Benoussaidh Anissa, Maurin Yves, Rampin Olivier
Analyse et Modélisation en Imagerie Biologique, Institut National de la Recherche Agronomique, Domaine de Vilvert, 78352 Jouy-en-Josas, France .
Am J Physiol Regul Integr Comp Physiol. 2004 Aug;287(2):R446-53. doi: 10.1152/ajpregu.00117.2004. Epub 2004 Mar 25.
The rat uterus receives an innervation from the lumbosacral and thoracolumbar segments of the spinal cord. These segments receive descending oxytocinergic projections from the paraventricular nucleus of the hypothalamus. We tested the hypothesis that oxytocin regulates uterine motility through a spinal site of action. Oxytocin was administered in anesthetized female rats either intrathecally at the lumbosacral or thoracolumbar spinal cord levels or intravenously. Uterine activity was revealed by measuring changes of intrauterine pressure using an indwelling balloon placed in one caudal uterine horn. The uterus displayed a spontaneous activity characterized by intrauterine pressure rises, the frequency, amplitude, and duration of which were dependent on the stage of the estrous cycle. Oxytocin delivered at the lumbosacral level affected the frequency (during proestrus, estrus, and diestrus) and amplitude (during proestrus and estrus) of uterine activity. During estrus, oxytocin delivered at the thoracolumbar level affected the frequency, amplitude, and duration of the intrauterine pressure rises. Intravenous oxytocin not only affected intrauterine pressure rises (namely amplitude during proestrus and estrus and frequency and duration during estrus) but also increased the basal tone during estrus. The effects of lumbosacral oxytocin were partly mimicked by the oxytocin agonist [Thr(4),Gly(7)]-oxytocin blocked by the oxytocin receptor antagonist atosiban and by hexamethonium. Arginine vasopressin delivered at the lumbosacral level had no effect. These results support our hypothesis that oxytocin released by descending paraventriculo-spinal pathways and acting on spinal oxytocin receptors modulates the activity of the uterus. This regulation is cycle dependent.
大鼠子宫接受来自脊髓腰荐段和胸腰段的神经支配。这些节段接受来自下丘脑室旁核的下行催产素能投射。我们检验了催产素通过脊髓作用位点调节子宫运动的假说。在麻醉的雌性大鼠中，于腰荐或胸腰脊髓水平鞘内注射或静脉注射催产素。通过使用置于子宫尾侧角的留置球囊测量子宫内压力变化来揭示子宫活动。子宫表现出以子宫内压力升高为特征的自发活动，其频率、幅度和持续时间取决于发情周期阶段。在腰荐水平给予的催产素影响子宫活动的频率（在动情前期、发情期和间情期）和幅度（在动情前期和发情期）。在发情期，在胸腰水平给予的催产素影响子宫内压力升高的频率、幅度和持续时间。静脉注射催产素不仅影响子宫内压力升高（即动情前期和发情期的幅度以及发情期的频率和持续时间），还增加发情期的基础张力。腰荐催产素的作用部分被催产素激动剂[Thr(4),Gly(7)]-催产素模拟，被催产素受体拮抗剂阿托西班和六甲铵阻断。在腰荐水平给予的精氨酸加压素无作用。这些结果支持我们的假说，即由下行室旁脊髓通路释放并作用于脊髓催产素受体的催产素调节子宫活动。这种调节是依赖周期的。
