Effects of transection of cervical sympathetic trunk on blood supply to placenta and plasma norepinephrine and nitric oxide in rats with pregnancy hypertension

Objective To investigate the effects of transection of cervical sympathetic trunk (TCST) on the blood flow of uterine artery (BFUA) and plasma concentrations of norepinephrine (NE) and nitric oxide (NO) in rats with pregnancy hypertension (PIH) . Methods Forty pregnant Wistar rats weighing 240-270 g were randomly divided into 5 groups with 8 animals in each group: control group( group C) , L-NAME induced hypertension groupl and 2 (group Bl, B2); TCST group and sham operation group. In control group no hypertension was induced. In group Bl and B2 hypertension was induced with L-NAME 12.5 mg.100-1 or 6.25 mg. 100-1 injected subcutaneously from 14 th to 20 th day of gestation. In TCST group TCST was performed on the 14th day of gestation and hypertension was induced as in group B1. In sham operation group cervical sympathetic trunk was exposed but not transected on the 14 th day of gestation and hypertension was induced as in group Bl. BFUA was measured and blood samples were taken from abdominal aorta for determination of plasma NE and NO concentrations on the 21 st day of gestation. Results (1) The mean BFUA during systole and systole + diastole was significantly lower in group Bl and B2 than that in group C ( P 0.05 or 0.01) . BFUA in group Bl was significantly than that in group B2 and TCST group (P 0.01). There was no significant difference in blood flow between right and left uterine artery (P 0.05). (2) The plasma NE levels in group Bl and B2 were significantly higher than in that in group C (P 0.01). The plasma NE level in group Bl was significantly higher than that in group B2 and TCST group (P 0.05 or 0.01). (3) The plasma NO levels in group Bl and B2 were significantly lower than in group C (P 0.01). Plasma NO level in group Bl was significantly lower than that in group B2 and TCST group (P 0.01) .Conclusion TCST can increase the plasma NO content and BFUA, and decrease the elevated sympathetic activity in rats with PIH.