Mechanisms responsible for the attenuating effects of estrogen on cardiovascular responses to psychological stress in the central nervous system and the peripheral vessels

(1)大鼠心理应激中去甲肾上腺素水平升高的性别差异笼子开关引起的轻度心理应激可引起雄性大鼠去甲肾上腺素水平升高，而雌性大鼠则不能。(2)雌激素对应激儿茶酚胺、NO代谢物(NOx)和4-羟基-2-壬烯-1的影响雌激素替代激素可抑制去卵巢大鼠应激所致的血浆去甲肾上腺素升高。此外，一氧化氮合酶(NOS)抑制剂可降低雌激素的这种作用。Western blotting分析显示，雌激素替代可增强肠系膜基础内皮一氧化氮合酶的表达。此外，雌激素替代降低了基础水平的血浆4-羟基-2-壬烯醛，这是氧化应激的标志，并倾向于提高血浆NOx水平。我们的结果表明，Est…雌激素替代对笼式应激诱导的大鼠脑内神经元激活的影响。应激诱导的神经元激活标志c-Fos的表达在以下脑区被检测到：外侧隔核、下丘脑室旁核(PVN)、下丘脑背内侧核(DMD)、弓状核、室旁核和蓝斑(LC)。雌激素替代可抑制应激诱导的c-Fos在PVN、DMD和LC中的表达。此外，雌激素替代增强了下丘脑室旁核内产生NO的神经元的激活。这些结果表明，雌激素替代至少部分通过NO减弱了这些脑区的神经元激活。这些结果表明，雌激素替代至少部分地通过其外周抗氧化作用和通过抑制去卵巢大鼠脑内神经元的激活来抑制心理应激的心血管反应。较少

(1) Sex difference in norepinephrine surge in response to psychological stress through nitric oxide in ratsA mild psychological stress induced by a cage-switch evoked a norepinephrine surge in the male, but not in the female rats. There was a sex difference in the norepinephrine surge in response to psychological stress through nitric oxide (NO), in association with pressor response.(2) Effects of estrogen on plasma catecholamine, NO metabolites (NOx) and 4-hydroxy-2-nonena1 during cage-switch stressEstrogen replacement tended to suppress plasma norepinephrine elevation induced by the stress in ovariectomized rat. Additionally, the NO synthase (NOS) inhibitor decreased this effect of estrogen. By Western blotting analysis, estrogen replacement enhanced basal endothelial NOS expression in mesenteries. Furthermore, estrogen replacement attenuated a basal level of plasma 4-hydroxy-2-nonenal, a marker for oxidative stress, and tended to enhance plasma NOx level.Our results suggest that est … More rogen attenuates the stress-induced pressor response by suppressing oxidative stress and enhancing NO bioavailability(3) Effects of estrogen replacement on neuronal activation induced by cage-switch stress in ovariectomized rat brainThe stress-induced elevations in c-Fos expressions, a marker for neuronal activation, were detected in the following brain areas : lateral septal nucleus, paraventricular hypothalamic nucleus (PVN), dorsomedial hypothalamic nucleus (DMD), arcuate hypothalamic nucleus, paraventricular thalamic nucleus, and locus coeruleus (LC). Estrogen replacement suppressed stress-induced c-Fos expressions in PVN, DMD and LC. In addition, estrogen replacement enhanced the activation of NO-producing neurons in PVN. These findings suggest that estrogen replacement attenuates neuronal activation in these brain areas, at least partly by NO.These results suggest that estrogen replacement suppresses cardiovascular responses to psychological stress at least partly through its anti-oxidative effect on the periphery and through its inhibitory effect on neuronal activation in the brain of ovariectomized rats. Less