The influence of increased uterine resting tonus on renal sympathetic nerve activity in pregnant rabbit
Kitanaka, T.; Hidaka, A.
Nihon Sanka Fujinka Gakkai Zasshi 41(6): 639-646
1989
ISSN/ISBN: 0300-9165 PMID: 2768961 Document Number: 338487
We have shown that an increase in uterine resting tonus causes an increase in maternal blood pressure and a decrease in renal blood flow, and a neural factor may control this phenomenon through a Utero-Renal Reflex in pregnant rabbits. To explore this possible neural factor, we examined the changes in renal synmpathetic nerve activity (R-SNA) in late pregnant rabbits under urethane anesthesia. SNA was measured with a bipolar electrode and renal cortical blood flow (RBF) was measured by a thermocouple method. An increase in uterine resting tonus was made by inserting a small balloon into the uterine cavity on the ovarian or cervical side. An increase in resting tonus on the ovarian side caused an increase in materanl blood pressure, increases in R-SNA and renal vascular resistance (RVR), and a decrease in RBF. However, an increase in resting tonus on the cervical side resulted in an increase in maternal blood pressure, slight increases in R-SNA and RVR, and an increase in RBF. These data indicate that an increase in uterine resting tonus can stimulate R-SNA, which in turn causes the deterioration of renal circulation.