Delayed sympathetic efferent responses to coronary baroreceptor unloading in anaesthetized dogs

The Journal of Physiology
M J DrinkhillR Hainsworth

Abstract

1. We previously reported that, although stimulation of coronary arterial baroreceptors results in reflex vasodilatation of a magnitude and a time course similar to that seen in response to carotid baroreceptor stimulation, the vasoconstriction that occurs when the stimulus to coronary baroreceptors is removed develops more slowly. We now report the results of experiments designed to investigate the site on the reflex are that is responsible for the delayed vasoconstriction. 2. In alpha-chloralose anaesthetized, artificially ventilated dogs, a perfusion circuit allowed independent control of pressures to the aortic root, including the coronary arteries, the aortic arch and the carotid sinuses. Electrophysiological recordings were made of afferent discharge in nerve fibres dissected from the vagus nerve, which responded to changes in coronary pressure, and from renal and lumbar efferent sympathetic nerves. Reflex vascular responses were assessed from changes in perfusion pressure to the systemic circulation, which was perfused at constant flow. 3. The afferent discharge from the coronary baroreceptors responded rapidly to both increases and decreases in coronary perfusion pressure. This indicates that prolonged activation of the...Continue Reading

Citations

Nov 10, 1998·The Journal of Physiology·N C McMahonR Hainsworth
Jun 22, 2011·The Journal of Physiology·Jonathan P MooreMark J Drinkhill
Sep 24, 2013·Experimental Physiology·Roger Hainsworth
Jul 28, 2017·Journal of Zoo and Wildlife Medicine : Official Publication of the American Association of Zoo Veterinarians·Anaemilia das Neves DinizFlávio Ribeiro Alves
Feb 5, 2019·American Journal of Physiology. Heart and Circulatory Physiology·Jonathan P Moore, Mark J Drinkhill
Oct 9, 2004·American Journal of Physiology. Heart and Circulatory Physiology·Tilmann DittingRoland Veelken
Sep 10, 2005·Journal of Applied Physiology·Shigehiko OgohPeter B Raven

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