RU486对硫酸皮质酮引起的头端延髓腹外侧区心血管神经元作用的影响

The responses of RU486 to the effects of corticosterone sulfate on cardiovascular neurons in the rostral ventrolateral medulla of rats

目的研究糖皮质激素（ＧＣ）的非基因组机制在交感神经活动调节中的作用。方法细胞外记录氨基甲酸乙酯麻醉的ＳＤ大鼠头端延髓腹外侧区（ＲＶＬＭ）被鉴定的心血管神经元的自发放电，观察微电泳硫酸皮质酮（Ｏ３ＲＴ对心血管神经元活动的影响，及其 ＧＣ受体拮抗剂 ＲＵ ４８６对ＣＯＲＴ导致神经元作用的影响。结果在ＲＶＬＭ共记录到３３个心血管神经元，微电泳硫酸皮质酮（ＣＯＲＴ）后２５（７６％）个神经元放电迅速加快，且具有剂量依赖性，余８个（２７％）心血管神经元自发放电没有变化；其中被ＣＯＲＴ兴奋的１２个单位微电泳ＲＵ４８６（糖皮质激素受体阻断剂）后神经元的基础放电没有明显变化（Ｐ＞０．０５），但能部分（９个单位）或完全（３个单位）阻断硫酸皮质酮导致的兴奋作用。结论Ｏ３ＲＴ对ＲＶＬＭ心血管神经元具有快速的兴奋作用，ＲＵ４８６并不改变ＲＶＬＭ心血管神经元的基础活动，但能部分或完全阻断ＣＯＲＴ导致的神经元兴奋作用。

AIM To study the roles of non- ge-nomic mechanism of glucocorticoid in the integration of sympathetic nervous system. METHODS The spontaneous discharge of the identified Cardiovascular neurons in the rostral ventrolateral medulla (RVLM) were extracellularly recorded in urethane-anaes- thetized rats. The effects of microiontophoresis of corticostersone sulfate (CORT) on the discharge of the cardiovascular neurons in the RVLM were observed. The responses of RU 486 (a blocker for cytosolic glucocorticoids) to the effects of CORT on the cardiovascular neurons were investigated. RESULTS Totally 33 Cardiovascular neurons in the RVLM were recorded, the firing rate of 25 (76% ) cardiovascular neurons increased by microiontophoresis of CORT. The effects of CORT were also positively correlated with the current. In 8 (24% ) cardiovascular neurons, microiontophoresis of CORT had no effect on their spontaneous discharge. In 12 of 33 cardiovascular neurons, which discharge increased by CORT, microiontophoresis of RU 486 had no responses to the baseline discharge of these cardiovascular neurons (P >0.05), but completely (3 neurons) or partially (9 neurons) blocked the excitatory effect induced by CORT. CONCLUSION CORT had rapid excitatory effects on the Caldiovascular neuronsin the RVLM. RU 486 had no responses to the baseline activity of the cardiovascular neurons, and but completely or partially blocked the effect of CORT on the cardiovascular neurons.