一氧化氮在家兔脑室注射P物质引起心血管效应中的作用

Interaction of nitric oxide and intracerebroventricularly administered substance P in cardiovascular in rabbits

目的 :探讨脑内P物质 (SP)的心血管效应与一氧化氮 (NO)的关系。方法 :家兔 18只 ,乌拉坦静脉麻醉 ,侧脑室注射SP(n =9) ,对照组注射人工脑脊液。记录给药前后平均动脉血压 (MAP)、左室收缩压 (LVSP)、左心室舒张末期压 (LVEDP)、心室内压最大上升速率 (+dp/dtmax)和下降速率 (-dp/dtmax)、心肌收缩成分实测最大缩短速度 (Vpm)、心率 (HR)。硝酸还原酶法测定家兔脑室注射SP(7 46nmol)前、后脑脊液中NO的含量。结果 :与对照组比较 ,侧脑室注射SP可引起MAP、HR、LVSP、LVEDP、+dp/dtmax、-dp/dtmax和Vpm的值明显增加 (P <0 0 5 ) ,小脑延髓池脑脊液中NO的含量显著降低 (P <0 0 0 1)。结论 :(1)脑内SP可增强麻醉家兔心脏的收缩功能 ,并能升高动脉血压。 (2 )脑内SP引起的心血管效应伴有NO的减少。

Objective To explore the interaction between nitric oxide (NO) and intracerebroventricular (icv.) substance P (SP) in cardiovascular regulation in anesthetized rabbits.Methods Rabbits anesthetized with urethane were intracerebroventricularly given SP (7 46?nmol),while artificial cerebrospinal fluid were given to controls.Cardiovascular responses induced by SP including heart rate (HR),mean arterial blood pressure (MAP),left ventricular systolic pressure (LVSP),left ventricular end diastolic pressure (LVEDP),the maximum velocity of ascending or descending in intraventricular pressure ( ±d p /d t max ) and the maximum shortening velocity (Vpm)of myocardial contractile element were recorded in computer with BL?310 biosoftware,and the content of NO in cerebrospinal fluid (CSF)were determined by nitrate reductase chemiluminescence in rabbits injected intracerebroventricularly with SP.Results (1)icv.SP induced significant increases of HR,MAP,LVSP,LVEDP,+d p /d t max ,-d p /d t max ,Vpm and the decreases in levels of NO in intracisternal CSF 10?min after injection.Conclusions (1)icv.SP can produce positively inotropic response in myocardium and increase arterial pressure in intact rabbits.(2)Decreased NO may be related to the cardiovascular responses to icv. SP.