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Interactions between circulating peptides and the central nervous system in hemodynamic regulation
G E Sander1, R F Lowe, M B Given
1Department of Medicine, Veterans Administration Medical Center, New Orleans, Louisiana.
The American Journal of Cardiology
|August 2, 1989
Summary
Enkephalins and endothelins trigger complex hemodynamic changes via opiate and vasoconstrictor mechanisms, influencing blood pressure and heart rate. Their effects depend on administration and receptor interactions.
Area of Science:
- Cardiovascular Physiology
- Neuropharmacology
Background:
- Enkephalins and endothelins are endogenous peptides with significant hemodynamic effects.
- Their administration can lead to complex changes in blood pressure and heart rate.
Purpose of the Study:
- To investigate the distinct hemodynamic responses to enkephalins and endothelins.
- To elucidate the underlying mechanisms involving autonomic tone and specific receptors.
Main Methods:
- Intravenous administration of enkephalins and endothelins in animal models and humans.
- Analysis of changes in blood pressure, heart rate, and autonomic nervous system activity.
- Investigation of receptor localization and modulation by anesthetics.
Main Results:
- Enkephalins increase blood pressure and heart rate via opiate receptor activation, affecting autonomic tone.
- Endothelin infusion increases heart rate and blood pressure, involving autonomic modification and vasoconstriction.
- Dose and administration rate influence endothelin's hemodynamic effects, with bolus doses causing vasodepression.
Conclusions:
- Both enkephalins and endothelins exert potent, dose-dependent hemodynamic effects.
- Mechanisms involve autonomic nervous system modulation and direct vascular actions.
- Specific receptor sites, like the area postrema, are crucial for mediating these responses.