Yu G Z, Kaba H, Okutani F, Takahashi S, Higuchi T
Department of Physiology, Kochi Medical School, Japan.
Neuroscience. 1996 Jun;72(4):1083-8. doi: 10.1016/0306-4522(95)00600-1.
Expanding on research showing that oxytocin originating in the hypothalamic paraventricular nucleus acts to decrease olfactory processing at the level of the olfactory bulb, we explored the importance of oxytocin acting on the olfactory bulb for the onset of maternal behaviour in Wistar rats. Experiment I was designed to test whether spontaneous maternal behaviour following natural delivery is blocked by bilateral infusions of a low dose (5 fmol) of the oxytocin antagonist d(CH2)5[Tyr(Me)2,Thr4,Tyr-NH2(9)]ornithine-vasotocin into the olfactory bulb immediately after the delivery of the first pup and again just before a test for maternal behaviour. Intrabulbar infusions of the antagonist markedly delayed the occurrence of all components (retrieval, licking, nest building, crouching) of maternal behaviour, whereas intracerebroventricular infusions of the antagonist were without effect on any component as compared with intrabulbar infusions of saline. Experiment 2 was undertaken to determine whether infusions of oxytocin into the bulb induce a rapid onset of maternal behaviour in virgin rats. Forty-eight hours before pup presentation virgins were ovariectomized and treated with oestradiol benzoate. Immediately before pup presentation a low dose (20 pmol) of oxytocin or saline was infused bilaterally into the bulb or lateral ventricle. Intrabulbar infusions of oxytocin induced full maternal behaviour in half of the animals tested within 2 h of pup exposure, in contrast to the ineffectiveness of intracerebroventricular infusions of oxytocin and intrabulbar infusions of saline. These results suggest that the olfactory bulb is a critical site where oxytocin acts to induce a rapid onset of maternal behaviour.
研究表明，起源于下丘脑室旁核的催产素会降低嗅球水平的嗅觉处理能力。在此基础上，我们探讨了催产素作用于嗅球对Wistar大鼠母性行为启动的重要性。实验一旨在测试，在第一只幼崽出生后立即以及在进行母性行为测试前，向嗅球双侧注入低剂量（5飞摩尔）的催产素拮抗剂d(CH2)5[Tyr(Me)2,Thr4,Tyr-NH2(9)]鸟氨酸-血管加压素，是否会阻断自然分娩后的自发母性行为。向嗅球内注入拮抗剂显著延迟了母性行为所有组成部分（找回、舔舐、筑巢、蹲伏）的出现，而与向嗅球内注入生理盐水相比，向脑室内注入拮抗剂对任何组成部分均无影响。实验二旨在确定向嗅球内注入催产素是否会在未生育的大鼠中迅速引发母性行为。在幼崽出现前48小时，对未生育的大鼠进行卵巢切除并用苯甲酸雌二醇进行处理。在幼崽出现前，立即向嗅球或侧脑室双侧注入低剂量（20皮摩尔）的催产素或生理盐水。与向脑室内注入催产素和向嗅球内注入生理盐水无效相比，向嗅球内注入催产素在幼崽暴露后2小时内使一半受试动物表现出了完整的母性行为。这些结果表明，嗅球是催产素作用以迅速引发母性行为的关键部位。
