Lantelme P, Lo M, Sassard J
Department of Physiology and Clinical Pharmacology, URA CNRS 1483, Faculty of Pharmacy, Lyon, France.
J Hypertens. 1994 Jul;12(7):791-5.
To investigate the link between cardiac hypertrophy, elevated blood pressure level and baroreflex impairment, we assessed cardiac baroreflex function in a hypertensive model almost devoid of cardiac hypertrophy, obtained by nitric oxide synthesis inhibition.
Thirteen adult male Wistar rats were treated orally with NG-nitro-L-arginine methyl ester (L-NAME, 50 mg/kg per 24 h) for 4 weeks. Fifteen control rats received tap water. At the end of the treatment aortic blood pressure was recorded continuously and the baroreceptor-heart rate curve was assessed by bolus injections of phenylephrine and sodium nitroprusside (10 different doses of each).
Mean blood pressure was higher in L-NAME rats than in control rats, whereas body weight was similar. Total heart weight and left ventricular weight did not differ between the groups. Cardiac baroreflex was reset in hypertensive rats, as indicated by a rightwards shift of the mean blood pressure-heart rate curve. Its gain was decreased significantly in L-NAME rats, whereas the heart rate range was not different between the two groups.
L-NAME hypertensive rats exhibit an original impairment of cardiac baroreflex, characterized by a range-independent decreased gain which is not due to cardiac hypertrophy.
为研究心脏肥大、血压升高与压力反射受损之间的联系，我们在通过一氧化氮合成抑制构建的几乎不存在心脏肥大的高血压模型中评估了心脏压力反射功能。
13只成年雄性Wistar大鼠口服Nω-硝基-L-精氨酸甲酯（L-NAME，每24小时50毫克/千克），持续4周。15只对照大鼠饮用自来水。治疗结束时，连续记录主动脉血压，并通过推注去氧肾上腺素和硝普钠（每种各10种不同剂量）评估压力感受器-心率曲线。
L-NAME大鼠的平均血压高于对照大鼠，而体重相似。两组之间的全心重量和左心室重量没有差异。高血压大鼠的心脏压力反射发生重调，表现为平均血压-心率曲线向右移位。L-NAME大鼠的压力反射增益显著降低，而两组之间的心率范围没有差异。
L-NAME高血压大鼠表现出一种原发性心脏压力反射受损，其特征是与范围无关的增益降低，且这并非由心脏肥大所致。
