Aloamaka C P, Ezimokhai M, Osman N A, Morrison J
Department of Obstetrics and Gynaecology, Faculty of Medicine and Health Sciences, United Arab Emirates University, Al Ain.
Exp Physiol. 1995 Jan;80(1):79-87. doi: 10.1113/expphysiol.1995.sp003836.
The study examined the effect of salt-induced hypertension on vascular relaxation in response to magnesium sulphate during pregnancy. Pregnant Wistar rats were fed for 6 weeks on a diet containing 0.3% (control) and 8.0% (test) sodium chloride. Aortic rings were then removed and contracted with 10(-7) M phenylephrine or 30 mM potassium chloride. High salt intake increased the systolic blood pressure of the rats and increased the relaxation of phenylephrine-contracted intact rings in response to magnesium sulphate. Neither endothelium removal nor treatment with 10(-6) M indomethacin altered the relaxation of rings from the two groups of rats, when contracted with potassium chloride. Both processes significantly (P < 0.05) and similarly decreased the sensitivity and the maximal relaxation of rings from test rats contracted with phenylephrine; the relaxation of rings from the control rats was not altered. The results suggest that the relaxation of isolated rat aortic rings contracted with phenylephrine is enhanced in pregnant rats with salt-induced hypertension. The mechanism involved in this enhancement is dependent on the vascular endothelium and receptor activation, and is indomethacin sensitive.
该研究考察了孕期盐诱导高血压对硫酸镁所致血管舒张的影响。将妊娠的Wistar大鼠分别喂食含0.3%（对照）和8.0%（试验）氯化钠的饲料6周。然后取出主动脉环，用10(-7)M去氧肾上腺素或30mM氯化钾使其收缩。高盐摄入增加了大鼠的收缩压，并增强了去氧肾上腺素预收缩的完整主动脉环对硫酸镁的舒张反应。当用氯化钾使两组大鼠的主动脉环收缩时，去除血管内皮或用10(-6)M吲哚美辛处理均未改变主动脉环的舒张情况。这两个过程均显著（P<0.05）且相似地降低了试验组大鼠去氧肾上腺素收缩的主动脉环的敏感性和最大舒张程度；对照组大鼠主动脉环的舒张未受影响。结果表明，在盐诱导高血压的妊娠大鼠中，与去氧肾上腺素收缩的离体大鼠主动脉环的舒张增强。这种增强所涉及的机制依赖于血管内皮和受体激活，且对吲哚美辛敏感。
