Abstract
David, Greta
Research Assistant, Cardiovascular Neuroscience, Department of Medicine, Flinders University of South Australia
Master of Biotechnology by Research completed 2009, Llewellyn-Smith Laboratory, Flinders University of South Australia
Pregnancy induced changes to the nerve supply in the rat uterus
In most pregnant women, blood vessels dilate, contributing to low blood pressure and an increase in blood flow, particularly those supplying the uterus. However, women with pre-eclampsia have high blood pressure combined with a reduced blood flow to the placenta and sometimes other maternal organs. Since nerves control blood vessel diameter, changes in the nerve supply to the uterus may be critical for normal vascular adaptations to pregnancy. As a first step towards identifying differences in the nerve supply to blood vessels in pre-eclamptic pregnancies, we defined how uterine nerves change during normal pregnancy by comparing virgin and near-term pregnant rats.
We studied sympathetic and parasympathetic nerves that increase or decrease in blood vessel diameter and sensory nerves that carry information from the uterus to the central nervous system. Our results show that the non-pregnant rat uterus contains high densities of sympathetic and parasympathetic and sensory nerves. The blood vessels, in particular, received a large supply of nerves. In the pregnant rats, sympathetic and parasympathetic and sensory nerves almost completely disappeared. Rare nerves occurred around a few blood vessels but nerve were absent around the vast majority of blood vessels.
This dramatic reduction in the nerve supply to the uterus is probably important in allowing increased blood flow to the uterus that is critical for maintaining a pregnancy. Understanding the normal changes in uterine innervation that occur during pregnancy and the factors causing these changes will be the foundation for future studies on the cause and treatment of pre-eclampsia.