吸猫的肺慢适应性感受器（SAR）放电模式的影响。变形是由于它们在功能残气量以及呼气末肺容积增加时对抗阻塞气道的吸气努力所致。在阻塞期间，约40%的SAR放电频率增加。在给予阿托品以消除气道平滑肌张力后，阻塞期间SAR放电的调制仍持续存在。在使猫麻痹并通过循环触发泵进行通气的无充气试验期间，SAR放电的相位调制被消除。我们得出以下结论：1）气道平滑肌张力的副交感神经调制对自主呼吸猫的SAR放电无明显贡献；2）在麻痹并通气的猫中进行的无充气试验（在神经吸气期间不进行肺充气）是检测SAR向延髓呼吸神经元投射是否存在的有效试验；3）在没有潮气量变化的情况下，变形会刺激一些SAR。因此，来自肺中感受器的感觉反馈，而不仅仅是胸壁中的感受器，可能提供有关异常胸壁形态的信息。
