[Maternal and fetal hemodynamics under simultaneous beta stimulation and beta1 blockade in a tocolysis model. Considerations on status of the neonatal beta receptor and transplacental passage of metoprolol].
This report summarizes the clinical experiences in the treatment of preterm labor using the combination of hexoprenaline and the beta 1-antagonist metoprolol. We found a dose dependency in the antagonism of positive inotropic effects primarily induced by the beta-stimulator hexoprenaline. To verify the pharmacological properties of metoprolol in transplacental passage we evaluated the plasma concentration of metoprolol in umbilical cord blood. There is quite a low concentration of the beta-blocker nearly 24 h after the last course of administration. The beta 2-receptor density--determined by (+/-)-125-iodocyanopindolol (ICYP) binding--and beta 2-receptor responsiveness--assessed by cyclic AMP response to isoprenaline stimulation--in lymphocytes derived from neonatal blood were also investigated. These results were compared with identical investigations in adult lymphocytes. The results indicate that in neonates beta 2-receptor density and responsiveness is significantly diminished in comparison to the adult controls. The present investigations induce a new concept for the estimation of concomitant fetal cardiovascular reactions under maternal beta-blockade.
D000318:Adrenergic beta-Agonists / Q000494:pharmacology*; D000319:Adrenergic beta-Antagonists / Q000494:pharmacology*; D000328:Adult; D000242:Cyclic AMP / Q000378:metabolism; D005260:Female; D005312:Fetal Blood / Q000378:metabolism; D005333:Fetus / Q000502:physiology; D006439:Hemodynamics / Q000187:drug effects*; D006594:Hexoprenaline / Q000378:metabolism / Q000494:pharmacology; D006801:Humans; D007231:Infant, Newborn; D008431:Maternal-Fetal Exchange; D008790:Metoprolol / Q000378:metabolism / Q000494:pharmacology; D007752:Obstetric Labor, Premature / Q000517:prevention & control*; D010920:Placenta / Q000378:metabolism; D011247:Pregnancy; D011943:Receptors, Adrenergic, beta / Q000378:metabolism*; D013997:Time Factors
D000318:Adrenergic beta-Agonists; D000319:Adrenergic beta-Antagonists; D011943:Receptors, Adrenergic, beta; D000242:Cyclic AMP; D006594:Hexoprenaline; D008790:Metoprolol
Maternale und fetale Hämodynamik unter gleichzeitiger beta-Stimulation und beta1-Blockade am Tokolysemodell. Berücksichtigung des neonatalen beta-Rezeptorenstatus und der transplazentaren Metoprolol-Passage).