Study for the afferent hypothalamic pathway for the milk-ejection reflex in the rat

大鼠喷乳反射下丘脑传入通路的研究

• 批准号: 11670061
• 负责人: KAZUMASA Honda
• 金额: $ 2.24万
• 依托单位: Fukui Medical University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1999
• 资助国家: 日本
• 起止时间: 1999 至 2000
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-11670061/
• 关键词: milk ejection; oxytocin cell; vasopressin cell; supraoptic nucleus; dorsomedial hypothalamus; hypothalamus; rat

We have previously reported that the dorsomedial hypothalamic nucleus (DMH) is the final relay site for the afferent pathway of the milk-ejection reflex in the rat (1992, Takano et al). The present experiments were undertaken to examine whether the DMH projects to supraoptic nuclei (SON) in both sides of the hypothalamus and contributes to the synchronized activation of oxytocin (OT) cells at milk-ejection reflex. In urethane anesthetized lactating rats, extracellular recordings of single OT cells in the SON were made. Twenty-six of 52 OT cells showed orthodromic excitation (OD+) or inhibition followed by the excitation (OD-+) in response to electrical stimulation of both ipsi-and contralateral DMH to the recording side. Eleven cells showed OD+ or OD-+ in responses to electrical stimulation of only ipsi-lateral DMH to the recording side. Continuous electrical stimulation of both ipsi- and contralateral DMH to the recording side at 10-50 Hz for 30-60 s increased firing rate in 7 of 12 O … More T cells tested. Fourty DMH cells were identified as projecting to the ipsilateral SON and 4 of them were also identified as projecting to the contralateral SON.Four cell were identified as projecting only to the contralateral SON.Of these, 25 were tested for theri firing pattern during milk ejection reflex. One cell, which had a projection to the contralateral SON, showed abrupt increase in firing rate (bursting activity similar to oxytocin cells) preceding milk ejection. This cell also showed an increase of basal firing rate in response to suckling stimulus. Two cells which had bilateral projectin and one cell which had a ipsilateral projectin showed reduction in firing rate preceding milk ejection. One cell which projected contralateral SON showed a reduction of firing rate in response to suckling stimulus. The results suggest that some of DMH neurones project to OT cells in both sides of hypothalamus and that these projections may contribute to the synchronized activation of OT cells during milk-ejection reflex. Less

我们之前报道过，下丘脑背内侧核（DMH）是大鼠泌乳反射传入通路的最终中继点（1992，Takano等）。本实验旨在探讨DMH是否投射到下丘脑两侧的视上核（SON），并参与泌乳反射时催产素（OT）细胞的同步激活。在氨基甲酸乙酯麻醉的哺乳期大鼠中，对SON中的单个OT细胞进行细胞外记录。52个OT细胞中有26个在单侧和对侧DMH对记录侧的电刺激下表现出正交兴奋（OD+）或抑制后的兴奋（OD-+）。11个细胞仅对记录侧单侧DMH的电刺激表现为OD+或OD-+。对单侧和对侧DMH进行10-50 Hz持续30-60 s的电刺激，12个T细胞中有7个细胞的放电率增加。40个DMH细胞被鉴定为向同侧SON突出，其中4个也被鉴定为向对侧SON突出。4个细胞被确定仅向对侧SON投射。其中25只在泌乳反射时进行了放电模式测试。其中一个细胞，有一个对侧SON的投射，在泌乳前表现出突然增加的放电率（爆发活动类似于催产素细胞）。该细胞在哺乳刺激下也表现出基础放电速率的增加。两个双侧突出的细胞和一个同侧突出的细胞在泌乳前的放电速率降低。一个投射对侧SON的细胞在哺乳刺激下表现出放电速率的降低。结果表明，一些DMH神经元投射到下丘脑两侧的OT细胞，这些投射可能有助于在泌乳反射中OT细胞的同步激活。少