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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。
Sixty-six anesthetized rats were treated with constant-flow perfusion of hindlimb, kidneys and mesenteric artery respectively. The vascular effects of direct injection of agmatine (AGM) into the perfusion loop were observed. The perfusion pressure Increase or decrease reflects the contraction and relaxation of blood vessels. The results obtained were as follows: (1) AGM (0, 105, 1 mg / kg) at various doses increased the perfusion pressure of the hindlimb vessels in a dose-dependent manner when injected into the femoral perfusion loop. Both pre-injection of imidazoline receptor (IR) and α2 adrenergic receptor (α2 AR) idazoxan (0 5 mg / kg) or injection of α2 adrenergic receptor blocker yohimbine (1 mg / kg) can completely inhibit the effect of AGM. (2) The direct injection of AGM into the renal vascular perfusion loop can also increase the perfusion pressure of renal vessels in a dose-dependent manner. In particular, high dose AGM (1 mg / mg) This effect can be completely blocked by idazoxan. In the pre-application yohimbine, then injected AGM caused by renal vascular perfusion pressure drop. (3) Injection of AGM in the mesenteric vascular perfusion loop dose-dependently reduced the perfusion pressure. This effect was completely blocked by idazoxan (0 5 mg / kg), whereas yohimbine (1 mg / kg) had no effect on this effect. Based on the above results, it is concluded that AGM has different effects on the vascular tone of hindlimb, kidney and mesenteric vascular beds.