家兔Bezold-Jarisch反射的血流动力学效应

HEMODYNAMIC EFFECTS OF THE BEZOLD-JARISCH REFLEX IN RABBIT

在40只麻醉兔,观察经冠脉内注射尼古丁诱发Bezold-Jarisch反射时的血流动力学变化。反射效应表现为心率减慢、动脉血压和左心室收缩压降低以及左心室内压微分值减小。切断两侧窦神经和减压神经后,上述效应增强;两侧迷走神经切断后,多数动物反射效应消失。 冠脉内注射尼古丁后,心输出量和总外周阻力均下降。人工起搏心脏以防止心率减慢时,对上述效应无明显影响。动物阿托品化并切除两侧星状神经节后,心率减慢基本消失,但动脉血压降低的程度并无明显变化。结果提示,Bezold-Jarisch反射时所表现的动脉血压降低,可归因于心输出量减少和总外周阻力降低,而以后者为主。

The Bezold-Jarisch reflex induced by intracoronary injection of nicotine(ICIN)of5 μg/kg was studied in 40 anesthetized rabbits.Heart rate(HR),arterial bloodPressure(ABP),left ventricular pressure(IVP),left ventricular dp/dt(LV dp/dt)and cardiac output(CO)were monitored and total peripheral resistance(TPR)was calculated.HR,ABP,LVP and LV dp/dt were decreased following ICIN.These inhibitory responses induced by ICIN were enhanced by sino-aortic denerva-tion but abolished by bilateral vagotomy.Decreases in CO and TPR were alsoobserved in response to ICIN.With the heart paced artificially to prevent brady-cardia,the decreases in CO,TPR and ABP were still significant.Bilateral stellateganglion section plus atropinization which abolished the decreases in HR and CO,did not significantly change the hypotensive response to ICIN.These data suggestthat he hypotension evoked by Bezold-Jarisch reflex in rabbit is largely due to thedecreases in TPR and partially caused by the decrease in CO.