期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2003
卷号：100
期号：17
页码：10073-10078
DOI：10.1073/pnas.1734109100
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Reflexes from the carotid body have been implicated in cardiorespiratory disorders associated with chronic intermittent hypoxia (CIH). To investigate whether CIH causes functional and/or structural plasticity in the carotid body, rats were subjected to 10 days of recurrent hypoxia or normoxia. Acute exposures to 10 episodes of hypoxia evoked long-term facilitation (LTF) of carotid body sensory activity in CIH-conditioned but not in control animals. The magnitude of sensory LTF depended on the length of CIH conditioning and was completely reversible and unique to CIH, because conditioning with a comparable duration of sustained hypoxia was ineffective. Histological analysis revealed no differences in carotid body morphology between control and CIH animals. Previous treatment with superoxide anion ([IMG]f1.gif" ALT="Formula" BORDER="0">) scavenger prevented sensory LTF. In the CIH-conditioned animals, carotid body aconitase enzyme activity decreased compared with controls. These observations suggest that increased generation of reactive oxygen species contribute to sensory LTF. In CIH animals, carotid body complex I activity of the mitochondrial electron transport is inhibited, suggesting mitochondria as one source of [IMG]f1.gif" ALT="Formula" BORDER="0"> generation. These observations demonstrate that CIH induces a previously uncharacterized form of reactive oxygen species-dependent, reversible, functional plasticity in carotid body sensory activity. The sensory LTF may contribute to persistent reflex activation of sympathetic nerve activity and blood pressure in recurrent apnea patients experiencing CIH.
