Estrogen replacement suppresses stress-induced cardiovascular responses in ovariectomized rats
Estrogen replacement suppresses stress-induced cardiovascular responses in ovariectomized rats
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DOI：
10.1152/ajpheart.00341.2004
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发表时间：
2004-11-01
影响因子：
4.8
通讯作者：
Yoshida, K
中科院分区：
文献类型：
--
作者：
Morimoto, K;Kurahashi, Y;Yoshida, K
我们评估的假设，慢性雌激素替代治疗卵巢切除大鼠通过内皮型一氧化氮合酶（eNOS）抑制应激诱导的心血管反应的有益效果。我们采用无线电遥测系统测量血压和心率（HR）。将11周龄的雌性Wistar大鼠切除卵巢并植入无线电遥测装置。4周后，将大鼠分配到安慰剂治疗组（安慰剂; n = 6）或17 β-雌二醇（雌激素; n = 8）治疗组，在麻醉下皮下植入安慰剂或17 β-雌二醇（1.5 mg/60天释放）丸剂。这些大鼠在雌激素或安慰剂治疗4周后经历两种类型的应激。在安慰剂组和雌激素组中，笼转换应激和束缚应激均迅速且持续地升高平均动脉压（MAP）和HR。然而，与安慰剂组相比，雌激素组的MAP和HR对笼转换应激的反应以及MAP对束缚应激的反应显著减弱，但HR反应不明显。一氧化氮合酶抑制剂，N-G-硝基-L-精氨酸甲酯，在饮用水，减少了升压反应的差异，以笼开关之间的雌激素和安慰剂组。此外，Western blot分析显示，与安慰剂组相比，雌激素组肠系膜中eNOS的表达增加。因此，我们第一次表明，肠系膜eNOS过表达可以解释至少部分为什么慢性雌激素治疗抑制增强的心血管反应，心理压力的卵巢切除大鼠。
We assessed the hypothesis that chronic estrogen replacement in ovariectomized rats has the beneficial effect of suppressing stress-induced cardiovascular responses through endothelial nitric oxide synthase ( eNOS). We employed a radiotelemetry system to measure blood pressure and heart rate (HR). Female Wistar rats aged 11 wk were ovariectomized and implanted with radiotelemetry devices. After 4 wk, the rats were assigned either to a placebo-treated group (Placebo; n = 6) or a group treated with 17beta-estradiol (Estrogen; n = 8) subcutaneously implanted with either placebo- or 17beta-estradiol (1.5 mg/60-day release) pellets under anesthesia. These rats underwent either of the two types of stress after 4 wk of estrogen or placebo treatment. Cage-switch stress and restraint stress rapidly and continuously elevated the mean arterial pressure ( MAP) and HR both in the Placebo and Estrogen groups. However, the MAP and HR responses to cage-switch stress and the MAP but not HR response to restraint stress were attenuated significantly in the Estrogen group compared with the Placebo group. A NOS inhibitor, N-G-nitro-L-arginine methyl ester, given in drinking water, reduced the difference in the pressor response to cage-switch between the Estrogen and Placebo groups. In addition, Western blot analysis showed that eNOS expression in the mesentery was increased in the Estrogen group compared with the Placebo group. Thus for the first time we showed that mesenteric eNOS overexpression could explain at least partly why chronic estrogen treatment suppressed the enhanced cardiovascular responses to psychological stress in the ovariectomized rat.