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 1h 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.