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Stimulating intestinal afferents reflexly activates cardiovascular system in cats
G A Ordway1, K R Boheler, J C Longhurst
1Department of Physiology, University of Texas Health Science Center, Dallas 75235.
The American Journal of Physiology
|February 1, 1988
Summary
Topical capsaicin and bradykinin applied to the jejunum reflexly activate the cardiovascular system in cats. Capsaicin activates chemically sensitive receptors, while bradykinin may involve mechanoreceptors.
Area of Science:
- Gastroenterology
- Cardiovascular Physiology
- Neuroscience
Background:
- Visceral afferents can reflexly activate the cardiovascular system.
- The effect of topical intestinal application of capsaicin and bradykinin on cardiovascular reflexes is unknown.
Purpose of the Study:
- To investigate whether topical application of capsaicin and bradykinin to the jejunum evokes cardiovascular reflex responses in cats.
Main Methods:
- Anesthetized cats received topical application of capsaicin or bradykinin to the jejunum.
- Cardiovascular parameters including mean arterial pressure, left ventricular pressure, systemic vascular resistance, and heart rate were monitored.
- Celiac and superior mesenteric ganglia were removed to assess the role of these structures.
Main Results:
- Capsaicin significantly increased mean arterial pressure, left ventricular pressure derivative, systemic vascular resistance, and heart rate.
- Bradykinin and bethanechol chloride caused dose-dependent cardiovascular activation and jejunal smooth muscle contraction.
- Capsaicin did not induce detectable smooth muscle contraction, suggesting mediation by chemically sensitive receptors.
Conclusions:
- Topical application of capsaicin and bradykinin to the jejunum reflexly activates the cardiovascular system in cats.
- Cardiovascular responses to capsaicin are mediated by chemically sensitive receptors, while bradykinin responses may involve mechanoreceptors.