Henley W N, Bellush L L, Notestine M A
Department of Zoological and Biomedical Sciences, Ohio University, Athens 45701.
Brain Res. 1992 May 8;579(2):211-8. doi: 10.1016/0006-8993(92)90053-c.
Five-week-old male spontaneously hypertensive rats (SHR) were either exposed to hypoxia or maintained in normoxia. Groups of rats were returned to normoxia after 8 or 12 weeks exposure to hypoxia while others remained in hypoxia or normoxia throughout the study. Subdivisions of the groups were sacrificed 2 or 6 weeks after return to normoxia at the same time as were rats continuously exposed to either normoxia or hypoxia. Hypoxia attenuated the development of systemic hypertension (P less than 0.05); however, this protection dissipated partially when rats were returned to normoxia. Norepinephrine concentration was significantly elevated and serotonin turnover (5-hydroxyindoleacetic acid/serotonin 5HIAA/5HT) was significantly decreased in caudal brainstem of hypoxic SHR and both were gradually normalized upon return to normoxia. Similarly, left ventricular hypertrophy was attenuated and adrenal catecholamine contents were increased with hypoxic exposure. Both gradually normalized upon return to normoxia. Mechanisms associated with the development of spontaneous hypertension reemerge when adult, previously hypoxic SHR are returned to a normoxic environment. These findings implicate long-term changes in central noradrenergic and serotonergic function as components of the cardiovascular adaptation to hypoxia which includes hypoxic moderation of spontaneous hypertension.
将5周龄雄性自发性高血压大鼠（SHR）暴露于低氧环境或维持在常氧环境中。在暴露于低氧环境8周或12周后，将大鼠组恢复到常氧环境，而其他大鼠在整个研究过程中一直处于低氧或常氧环境。在恢复到常氧环境2周或6周后，对各亚组进行处死，同时处死持续暴露于常氧或低氧环境的大鼠。低氧减弱了系统性高血压的发展（P<0.05）；然而，当大鼠恢复到常氧环境时，这种保护作用部分消失。低氧SHR的尾侧脑干中去甲肾上腺素浓度显著升高，5-羟色胺周转率（5-羟吲哚乙酸/5-羟色胺5HIAA/5HT）显著降低，恢复到常氧环境后两者均逐渐恢复正常。同样，低氧暴露可减轻左心室肥厚，并增加肾上腺儿茶酚胺含量。恢复到常氧环境后两者均逐渐恢复正常。当成年的、先前处于低氧环境的SHR恢复到常氧环境时，与自发性高血压发展相关的机制再次出现。这些发现表明，中枢去甲肾上腺素能和5-羟色胺能功能的长期变化是心血管系统对低氧适应的组成部分，其中包括低氧对自发性高血压的缓解作用。
