کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
2848404 1571351 2007 9 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Evolving in thin air—Lessons from the llama fetus in the altiplano
موضوعات مرتبط
علوم زیستی و بیوفناوری بیوشیمی، ژنتیک و زیست شناسی مولکولی فیزیولوژی
پیش نمایش صفحه اول مقاله
Evolving in thin air—Lessons from the llama fetus in the altiplano
چکیده انگلیسی

Compared with lowland species, fetal life for mammalian species whose mothers live in high altitude is demanding. For instance, fetal llamas have to cope with the low fetal arterial PO2PO2 of all species, but also the likely superimposition of hypoxia as a result of the decreased oxygen environment in which the mother lives in the Andean altiplano. When subjected to acute hypoxia the llama fetus responds with an intense peripheral vasoconstriction mediated by alpha-adrenergic mechanisms plus high plasma concentrations of catecholamines and neuropeptide Y (NPY). Endothelial factors such as NO and endothelin-1 also play a role in the regulation of local blood flows. Unlike fetuses of lowland species such as the sheep, the llama fetus shows a profound cerebral hypometabolic response to hypoxia, decreasing cerebral oxygen consumption, Na–K-ATPase activity and temperature, and resulting in an absence of seizures and apoptosis in neural cells. These strategies may have evolved to prevent hypoxic injury to the brain or other organs in the face of the persistent hypobaric hypoxia of life in the Andean altiplano.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Respiratory Physiology & Neurobiology - Volume 158, Issues 2–3, 30 September 2007, Pages 298–306
نویسندگان
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