Arsenault Julie, Moreau-Bussiere Francois, Reix Philippe, Niyonsenga Theophile, Praud Jean-Paul
Respiratory Research Unit, Department of Public Health, Faculty of Medicine, University of Sherbrooke, Sherbrooke, Quebec, Canada J1H 5N4, USA.
J Appl Physiol (1985). 2003 May;94(5):1978-86. doi: 10.1152/japplphysiol.00480.2002. Epub 2003 Jan 24.
The postnatal development of ventilatory reflexes originating from bronchopulmonary receptors was assessed in preterm vs. full-term lambs. Ventilation and arterial pressure were repeatedly measured in 10 preterm (gestational age, 132 days) and 7 full-term lambs without sedation from day 1 to day 42. The Hering-Breuer inhibitory reflex (slowly adapting stretch receptors) was assessed by the increase in expiratory time during end-inspiratory occlusion. The pulmonary chemoreflex (C-fiber endings) was assessed by the initial apnea + bradycardia + systemic hypotension and the secondary tachypnea after capsaicin intravenous injection. Results show the following. 1) Premature birth did not modify the maturation of the Hering-Breuer reflex. 2) Whereas a classic pulmonary chemoreflex was observed in the very first hours of life in preterm lambs, the tachypneic component of this reflex was weaker than in full-term lambs on day 1. 3) Premature birth led to a reversed postnatal maturation of this tachypneic response (tendency to increase with postnatal age). Our findings suggest that premature birth in lambs modifies postnatal maturation of the pulmonary chemoreflex.
在早产与足月出生的羔羊中评估了源自支气管肺感受器的通气反射的产后发育情况。在出生第1天至第42天期间，对10只早产羔羊（胎龄132天）和7只足月出生的羔羊在未使用镇静剂的情况下反复测量通气和动脉压。通过吸气末闭塞期间呼气时间的增加来评估黑林-布雷尔抑制反射（慢适应性牵张感受器）。通过静脉注射辣椒素后最初的呼吸暂停+心动过缓+全身性低血压以及继发性呼吸急促来评估肺化学反射（C纤维末梢）。结果如下。1）早产并未改变黑林-布雷尔反射的成熟过程。2）虽然在早产羔羊出生后的最初几个小时就观察到了典型的肺化学反射，但在出生第1天，该反射的呼吸急促成分比足月出生的羔羊弱。3）早产导致这种呼吸急促反应的产后成熟过程逆转（有随出生后年龄增加的趋势）。我们的研究结果表明，羔羊早产会改变肺化学反射的产后成熟过程。
