清醒大鼠下丘脑室旁核内的甘氨酸对压力感受性反射的影响

发布时间：2018-02-21 05:04

本文关键词： 下丘脑室旁核压力感受性反射甘氨酸士的宁脑部微量透析法　出处：《延边大学》2009年硕士论文　论文类型：学位论文

【摘要】： 下丘脑室旁核(hypothalamic paraventricular nucleus,PVN)是内分泌系统和自主神经系统的整合中枢,也是调节机体内环境稳态和心血管活动的重要结构之一。据报道,PVN在正常或应激状态下有着加强心血管活动的作用。但是,这些研究多数是直接或间接刺激PVN后观察了心血管活动的变化,没有对参与心血管活动调节的PVN内的神经递质做进一步的研究,尤其对PVN参与正常压力感受性反射调节的神经化学机制报道稀少。甘氨酸是中枢神经系统中分布较广泛的氨基酸类神经递质,研究表明包括PVN在内的下丘脑有甘氨酸能神经元的分布,但甘氨酸在这些部位的作用及其机制尚不清楚。为了阐明PVN参与正常压力感受性反射调节的部分神经化学机制,也为了明确PVN内的甘氨酸在此反射调节中的作用,本实验利用清醒大鼠,在静脉注射苯肾上腺素诱发压力感受性反射的同时利用脑部微量透析法和高效液相色谱分析法,观察PVN区细胞外液中的甘氨酸(Gly)含量的变化。其次,通过PVN区灌流甘氨酸受体阻断剂士的宁(strychnine)和激动剂甘氨酸,进一步探讨了PVN区甘氨酸参与压力感受性反射中枢调节的具体机制。实验结果如下: 1.静脉注射苯肾上腺素诱发压力感受性反射,血压由正常的(99.5±14.2)mmHg上升到(149.8±19.5)mmHg(P＜0.01),心率反射性地从(400.8±33.1)次/分下降到(273.4±40.8)次/分(P＜0.01);PVN区细胞外液中甘氨酸水平由注射前的100%升高到162.89%±27.93%(P＜0.05)。 2.向PVN区灌流甘氨酸受体阻断剂士的宁(100μmol/L)20分钟,同时静脉给予与对照组相同剂量的苯肾上腺素诱发压力感受性反射。和对照组相比,阻断剂使用组,血压升高的幅度明显升高(P＜0.001),而心率下降的幅度却明显降低(P＜0.001),导致压力感受性反射的敏感性(ΔHR/ΔMAP)明显减少(P＜0.001)。 3.向PVN区灌流甘氨酸(1mmol/L)20分钟,同时静脉给予与对照组相同剂量的苯肾上腺素诱发压力感受性反射。和对照组相比,甘氨酸使用组,血压升高的幅度升高不明显(P＞0.05),而心率下降的幅度却明显升高(P＜0.001),导致压力感受性反射的敏感性(ΔHR/ΔMAP)明显增加(P＜0.001)。结论: PVN内的甘氨酸通过士的宁敏感的甘氨酸受体对压力感受性反射活动起易化作用。
[Abstract]:Hypothalamic paraventricular nucleus (PVN) is the integration center of endocrine system and autonomic nervous system. PVN is also one of the important structures that regulate homeostasis and cardiovascular activity in the body. PVN is reported to enhance cardiovascular activity in normal or stressed state. Most of these studies observed changes in cardiovascular activity after direct or indirect stimulation of PVN, with no further study of neurotransmitters in PVN involved in cardiovascular regulation. In particular, there are few reports on the neurochemical mechanism of PVN involved in normal baroreflex regulation. Glycine is a widely distributed amino acid neurotransmitter in the central nervous system. Studies have shown that the hypothalamus, including PVN, has the distribution of glycinergic neurons, but the role of glycine in these sites and its mechanism are not clear. In order to elucidate some neurochemical mechanisms of PVN involved in the regulation of normal baroreflex. In order to elucidate the role of glycine in the regulation of reflex in PVN, the baroreflex was induced by intravenous injection of phenylephrine in awake rats, and microdialysis and high performance liquid chromatography were used in this study. The changes of glycine glycine in extracellular fluid of PVN region were observed. Secondly, the glycine receptor blocker strychnine (strychnine) and the agonist glycine were perfused through the PVN region. Furthermore, the mechanism of glycine in PVN region involved in baroreflex regulation was discussed. The results are as follows:. 1. The blood pressure increased from 99.5 卤14.2mm Hg to 149.8 卤19.5mm Hg (P < 0.01), and the heart rate reflex decreased from 400.8 卤33.1 times / min to 273.4 卤40.8 times / min (P < 0.01). The level of glycine in extracellular fluid increased from 100% before injection to 162.89% 卤27.931g / min (P < 0.05). 2. The glycine receptor blocker, strychnine, was perfused into the PVN area for 100 渭 mol/L)20 minutes, and the baroreflex was induced by the same dose of phenylephrine as that in the control group. The amplitude of blood pressure rise was significantly increased (P < 0.001), while the decrease of heart rate was significantly decreased (P < 0.001), which resulted in a marked decrease in the sensitivity of baroreflex (螖 HR- / 螖 MAPP) (P < 0.001). 3. One mmol / L of glycine was perfused into the PVN area for 20 minutes, and the same dose of phenylephrine was given to induce baroreflex in the control group for 20 minutes. Compared with the control group, the glycine group was given the same dose of phenylephrine to induce baroreflex. The amplitude of elevation of blood pressure was not significant (P > 0.05), but the decrease of heart rate was significantly increased (P < 0.001), which resulted in a marked increase in the sensitivity of baroreflex (螖 HR- / 螖 MAPP) (P < 0.001). Conclusion:. Glycine in PVN facilitates baroreflex activity through strychnine-sensitive glycine receptors.
【学位授予单位】：延边大学
【学位级别】：硕士
【学位授予年份】：2009
【分类号】：R33

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