慢性应激性高压大鼠中刺激弓状核引起的压作用

Hypertension was induced by chronic foot-shock and noise stress in adult male Sprague-Dawley rats. Microinjection of 0.3 microliters (150 mmol) sodium glutamate (Glu) into the nucleus arcuatus (ARC) elicited a significant depressor effect in rats with chronic stress-induced hypertension. The depressor effect induced by excitation of ARC neurons was attenuated significantly by microinjection of 0.3 microliters beta-endorphin antiserum (beta-EPAS) into the dorso-medial periaqueductal gray (PAG) or 0.1 microliters into the area of locus coeruleus (LC) due to blockage of beta-endorphinergic fibres from ARC to PAG or LC.     

7.5%氯化钠溶液对失血性低血压狗升压作用的中枢机制

９对狗作头部交叉循环,４对狗作脑交叉循环后,股动脉失血使平均动脉压（ＭＡＰ）降至５．３３ｋＰａ左右,维持３０ｍｉｎ。从其中一只狗（Ａ狗）股静脉输入占总失血量１０％的７．５％ＮａＣｌ溶液（实验组）,或生理盐水（对照组）;另一只狗（Ｂ狗）不作任何处理。结果：实验组Ａ,Ｂ两狗动脉血压（ＡＰ）均显著回升,并维持至输液后６０ｍｉｎ,其中收缩压（ＳＰ）回升幅度大于舒张压（ＤＰ）,脉压（ＰＰ）加大。对照组ＡＰ回升值无统计学意义。实验组及对照组心率（ＨＲ）均无明显变化。动脉血红细胞比容皆下降,但其下降值组间比较,Ｐ＞０．０５。实验组Ａ狗血浆钠有意义地增高,Ｐ＜０．０１;Ｂ狗变化同对照组。结果提示：在７．５％ＮａＣｌ溶液恢复失血性低血压的作用机制中,中枢神经系统起重要作用。     

慢性应激性高血压大鼠中刺激弓状核引起的降压作用

用电击足底加噪音刺激的慢性应激方法,使成年雄性Sprague-Dawley大鼠获得持续性高血压。在这种慢性应激性高血压大鼠弓状核区微量注射0.3μL-谷氨酸钠(150mmol),可导致明显的血压下降。分别在中脑导水管周围灰质背内侧区和蓝斑区微量注射0.3μl和0.1μlβ—内啡肽抗血清后,上述弓状核神经元兴奋导致的降压效应明显减弱。结果表明,大鼠获得慢性应激性高血压后,弓状核神经元的兴奋具有明显降压作用,此作用可能与弓状核β—内啡肽能神经元的下行投射纤维的活动有关。