The roles of the alpha1-adrenergic receptor subtypes in rat embryonic implantation.

OBJECTIVE

To focus on the possible roles of alpha(1)-adrenergic receptors (alpha(1)-ARs) in rat embryonic implantation.

DESIGN

Laboratory study.

SETTING

Animal and pharmacology laboratory at Department of Pharmacodynamics and Biopharmacy, University of Szeged, Hungary.

ANIMAL(S): Pregnant and nonpregnant Sprague-Dawley rats.

INTERVENTION(S): Uterus tissues were collected during the peri-implantation period.

MAIN OUTCOME MEASURE(S): 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.

RESULT(S): 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.

CONCLUSION(S): We assume that the alpha(1A)-AR predominance plays a crucial role in embryonic implantation in the rat.