Krause Diana N, Duckles Sue P, Pelligrino Dale A
Department of Pharmacology, School of Medicine, University of California, Irvine, 92697-4625, USA.
J Appl Physiol (1985). 2006 Oct;101(4):1252-61. doi: 10.1152/japplphysiol.01095.2005. Epub 2006 Jun 22.
The cerebral vasculature is a target tissue for sex steroid hormones. Estrogens, androgens, and progestins all influence the function and pathophysiology of the cerebral circulation. Estrogen decreases cerebral vascular tone and increases cerebral blood flow by enhancing endothelial-derived nitric oxide and prostacyclin pathways. Testosterone has opposite effects, increasing cerebral artery tone. Cerebrovascular inflammation is suppressed by estrogen but increased by testosterone and progesterone. Evidence suggests that sex steroids also modulate blood-brain barrier permeability. Estrogen has important protective effects on cerebral endothelial cells by increasing mitochondrial efficiency, decreasing free radical production, promoting cell survival, and stimulating angiogenesis. Although much has been learned regarding hormonal effects on brain blood vessels, most studies involve young, healthy animals. It is becoming apparent that hormonal effects may be modified by aging or disease states such as diabetes. Furthermore, effects of testosterone are complicated because this steroid is also converted to estrogen, systemically and possibly within the vessels themselves. Elucidating the impact of sex steroids on the cerebral vasculature is important for understanding male-female differences in stroke and conditions such as menstrual migraine and preeclampsia-related cerebral edema in pregnancy. Cerebrovascular effects of sex steroids also need to be considered in untangling current controversies regarding consequences of hormone replacement therapies and steroid abuse.
脑血管系统是性类固醇激素的靶组织。雌激素、雄激素和孕激素都会影响脑循环的功能和病理生理学。雌激素通过增强内皮源性一氧化氮和前列环素途径来降低脑血管张力并增加脑血流量。睾酮则有相反的作用，会增加脑动脉张力。雌激素可抑制脑血管炎症，而睾酮和孕激素则会加剧炎症。有证据表明，性类固醇还会调节血脑屏障的通透性。雌激素通过提高线粒体效率、减少自由基生成、促进细胞存活和刺激血管生成，对脑内皮细胞具有重要的保护作用。尽管关于激素对脑血管的影响已经有了很多了解，但大多数研究都涉及年轻健康的动物。越来越明显的是，激素的作用可能会因衰老或糖尿病等疾病状态而发生改变。此外，睾酮的作用很复杂，因为这种类固醇还会在全身以及可能在血管本身内转化为雌激素。阐明性类固醇对脑血管系统的影响对于理解中风中的男女差异以及月经偏头痛和妊娠子痫前期相关脑水肿等病症非常重要。在理清当前关于激素替代疗法和类固醇滥用后果的争议时，也需要考虑性类固醇的脑血管效应。
