Sawada Y, Sakamaki T, Nakamura T, Sato K, Ono Z, Murata K
Second Department of Internal Medicine, Gunma University School of Medicine, Maebashi, Japan.
J Hypertens. 1994 Jul;12(7):745-50.
Although a decreased responsiveness to acetylcholine, an endothelium-dependent vasodilator, has been reported in arteries isolated from spontaneously hypertensive rats (SHR), the precise role of nitric oxide (NO) in the in vivo regulation of blood pressure is not clear. We investigated the effects of acetylcholine and of NG-nitro-L-arginine methyl ester (L-NAME), an NO synthase inhibitor, on mean arterial pressure and the production of NO metabolites (nitrate and nitrite) in SHR and in Wistar-Kyoto (WKY) rats, their normotensive control strain.
We determined serum levels of nitrate and nitrite before and after the intravenous injection of 40 micrograms/kg acetylcholine following the administration of L-NAME (30 mg/kg) or its vehicle in adult SHR and WKY rats.
Acetylcholine administration significantly reduced mean arterial pressure in both SHR and WKY rats, accompanied by a significant rise in serum nitrate and nitrite. Administration of L-NAME significantly increased the mean arterial pressure in SHR and in WKY rats. L-NAME inhibited the hypotension induced by acetylcholine and the rise in serum nitrate and nitrite both in SHR and in WKY rats.
The release of NO stimulated by acetylcholine was unaltered in SHR, supporting previous in vitro results.
尽管有报道称，从自发性高血压大鼠（SHR）分离出的动脉对内皮依赖性血管舒张剂乙酰胆碱的反应性降低，但一氧化氮（NO）在体内血压调节中的精确作用尚不清楚。我们研究了乙酰胆碱和NO合酶抑制剂NG-硝基-L-精氨酸甲酯（L-NAME）对SHR和Wistar-Kyoto（WKY）大鼠（其正常血压对照品系）平均动脉压及NO代谢产物（硝酸盐和亚硝酸盐）生成的影响。
我们在成年SHR和WKY大鼠中，给予L-NAME（30mg/kg）或其溶媒后，静脉注射40μg/kg乙酰胆碱前后，测定血清硝酸盐和亚硝酸盐水平。
给予乙酰胆碱后，SHR和WKY大鼠的平均动脉压均显著降低，同时血清硝酸盐和亚硝酸盐显著升高。给予L-NAME后，SHR和WKY大鼠的平均动脉压均显著升高。L-NAME抑制了乙酰胆碱诱导的SHR和WKY大鼠的低血压以及血清硝酸盐和亚硝酸盐的升高。
乙酰胆碱刺激的NO释放在SHR中未改变，支持先前的体外研究结果。
