Viau Victor, Lee Patricia, Sampson Jeff, Wu Janice
Department of Anatomy and Cell Biology, University of British Columbia, 2177 Wesbrook Mall, Vancouver, British Columbia, Canada V6T 1Z3.
Endocrinology. 2003 Jul;144(7):3067-75. doi: 10.1210/en.2003-0064.
To gauge the strength by which the testes influence stress-induced activation of neurosecretory neurons in the paraventricular nucleus, we studied within medial parvocellular neurons the effects of gonadectomy on restraint-induced Fos-immunoreactivity and on CRH and arginine vasopressin (AVP) heteronuclear (hn) RNA expression levels. Relative to intact male rats (sham-gonadectomized), gonadectomized rats showed a significantly greater number of medial parvocellular neurons recruited to express Fos protein evident at 0.5 h and from 1-4 h after the onset of 30-min restraint exposure. Restraint provoked a transient increase in hnCRH levels that was maximal at the end of restraint and this was significant only in gonadectomized rats. Both intact and gonadectomized rats displayed an increase in AVP hnRNA expression levels in response to restraint exposure; however, it was significantly greater in gonadectomized rats. All of these responses were accompanied by a higher corticosterone response in gonadectomized compared with intact rats and negatively correlated with plasma testosterone concentrations, with the exception of stress-induced CRH transcription. These findings indicate an inhibitory role for testosterone on stress-induced indexes of synaptic (Fos) and transcriptional (AVP hnRNA) activation among hypophysiotropic paraventricular neurons and provide meaningful end points with which to pursue how and where androgens operate on stress-related input to the paraventricular nucleus motor neurons.
为了评估睾丸对压力诱导的室旁核神经分泌神经元激活的影响强度，我们在内侧小细胞神经元中研究了去势对束缚诱导的Fos免疫反应性以及促肾上腺皮质激素释放激素（CRH）和精氨酸加压素（AVP）异核（hn）RNA表达水平的影响。与完整雄性大鼠（假去势）相比，去势大鼠在30分钟束缚暴露开始后0.5小时以及1 - 4小时，内侧小细胞神经元中被招募来表达Fos蛋白的数量显著更多。束缚引起hnCRH水平短暂升高，在束缚结束时达到最大值，且仅在去势大鼠中显著。完整和去势大鼠在束缚暴露后AVP hnRNA表达水平均升高；然而，去势大鼠中的升高更为显著。与完整大鼠相比，去势大鼠的所有这些反应都伴随着更高的皮质酮反应，并且除了应激诱导的CRH转录外，与血浆睾酮浓度呈负相关。这些发现表明睾酮对促垂体室旁神经元中应激诱导的突触（Fos）和转录（AVP hnRNA）激活指标具有抑制作用，并为研究雄激素如何、在何处作用于室旁核运动神经元的应激相关输入提供了有意义的终点。
