Effect of morphine on the reduced uteroplacental perfusion model of pre-eclampsia in rats

Abstract Objectives To investigate the effect of morphine on the reduced uteroplacental perfusion pressure (RUPP) model of pre-eclampsia in rats. Study design The abdominal aorta and ovarian arteries of pregnant rats were isolated and clipped on gestational day 14. The chronic morphine treatment group received naltrexone 5 mg/kg 1 h before each dose of morphine. L-nitromonomethylarginine 2 mg/kg was administrated in the same pattern. The control group received saline 10 ml/kg. Systolic blood pressure, blood urea nitrogen (BUN), creatinine, creatinine clearance, urinary protein, urinary nitrite/nitrate excretion, and fetal and placental weights were determined. Results Morphine significantly reduced systolic blood pressure, fetal and placental weights, plasma BUN, creatinine and urinary protein in RUPP rats compared with control rats. Urinary nitrite/nitrate excretion and creatinine clearance were significantly increased in response to morphine treatment. Conclusion Morphine reduced blood pressure and improved renal function in the RUPP model of pre-eclampsia, but this was associated with reduced fetal and placental weights.