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

• 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
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-05670066/
• 关键词: Oxytocin; Milk ejection reflex; Neurohypophyseal hormone; Synchronization mechanism; Busting firing; Palsatile release; Supraoptic nucleus; burst発射; 視床下部; 下垂体後葉; 同期化

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.

催产素在哺乳期大鼠中以脉冲方式释放。然而，不仅产生脉冲释放的神经机制，而且它的位置还不清楚。在背内侧核及其附近发现了投射到视上核的神经元，并在射乳前出现动作电位爆发（爆发神经元）。我们测试了哺乳刺激对这些神经元背景活动的影响，发现哺乳刺激使催产素神经元的放电频率增加，而从母体中取出幼崽使其放电频率降低。由于催产素神经元的背景活动不受哺乳刺激的影响，提示爆发神经元可能参与了乳汁喷射爆发的门控机制。为了探讨催产素神经元射乳爆发同步化的神经机制，在中脑半横断的哺乳期大鼠双侧视上核（SON）记录催产素神经元的活动。在双侧哺乳期间，不仅完整侧记录到的催产素神经元，而且损伤侧记录到的催产素神经元也显示出喷乳爆发。当两侧的催产素神经元都能被记录下来并显示出喷奶爆发时，它们总是很好地同步。在大鼠下丘脑中部半横断后，取双侧SON，进行组织切片。记录到完整侧的排乳爆发，但未记录到损伤侧的排乳爆发。因此，催乳爆发的同步机制很可能位于中脑和下丘脑中部之间的区域。

项目成果

Wang, Y-F.: "Is the mechanism synchronizing milk ejection burst of oxytocin cell in the hypothalamus?" Folia Endocrinologica Japonica. Vol.69. 877 (1993)

Wang, Y-F.：“下丘脑催产素细胞同步喷乳爆发的机制是吗？”

Wang, Y-F.: "Effects of hemitransection of the medbrain on milk-ejection burst of oxytocin neurones in lactating rat." Jounal of Endocrinology. Vol.144 (in press). (1995)

Wang, Y-F.：“中脑半横切对哺乳期大鼠催产素神经元喷乳爆发的影响。”

Wang,Y-F.: "Is the mechanism synchronizing milk ejection burst of oxytocin cell in the hypothalamus?" 日本内分泌学会雑誌. 69. 877- (1993)

Wang, Y-F.：“下丘脑中催产素细胞的乳汁喷射爆发是同步的吗？” 日本内分泌学会杂志 69. 877- (1993)。

Wang,Y-F.: "Location of the synchronization mechanism for the burst activity of oxytocin neurons during milk ejection reflex." The Japanese Journal of Physiology. 44Suppl.1. S266 (1994)

Wang，Y-F.：“泌乳反射过程中催产素神经元爆发活动的同步机制的位置。”

Wang,Y-F.,Negoro,H.,Honda,K.: "Is the mechanism synchronizing milk ejection burst of oxytocin cell in the hypothalamus?" 日本内分泌学会雑誌. 69. 877 (1993)

Wang, Y-F., Negoro, H., Honda, K.：“下丘脑中催产素细胞的泌乳爆发是同步的吗？” 日本内分泌学会杂志 69. 877 (1993)。