This Article Full Text Full Text (PDF) Submit a related Letter to the Editor Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Copyright Permission Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Chanrachakul, B. Articles by Khan, R. N. Search for Related Content PubMed PubMed Citation Articles by Chanrachakul, B. Articles by Khan, R. N.

Reduced Expression of Immunoreactive ß₂-Adrenergic Receptor Protein in Human Myometrium with Labor

Academic Division of Obstetrics and Gynecology, Derby City General Hospital, University of Nottingham (B.C., B.M.-B., A.T., R.N.K.), Derby, United Kingdom DE22 3NE; Academic Division of Obstetrics and Gynecology, Queen’s Medical Center, University of Nottingham (G.R., F.B.-P.), Nottingham, United Kingdom NG7 2UH; and Academic Division of Obstetrics and Gynecology, St. George’s Hospital Medical School, University of London (S.A.), London, United Kingdom SW17 0RE

Address all correspondence and requests for reprints to: Dr. Raheela N. Khan, Academic Division of Obstetrics and Gynecology, University of Nottingham, Clinical Sciences Building, Derby City General Hospital, Uttoxeter New Road, Derby, United Kingdom DE22 3NE. E-mail: raheela.khan{at}nottingham.ac.uk.

A considerable body of evidence exists suggesting that the ß₂-adrenergic receptor (ß₂-AR) mediates uterine relaxation. However, little information exists on the localization, distribution, or expression of ß₂-ARs in the human myometrium during the nonpregnant to labor transition. We have used immunochemical methods to investigate ß₂-AR localization and expression in the nonpregnant, term pregnant, and term parturient uterus. Myometrial biopsies were obtained from 1) nonpregnant, menstruating women undergoing hysterectomy; 2) singleton term pregnant women undergoing elective cesarean section before the onset of labor; or 3) singleton term pregnant women undergoing emergency cesarean section after spontaneous labor. Tissues were processed for immunohistochemistry, immunofluorescence, and Western blotting and a primary polyclonal antibody specific to the human ß₂-AR to identify immunoreactive myometrial ß₂-AR. Protein levels were subsequently quantified by densitometry relative to rat brain protein. Immunohistochemistry and immunofluorescence demonstrated the presence of ß₂-AR predominantly at the plasma membrane and also in the cytosol of myometrial cells. A 2-fold decrease in protein levels of the ß₂-AR was apparent in the myometrium of labor compared with that of nonpregnant and pregnant nonlaboring women (P < 0.05). These results demonstrate that down-regulation of ß₂-AR protein with labor may constitute a contributory mechanism by which uterine quiescence is removed at term.

This work was supported by the Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Thailand (to B.C.).

Abbreviations: ß₂-AR, ß₂-Adrenergic receptor; HBSS, Hanks’ balanced salt solution.

This article has been cited by other articles:

				T. Croci, R. Cecchi, P. Marini, C. Rouget, N. Viviani, G. Germain, F. Guagnini, Y. Fradin, L. Descamps, M. Pascal, et al. In Vitro and in Vivo Pharmacological Characterization of Ethyl-4-{trans-4-[((2S)-2-hydroxy-3-{4-hydroxy-3[(methylsulfonyl)amino]-phenoxy}propyl) Amino]cyclohexyl}benzoate Hydrochloride (SAR150640), a New Potent and Selective Human beta3-Adrenoceptor Agonist for the Treatment of Preterm Labor J. Pharmacol. Exp. Ther., June 1, 2007; 321(3): 1118 - 1126. [Abstract] [Full Text] [PDF]

				A. Shmygol, K. Noble, and S. Wray Depletion of membrane cholesterol eliminates the Ca2+-activated component of outward potassium current and decreases membrane capacitance in rat uterine myocytes J. Physiol., June 1, 2007; 581(2): 445 - 456. [Abstract] [Full Text] [PDF]

				C. Rouget, M. Bardou, M. Breuiller-Fouche, C. Loustalot, H. Qi, E. Naline, T. Croci, D. Cabrol, C. Advenier, and M. J. Leroy {beta}3-Adrenoceptor Is the Predominant {beta}-Adrenoceptor Subtype in Human Myometrium and Its Expression Is Up-Regulated in Pregnancy J. Clin. Endocrinol. Metab., March 1, 2005; 90(3): 1644 - 1650. [Abstract] [Full Text] [PDF]

				B. Chanrachakul, F. B. Pipkin, and R. N. Khan Contribution of coupling between human myometrial {beta}2-adrenoreceptor and the BKCa channel to uterine quiescence Am J Physiol Cell Physiol, December 1, 2004; 287(6): C1747 - C1752. [Abstract] [Full Text] [PDF]