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Effect of vasopressin on systemic capacity
1Department of Medicine, Yale University School of Medicine, New Haven, Connecticut 06510.
The American Journal of Physiology
|November 1, 1991
Summary
Vasopressin (VP) initially decreases systemic capacity (SC) by reducing splanchnic capacity, which may aid cardiac output during hemorrhage. This effect is primarily due to reduced gastrointestinal blood flow.
Area of Science:
- Physiology
- Pharmacology
Background:
- Systemic capacity (SC) is a critical determinant of cardiovascular function.
- Vasopressin (VP) is a hormone with known effects on vascular tone and blood pressure.
Purpose of the Study:
- To investigate the acute effects of vasopressin (VP) on systemic capacity (SC) in an animal model.
- To elucidate the mechanisms underlying VP-induced changes in SC, particularly concerning splanchnic circulation.
Main Methods:
- Utilized an ex vivo blood flow model in anesthetized pigs to measure SC.
- Administered vasopressin (VP) and monitored systemic arterial pressure, oxygenator volume, portal venous pressure, and portal flow.
- Performed evisceration to isolate the effects of VP on SC independent of splanchnic organs.
Main Results:
- Vasopressin (VP) administration significantly increased mean arterial pressure.
- VP caused a prompt and significant decrease in systemic capacity (SC), primarily due to reduced splanchnic capacity.
- Portal venous pressure and flow decreased, while transhepatic venous resistance increased.
- After evisceration, VP administration resulted in an increase in SC, indicating the splanchnic bed's role.
Conclusions:
- Vasopressin (VP) acutely reduces systemic capacity (SC) through a decrease in splanchnic capacity, likely mediated by reduced gastrointestinal arterial inflow and portal pressure.
- These findings suggest that VP's initial effects on SC could be beneficial for ventricular filling and cardiac output, especially in compensatory responses to hemorrhage.