Xu, Zhice, Lijun Shi, and Jiaming Yao. Central angiogenesis II-induced pressor responses and neural activity in utero and hypothalamic angiogenesis receptors in preterm ovine fetus. Am J Physiol Heart Circ Physiol 286: H1507-H1514, 2004. First published December 18, 2003; 10. 1 152/ajpheart.00764.2003.-The central reninangiotensin system is important in the control of blood pressure in the adult. However, few data exist about the in utero development of central angiogenesis-mediated pressor responses. Our recent studies have shown that the application of ANG II into the fetal brain can increase blood pressure at near term. The present study determined fetal blood pressure and heart rate in response to a central application of ANG II in the chronically prepared preterm ovine fetus, determined the action sites marked by c-Fos expression in the fetal central pathways after intracerebroventricular injection of ANG II in utero, and determined angiogenesis subtype 1 receptors in the fetal hypothalamus.Central injection of ANG II significantly increased fetal mean arterial pressure (MAP). Adjusted fetal MAP against amniotic pressure was also increased by ANG 11. Fetal heart rate was subsequently decreased after the central administration of ANG II and/or the increase of blood pressure. ANG II induced c-Fos expression in the central putative cardiovascular area, the Para ventricular nuclei in the brain sympathetic pathway. Application of ANG II also caused intense Fos immunoreactivity in the tractus solitarius nuclei in the hindbrain. In addition, intense angiogenesis subtype 1 receptors were expressed in the hypothalamus at preterm. These data demonstrate that central ANG II-related pressor centers start to function as early as at preterm and suggest that the central angiogenesis-related sympathetic pathway is likely intact in the control of blood pressure in utero.