The effects of estrogen on the α2-adrenergic receptor subtypes in rat uterine function in late pregnancy in vitroReportar como inadecuado




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Croatian medical journal, Vol.57 No.2 April 2016. -

Aim To assess the effect of 17β-estradiol pretreatment on

the function and expression of α2- adrenergic receptors

ARs subtypes in late pregnancy in rats.

Methods Sprague-Dawley rats n = 37 were treated with

17β-estradiol for 4 days starting from the 18th day of pregnancy.

The myometrial expression of the α2-AR subtypes

was determined by real time polymerase chain reaction

and Western blot analysis. In vitro contractions were stimulated

with -noradrenaline, and its effect was modified

with the selective antagonists BRL 44408 α2A, ARC 239

α2B-C, and spiroxatrine α2A. The cyclic adenosine monophosphate

cAMP accumulation was also measured. The

activated G-protein level was investigated by guanosine

5’-O-gamma-thiotriphosphate GTPγS binding assay.

Results 17β-estradiol pretreatment decreased the contractile

effect of -noradrenaline via the α2-ARs, and abolished

the contractile effect via the α2B-ARs. All the α2-AR

subtypes’ mRNA was significantly decreased. 17β-estradiol

pretreatment significantly increased the myometrial cAMP

level in the presence of BRL 44408 P = 0.001, ARC 239

P = 0.007, and spiroxatrine P = 0.045, but did not modify

it in the presence of spiroxatrine + BRL 44408 combination

P = 0.073. It also inhibited the G-protein-activating effect

of -noradrenaline by 25% in the presence of BRL 44408 +

spiroxatrine combination.

Conclusions The expression of the α2-AR subtypes is sensitive

to 17β-estradiol, which decreases the contractile response

of -noradrenaline via the α2B-AR subtype, and

might cause changes in G-protein signaling pathway. Estrogen

dysregulation may be responsible for preterm labor

or uterine inertia via the α2-ARs



Autor: Judit Hajagos-Tóth - ; Department of Pharmacodynamics andBiopharmacy, Faculty of Pharmacy,University of Szeged, Szeged,Hungary J

Fuente: http://hrcak.srce.hr/



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