The rabbit: a suitable model for investigation of vascular responsiveness during pregnancy

The decreased vascular response to angiotensin II that characterizes normal pregnancy is lost in pregnancy induced hypertension and associated with an increase in response to norepinephrine. These alterations in vascular responsiveness have not been thoroughly investigated and are poorly understood. Suitable models manifesting physiologic conditions known to exist in human pregnancy have not been satisfactorily demonstrated. We investigated the chronically catheterized and unmedicated rabbit for similarities of four conditions known to occur during human pregnancy. We compared mean arterial pressure and vascular response to angiotensin II and to norepinephrine in 19 non-pregnant and 16 pregnant animals. Plasma levels of angiotensin II, norepinephrine, epinephrine, and dopamine levels were measured and compared. We found striking similarities for conditions investigated in our rabbit model when compared with data reported in the literature for human pregnancy. We conclude the rabbit is a suitable model for investigating alterations of vascular response during pregnancy.