Increased alpha-1 Adrenoceptor Expression in Pregnant Rats with Subrenal Aortic Coarctation

Abstract

The progression of pregnancy is associated with attenuation in vasopressor response to adrenergic agonists. In pregnancy-induced hypertension this attenuation is reverted. It is not known if this reversion involves alpha-1 adrenoceptor expression. Objective. In this work we propose that in pregnant rats with subrenal aortic coarctation there are changes in the expression of alpha-1 adrenergic receptors in the thoracic and abdominal aorta during pregnancy. Methods. We used non-pregnant, normal pregnant and pregnant with subrenal aortic coarctation female Wistar rats. Pregnancy-induced hypertension indicators, systolic blood pressure, 24 hours proteinuria, pup weight and maternal weight were measured. Dose response curves to phenylephrine were carried out to determine vascular reactivity along pregnancy. Alpha 1-adrenoceptors were detected from thoracic and abdominal aorta using immunoblot. Results. Results show significant increases in arterial pressure and proteinuria in pregnant rats with SRAC at the end of the third week. Pregnancy reduces alpha_{-1-A, -B} and _-D adrenoceptor expression and this event is reverted by subrenal aortic coarctation. This phenomenon is more apparent in the abdominal segment of the aorta. Conclusions. These findings suggest that subrenal aortic coarctation is a good animal model of pregnancy-induced hypertension and that α₁-adrenoceptors participate in its physiopathology increasing their expression in a segment-dependent manner.

Keywords:

• Pregnancy
• Preeclampsia
• Adrenoceptors
• Hypertension
• Rat
• Animal models

ACKNOWLEDGMENTS

This work was supported by grant 46217 from Consejo Nacional de Ciencia y Tecnología (CONACYT) and grants 20050214 and 20060047 from Secretaría de Investigación y Posgrado del Instituto Politécnico Nacional (SIP-IPN).