| Objectives: To determine the influence of chronic hypoxia during pregnancy on vascular tone of renal interlobar arteries in the male offspring and the underlying mechanism.Methods: Pregnant rats were randomly divided into the control(21% oxygen) and hypoxia group(10.5% oxygen) from gestational day 4 to 21. Some of the pregnant rats were sacrificed on day 21 of gestation for fetal studies. Others were allowed to give birth naturally. Body weight and kidney weight were tested in the fetus and the offspring. Blood pressure and vascular responses were measured in 5-month-old male offspring. Currents of calcium and potassium were measured in smooth muscle cells. And the relative protein expressions were tested by the method of western blot.Results: Following chronic hypoxia during pregnancy, phenylephrine induced significantly higher pressor responses and greater vasoconstrictions in the offspring. Nitric oxide mediated vessel relaxation was damaged. Phenylephrine and Bay K8644-stimulated vasoconstriction was significantly higher in the perinatal hypoxia group. The activity and expression of L-type calcium channel(Cav1.2) was up-regulated. The whole-cell currents of calcium channels and the currents of Cav1.2 were increased compared with the control. In addition, the function and currents of whole-cell K+ was decreased exposed to prenatal hypoxia. Activity of large-conductance Ca2+-activated K+ channels and the expression of BK was decreased in the perinatal hypoxia group.Conclusion: The data suggest new information regarding the influence of prenatal hypoxia on the development of the renal vascular system, and possible underlying mechanisms including Cav1.2 and BK channels. |
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