PDF(Pubmed)
Abstract：
Chronic hypoxia (CH) from birth attenuates the acute hypoxic ventilatory response (HVR) in rats and other mammals, but CH is often reported to augment the HVR in adult mammals. To test the hypothesis that this transition - from blunting to augmenting the HVR - occurs in the third or fourth postnatal week in rats, juvenile and adult rats were exposed to normobaric CH (12% O2) for 7 days and the HVR was assessed by whole-body plethysmography. No transition was observed, however, and the acute HVR was reduced by 61 - 85% across all ages studied. The failure to observe an augmented HVR in adult rats could not be explained by the substrain of Sprague Dawley rats used, the duration of the CH exposure, the order in which test gases were presented, the level of hypoxia used for CH and to assess the HVR, or the effects of CH on the metabolic response to hypoxia and the hypercapnic ventilatory response. A literature survey revealed several distinct patterns of ventilatory acclimatization to hypoxia (VAH) in adult rats, with most studies (77%) revealing a decrease or no change in the acute HVR after CH. In conclusion, the effects of CH on respiratory control are qualitatively similar across age groups, at least within the populations of Sprague Dawley rats used in the present study, and there does not appear to be one \"typical\" pattern for VAH in adult rats.
摘要：
出生时的慢性缺氧（CH）减弱了大鼠和其他哺乳动物的急性低氧通气反应（HVR）。但据报道，CH通常会增加成年哺乳动物的HVR。为了检验这种转变-从钝化到增加HVR-发生在大鼠出生后第三周或第四周的假设，幼年和成年大鼠暴露于常压CH（12％O2）7天，并通过全身体积描记术评估HVR。没有观察到过渡，然而,在所有研究的年龄段，急性HVR降低了61-85%。无法用所用的SpragueDawley大鼠的基质来解释成年大鼠未能观察到增强的HVR，CH暴露的持续时间，测试气体的顺序，用于CH和评估HVR的缺氧水平，或CH对缺氧代谢反应和高碳酸血症通气反应的影响。文献调查显示，成年大鼠对缺氧（VAH）的通气适应有几种不同的模式，大多数研究(77%)显示CH后急性HVR降低或无变化。总之,CH对呼吸控制的影响在各年龄组在质量上相似，至少在本研究中使用的SpragueDawley大鼠种群中，在成年大鼠中，VAH似乎没有一个“典型”模式。
