ADRENERGIC MECHANISM OF VAGAL CARDIOSTIMULATION

Publisher Website
Google Scholar
Abstract
In the atropinized, isolated cat heart, perfused with Tyrode soln., the excitation of the cervical vagus induces positive ino-and chronotropic effects on both atria and ventricles. This vagal cardiostimulating effect is abolished by nicotine in conens. of 1 to 2 mg./l. Along with the cardiostimulation produced by the vagus, an epinephrine-like substance is released in the heart, the perfusate acquiring the property of relaxing the rectal cecum of the fowl. A similar effect on cardiac activity and the release of a substance that exerts a similar relaxing effect on the cecal tonus is obtained by excitation of the pre- or post-ganglionic cardiac sympathetic and by intracoronary injn. of acetylcholine. These results are interpreted as indicative of the existence in the heart of adrenergic ganglia connected with the vagus.
Keywords