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Role of adrenergic receptor subtypes in the control of human placental blood vessels
Author(s) -
Resch BÉla Endre,
Ducza Eszter,
GÁspÁr RÓbert,
Falkay George
Publication year - 2003
Publication title -
molecular reproduction and development
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.745
H-Index - 105
eISSN - 1098-2795
pISSN - 1040-452X
DOI - 10.1002/mrd.10337
Subject(s) - biology , receptor , placenta , adrenergic receptor , endocrinology , medicine , stimulation , messenger rna , vasoconstriction , adrenergic , blood vessel , pregnancy , fetus , gene , biochemistry , genetics
Statements of the Problem: The use of β2‐Adrenergic Receptor (AR) agonists and the potential use of α1‐AR blockers as tocolytics raise the question of how they influence placental circulation. The receptor profile was characterized via the amounts of the mRNA of α1‐AR subtypes and β2‐ARs. The mRNAs were detected by reverse transcription‐polymerase chain reaction. Electric field stimulation (EFS) was applied to test the pharmacological reactivity of the placental vessels. Expressions of β2‐ and all subtypes of α1‐AR mRNA were demonstrated in human placental vessels, and were significantly higher in the arteries. A significant difference was not found between the veins and the arteries as concerns the amount of α1D‐AR mRNA. There was a preponderance of α1A‐ and α1B‐AR mRNA as compared to α1D‐AR mRNA both in the arteries and in the veins. β2‐AR agonists and α1‐AR antagonists antagonized the EFS‐induced contractions of the placental arteries in a dose‐dependent manner. These effects were significantly less marked on veins at all applied doses. Urapidil antagonized the EFS‐induced contractions of both the placental arterial and vein rings in a dose‐dependent manner. The β2‐, α1A‐, and α1B‐AR are the important subtypes involved in the regulation of the contractility of the human term placental vessels. The possible increase in placental blood flow mediated by these ARs can even be beneficial during pregnancy. Accordingly, the use of β2‐AR agonists and the potential use of α1‐blockers as tocolytics seem safe on the basis of in vitro examinations as concerns the placental circulation. Mol. Reprod. Dev. 66: 166‐171, 2003. © 2003 Wiley‐Liss, Inc.