The effect of the timing of discrete bursts of efferent vagal impulses on heart rate was determined in anesthetized dogs. Two modes of stimulation were employed. In the first mode, one stimulus burst was delivered per cardiac cycle. As the time from the beginning of the P wave to the vagal stimulus (P-St interval) was progressively increased, there was first a progressive lengthening of the car...

OBJECTIVE Previous vagus nerve stimulation (VNS) studies have demonstrated antinociceptive effects, and recent noninvasive approaches, termed transcutaneous-vagus nerve stimulation (t-VNS), have utilized stimulation of the auricular branch of the vagus nerve in the ear. The dorsal medullary vagal system operates in tune with respiration, and we propose that supplying vagal afferent stimulation ...

STUDIES on myocardial contractility and coronary flow during vagal stimulation have yielded inconsistent results. This may be due to the fact that in most studies heart rate was not maintained constant and both ventricular function and coronary blood flow are influenced by changes in heart rate. When heart rate was maintained constant, no change in myocardial contractility was found." In the pr...

The mechanisms responsible for slowing cardiac impulse conduction through the atrioventricular (AV) node are not well understood but include anatomical architecture, presence of cells with diverse electrophysiological characteristics, and modulation by autonomic nervous system. The present study was designed to determine the site of vagally induced slowing of conduction through the AV node. We ...

To understand vago-vagal reflexes, one must have an appreciation of the events surrounding the encoding, integration, and central transfer of peripheral sensations by vagal afferent neurons. A large body of work has shown that vagal afferent neurons have nonuniform properties and that distinct subpopulations of neurons exist within the nodose ganglia. These sensory neurons display a considerabl...

Previous studies have indicated that neurons in the dorsomedial hypothalamic nucleus (DMN) receive feeding-related signals from the gastric vagal nerves, glycemia as well as leptin. On the other hand, it is intriguing that the cerebellum participates in regulating nonsomatic visceral activities including food intake via the direct cerebellohypothalamic projections. The present study was designe...

In the anesthetized, open-chest dog, electrical stimulation of the cardiac ends of the transected cervical vagus nerves produced effects on heart rate and A-V transmission that were dependent upon the P-St interval, i.e., the time from the beginning of the P wave to the beginning of the stimulus. When one vagal stimulus was delivered per cardiac cycle, the pacemaker response curve (curve of the...

We sought to define the effects of maturation and hyperoxic stress on nitric oxide (NO)-induced modulation of bronchopulmonary responses to stimulation of vagal preganglionic nerve fibers. Experiments were performed on decerebrate, paralyzed, and ventilated rat pups at 6-7 days (n = 21) and 13-15 days of age (n = 23) breathing room air and on rat pups 13-15 days of age (n = 19) after exposure t...

a chronically implantable device to be placed around the cervical right vagus. An anterior myocardial infarction was produced in 161 dogs; 1 month later an exercise stress test was performed on the 105 survivors. Toward the end of the test the circumflex coronary artery was occluded for 2 minutes. Fifty-nine (56%) dogs developed ventricular fibrillation and, before this test was repeated, were ...

BACKGROUND The authors previously showed that propofol attenuates bronchoconstriction. Recently, a newer formulation of propofol with metabisulfite preservative has been introduced. metabisulfite causes airway narrowing in asthmatics. Therefore, we tested whether the preservative metabisulfite abolishes the ability of propofol to attenuate bronchoconstriction. The authors used a sheep model in ...