Rivalland E T A, Iqbal J, Clarke I J, Turner A I, Tilbrook A J
Department of Physiology, Monash University, Clayton, Victoria 3800, Australia.
Neuroscience. 2005;132(3):755-66. doi: 10.1016/j.neuroscience.2005.01.045.
The paraventricular nucleus (PVN) is integral to regulation of the hypothalamo-pituitary-adrenal (HPA) axis and contains cells producing corticotrophin-releasing hormone (CRH), arginine vasopressin (AVP) and enkephalin. We used immunohistochemistry to map these peptides and to resolve the extent of co-localization within PVN cells in intact and gonadectomized male and female sheep. Immunoreactive (ir) CRH, AVP and enkephalin cells were mapped in two rams and two ewes at 180 mum intervals throughout the rostro-caudal extent of the PVN. Similar distributions of AVP-ir cells occurred in both sexes whereas CRH-ir and enkephalin-ir cells extended more rostrally in rams. In groups (n=4) of intact and gonadectomized sheep of both sexes, co-localization and distribution of neuropeptides was influenced by sex and gonadectomy. Males had more AVP and CRH cells than females. Intact animals had more AVP cells than gonadectomized animals. There were no differences between groups in the number or percentage of cells that stained for both CRH and AVP or in the number of cells that stained for both CRH and enkephalin. Differences were observed in the percentage of enkephalin cells that contained CRH with males having a greater percentage of co-localized cells than did females. Differences were also observed in the number and percentage of cells that stained for both enkephalin and AVP; the number of cells that stained for both neuropeptides was greater in males than in females and greater in intact animals than in gonadectomized animals. Differences were observed in the percentage of AVP cells that contained enkephalin, and in the percentage of enkephalin cells that contained AVP with males having a greater percentage of co-localized cells than did females. We conclude that sex and gonadal status affect peptide distribution in the PVN of the sheep which may provide an anatomical basis for sex differences in HPA axis responses to stress.
室旁核（PVN）对于下丘脑-垂体-肾上腺（HPA）轴的调节至关重要，并且包含产生促肾上腺皮质激素释放激素（CRH）、精氨酸加压素（AVP）和脑啡肽的细胞。我们运用免疫组织化学方法来绘制这些肽类的分布图，并确定完整及性腺切除的雄性和雌性绵羊PVN细胞内共定位的程度。在两只公羊和两只母羊中，以180微米的间隔，在PVN的整个 rostro - caudal范围内绘制免疫反应性（ir）CRH、AVP和脑啡肽细胞的分布图。AVP免疫反应细胞在两性中的分布相似，而CRH免疫反应细胞和脑啡肽免疫反应细胞在公羊中向更靠前的方向延伸。在完整及性腺切除的两性绵羊组（每组n = 4）中，神经肽的共定位和分布受性别和性腺切除的影响。雄性的AVP和CRH细胞比雌性多。完整动物的AVP细胞比性腺切除动物多。在同时对CRH和AVP染色的细胞数量或百分比，以及对CRH和脑啡肽都染色的细胞数量方面，各组之间没有差异。在含有CRH的脑啡肽细胞百分比方面观察到差异，雄性共定位细胞的百分比高于雌性。在同时对脑啡肽和AVP染色的细胞数量和百分比方面也观察到差异；同时对这两种神经肽染色的细胞数量在雄性中多于雌性，在完整动物中多于性腺切除动物。在含有脑啡肽的AVP细胞百分比，以及含有AVP的脑啡肽细胞百分比方面观察到差异，雄性共定位细胞的百分比高于雌性。我们得出结论，性别和性腺状态会影响绵羊PVN中的肽类分布，这可能为HPA轴对应激反应的性别差异提供解剖学基础。
