Meddle S L, Leng G, Selvarajah J R, Bicknell R J, Russell J A
Department of Biomedical Sciences, University of Edinburgh Medical School, George Square, EH8 9XD, Edinburgh, UK.
Neuroscience. 2000;101(4):1013-21. doi: 10.1016/s0306-4522(00)00300-6.
Sensory input from female reproductive structures is paramount for the co-ordination of neuroendocrine changes at parturition. Using a retrograde tracer (fluorescent latex microspheres) in combination with Fos (as an indicator of neuronal activation) and tyrosine hydroxylase (to identify catecholaminergic neurons) immunocytochemistry we identified cells within the brainstem and main olfactory bulb that project to the supraoptic nucleus, and which become significantly activated at parturition (compared to virgin rats and rats on the day of expected parturition). Within the A2/C2 region in the nucleus tractus solitarii, 60% of the projecting activated cells were catecholaminergic, as were 59% of such cells in the A1/C1 region of the ventrolateral medulla. This suggests that oxytocin and vasopressin neurons within the supraoptic nucleus are stimulated at parturition via afferent inputs from the brainstem, but the input is not exclusively noradrenergic. Within the mitral layer of the main olfactory bulb, cells that projected to the supraoptic nucleus were significantly activated, suggesting that the olfactory system may regulate supraoptic nucleus cell firing at parturition. The preoptic area, organum vasculosum of the lamina terminalis and medial amygdala contained cells that projected to the supraoptic nucleus but these projections were not significantly activated at parturition, although non-projecting cells in these regions were. On the expected day of parturition, but before birth, projections from the organum vasculosum of the lamina terminalis to the supraoptic nucleus became significantly activated. These findings provide evidence of direct afferent pathways to the supraoptic nucleus from the brain stem and olfactory bulbs that are activated at parturition.
来自雌性生殖结构的感觉输入对于分娩时神经内分泌变化的协调至关重要。我们使用逆行示踪剂（荧光乳胶微球）结合Fos（作为神经元激活的指标）和酪氨酸羟化酶（用于识别儿茶酚胺能神经元）免疫细胞化学方法，鉴定出脑干和主嗅球内投射到视上核的细胞，这些细胞在分娩时（与未生育的大鼠和预期分娩当天的大鼠相比）会显著激活。在孤束核的A2/C2区域，60%的投射激活细胞是儿茶酚胺能的，在延髓腹外侧的A1/C1区域，此类细胞的比例为59%。这表明视上核内的催产素和加压素神经元在分娩时通过来自脑干的传入输入受到刺激，但该输入并非仅为去甲肾上腺素能。在主嗅球的二尖瓣层，投射到视上核的细胞被显著激活，这表明嗅觉系统可能在分娩时调节视上核细胞的放电。视前区、终板血管器和内侧杏仁核含有投射到视上核的细胞，但这些投射在分娩时并未显著激活，尽管这些区域的非投射细胞被激活了。在预期分娩日但在出生前，终板血管器到视上核的投射变得显著激活。这些发现提供了在分娩时被激活的从脑干和嗅球到视上核的直接传入通路的证据。
