The roles of the α1-adrenergic receptor subtypes in rat embryonic implantation

Abstract

To focus on the possible roles of alpha(1)-adrenergic receptors (alpha(1)-ARs) in rat embryonic implantation. Laboratory study. Animal and pharmacology laboratory at Department of Pharmacodynamics and Biopharmacy, University of Szeged, Hungary. Pregnant and nonpregnant Sprague-Dawley rats. Uterus tissues were collected during the peri-implantation period. We used a reverse transcription-polymerase chain reaction (RT-PCR) and Western blotting to demonstrate the expressions of mRNAs and the protein expressions of the alpha(1)-AR subtypes in the early-pregnant uterus. Electric field stimulation was applied to test the pharmacologic reactivity of the alpha(1A)-AR, and the physiologic role of this receptor was tested in a knock-down transformed animal model using an antisense oligonucleotide that elicits sequence-selective inhibition of the alpha(1A)-AR gene expression. The presence of all alpha(1)-AR subtypes (alpha(1A), alpha(1B), and alpha(1D)) was proved, with a predominance of alpha(1A)-AR. The maximal expression of the alpha(1A)-AR was attained on the day of implantation. The selective alpha(1A) antagonist 5-methylurapidil inhibited the contraction in a dose-dependent manner. The number of implantation sites was decreased ( approximately 75%) in the alpha(1A)-AR knock-down transformed rats. We assume that the alpha(1A)-AR predominance plays a crucial role in embryonic implantation in the rat.