Interaction between cionidine and N-methyi-D-aspartate receptors in the caudal ventrolaterai medulla of rats

It is known that the caudal ventrolateral medulla (CVLM) plays an important role in controlling blood pressure and mediating the cardiovascular effects of centrally acting antihypertensive drugs such as clonidine. Recently, the effect of clonidine was believed to be related to the functional states of N-methyl-D-aspartate (NMDA) receptors. The present work was designed to observe the interactions between clonidine and NMDA receptor in the CVLM.     

尾端延髓腹外侧区咪唑啉受体在可乐定中枢降压效应中的作用

目的:探讨大鼠尾端延髓腹外侧区(CVLM)在介导可乐定降压机制中的作用.方法:氨基甲酸乙酯麻醉SD大鼠20只,体质量250～350 g,应用微量注射和动脉插管记录血压等方法观察CVLM给予咪唑啉1和α2-肾上腺素受体阻断剂对可乐定导致的心血管活动的影响.结果:双侧CVLM预先微量注射咪唑啉1和α2-肾上腺素受体阻断剂idazoxan(5 nmol)不仅能降低平均动脉血压[(-17.3±6.9)mmHg,1 mmHg=0.133 kPa,P＜0.01]和心率[(-23.9±3.6)次/min,P＜0.01],而且能完全阻断静脉注射可乐定(10 μg/kg)导致的降压[(-29.5±6.1)vs(-1.4±2.3)mmHg,P＜0.01]和降心率效应[(-30.8±6.7)vs(-3.0±4.6)次/min,P＜0.01],而预先CVLM微量注射α2-肾上腺素受体阻断剂育亨宾(500 pmo1)则不能影响可乐定导致的心血管效应.结论:CVLM咪唑啉受体1参与可乐定的中枢降压效应.     

Cardiovascular effects of agmatine within the rostral ventrolateral medulla are similar to those of clonidine in anesthetized rats

Agmatine was isolated from bovine brain in 1994. It exhibits various functions, as a consequence of which it meets the criteria for an endogenous brain neurotransmitter. However, its physiological action on the cardiovascular system remains unclear. This study was designed to clarify its cardiovascular effects when administered into the rostral ventrolateral medulla （RVLM） in anesthetized and paralyzed rats. Unilateral injection of clonidine （5 nmol） into the RVLM significantly decreased mean arterial pressure （MAP） and heart rate （HR）.     

大鼠头端延髓腹外侧区NMDA受体在动脉压力感受器反射中的作用

目的：研究大鼠头端延髓腹外侧区（ＲＶＬＭ）谷氨酸ＮＭＤＡ受体在介导动脉压力感受器反射（ＡＢＲ）中的作用。方法：在氨基甲酸乙酯麻醉的大鼠ＲＶＬＭ双侧各微注射０．１μ１的５０ｍｏｌ／Ｌ,氯胺酮,观察动脉血压,心率以及ＡＢＲ的变化。结果：双侧ＲＶＬＭ内微注射氯胺酮后动脉血压和心率明显下降（Ｐ〈０．０５）,同时能部分或完全阻断ＡＢＲ（Ｐ〈０．０５）。结论：谷氨酸ＮＭＤＡ受体在维持交感心血管活动的紧张性兴奋     

Cardiovascular effects of agmatine within the rostral ventrolateral medulla are similar to those of clonidine in anesthetized rats

Agmatine was isolated from bovine brain in 1994. It exhibits various functions, as a consequence of which it meets the criteria for an endogenous brain neurotransmitter. However, its physiological action on the cardiovascular system remains unclear. This study was designed to clarify its cardiovascular effects when administered into the rostral ventrolateral medulla （RVLM） in anesthetized and paralyzed rats. Unilateral injection of clonidine （5 nmol） into the RVLM significantly decreased mean arterial pressure （MAP） and heart rate （HR）.     

大鼠延髓腹外侧区在可乐定心血管效应中的作用

目的：探讨大鼠延髓腹外侧区（VLM）在介导可乐定心血管效应中的作用。方法：氨基甲酸乙酯麻醉SD大鼠，应用微量注射和细胞外记录等方法观察尾端延髓腹外侧区（CVLM）和头端延髓腹外侧区（RVLM）内局部给予可乐定导致的心血管活动变化。结果：单侧CVLM微量注射可乐定（5nmol/100nl,n=10)不仅能明显升主动脉血压（AP）和增加心率（HR）（P＜0．01），而且能增加同侧RVLM压力敏感性神经元（n=80)的放电频率（P＜0．01），而单侧RVLM微量注射可乐定（5nmol/100nl,n=9)，明显降低AP和HR（P＜0．01）。结论：RVLM和CVLM在介导可乐定的心血管效应中具有不同的作用。     

中青年原发性高血压与延髓腹外侧血管压迫的相关性研究

目的以MRI、MRTA探讨中青年原发性高血压与延髓头侧腹外侧血管压迫的相关性。方法 2位有经验的影像诊断医师共同分析29例原发性高血压病人、20例正常对照组的MRI、MRTA。结果原发性高血压组中20例（69%）,对照组中4例（20%）延髓腹外侧部受压。原发性高血压组,延髓腹外侧血管压迫的比例明显高于对照组（P〈0.01）。结论中青年原发性高血压与延髓腹外侧血管压迫有关。