Zhang L, Dyer D C, Hembrough F B, Isla M
Department of Veterinary Physiology and Pharmacology, College of Veterinary Medicine, Iowa State University, Ames 50011.
Eur J Pharmacol. 1991 Jun 25;199(2):179-84. doi: 10.1016/0014-2999(91)90455-y.
Pregnant sheep and their fetuses were instrumented between 110 to 120 days of gestation (term, 145 days) for monitoring maternal and fetal arterial blood pressure, heart rate and blood flow in the maternal uterine and fetal intra-abdominal umbilical arteries. The administration of 2,5-dimethoxy-4-methylamphetamine (DOM, a 5-HT2 agonist) i.v. to the ewe in doses ranging from 1 to 20 micrograms/kg of ewe body weight produced dose-dependent decreases in the blood flow of the uterine and umbilical arteries. This was accompanied by an increase in the arterial blood pressure of the mother and fetus and a decrease in the fetal heart rate. DOM significantly increased the vascular resistance to blood flow in the uterine and umbilical arteries. The maximal increase in the vascular resistance of the uterine and umbilical arteries was 19.6- and 2.6-fold, respectively. Ketanserin, a 5-HT2 antagonist (1 mg/kg), administrated 30 min prior to DOM significantly inhibited the reduction in blood flow in the uterine and umbilical arteries to DOM and blocked the increased vascular resistance in these vessels. The inhibitory effects of ketanserin on the responses to DOM in the uterine and umbilical arteries were surmountable. Our results indicate that DOM is a potent constrictor of the uterine and umbilical vasculature which may lead to fetal distress as evidenced by a decrease in fetal heart rate and arterial blood PO2. 5-HT2 receptor stimulation by DOM may be involved in these effects since they were blocked by ketanserin.
在妊娠110至120天（足月为145天）期间，对怀孕母羊及其胎儿进行仪器植入，以监测母羊和胎儿的动脉血压、心率以及母羊子宫和胎儿腹内脐动脉的血流情况。静脉注射2,5 - 二甲氧基 - 4 - 甲基苯丙胺（DOM，一种5 - HT2激动剂），剂量范围为每千克母羊体重1至20微克，会使子宫和脐动脉的血流呈剂量依赖性减少。同时，母羊和胎儿的动脉血压升高，胎儿心率降低。DOM显著增加了子宫和脐动脉对血流的血管阻力。子宫和脐动脉血管阻力的最大增加分别为19.6倍和2.6倍。5 - HT2拮抗剂酮色林（1毫克/千克）在DOM给药前30分钟给予，可显著抑制子宫和脐动脉对DOM的血流减少，并阻断这些血管中增加的血管阻力。酮色林对子宫和脐动脉中DOM反应的抑制作用是可克服的。我们的结果表明，DOM是子宫和脐血管系统的强效收缩剂，可能导致胎儿窘迫，表现为胎儿心率和动脉血氧分压降低。DOM对5 - HT2受体的刺激可能参与了这些效应，因为它们被酮色林阻断。
