[Effect of serotonin on uteroplacentofetal circulatory system in pregnant rabbit].
The effects of serotonin (5-hydroxytryptamine) on the uteroplacentofetal circulatory system were studied in pregnant rabbits. Serotonin infusion (50 micrograms/kg) induced transient, but significant fetal bradycardia (deceleration), without any significant changes in maternal blood pressure, heart rates, pO2, pCO2 and uterine activities. Pretreatment with methysergide, a serotonin antagonist, with a dose of 2.5 mg/kg blocked the inhibitory effect of serotonin on fetal heart rate. However, methysergide itself produced the uterine contraction associated with mild fetal bradycardia. Direct injection of serotonin (1,000 micrograms/kg) into fetuses did not produce any changes in fetal heart rates. These data indicated that serotonin would influence the uteroplacental vasculature, which in turn induced fetal bradycardia.
D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D005260:Female; D005316:Fetal Distress / Q000209:etiology; D005318:Fetal Heart / Q000502:physiology; D006339:Heart Rate / Q000187:drug effects; D006439:Hemodynamics / Q000187:drug effects; D008431:Maternal-Fetal Exchange / Q000187:drug effects; D008784:Methysergide / Q000494:pharmacology; D011225:Pre-Eclampsia / Q000209:etiology; D011247:Pregnancy; D011270:Pregnancy, Animal; D011817:Rabbits; D012701:Serotonin / Q000494:pharmacology / Q000502:physiology*
D012701:Serotonin; D008784:Methysergide