title: Increase of placental sensitivity to melatonin and the alteration to its local synthesis in hypertensive syndromes in pregnancy.
abstract: OBJECTIVE
  To evaluate the relation between hypertensive syndromes and melatonin, and its possible protective role against lesions due to hypertension.
  
  
  METHODS
  Placentas were classified into gestational hypertension (GH), chronic hypertension (CH), pre-eclampsia (PE) and pre-eclampsia superimposed on chronic hypertension, and morphologically examined by hematoxylin-eosin and periodic acid Schiff methods. Immunohistochemistry was performed to detect tryptophan hydroxylase (TH) and melatonin receptor 1A (MR-1A).
  
  
  RESULTS
  MR-1A expression was higher in all types of hypertensive syndromes in pregnancy (HSP), mainly in cases with GH, in Caesarean section delivery, preterm placentas and in the cases with alterations in the placental morphology, particularly those presenting inflammation. The expression of TH was higher in cases with CH when compared with the control. This expression was lower in primigestas, in the cases of inflammation and with PE.
  
  
  CONCLUSIONS
  HSP therapies should be considered and studied, especially in the cases of HSP associated with PE, in which the placenta is more sensitive as it has more receptors, but its synthesis ability is reduced. As for GH and CH, the possible benefits should be evaluated, since the local placental ability to produce melatonin still exists.
authors.affiliation: General Pathology Department, Triângulo Mineiro Federal University, Uberaba, Minas Gerais, Brazil.
authors.forename: Douglas de Resende
authors.initials: Dde R
authors.lastname: Yamamoto
authors.forename: Leandro de Resende
authors.initials: Lde R
authors.lastname: Yamamoto
authors.forename: Laura Penna
authors.initials: LP
authors.lastname: Rocha
authors.forename: Juliana Reis
authors.initials: JR
authors.lastname: Machado
authors.forename: Camila Souza de Oliveira
authors.initials: CS
authors.lastname: Guimarães
authors.forename: Marlene Antônia Dos
authors.initials: MA
authors.lastname: Reis
authors.forename: Rosana Rosa Miranda
authors.initials: RR
authors.lastname: Corrêa
mesh_terms: D005260:Female; D006801:Humans; D046110:Hypertension, Pregnancy-Induced / Q000201:enzymology*; D008550:Melatonin / Q000096:biosynthesis*; D010920:Placenta / Q000201:enzymology*; D011247:Pregnancy; D044122:Receptor, Melatonin, MT1 / Q000378:metabolism*; D012189:Retrospective Studies; D014365:Tryptophan Hydroxylase / Q000378:metabolism*
chemical_list: D044122:Receptor, Melatonin, MT1; D014365:Tryptophan Hydroxylase; D008550:Melatonin