下丘脑后核在中枢CRF能神经系统心血管调控中的作用与下丘脑后核orexin能神经系统的心血管调控功能

发布时间：2018-06-12 05:42

本文选题：下丘脑后核(PH) + 心血管调控　；参考：《南京大学》2016年博士论文

【摘要】：促肾上腺皮质激素释放因子(corticotrophin releasing factor, CRF) 和 orexin是中枢神经系统中两类重要的神经肽,在机体的许多生理功能调节,如心血管活动调控中发挥着关键作用。在下丘脑这一心血管和自主性活动调控高级中枢中,不仅分布着能够合成CRF或orexin的神经元,而且有CRP受体和orexin受体的大量表达。下丘脑后核(The posterior hypothalamic nucleus, PH)是下丘脑中参与心血管调控的重要结构之一。电刺激或化学刺激大鼠PH显著升高心率、血压和交感神经活动；且慢性深部脑刺激慢性丛集性头痛(一种血管性头痛)患者PH伴随着心血管系统交感兴奋性驱动增强。因此,本论文旨在研究PH在中枢CRF能神经系统心血管活动调控中的作用以及源自PH的orexin能神经系统的心血管调控功能,从而有助于理解中枢CRF能和orexin能两大神经肽系统在机体心血管调控中的作用及机制。具体研究结果如下：一、CRF通过兴奋PH神经元产生心动过速反应CRF是一种与应激密切相关的肽类激素,在心血管活动调控中发挥关键作用。应用实时定量RT-PCR、免疫荧光组织化学、在体心血管活动记录,并结合离体、在体电生理学记录技术,我们研究了CRY对PH这一应激相关心血管活动调控中枢中神经元的作用及其受体机制,特别是PH在CRF的中枢心血管调控功能中的作用。我们的研究发现,大鼠PH神经元上有CRF 1型受体(CRFR1)和CRF 2型受体(CRFR2)的共表达。离体脑片全细胞膜片钳记录表明,CRF能够通过CRFR1 和 CRFR2的共同介导直接兴奋PH神经元。在体研究表明PH中微量注射CRF可浓度依赖性地增加心率,但对血压和肾交感神经活动(sympathetic nerve activity, RSI JA)没有影响。CRFR1 和 CRFR2共同介导了这一CRF诱导的心动过速反应。进一步地,双侧迷走神经切断不能阻断CRF经PH诱导的心动过速,但静脉注射肾上腺素p受体阻断剂普洛萘尔可以完全阻断这一CRF诱导的心动过速反应。此外,PH中微量注射CRF可以引起喙端腹外侧延髓rostral ventrolateral medulla, RVLM)神经元和喙端腹内侧延髓(rostralventromedial medulla, RVMM)神经元放电频率的变化,且这一变化以兴奋性反应为主。但PH中微量注射CRF对迷走神经运动背核(dorsal motor nucleus of the vagus nerve, DMNV)神经元的放电活动没有影响。这一结果表明,PH是中枢CRF能神经系统调节心率的重要靶区之一；PH-RVLM/RVMM-心交感神经通路,而非PH-DMNV-迷走神经通路,参与介导了中枢CRF的心动过速效应。二、PH orexin能神经元对心血管活动的调控及其机制除下丘脑外侧区和穹窿周区之外,PH也是中枢orexin能神经系统的重要起源之一。作为全脑功能调节者,中枢orexin能神经系统不仅参与了睡眠觉醒、能量平衡、神经内分泌、奖赏、情绪和躯体运动调控,而且在机体心血管活动调节中发挥重要作用。由于PH亦是心血管活动调节的一个重要中枢,我们在本项目中深入研究了PH中orexin能神经元的中枢心血管活动调控作用,及其神经环路和受体、离子机制。我们的研究结果表明,第四脑室内微量注射orexin1型受体(OX1R)阻断剂(SB334867)和 orexin 2型受体(OX2R)阻断剂(TCSOX2 29)可以显著降低由bicuculline (GABAA受体阻断剂)去抑制PH神经元所诱发的动脉血压升高、心动过速和肾交感神经兴奋性反应,提示PH中的orexin能神经元参与了PH的心血管活动调控。顺行示踪和免疫荧光组织化学实验表明,PH 中 orexin能神经元有向脑干心血管活动调控中枢RVMM的中等密度神经纤维投射和向RVLM的极少量投射。RVMM中微量注射SB334867或者TCS OX2 29均可显著减弱去抑制PH诱导的升压、心动过速和肾交感神经兴奋性反应。但RVLM中微量注射SB334867或者TCS oX2 29则无此阻断效应。离体脑片全细胞膜片钳记录表明,orexin受体两种亚型OX1R和OX2R及与它们耦联的内向整流K~+离子通道、Na~+-Ca~(2+)交换体和非选择性阳离子通道共同介导了orexin 对 RVMM神经元的兴奋性效应。这一研究结果表明,PH中orexin能神经元在中枢心血管活动调控中发挥了重要作用,而PH中orexin能神经元向RVMM而非RVLM的神经投射可能介导了PH的心血管调控作用。
[Abstract]:Adrenocorticotropic hormone releasing factor (corticotrophin releasing factor, CRF) and orexin are two important neuropeptides in the central nervous system, which play a key role in the regulation of many physiological functions, such as cardiovascular activities. In the hypothalamus, this cardiovascular and autonomic activity regulation is not only distributed in the advanced center. Neurons that can synthesize CRF or orexin and have a large number of CRP receptors and orexin receptors. The posterior nucleus of the hypothalamus (The posterior hypothalamic nucleus, PH) is one of the important structures involved in cardiovascular regulation in the hypothalamus. Electrical stimulation or chemical stimulation of rats PH significantly increases heart rate, blood pressure and sympathetic nerve activity; and chronic deep part PH, which stimulates chronic cluster headache (a vascular headache), is accompanied by a sympathetic stimulation of the cardiovascular system. Therefore, this paper aims to study the role of PH in the regulation of cardiovascular activities in the central CRF nervous system and the cardiac and vascular regulation of the orexin energy system derived from PH, thus helping to understand the central CRF energy. The role and mechanism of the two major neuropeptide systems of orexin in cardiovascular regulation. The results are as follows: 1, CRF is a peptide hormone closely related to stress, which is closely related to stress, and plays a key role in the regulation of cardiovascular activities. The application of real-time quantitative RT-PCR and immunofluorescence tissue is used in the regulation of CRF. Chemistry, in vivo cardiovascular activity records, and in vitro, in vivo electrophysiological recording techniques, we studied the role of CRY on neurons in the regulation of cardiovascular activity in the stress related PH and its receptor mechanism, especially the role of PH in the central cardiovascular regulation of CRF. Our study found that there are CRF in rat PH neurons. The co expression of type 1 receptor (CRFR1) and CRF type 2 receptor (CRFR2). Whole cell patch clamp recording in isolated brain shows that CRF can directly excitate PH neurons through the common mediating of CRFR1 and CRFR2. In vivo studies have shown that microinjection CRF in PH can increase heart rate in a concentration dependent manner, but for blood pressure and renal sympathetic activity (sympathetic nerve activi) Ty, RSI JA) did not affect both.CRFR1 and CRFR2 to mediate this CRF induced tachycardia reaction. Further, bilateral vagotomy does not block the CRF via PH induced tachycardia, but intravenous adrenaline blocker pralanyl can completely block this CRF induced tachycardia. Furthermore, PH is a trace of the tachycardia. Injection of CRF can cause the changes in the discharge frequency of the neurons and the ventral medulla of the ventral medulla (rostralventromedial medulla, RVMM) in the ventral medulla of the beak terminal ventrolateral medulla and the ventral medulla of the beak and the ventral medulla of the beak. The variation of the discharge frequency of the neurons in the ventral medulla of the ventromedial medulla (rostralventromedial medulla, RVMM) is mainly dependent on the excitatory response. However, the microinjection of CRF to the dorsal nucleus of the vagus nerve (dorsal motor) can be used in PH. The discharge activity of us nerve, DMNV) neurons has no effect. This result shows that PH is one of the important target areas for the central CRF energy system to regulate heart rate; the PH-RVLM/RVMM- cardiac sympathetic pathway, not the PH-DMNV- vagus pathway, is involved in mediating the tachycardia effect of central CRF. Two, PH orexin energy modulates the modulation of cardiovascular activity. In addition to the lateral hypothalamus and the fornix region, PH is also one of the important origins of the central orexin energy system. As a whole brain function regulator, the central orexin energy system not only participates in sleep awakening, energy balance, neuroendocrine, reward, emotional and physical regulation, but also regulates the cardiovascular activity of the body. It plays an important role. Since PH is also an important center for the regulation of cardiovascular activity, we have studied the central cardiovascular activity of orexin neurons in PH, and its neural loop and receptor, ion mechanism in this project. Our results show that the microinjection of orexin1 type receptor (OX1R) in the fourth brain is blocked. The agent (SB334867) and orexin 2 receptor (OX2R) blocker (TCSOX2 29) can significantly reduce the arterial blood pressure, tachycardia and renal sympathetic excitatory response induced by the bicuculline (GABAA receptor blocker) to inhibit the PH neurons, suggesting that the orexin neurons in PH are involved in the regulation of cardiovascular activity in PH. The immunofluorescence histochemical experiments showed that the orexin neurons in PH had moderate density nerve fibers projecting to the central RVMM of the brain stem and a very small projection of RVLM to the RVLM, and the microinjection of SB334867 or TCS OX2 29 in.RVMM could significantly weaken the suppression of PH induced pressor, tachycardia and the excitatory response of the renal sympathetic nerve. However, microinjection of SB334867 or TCS oX2 29 in RVLM had no blocking effect. The whole cell patch clamp recording of isolated brain slices showed that the two subtypes of orexin receptor OX1R and OX2R and the inward rectifier K~+ ion channels coupled with them, Na~+-Ca~ (2+) exchangers and non selective cation channels mediate the orexin on RVMM neurons. The results show that the orexin neurons in PH play an important role in the regulation of central cardiovascular activities, while orexin neurons in PH to RVMM, not RVLM, may mediate the cardiovascular regulation of PH.
【学位授予单位】：南京大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：Q42

【参考文献】