Interaction of carotid chemoreceptor and pulmonary inflation reflexes in circulatory regulation in conscious dogs.

The interaction of carotid chemoreceptor and pulmonary inflation reflex control of peripheral and coronary vasoactivity and myocardial contractility was examined in conscious dogs. Stimulation of carotid chemoreceptors resulted in an increase in rate and depth of respiration, an increase in myocardial contractility, and more intense vasoconstriction in the iliac than in the mesenteric, renal, or cerebral beds. The coronary bed responded primarily with vasodilation. The increase in rate and depth of respiration stimulated pulmonary inflation reflexes, which in turn were partially responsible for the coronary vasodilation, but also attenuated the positive inotropic response and even reversed the initial peripheral vasoconstriction to a period of significant vasodilation.