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Fetal swallowing: response to systemic hypotension.
M G Ross1, D J Sherman, M G Ervin
1Department of Obstetrics and Gynecology, Harbor-University of California, Los Angeles, Torrance 90509.
The American Journal of Physiology
|January 1, 1990
Summary
Fetal swallowing and endocrine responses to hypotension were studied. Systemic hypotension suppressed fetal swallowing despite increased plasma renin activity and arginine vasopressin.
Area of Science:
- Fetal Physiology
- Endocrinology
- Cardiovascular Regulation
Background:
- Fetal swallowing is crucial for gastrointestinal development and amniotic fluid homeostasis.
- The endocrine response to hypotension in fetal sheep is not fully understood.
- Investigating fetal responses to hypotension provides insights into developmental physiology.
Purpose of the Study:
- To investigate the effects of systemic hypotension on fetal swallowing and endocrine function in ovine fetuses.
- To determine if the renin-angiotensin system and arginine vasopressin are activated during hypotension-induced suppression of swallowing.
Main Methods:
- Chronically instrumented ovine fetuses (125 +/- 2 days gestation) were used.
- Electromyogram recordings of swallowing, esophageal flow measurements, and arterial/venous catheterization were performed.
- Systemic hypotension was induced via intravenous sodium nitroprusside infusion.
Main Results:
- Sodium nitroprusside infusion significantly decreased fetal mean arterial blood pressure.
- Fetal plasma renin activity and arginine vasopressin levels increased significantly.
- Fetal swallowing electromyogram activity and esophageal flow significantly decreased during hypotension.
Conclusions:
- Systemic hypotension suppresses fetal swallowing in ovine fetuses.
- This suppression occurs despite the activation of the renin-angiotensin system and arginine vasopressin release.
- These findings highlight a complex interplay between cardiovascular regulation and swallowing reflexes in the fetus.