Studies on burst activity of oxytocin neuron similar to that observed at the milk-ejection reflex in the brain slice

对催产素神经元爆发活动的研究类似于在脑切片中观察到的喷乳反射

• 批准号: 09670068
• 负责人: NEGORO Hideo
• 金额: $ 1.86万
• 依托单位: Fukui Medical School
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1997
• 资助国家: 日本
• 起止时间: 1997 至 1998
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09670068/
• 关键词: milk-ejection reflex; oxytocin neuron; burst firing; noradrenalin; phenylephrine; brain slice; supraoptic nucleus; synchronized firing; フェニレノリン; フェニレフリン

At the milk-ejection reflex in rats oxytocin neurons show burst firing for 2-3 seconds in response to sucking stimuli by pups. Consequently oxytocin is secreted from the posterior pituitary gland to eject milk from mammary gland. We aimed to know whether this burst activity originates from endogenous property of the oxytocin neurons. In addition, the involvement of nitric oxide (NO) in the burst fring was examined.From 32 male rats hypothalamic slice preparations were made. We recorded from 65 neurons in the supraoptic nucleus using glass microelectrodes. We identified these neurons as oxytocinergic from their firing pattern. We observed burst activity in 4.6% of these neurons. The mean amplitude of the burst activity was 32.3 spikes, duration was 2.7 sec and after inhibition lasted for 2.7 sec. Additional forty one oxytocin neurons were recorded from other 26 rats after application of phenylephrine at the dose of 10^<-8> - 10^<-5> M.We observed burst activity in 39% of the neurons. The burst firing was irregular. We succeeded in recording from four paired oxytocin neurons, burst activity did not occur synchronously. NO donor, sodium nitroprusside, injected in the lateral ventricle of lactating rats inhibited milk ejection and Fos expression in the paraventricular and supraoptic nuclei.From the these results, we conclude that the mechanism for the burst activity at the milk- ejection reflex at least in part originates from endogenous property of oxytocin neurons and that this mechanism is facilitated by adrenergic input. The synchronizing mechanism is located outside of the paraventricular or supraoptic nuclei and influenced by NO activity .We will continue this project by introducing an equipment that can record from 64 neurons simultaneously.

在大鼠的泌乳反射中，催产素神经元在幼崽的吮吸刺激下会爆发2-3秒。因此，催产素从垂体后腺分泌，使乳汁从乳腺排出。我们的目的是了解这种爆发活动是否源于催产素神经元的内源性特性。此外，还研究了一氧化氮（NO）在破裂层中的作用。32只雄性大鼠下丘脑切片制备。我们用玻璃微电极记录了65个视上核神经元。我们从这些神经元的放电模式确定它们是催产素能神经元。我们在4.6%的这些神经元中观察到爆发活动。另外26只大鼠在10^<-8> m - 10^<-5> m的剂量下，记录了41个催产素神经元，其中39%的神经元有爆发活动。爆炸射击是不规则的。我们成功地记录了四个配对的催产素神经元，爆发活动并没有同步发生。NO供体硝普钠注射于泌乳大鼠侧脑室，可抑制泌乳量及室旁核和视上核Fos的表达。根据这些结果，我们得出结论，泌乳反射爆发活动的机制至少部分源于催产素神经元的内源性特性，而肾上腺素能输入促进了这一机制。同步机制位于室旁核或视上核外，受NO活性影响。我们将继续这个项目，引入一种可以同时记录64个神经元的设备。

项目成果

C.O.Okere, H.Kaba, K.Seto and T.Higuchi: "Intracerebroventricular injection of a nitric oxide donor attenuates Fos expression in the paraventricular and supraoptic nuclei of lactating rats" Brain Research. (in press).

C.O.Okere、H.Kaba、K.Seto 和 T.Higuchi：“脑室内注射一氧化氮供体可减弱哺乳大鼠室旁核和视上核中的 Fos 表达”《大脑研究》。

Y.-F.Wang, H.Negoro, K.Honda: "Effects of interhemispheric sections of the hypothalamus on milk-ejection bursts of supraoptic oxytocin neurones during bilateral and unilateral suckling in tha rat" Neuroscience Letter. 227 (1). 17-20 (1997)

Y.-F.Wang、H.Negoro、K.Honda：“下丘脑半球间部分对大鼠双侧和单侧哺乳期间视上催产素神经元喷乳爆发的影响”《神经科学快报》。

Y-F.Wang, H.Negoro and K.Honda: "Effect of interhemispheric sections of the hypothalamus on milk-ejection bursts of supraoptic oxytocin neurones during ilateral and unilateral suckling in the rat" Neuroscience letter. 227. 17-20 (1997)

Y-F.Wang、H.Negoro 和 K.Honda：“下丘脑半球间部分对大鼠单侧和单侧哺乳期间视上催产素神经元喷乳爆发的影响”《神经科学》通讯。

C.O.Okere, H.Kava, K.Seto, T.Higuchi: "Intracerebroventricular injection of a nitric oxide donor attenuates Fos expression in the paraventricular and supraoptic nuclei of lactating rats." Brain Research. (in press).

C.O.Okere、H.Kava、K.Seto、T.Higuchi：“脑室内注射一氧化氮供体可减弱哺乳大鼠室旁核和视上核中的 Fos 表达。”