区域性血管床对局部注射胍丁胺的不同反应(英文)

Differential responses of regional vascular beds to local injection of agmatine in rats

在 6 6只麻醉大鼠 ,分别采用后肢、肾脏和肠系膜动脉在体恒流灌注法 ,观察了向灌流环路中直接注射胍丁胺 (agmatine ,AGM)的血管效应 ,以所引起的灌流压增减反映血管的收缩和舒张。所得结果如下 :(1)不同剂量的AGM (0 1、0 5、1mg/kg)注射于股部灌注环路时 ,可剂量依赖性地增高后肢血管的灌流压。无论预先注射咪唑啉受体 (imidazolinereceptor,IR)和α2 肾上腺素能受体阻断剂 (α2 adrenergicreceptor,α2 AR)idazoxan (0 5mg/kg)或注射α2 肾上腺素能受体阻断剂yohimbine (1mg/kg)均可完全阻抑上述AGM的效应。(2 )向肾血管灌注环路中直接注射AGM也可剂量依赖性地增高肾血管的灌流压 ,需特别指出的是 :大剂量AGM (1mg/mg)引起肾血管双相的灌流压增高 ,此效应可被idazoxan完全阻断。而在预先应用yohimbine后 ,再注射AGM则引起肾血管灌流压降低。 (3)在肠系膜血管灌流环路中注射AGM可剂量依赖性地降低其灌流压。此效应可被idazoxan (0 5mg/kg)完全阻断 ,而yohimbine (1mg/kg)对此无作用。根据上述结果得出的结论是 ,AGM对后肢、肾脏和肠系膜血管床的血管紧张性具有不同的作用。

In 66 anaesthetized rats, the effects of local injection of agmatine on femoral, renal, and mesenteric vascular beds were investigated respectively by constant flow perfusion method. The results are as follows. (1) Agmatine (0 1, 0 5, 1 mg/kg) increased the perfusion pressure (PP) of femoral vascular bed in a dose-dependent manner. The effect of agmatine (1 mg/kg) was completely blocked by pretreatment with idazoxan (0 5 mg/kg), an antagonist for imidazoline receptors (IR) and α 2-adrenergic receptors (α 2-AR), and yohimbine (1 mg/kg), a selective α 2-AR antagonist. (2) Agmatine also increased the PP of renal vascular bed in a dose-dependent manner, and agmatine at high dose (1 mg/kg) caused a biphasic increase of PP in renal vascular bed. Idazoxan blocked these effects completely, while yohimbine led the agmatine-induced effect to a decrease in the PP of renal vascular bed. (3) Agmatine decreased the PP of mesenteric vascular bed in a dose-dependent manner, an effect which was completely blocked by idazoxan, but unaffected by yohimbine. From the results obtained, it is concluded that agmatine differentially affects the vascular tone in the femoral, renal, and mesenteric vascular beds.