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Cardiac norepinephrine output during carotid body stimulation
Archives Internationales De Physiologie Et De Biochimie
|April 1, 1976
Summary
Stimulating carotid body receptors in dogs with hypoxic blood increases heart norepinephrine release and coronary flow. Vagotomy reduced this coronary flow increase but still elevated norepinephrine release, decreasing myocardial stores.
Area of Science:
- Cardiovascular Physiology
- Autonomic Nervous System
- Neuroendocrinology
Background:
- The carotid body acts as a chemoreceptor, sensing blood oxygen levels.
- Norepinephrine plays a crucial role in cardiac function and regulation.
- The vagus nerve influences cardiovascular responses.
Purpose of the Study:
- To investigate the effects of carotid body stimulation on coronary flow and myocardial norepinephrine release in dogs.
- To determine the role of the vagus nerve in mediating these responses.
Main Methods:
- Selective stimulation of carotid body receptors using hypoxic blood in a series of 7 dogs.
- Measurement of coronary blood flow.
- Assessment of norepinephrine release from the heart.
- Comparison of responses before and after vagotomy.
Main Results:
- Hypoxic stimulation of carotid body receptors increased coronary flow and norepinephrine release.
- Vagotomy attenuated the increase in coronary flow but augmented norepinephrine release.
- Carotid body stimulation led to a decrease in myocardial norepinephrine content.
Conclusions:
- Carotid body chemoreceptors significantly influence cardiac hemodynamics and catecholamine release.
- The vagus nerve modulates the coronary flow response to carotid body stimulation.
- Increased sympathetic outflow, indicated by norepinephrine release, contributes to altered myocardial function during hypoxia.