van der Grinten C P, de Vries W R, Luijendijk S C
Department of Pulmonology, University Hospital Maastricht, Netherlands.
Respir Physiol. 1992 Nov;90(2):159-72. doi: 10.1016/0034-5687(92)90078-b.
The impact of varying the end-expiratory transpulmonary pressure (PE'tp) on phrenic (Phr) and parasternal intercostal (IC) activity early in inspiration was studied in 12 spontaneously breathing, anaesthetized cats. PE'tp was varied in a stepwise fashion by rapidly changing the tracheal pressure (Ptr) from ambient pressure to a pressure in the range between -1.2 and +1.2 kPa relative to ambient pressure, and vice versa. The amplitudes of integrated Phr and IC activity were determined in each breath at three particular points in time (t), corresponding to 0.1, 0.2 and 0.3 sec after the onset of Phr activity, respectively. For all three values of t, Phr and IC activity increased with a decrease in Ptr and decreased with an increase in Ptr. The relationships between Phr activity and PE'tp and between IC activity and PE'tp could be described satisfactorily by mono-exponential functions. An increase in PE'tp of 0.1 kPa resulted in a decrease in Phr activity of 16%, 13% and 12% for the 3 aforementioned values of t, respectively. For IC activity the corresponding values were 42%, 42% and 36%, respectively. After bilateral vagotomy no changes in Phr activity in response to changes in Ptr were observed any more, whereas the changes in IC activity had decreased to about one tenth of the corresponding values obtained before vagotomy. Apparently, extra-vagal mechanisms contribute for a small part to the effect of changes in PE'tp on IC activity. Our results indicate that relatively small changes in PE'tp may have a large impact on central inspiratory output.
在12只自主呼吸、麻醉的猫身上，研究了呼气末跨肺压（PE'tp）变化对吸气早期膈神经（Phr）和胸骨旁肋间肌（IC）活动的影响。通过将气管压力（Ptr）从环境压力迅速改变为相对于环境压力在-1.2至+1.2 kPa范围内的压力，以逐步方式改变PE'tp，反之亦然。在Phr活动开始后的三个特定时间点（t），分别对应于0.1、0.2和0.3秒，测定每次呼吸中Phr和IC活动的积分幅度。对于所有三个t值，Phr和IC活动均随Ptr降低而增加，随Ptr升高而降低。Phr活动与PE'tp之间以及IC活动与PE'tp之间的关系可用单指数函数满意地描述。对于上述三个t值，PE'tp每增加0.1 kPa，Phr活动分别降低16%、13%和12%。对于IC活动，相应的值分别为42%、42%和36%。双侧迷走神经切断术后，未再观察到Ptr变化时Phr活动的改变，而IC活动的改变已降至迷走神经切断术前相应值的约十分之一。显然，迷走神经外机制对PE'tp变化对IC活动的影响有一小部分作用。我们的结果表明，PE'tp的相对小变化可能对中枢吸气输出有很大影响。
