In utero development of central ANG-stimulated pressor response and hypothalamic fos expression.
Central renin-angiotensin system (RAS) is as important as the peripheral RAS in the control of the cardiovascular homeostasis in the adult. However, previous fetal studies on angiotensin II (ANG II)-induced cardiovascular responses focused exclusively on the peripheral side. Thus, few data exist characterizing the in utero development of central angiotensin-mediated pressor responses. The present study determined cardiovascular responses to central application of ANG II in the chronically prepared near-term ovine fetus, and determined the action sites marked by c-fos expression in the fetal hypothalamus following intracerebroventricular (icv) injection of ANG II in utero. ANG II significantly increased fetal systolic, diastolic, and mean arterial pressure (MAP) within 5 min after injection of this peptide into the brain. Adjusted fetal MAP against amniotic pressure was also increased by icv ANG II, associated with increased c-fos in the central putative cardiovascular area--the paraventricular nuclei (PVN). Application of ANG II also induced intense c-fos expression in the supraoptic nuclei (SON), accompanied by a significant increase of fetal plasma vasopressin (AVP) levels, while maternal blood pressure (BP) and plasma AVP concentration were not changed. These results indicate that the central ANG II-mediated pressor response is functional at the last third of gestation, acting at the sites consistent with the cardiovascular neural network in the hypothalamus.
Xu
Zhice
Z
Department of Obstetrics and Gynecology and Division of Vascular Surgery, Harbor-UCLA Medical Center and Research and Education Institute, 1124 West Carson Street, RB-1, Torrance, CA 90502, USA. zxu@gcrc.rei.edu
Shi
Lijun
L
Hu
Fang
F
White
Rodney
R
Stewart
Lauren
L
Yao
Jiaming
J
D000804:Angiotensin II / Q000378:metabolism* / Q000494:pharmacology; D000818:Animals; D001127:Arginine Vasopressin / Q000097:blood; D001794:Blood Pressure / Q000187:drug effects / Q000502:physiology*; D005260:Female; D005333:Fetus / Q000196:embryology / Q000502:physiology*; D007031:Hypothalamus / Q000187:drug effects / Q000196:embryology / Q000378:metabolism*; D007150:Immunohistochemistry; D007276:Injections, Intraventricular; D009415:Nerve Net / Q000187:drug effects / Q000196:embryology / Q000378:metabolism; D009474:Neurons / Q000187:drug effects / Q000378:metabolism; D010286:Paraventricular Hypothalamic Nucleus / Q000187:drug effects / Q000378:metabolism; D011247:Pregnancy; D016760:Proto-Oncogene Proteins c-fos / Q000187:drug effects / Q000378:metabolism*; D012756:Sheep; D013495:Supraoptic Nucleus / Q000187:drug effects / Q000378:metabolism
D016760:Proto-Oncogene Proteins c-fos; D000804:Angiotensin II; D001127:Arginine Vasopressin