Experiments were performed in anesthetized sino aortic denervated dogs to determine whether vagally innervated atrial and ventricular receptors had a tonic influence on the vasomotor center. In 5 dogs the lungs were removed; an oxygenator circuit received blood from the jugular veins and inferior vena cava and delivered it at constant flow into the aorta. The ventricles, left coronary artery and atrial septum were removed and the atria transformed into a common pouch by a plug tied at the level of the atrio ventricular groove. The beating atria were perfused by the mobilized cannulated right coronary artery. Cervical vagal cold block produced an increase in mean aortic pressure of 27 ± 2 mm Hg (mean ± SE). Removal of the atria abolished the response. In 5 dogs the lungs were removed and the heart left in situ to support the systemic circulation. The oxygenator circuit received blood from the pulmonary arteries and delivered it at constant flow into the left atrium. The atria were denervated by dissection from the mediastinum and incision and reanastomosis of the septum and lateral walls. Intracardiac pressures were normal. Vagal block produced an increase in mean aortic pressure of 23 ± 2 mm Hg. Stripping the aorta and the pulmonary trunk abolished the response. Thus vagally innervated receptors in both atria and ventricles exert a tonic vasomotor inhibition.
|Number of pages||1|
|Issue number||3 I|
|Publication status||Published - 1974|
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