Cholinergic signal activated renin angiotensin system associated with cardiovascular changes in the ovine fetus.
Cholinergic regulation is important in the control of cardiovascular and endocrine responses. The mechanisms behind cardiovascular responses induced by cholinergic activation are explored by studying hormonal systems, including renin-angiotensin and vasopressin (VP).



In chronically prepared fetal sheep, intravenous infusion of the cholinergic agonist carbachol increased fetal systolic, diastolic, and mean arterial pressure accompanied with bradycardia at near-term. Although intravenous administration of carbachol had no effect on plasma VP concentrations, this agonist increased angiotensin I and angiotensin II levels in fetal plasma. Fetal blood values, including sodium, osmolality, nitric oxide, hemoglobin, and hematocrit were unchanged by intravenous carbachol.



Cholinergic activation by carbachol controls fetal blood pressure and heart rate in utero. An over-activated fetal renin-angiotensin-system (RAS) is associated with changes in vascular pressure following intravenous administration of carbachol, indicating that the cholinergic stimulation-mediated hormonal mechanism in the fetus might play a critical role in the regulation of cardiovascular homeostasis.
Geng
Chunsong
C
Perinatal Origin Diseases Research Institute, First Affiliated Hospital of Soochow University, Suzhou, China.
Mao
Caiping
C
Wu
Lei
L
Cheng
Yu
Y
Liu
Rulu
R
Chen
Bingxin
B
Chen
Ling
L
Zhang
Lubo
L
Xu
Zhice
Z
D000818:Animals; D002217:Carbachol; D018679:Cholinergic Agonists; D005260:Female; D005312:Fetal Blood / Q000378:metabolism; D005318:Fetal Heart / Q000502:physiology*; D011247:Pregnancy; D011270:Pregnancy, Animal / Q000378:metabolism*; D011950:Receptors, Cholinergic / Q000378:metabolism*; D012084:Renin-Angiotensin System; D012756:Sheep; D014667:Vasopressins / Q000097:blood*
D018679:Cholinergic Agonists; D011950:Receptors, Cholinergic; D014667:Vasopressins; D002217:Carbachol