The carotid sinus baroreceptor reflex in conscious rabbits

• Published in: The Journal of physiology Vol. 298; no. 1; pp. 321 - 331
• Main Authors: Faris, I B, Iannos, J, Jamieson, G G, Ludbrook, J
• Format: Journal Article
• Language: English
• Published: England The Physiological Society 01-01-1980
• Subjects: Animals; Blood Pressure - drug effects; Carotid Sinus - innervation; Carotid Sinus - physiology; Consciousness; Heart Rate - drug effects; Pressoreceptors - physiology; Propranolol - pharmacology; Rabbits; Reflex - drug effects; Reflex - physiology; Scopolamine Derivatives - pharmacology
• ISSN: 0022-3751; 1469-7793
• DOI: 10.1113/jphysiol.1980.sp013083

1. A method is described for altering the pressure across the wall of the carotid sinus in conscious rabbits by enclosing
the carotid bifurcation in a rigid, fluid-filled capsule. The extracapsular arterial baroreceptors were denervated. 2. The
baroreceptor--heart rate reflex, elicited by injecting vasoactive drugs or inflating aortic and vena caval cuffs, was used
to test the new method. The function of the carotid sinus was shown to be unaffected by enclosure in the capsule. Denervation
of the extracapsular baroreceptors reduced the gain of the baroreceptor--heart rate reflex two- to threefold. 3. The characteristics
of the carotid baroreceptor reflex were studied in sixteen animals by the capsule method. Median estimates of maximum gain,
and the range over which blood pressure changed, were 1.1 mmHg/mmHg and 57 mmHg respectively. There was good agreement between
duplicate estimates made 1--20 days apart. 4. There was only a weak association between the effects on blood pressure and
heart rate of altering carotid sinus transmural pressure. Autonomic blockade of the heart, so that its rate was fixed, did
not reduce the gain or range of blood pressure change.