Department of Psychiatry and Behavioral Sciences, University of Washington, Seattle, WA 98195, USA.
Neuroscience. 2011 Mar 10;176:120-31. doi: 10.1016/j.neuroscience.2010.12.019. Epub 2010 Dec 20.
Previous studies showed that chronic estrogen treatment increases tryptophan hydroxylase-2 (TpH2) mRNA in the caudal dorsal raphe nucleus (DRN), and this increase was associated with decreased anxiety. The present study explored the interaction of estrogen and targeted, bidirectional manipulation of TpH2 expression in the caudal DRN by knockdown or viral overexpression, to decrease or increase tryptophan hydroxylase expression respectively, on anxiety behavior. Rats were ovariectomized and replaced with empty or estradiol capsules (OVX, OVX/E, respectively). Animals received microinfusions of either antisense TpH2 or control morpholino oligonucleotides into caudal DRN and were later tested in the open field test. A separate group of animals were microinfused with TpH2-GFP or GFP-only herpes simplex viral vectors into caudal DRN and tested in the open field. The bidirectional impact of manipulations on TpH2 expression was confirmed using a combination of quantitative protein and mRNA measurements; TpH2 expression changes were limited to discrete subregions of DRN that were targeted by the manipulations. Estradiol decreased anxiety in all behavioral measures. In the OVX/E group, TpH2 knockdown significantly decreased time spent in the center of the open field, but not in the OVX group, suggesting that TpH2 knockdown reduced the anxiolytic effects of estrogen. Conversely, TpH2 overexpression in the OVX group mimicked the effects of estrogen, as measured by increased time spent in the center of the open field. These results suggest that estrogen and TpH2 in the caudal DRN have a critical interaction in regulating anxiety-like behavior.
先前的研究表明，慢性雌激素处理会增加尾部背侧中缝核（DRN）中的色氨酸羟化酶-2（TpH2）mRNA，而这种增加与焦虑减轻有关。本研究通过敲低或病毒过表达来探索雌激素与尾部 DRN 中 TpH2 表达的靶向、双向操纵的相互作用，分别降低或增加色氨酸羟化酶的表达，以研究其对焦虑行为的影响。大鼠被卵巢切除术切除，并分别用空或雌二醇胶囊（OVX，OVX/E）替代。动物接受尾部 DRN 中的反义 TpH2 或对照 morpholino 寡核苷酸的微输注，并随后在旷场测试中进行测试。另一组动物接受 TpH2-GFP 或 GFP 仅单纯疱疹病毒载体的微输注，并在旷场中进行测试。通过定量蛋白和 mRNA 测量的组合，证实了操纵对 TpH2 表达的双向影响；TpH2 表达的变化仅限于 DRN 的离散亚区，这些亚区是操纵的目标。雌激素降低了所有行为测量中的焦虑。在 OVX/E 组中，TpH2 敲低显著减少了旷场中央的时间，但在 OVX 组中没有，这表明 TpH2 敲低降低了雌激素的抗焦虑作用。相反，在 OVX 组中 TpH2 的过表达模拟了雌激素的作用，如旷场中央时间的增加所测量的那样。这些结果表明，雌激素和尾部 DRN 中的 TpH2 在调节类似焦虑的行为方面具有关键的相互作用。
