Yu J, Zhang J F, Fletcher E C
Pulmonary Division, Department of Medicine, University of Louisville, Louisville, Kentucky 40292, USA.
J Appl Physiol (1985). 1998 Oct;85(4):1485-92. doi: 10.1152/jappl.1998.85.4.1485.
Respiratory response to selective activation of vagal afferents in the peripheral airways was investigated in anesthetized, open-chest, and artificially ventilated rabbits. Phrenic activity was used as an index of central respiratory drive before and after injection of hypertonic saline (8.1%, 0.1 ml) into the periphery of the lung to stimulate the afferents. The amplitude of "integrated" phrenic activity and phrenic burst rate increased by 19 +/- 3.4 and 53.7 +/- 12.7% (n = 23; P < 0.001), respectively. The response peaked at 5.5 +/- 1.6 s and returned to the baseline at 7 min (median) after the injection. The magnitude of the response was positively related to the concentration of injected NaCl. The response could not be elicited by injection of normal saline and was abolished by vagotomy. Because artificial ventilation caused phrenic activity to be entrained with the ventilator, respiratory drive was further assessed after the ventilator was stopped. Again, neural hyperpnea and tachypnea were observed. Because activation of a small fraction of the pulmonary peripheral afferents resulted in vigorous stimulation of respiratory drive, we speculate that initiation of this reflex may contribute to hyperpnea and tachypnea under both physiological and pathophysiological conditions.
在麻醉、开胸并人工通气的兔身上，研究了外周气道迷走传入神经选择性激活后的呼吸反应。在向肺周边注射高渗盐水（8.1%，0.1 ml）以刺激传入神经之前和之后，将膈神经活动用作中枢呼吸驱动的指标。“整合”膈神经活动的幅度和膈神经爆发频率分别增加了19±3.4%和53.7±12.7%（n = 23；P < 0.001）。反应在注射后5.5±1.6秒达到峰值，并在7分钟（中位数）后恢复到基线。反应的幅度与注射的氯化钠浓度呈正相关。注射生理盐水不能引发该反应，迷走神经切断后该反应消失。由于人工通气使膈神经活动与呼吸机同步，在停止呼吸机后进一步评估呼吸驱动。再次观察到神经性呼吸急促和呼吸过速。由于激活一小部分肺外周传入神经会导致呼吸驱动的强烈刺激，我们推测这种反射的启动可能在生理和病理生理条件下都有助于呼吸急促和呼吸过速。
