Massicotte G, St-Louis J, Parent A, Schiffrin E L
Experimental Hypertension Laboratory, Clinical Research Institute of Montréal, Qué., Canada.
Can J Physiol Pharmacol. 1987 Dec;65(12):2466-71. doi: 10.1139/y87-391.
We have investigated the in vitro vascular responses to vasoconstrictor agents in pregnant normotensive (Sprague-Dawley (SDR) and Wistar-Kyoto (WKR] and spontaneously hypertensive rats (SHR) to measure the sensitivity and contractility of blood vessels of pregnant rats. In the perfused mesenteric vascular bed from rats on the 21st day of gestation, the concentration-response curves for the increase in perfusion pressure by arginine8-vasopressin and norepinephrine were displaced to the right by comparison to nonpregnant female rats when all strains of rats were considered together. The increase in EC50 to both agents in pregnant rats was from 1.3- to 2.7-fold in the mesenteric bed; SDR showed the highest increase in EC50, followed by SHR and WKR. No consistent effect was observed on the maximum response. Similar results were obtained in isolated portal veins for angiotensin II and norepinephrine, except that the increase in EC50 in pregnant rats was smaller in magnitude (from 1.0 to 1.7) and followed the same interstrain pattern. These data show that the decreased responsiveness to vasoconstrictor agents in pregnant rats observed in vitro is similar in normotensive and hypertensive rats and suggest that the factor(s) responsible for this effect is a phenomenon affecting vascular smooth muscle in both arteries and veins.
我们研究了妊娠正常血压大鼠（斯普拉格-道利大鼠（SDR）和Wistar-Kyoto大鼠（WKR））以及自发性高血压大鼠（SHR）的血管对血管收缩剂的体外反应，以测量妊娠大鼠血管的敏感性和收缩性。在妊娠第21天大鼠的灌注肠系膜血管床中，当将所有品系的大鼠综合考虑时，与未妊娠的雌性大鼠相比，精氨酸8-血管加压素和去甲肾上腺素引起的灌注压力升高的浓度-反应曲线向右移位。妊娠大鼠对这两种药物的半数有效浓度（EC50）增加，在肠系膜床中为1.3至2.7倍；SDR的EC50增加最多，其次是SHR和WKR。未观察到对最大反应有一致的影响。在分离的门静脉中，血管紧张素II和去甲肾上腺素也得到了类似的结果，只是妊娠大鼠的EC50增加幅度较小（从1.0到1.7），且遵循相同的品系间模式。这些数据表明，在体外观察到的妊娠大鼠对血管收缩剂的反应性降低在正常血压和高血压大鼠中相似，提示导致这种效应的因素是一种影响动脉和静脉血管平滑肌的现象。
