G protein-coupled estrogen receptor 1-mediated effects in the rat myometrium. Academic Article uri icon

start page

  • C1262

end page

  • C1269

abstract

  • G protein-coupled estrogen receptor 1 (GPER), also named GPR30, has been previously identified in the female reproductive system. In this study, GPER expression was found in the female rat myometrium by reverse transcriptase-polymerase chain reaction and immunocytochemistry. Using GPER-selective ligands, we assessed the effects of the GPER activation on resting membrane potential and cytosolic Ca(2+) concentration ([Ca(2+)](i)) in rat myometrial cells, as well as on contractility of rat uterine strips. G-1, a specific GPER agonist, induced a concentration-dependent depolarization and increase in [Ca(2+)](i) in myometrial cells. The depolarization was abolished in Na(+)-free saline. G-1-induced [Ca(2+)](i) increase was markedly decreased by nifedipine, a L-type Ca(2+) channel blocker, by Ca(2+)-free or Na(+)-free saline. Intracellular administration of G-1 produced a faster and transitory increase in [Ca(2+)](i), with a higher amplitude than that induced by extracellular application, supporting an intracellular localization of the functional GPER in myometrial cells. Depletion of internal Ca(2+) stores with thapsigargin produced a robust store-activated Ca(2+) entry; the Ca(2+) response to G-1 was similar to the constitutive Ca(2+) entry and did not seem to involve store-operated Ca(2+) entry. In rat uterine strips, administration of G-1 increased the frequency and amplitude of contractions and the area under the contractility curve. The effects of G-1 on membrane potential, [Ca(2+)](i), and uterine contractility were prevented by pretreatment with G-15, a GPER antagonist, further supporting the involvement of GPER in these responses. Taken together, our results indicate that GPER is expressed and functional in rat myometrium. GPER activation produces depolarization, elevates [Ca(2+)](i) and increases contractility in myometrial cells.

date/time value

  • 2011

Digital Object Identifier (DOI)

  • 10.1152/ajpcell.00501.2010

PubMed Identifier

  • 21865584

volume

  • 301

number

  • 5

keywords

  • Animals
  • Benzodioxoles
  • Calcium
  • Calcium Channel Blockers
  • Cyclopentanes
  • Enzyme Inhibitors
  • Female
  • Membrane Potentials
  • Myometrium
  • Nifedipine
  • Quinolines
  • Rats
  • Rats, Sprague-Dawley
  • Receptors, G-Protein-Coupled
  • Thapsigargin
  • Uterine Contraction