Harper M A, Rose J C
Am J Obstet Gynecol. 1987 Aug;157(2):448-53. doi: 10.1016/s0002-9378(87)80192-8.
Other investigators have reported that intravenous infusion of synthetic arginine vasopressin into fetal lambs increases mean arterial pressure and decreases heart rate. To determine if the bradycardia produced by arginine vasopressin is a reflex response to the increase in blood pressure, we studied the effect of arginine vasopressin infusion on heart rate with and without blocking the increase in blood pressure. We performed 34 experiments in 12 chronically cannulated fetal lambs between 103 and 137 days' gestation. All animals had normal blood gas and pH values. Infusion of arginine vasopressin increased mean arterial pressure 10.1 +/- 1.1 mm Hg and decreased heart rate 50 +/- 8 bpm. Fetal heart rate decreased similarly when arginine vasopressin was infused and the hypertensive response was blocked with nitroprusside or a selective vasoconstrictor antagonist. [1-(beta-mercapto-beta,beta-cyclopentamethylene propionic acid) 2-(O-methyl)tyrosine] arginine vasopressin. For comparison we also studied five adult nonpregnant ewes. Bradycardia was observed in the adults after infusion of arginine vasopressin alone and when the hypertensive response was blocked with the vasoconstrictor antagonist. We conclude that arginine vasopressin infusion causes a fall in heart rate independent of any increase in blood pressure in both the fetal lamb and the adult sheep.
其他研究人员报告称，向胎羊静脉输注合成精氨酸加压素会使平均动脉压升高，心率降低。为了确定精氨酸加压素引起的心动过缓是否是对血压升高的反射性反应，我们研究了在不阻断和阻断血压升高的情况下，输注精氨酸加压素对心率的影响。我们对12只妊娠103至137天的慢性插管胎羊进行了34项实验。所有动物的血气和pH值均正常。输注精氨酸加压素使平均动脉压升高10.1±1.1毫米汞柱，心率降低50±8次/分钟。当输注精氨酸加压素并用硝普钠或选择性血管收缩剂拮抗剂阻断高血压反应时，胎心率也有类似降低。[1-(β-巯基-β,β-环戊亚甲基丙酸)2-(O-甲基)酪氨酸]精氨酸加压素。作为对照，我们还研究了5只成年未孕母羊。单独输注精氨酸加压素以及用血管收缩剂拮抗剂阻断高血压反应后，成年羊均出现心动过缓。我们得出结论，输注精氨酸加压素会导致胎羊和成年羊的心率下降，且与血压升高无关。
