title: Action of alpha-methyldopa on human umbilical circulation in vitro.
abstract: To determine the possible effects of alpha-methyldopa on the motility of human umbilical artery, a total of 53 arterial segments were perfused with different concentrations of the drug as follows: 38 segments with 125, 250 and 500 ng/ml of the drug, 9 segments with 500 ng/ml alpha-methyldopa in combination with 10(-7) M yohimbine, and 6 segments with 10(-7) M yohimbine alone. alpha-Methyldopa had a vasoconstrictor effect at all doses employed, with a clear dose-effect correlation (p less than 0.01). The vasoconstrictor effect of 500 ng/ml alpha-methyldopa was fully inhibited in the presence of 10(-7) M yohimbine. These results suggest that alpha 2-adrenergic receptors are present in the umbilical circulation and that alpha-methyldopa may play a role in the control of this circulation.
authors.affiliation: Department of Gynecology and Obstetrics, Faculty of Medicine of Ribeirão Preto, University of São Paulo, Brazil.
authors.forename: L C
authors.initials: LC
authors.lastname: França
authors.forename: S P
authors.initials: SP
authors.lastname: da Cunha
authors.forename: R S
authors.initials: RS
authors.lastname: Meirelles
authors.forename: C C
authors.initials: CC
authors.lastname: Dias
authors.forename: A
authors.initials: A
authors.lastname: Yassin
mesh_terms: D001775:Blood Circulation / Q000187:drug effects*; D004353:Drug Evaluation, Preclinical; D004359:Drug Therapy, Combination; D006439:Hemodynamics / Q000187:drug effects*; D006801:Humans; D007231:Infant, Newborn; D008750:Methyldopa / Q000008:administration & dosage / Q000494:pharmacology*; D014469:Umbilical Arteries / Q000187:drug effects*; D015016:Yohimbine / Q000008:administration & dosage / Q000494:pharmacology
chemical_list: D015016:Yohimbine; D008750:Methyldopa