Function of the rat carotid body chemoreceptors in ageing
Function of the rat carotid body chemoreceptors in ageing
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DOI：
10.1111/j.1471-4159.2006.04094.x
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发表时间：
2006-11-01
影响因子：
4.7
通讯作者：
Gonzalez, Constancio
中科院分区：
文献类型：
--
作者：
Conde, Silvia V.;Obeso, Ana;Gonzalez, Constancio
一些与年龄相关的呼吸反应缺陷被归因于颈动脉体部(CB)动脉化学感受器功能的下降，但对CB在衰老中的功能缺乏系统的研究。我们对3-24月龄大鼠的特定化学感受器组织进行了定量形态计量学研究，通过测定常氧和低氧时化学感受器神经递质儿茶酚胺的含量、合成和释放来评价化学感受器细胞的功能，通过测定常氧、低氧和高碳酸血症时颈动脉窦神经(CSN)的化学感觉活性来测定完整器官的功能活性。我们发现，随着年龄的增长，CBS增大，但同时化学感受器组织的百分比也随之减少。儿茶酚胺的CB含量和周转时间随年龄增长而增加。低氧刺激化学感受器细胞后，12个月龄大鼠的儿茶酚胺释放较少，但非特异性去极化刺激在所有年龄段都能引起类似的释放。同时，CSN对低氧的反应性显著下降，但对酸性高碳酸血症刺激的反应性没有明显下降，这被评估为CSN的化学感觉活动。我们得出的结论是，在老年哺乳动物中，化学感受器细胞功能低下，导致外周呼吸驱动减少。
Some age-related deficits in the ventilatory responses have been attributed to a decline in the functionality of the carotid body (CB) arterial chemoreceptors, but a systematic study of the CB function in ageing is lacking. In rats aged 3-24 months, we have performed quantitative morphometry on specific chemoreceptor tissue, assessed the function of chemoreceptor cells by measuring the content, synthesis and release of catecholamines (a chemoreceptor cell neurotransmitter) in normoxia and hypoxia, and determined the functional activity of the intact organ by measuring chemosensory activity in the carotid sinus nerve (CSN) in normoxia, hypoxia and hypercapnic acidosis. We found that with age CBs enlarge, but at the same time there is a concomitant decrease in the percentage of chemoreceptor tissue. CB content and turnover time for their catecholamines increase with age. Hypoxic stimulation of chemoreceptor cells elicits a smaller release of catecholamines in rats after 12 months of age, but a non-specific depolarizing stimulus elicits a comparable release at all ages. In parallel, there was a marked decrease in the responsiveness to hypoxia, but not to an acidic-hypercapnic stimulus, assessed as chemosensory activity in the CSN. We conclude that in aged mammals chemoreceptor cells become hypofunctional, leading to a decreased peripheral drive of ventilation.