Key result
Intravenous infusion of carbachol increased fetal blood pressure and induced bradycardia, accompanied by increased angiotensin I and II levels, indicating cholinergic regulation of cardiovascular homeostasis.
Why the study?
Does intravenous carbachol alter cardiovascular and hormonal responses in fetal sheep?
Does intravenous carbachol alter cardiovascular and hormonal responses in fetal sheep?
Cholinergic activation by carbachol increases blood pressure and induces bradycardia in fetal sheep, associated with an over-activated renin-angiotensin system.
Cholinergic effects on fetal hemodynamics in sheep leave open translation to human perinatal cardiovascular regulation.
AIM: 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). RESULTS: 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. CONCLUSION: 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.
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Geng et al. (2009) studied Fetal cardiovascular and endocrine responses. Intravenous infusion of the cholinergic agonist carbachol was evaluated on Fetal blood pressure, heart rate, and hormonal levels. Intravenous infusion of carbachol increased fetal blood pressure and induced bradycardia, accompanied by increased angiotensin I and II levels, indicating cholinergic regulation of cardiovascular homeostasis.
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