www.aana.com/aanajournalonline.aspx Despite numerous medications designed to eliminate or decrease seizures, an estimated 20% of epileptic patients in the United States remain refractory to these agents. Vagal nerve stimulation can decrease the number of seizure episodes. In 1997, the US Food and Drug Administration approved the first implantable stimulation device for the treatment of medicall...

The effect of N omega-nitro-L-arginine methyl ester (L-NAME), an inhibitor of endothelium-derived relaxing factor production, on the vasodilator response to efferent vagal stimulation was investigated in the pulmonary vascular bed of the intact-chest cat under conditions of controlled blood flow and constant left atrial pressure. When pulmonary vascular tone was increased with U46619, efferent ...

In anesthetized dogs with the chest open, supramaximal stimulation of the left cardiac sympathetic nerves at 2 and 4 Hz produced an increase of 40-50% in ventricular contractile force (CF) and of 40-65% in coronary sinus blood flow. At these frequencies of stimulation, norepinephrine (NE) overflow into the coronary sinus was 29.8 +/- 5.1 (SE) and 54.9 +/- 13.2 ng/min, respectively. Concurrent, ...

Vagal effects on atrioventricular (AV) nodal conduction are accentuated by increases in heart rate. To establish the mechanism of these rate-dependent negative dromotropic actions, we studied the properties governing AV nodal adaptation to changes in heart rate in chloralose-anesthetized dogs in the absence and presence of bilateral cervical vagal nerve stimulation (20 Hz, 0.2 msec). Stimulatio...

In vitro studies indicate that muscarinic cholinergic inhibition of beta-adrenergic cardiac responses may be modulated in part by nitric oxide (NO). To evaluate the role of NO in parasympathetic inhibition of the beta-adrenergic contractile response in vivo, we assessed the inotropic response to dobutamine before and during bilateral vagus nerve stimulation in closed-chest dogs. Dobutamine admi...

Zheng, Huiyuan, and Hans-Rudolf Berthoud. Functional vagal input to gastric myenteric plexus as assessed by vagal stimulation-induced Fos expression. Am J Physiol Gastrointest Liver Physiol 279: G73–G81, 2000.—Immunohistochemical detection of c-Fos expression was used to identify gastric myenteric plexus neurons that receive excitatory input from vagal efferent neurons activated by electrical s...

The turnover of neurotransmitter is a direct measure of neuronal function, varying with the impulse activity of the nerve. It is not known if vagal stimulation increases acetylcholine release uniformly throughout the heart, or if modification of neural signals occurs between the vagal nerve trunks and postganglionic synaptic terminals. The rate constant of acetylcholine turnover was measured in...

Animals pretreated with appropriate closes of anticholinesterase agents develop auricular flutter and fibrillation following injection of acetylcholine or vagal stimulation. Depression of normal sinoauricular nodal function facilitates induction of fibrillation. During fibrillation, additional injections of acetylcholine, or vagal stimulation, increase the rate of fibrillation. Atropine in smal...

BACKGROUND The aim of this study was to evaluate whether selective radiofrequency (RF) catheter ablation of the atrial sites in which high-frequency stimulation induces vagal reflexes prevents paroxysmal atrial fibrillation (AF). METHODS AND RESULTS Ten patients with episodes suggestive of vagal-induced paroxysmal AF and no heart disease were selected for percutaneous epicardial and endocardi...

The importance of neural elements in the control of both endocrine and exocrine pancreatic secretory functions and their coordination with gastrointestinal, hepatic, and general homeostatic functions is increasingly recognized. To better characterize the vagal efferent input to the pancreas, the capacity of electrical vagal stimulation to induce expression of c-Fos in neurochemically identified...