Laboratoire de Physiologie Générale, URA 309 CNRS, Université Louis Pasteur, 21 rue René Descartes, 67084 Strasbourg, France.
J Neuroendocrinol. 1991 Apr 1;3(2):163-71. doi: 10.1111/j.1365-2826.1991.tb00259.x.
Abstract Several regions of the forebrain possess high densities of oxytocin (OT)-binding sites including the bed nucleus of the stria terminalis (BST) and lateral septum (LS). In order to examine whether these regions participate in the central facilitation of the milk ejection reflex by OT, microinjections of OT (1 ng in 100 nl containing Janus Green dye) were made into the BST (13 tests) or LS (9 tests) of anaesthetized, suckled rats, while recording the electrical activity of OT neurons in the contralateral supraoptic nucleus. Histological localization of injection sites using Janus Green demonstrated that all BST injections were close to the anterior commissure, and LS injections were all located in the ventral division of the LS. Film autoradiographic visualization of OT-binding sites (in 7 tests using [(125)I]OT antagonist) confirmed that the BST and LS injections were located within regions of high OT binding. Injections into both regions facilitated the milk ejection reflex by increasing either the frequency and/or amplitude of OT neuron bursts, or by triggering bursts in animals that previously had shown no milk ejection responses; the mean number of milk ejections in the 30 min before and after injection increasing from 1.6.0.5 to 3.6.0.5 for BST and from 1.5.0.6 to 3.9.0.4 for LS. The OT microinjections had a more variable effect on background activity of OT neurons, increasing firing in some cases and not in others. This facilitatory effect was similar to that induced by microinjections into the lateral ventricle, but was smaller and delayed compared to that induced by injection into the third ventricle (9 tests), possibly due to unilateral activation of target sites. The facilitatory effect was unlikely to have been due to diffusion of OT into the ventricle, since injections into control sites (striatum and thalamus) at similar distances from the ventricle (9 tests) had no facilitatory effect (number of bursts during 30 min before and after injection; 2.2.0.5 and 1.8.0.5, respectively). These data suggest that limbic structures (BST and LS) participate in the action of central OT on the pattern of milk ejections in the suckled rat.
摘要 前脑的几个区域具有高浓度的催产素 (OT) 结合位点，包括终纹床核 (BST) 和外侧隔核 (LS)。为了研究这些区域是否参与 OT 对乳汁排出反射的中枢促进作用，在麻醉、哺乳的大鼠 BST（13 次测试）或 LS（9 次测试）中注入 OT（1 ng，100 nl 中含有 Janus Green 染料），同时记录对侧视上核中 OT 神经元的电活动。使用 Janus Green 进行的注射部位组织学定位表明，所有 BST 注射均靠近前连合，LS 注射均位于 LS 的腹侧部分。使用 [(125)I]OT 拮抗剂的 7 次测试中的 OT 结合位点的胶片放射自显影显示，BST 和 LS 注射均位于 OT 结合高的区域内。向两个区域内注射 OT 可通过增加 OT 神经元爆发的频率和/或幅度，或通过在先前未显示乳汁排出反应的动物中引发爆发来促进乳汁排出反射；注射前 30 分钟和注射后的平均乳汁排出次数从 BST 的 1.6.0.5 增加到 3.6.0.5，LS 从 1.5.0.6 增加到 3.9.0.4。OT 微注射对 OT 神经元的背景活动有更可变的影响，在某些情况下增加放电，而在其他情况下则不增加。这种促进作用与向侧脑室微注射诱导的作用相似，但与向第三脑室注射诱导的作用相比较小且延迟（9 次测试），可能是由于目标部位的单侧激活。这种促进作用不太可能是由于 OT 扩散到脑室中，因为向脑室（9 次测试）相似距离的对照部位（纹状体和丘脑）注射没有促进作用（注射前后 30 分钟内的爆发次数；分别为 2.2.0.5 和 1.8.0.5）。这些数据表明，边缘结构（BST 和 LS）参与了 OT 对哺乳大鼠乳汁排出模式的中枢作用。
