内皮─氧化氮的减少引起Dahl高血压大鼠异常的血管反应

本文研究目的在于观察Dahl高血压大鼠对去甲肾上腺素（NE）收缩反应增强，对乙酰胆碱（ACH）舒张反应减弱，是否与血管内皮NitricOxide（NO）有关。7—8周龄雄性Dahl盐敏感（DS）大鼠和盐抵抗（DR）大鼠，各随机分两组，分别给予正常盐或高盐饮食，每周尾套管法测血压和体重，4周后麻醉状态下取胸主动脉，用于离体血管反应性研究。结果显示：高盐饮食的DS大鼠尾动脉血压明显升高，NE诱导的收缩反应也明显高于其它三组，去内皮及体外L—NAME的处理，可以消除这一差别。同时Dahl高血压大鼠，ACh诱导的舒张反应也明显减弱。体外Larginine的使用，不同程度地降低了NE诱导的收缩反应，但不能废除组间差异。结论：NO合成酶功能障碍可能是Dahl高血压大鼠异常血管反应的原因。

DECREASED NITRIC OXIDE IS RESPONSIBLE FOR THE ABNORMAL VASCULAR RESPONSES TO NE AND ACh IN HYPERTENSIVE DAHL RAT

The study was intended to investigate Whether an enhanced constriction response to norepinephrine (NE) and a reduced en-dothelium - dependent relaxing response to acetylcholine (ACh) was relevant to the hy-pertensive Dahl rats or not. The 7-8weeks old male Dahl salt-sensitive (DS) and salt - resistant (DR) rats were partly fed by normal salt diet (0. 4%NaCL) or partly fed by high salt diet (8%NaCL). The aortic rings with or without endothelium were used to investigate the vascular responses to NE and ACh. Systolic blood pressure was elevated significantly (P<0.05) in the DS rats fed by 8%NaCL but not in the DS rats fed by 0. 4% NaCL and the DR rats fed by either 8% or 0. 4% NaCL, In the hyperten-sive Dahl rast, NE - induced constricting response was significantly higher, Remove of endothelium and L - NAME treatment abrogated the differences between the groups. Endothelium - dependent relax-ation to ACh, in the hypertensive Dahl rats, exhibited markedly lower than the other three groups. L-arginine treatment in vit-ro did not dispel the differences of NE -in- duced responses between the hypertensive Dahl rats and the nomotensive Dahl rats. Our data suggested that impaired L - arginine NO pathway should be responsible for the abnormal vascular responses to NE and ACh. Dysfunction of NO production is likeiy due to redueced activation of NOS.