Instituto de Biomedicina de Sevilla (IBIS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville 41013, Spain.
Pflugers Arch. 2010 Apr;459(5):775-83. doi: 10.1007/s00424-009-0774-8. Epub 2010 Jan 5.
In this study, we explored the presence of aquaporins (AQPs), a family of membrane water channel proteins, in carotid body (CB) type I chemoreceptor cells. The CB is a polymodal chemoreceptor whose major function is to detect changes in arterial O2 tension to elicit hyperventilation during hypoxia. The CB has also been proposed to function as a systemic osmoreceptor, thus we hypothesized that the presence of AQPs in type I cell membrane may confer higher sensitivity to osmolarity changes and hence accelerate the activation of chemoreceptor cells. We detected the expression of AQP1, AQP7, and AQP8 in the CB and confirmed the location of AQP1 in type I cells. We have also shown that inhibition of AQP1 expression clearly reduced type I cell swelling after a hyposmotic shock, demonstrating that AQP1 has a major contribution in transmembrane water movement in these chemoreceptor cells. Interestingly, CB AQP1 expression levels change during postnatal development, increasing during the first postnatal weeks as the organ matures. In conclusion, in this study, we report the novel observation that AQPs are expressed in the CB. We also show that AQP1 mediates water transport across the cell membrane of type I cells, supporting the contribution of this protein to the osmoreception function of the CB.
在这项研究中，我们探讨了水通道蛋白（AQP）在颈动脉体（CB）I 型化学感受器细胞中的存在。CB 是一种多模式化学感受器，其主要功能是检测动脉氧张力的变化，以在缺氧时引发过度通气。CB 也被认为是一种全身渗透压感受器，因此我们假设 AQP 在细胞膜中的存在可能赋予对渗透压变化更高的敏感性，并加速化学感受器细胞的激活。我们检测到 CB 中 AQP1、AQP7 和 AQP8 的表达，并证实 AQP1 存在于 I 型细胞中。我们还表明，AQP1 表达的抑制在低渗冲击后明显减少了 I 型细胞的肿胀，表明 AQP1 在这些化学感受器细胞的跨膜水运动中具有重要作用。有趣的是，CB AQP1 的表达水平在出生后发育过程中发生变化，在器官成熟过程中，在出生后的第一周增加。总之，在这项研究中，我们报告了一个新的观察结果，即 AQP 在 CB 中表达。我们还表明，AQP1 介导 I 型细胞跨膜的水转运，支持该蛋白对 CB 渗透压感知功能的贡献。
