A study on the neural mechanism of pulsatile secretion of oxzytocin during suckling in the rat

大鼠哺乳期催产素脉动分泌的神经机制研究

基本信息

批准号：
05670066
负责人：
NEGORO Hideo
金额：
$ 1.41万
依托单位：
Fukui Medical School
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1993
资助国家：
日本
起止时间：
1993 至 1994
项目状态：
已结题

项目摘要

Oxytocin is known to be released in a pulsatile fashion during suckling in the latating rat. However, not only the neural mechanism to produce the pulsatile release but also its location have not been made clear. We found neurons projecting to the supraoptic nucleus and showing bursts of action potentials before milk ejection (bursting neuron) in the dorsomedial nuclers and its vicinity. We tested the effect of suckling stimuli on the background activity of those neurons and found that suckling stimuli increased the firing rate of the neuron and the removal of pups from the mother decreased it. Since the background activity of oxytocin neuron is not influenced by suckling stimuli it is suggested the bursting neuron may participate in the gating mechanism for milk ejection bursts. In order to investigate the location of the neural mechanism responsible for the synchronization of milk ejection bursts of oxytocin neurones the activity of oxytocin neurons was recorded from the supraoptic nuclei (SON) bilaterally in the lactating rats with hemitransection of the midbrain. During bilateral suckling not only the oxytocin neurones recorded from the intact side but also those recorded from the lesioned side displayd milk-ejection bursts. When oxytocin neurons could be recorded on both sides and displayd milk-ejection bursts, they were always well synchronized. Recoding from bilateral SON was also made in the rat with hemitransection in the mid-hypothalamus. Milk ejection burst were recorded from the intact side but no bursts were recorded from the lesioned side. Thus it is very likely that the synchronization mechanism for milk ejection burst is located in the region between the midbrain and the midhypothalamus.

已知催产素在延迟大鼠的哺乳过程中以搏动方式释放。但是，不仅可以产生脉动释放的神经机制，而且尚未明确其位置。我们发现神经元投射到上核上，并在牛奶射出（爆发神经元）及其附近显示出动作电位爆发。我们测试了哺乳刺激对这些神经元背景活动的影响，发现哺乳刺激提高了神经元的发射速率，而从母亲那里清除了幼犬。由于催产素神经元的背景活性不受哺乳刺激的影响，因此建议神经元爆发可能参与牛奶喷射爆发的门控机制。为了研究负责催产素神经元牛奶射精爆发的神经机制的位置，在双侧乳核（SON）中记录了催产素神经元的活性，并在泌乳大鼠的上侧带有中脑中横流。在双侧哺乳过程中，不仅是从完整侧记录的催产素神经元，而且还记录在病变的侧面显示牛奶批量爆发中。当催产素神经元可以在两侧记录并显示出牛奶换爆的爆发时，它们总是同步。双侧儿子还从大鼠中进行了复合，并在中间的甲壳虫中进行了溶血。从完整的一侧记录了牛奶的喷射爆发，但没有从病变的一侧记录爆发。因此，牛奶射精爆发的同步机制很可能位于中脑和中部丘脑之间的区域。