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Vagus nerve stimulation (VNS) is a medical treatment that involves delivering electrical impulses to the vagus nerve. It is used as an add-on treatment for certain types of intractable epilepsy , cluster headaches, treatment-resistant depression and stroke rehabilitation.
A vagal maneuver is an action used to stimulate the parasympathetic nervous system by activating the vagus nerve.The vagus nerve is the longest nerve of the autonomic nervous system and helps regulate many critical aspects of human physiology, including heart rate, blood pressure, sweating, and digestion through the release of acetylcholine.
Measurements of vagal tone can be performed by means of either invasive or noninvasive procedures. Invasive procedures are in the minority and include vagus nerve stimulation by specific manual, breathing or electrical techniques. Noninvasive techniques mainly rely on the investigation of heart rate and heart rate variability. [4] [5] [6]
Joseph signed on and began using a non-invasive VNS device that delivers electrical stimulation to the vagus nerve through the ear, twice a day for 10 minutes at a time. The longest nerve in the ...
The vagal afferents are activated during the gastric phase of digestion when the corpus and fundus of the stomach are distended secondary to the entry of a food bolus. The stimulation of the mechanical receptors located in the gastric mucosa stimulates the vagus afferents.
The vagus nerve is also responsible for regulating inflammation in the body, via the inflammatory reflex. [7] Efferent vagus nerve fibers innervating the pharynx and back of the throat are responsible for the gag reflex. In addition, 5-HT 3 receptor-mediated afferent vagus stimulation in the gut due to gastroenteritis is a cause of vomiting. [8]
The vagus nerve plays a crucial role in heart rate regulation by modulating the response of sinoatrial node; vagal tone can be quantified by investigating heart rate modulation induced by vagal tone changes. As a general consideration, increased vagal tone (and thus vagal action) is associated with a diminished and more variable heart rate.
Positive dromotropy increases conduction velocity (e.g. epinephrine stimulation), negative dromotropy decreases velocity (e.g. vagal stimulation). [4] Non-dihydropyridine calcium channel blockers such as verapamil block the slow inward calcium current in cardiac tissues, thereby having a negatively dromotropic, chronotropic and inotropic effect ...