Department of Pathology, University of Arizona College of Medicine, 1501 North Campbell Avenue, Tucson, Arizona 85724, USA.
Endocrinology. 2011 Jul;152(7):2750-9. doi: 10.1210/en.2010-1230. Epub 2011 Apr 26.
Estrogen has pronounced effects on thermoregulation, but the anatomic sites of integration between the reproductive and thermoregulatory axes are unknown. In this study, we tested whether estradiol-17β (E(2)) treatment would alter the activity of thermoregulatory brain regions responding to mild changes in ambient temperature (T(AMBIENT)). Core and tail skin temperatures were recorded at the ambient temperatures of 20, 24, or 31 C in ovariectomized (OVX) rats with and without E(2). Neuronal activity was evaluated by counting the number of Fos-immunoreactive cells in the brains of rats killed 90 min after exposure to one of the three ambient temperatures. Of 14 brain areas examined, the median preoptic nucleus (MnPO) was the only site that exhibited increased Fos immunoreactivity at the high T(AMBIENT) of 31 C. At 24 C, OVX rats exhibited increased numbers of MnPO Fos-immunoreactive cells, compared with OVX + E(2) rats. Interestingly, tail skin vasomotion and MnPO Fos expression were affected in a similar manner by T(AMBIENT) and E(2) treatment. In the arcuate nucleus and anteroventral periventricular nucleus (AVPV), Fos immunoreactivity was highest at the low T(AMBIENT) of 20 C, with inhibitory (arcuate nucleus) and stimulatory (AVPV) effects of E(2). No other areas responded to both T(AMBIENT) and E(2) treatment. These results implicate the MnPO, the arcuate nucleus, and the AVPV as sites of integration between the reproductive and thermoregulatory axes. Combined with studies showing the importance of MnPO neurons in heat-defense pathways, the MnPO emerges as a likely site for E(2) modulation of thermoregulatory vasomotion.
雌激素对体温调节有显著影响，但生殖轴和体温调节轴之间的整合解剖部位尚不清楚。在这项研究中，我们测试了雌二醇-17β（E2）处理是否会改变对环境温度（T 环境）轻度变化作出反应的体温调节脑区的活动。在有和没有 E2 的去卵巢（OVX）大鼠中，在环境温度为 20、24 或 31°C 时记录核心和尾部皮肤温度。在暴露于三种环境温度之一 90 分钟后，通过计数大鼠大脑中 Fos 免疫反应性细胞的数量来评估神经元活性。在检查的 14 个脑区中，只有中前脑核（MnPO）在环境温度为 31°C 的高温下表现出 Fos 免疫反应性增加。在 24°C 时，与 OVX+E2 大鼠相比，OVX 大鼠的 MnPO 中 Fos 免疫反应性细胞数量增加。有趣的是，尾部皮肤血管运动和 MnPO 的 Fos 表达受 T 环境和 E2 处理的影响方式相似。在弓状核和前腹侧脑室下核（AVPV）中，Fos 免疫反应性在低温 20°C 时最高，E2 具有抑制（弓状核）和刺激（AVPV）作用。没有其他区域对 T 环境和 E2 处理都有反应。这些结果表明，MnPO、弓状核和 AVPV 是生殖轴和体温调节轴之间的整合部位。结合研究表明 MnPO 神经元在热防御途径中的重要性，MnPO 作为 E2 调节体温调节血管运动的可能部位出现。
