Ontogeny of imidazoline binding sites in the human placenta

Krisztina Bagaméry, László Kovács, Sándor Viski, T. Nyári, G. Falkay

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

Introduction. Non-adrenergic imidazoline binding sites (IBS) were described as pharmacologically distinct from α2-adrenergic receptors. Recently it was shown that the human placenta is the richest source of IBS, however, no function has been assigned to this new putative receptor. As concerns the presence of α2-adrenoceptors in the human placenta, it was reported that no α2-receptors were detected in human placental membranes with the radiolabelled α2-adrenoceptor antagonist [3H]rauwolscine or the α2-adrenoceptor agonist [3H]clonidine. This scientific contradiction has been solved when the authors have recently demonstrated that IBS and α2-adrenoceptors coexist in human term placental membranes. Study objective. Scientific literature does not provide any information regarding the ontogeny of IBS. The present study intended to determine the density of IBS and α2-adrenoceptors in correlation with gestational age. Materials and methods. Human first and second trimester placentas (6-10 and 14-18 weeks of gestation, respectively) were obtained immediately following the interruption of gestation, third trimester placentas (38-40 weeks) were obtained after normal vaginal delivery. Human placental membrane fractions were prepared and radioligand binding assays were performed in duplicate, using [3H]RX 821002 and [3H]RX 781094 (idazoxan) as radioligands. Results. According to the results of the binding assays, the concentration of α2-adrenoceptors decreased with the advancing gestational age. In contrast with this pattern, the density of IBS significantly increased. Conclusion. Our present results demonstrated that the density of IBS shows a significantly increasing tendency throughout gestation. The unique position of the placenta between maternal and fetal circulations determines its function as a mediator in transport mechanisms. The increasing expression of IBS in the growing placenta might suggest a role for these sites in the mediation of the transport of nutrients, ions, etc.

Original languageEnglish
Pages (from-to)89-92
Number of pages4
JournalActa Obstetricia et Gynecologica Scandinavica
Volume78
Issue number2
Publication statusPublished - 1999

Fingerprint

Imidazolines
Placenta
Adrenergic Receptors
Binding Sites
Idazoxan
Pregnancy
Gestational Age
Membranes
Literature
Radioligand Assay
Yohimbine
Ion Transport
Third Pregnancy Trimester
Clonidine
Second Pregnancy Trimester
First Pregnancy Trimester
Mothers
Food

Keywords

  • Imidazoline binding site
  • Ontogeny
  • Placenta
  • Radioligand binding techniques

ASJC Scopus subject areas

  • Obstetrics and Gynaecology

Cite this

Ontogeny of imidazoline binding sites in the human placenta. / Bagaméry, Krisztina; Kovács, László; Viski, Sándor; Nyári, T.; Falkay, G.

In: Acta Obstetricia et Gynecologica Scandinavica, Vol. 78, No. 2, 1999, p. 89-92.

Research output: Contribution to journalArticle

Bagaméry, Krisztina ; Kovács, László ; Viski, Sándor ; Nyári, T. ; Falkay, G. / Ontogeny of imidazoline binding sites in the human placenta. In: Acta Obstetricia et Gynecologica Scandinavica. 1999 ; Vol. 78, No. 2. pp. 89-92.
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