Placental gene expression of calcitonin gene-related peptide and nitric oxide synthases in preeclampsia: effects of magnesium sulfate.

OBJECTIVE To determine placental gene expression of calcitonin gene-related peptide (CGRP), calcitonin receptor-like receptor (CRLR), receptor activity modifying protein 1 (RAMP1), and endothelial and inducible nitric oxide synthases (eNOS and iNOS) in mild preeclampsia, and to assess the effects of magnesium sulfate (MgSO4). METHODS Term placentas were obtained from 10 normotensive (NT group), 10 preeclamptic (PE) patients treated with 0.9% NaCl solution (PES group), and 8 PE women who received MgSO4 (PEMgSO4 group). The levels of mRNA were evaluated by real-time PCR. RESULTS Placental gene expression of CRLR, RAMP1 and iNOS were significantly higher (p < 0.001) in the PES group than in the NT group, without changes in CGRP. In addition, eNOS expression was 67% lower (p < 0.001) in the PES group. When compared with the PES group, the PEMgSO4 group showed significantly higher expression (p < 0.05) of CGRP, CRLR and eNOS, while iNOS was significantly lower (p < 0.05). CONCLUSION Placental gene expression of CRLR, RAMP1 and iNOS is higher in preeclampsia than in normal pregnancy, and MgSO4 treatment increased CGRP and CRLR and presented opposite effects upon eNOS and iNOS.