• The Korean Journal of Physiology
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• v.6 no.2
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• pp.31-37
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• 1972

The right cervical vagus nerve was electrically stimulated for 30 sec, and 30 minutes recording cardiac rate responses and electrocardiogram. The main purposes of the present experiment are to determine effect of stimulation frequency on the maintenance of cardiac rate responses and to determine recovery time of sinus rhythm after asystole period followed by idioventricular rhythm during prolonged electrical stimulation of the vagus, and the optimal stimulation parameters for vagal stimulation were studied as well. The results obtained are summarized as follows: 1. The maximum negative chrontropic responses were obtained with the following ranges of electrical parameters. Intensity: 3V-7V, Frequency: 20/sec-60/sec, and pulse duration: 5 msec-20 msec. 2. Compared with the responses from sympathetic effectors, cardiac rate responses to electrical stimulation of vagus nerve were well maintained with all stimulation frequencies. 3. At all stimulation frequencies except 20/sec, sinus node started to take over primary pacemaker activity when cardiac rates were restored to about 38-40/min. 4. It was indicated that upper limit of idioventricular rhythm does not exceed 38-40/min. 5. With the stimulation parameter set of 20/sec-5 msec-3 V, sinus rhythm did not appear during 30 minutes of stimulation period. Therefore, this electrical parameter set appears to be optimal for elicitation of prolonged and maximum cardiac rate responses by vagal stimulation.

• Journal of Korean Neurosurgical Society
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• v.42 no.1
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• pp.16-19
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• 2007

Objective : This report describes the clinical study of the surgical method of lateral third infraclavicular implantation of vagal nerve stimulation (VNS) generator through the axillary wrinkle incision. Methods : In a retrospective study, the data for 20 patients with medically intractable epilepsy treated by this approach were examined. The mean age was 31.4 years (range : 14-50), and the mean follow-up period was 12.15 months (range : 4-21 months). The male to female ratio was 2.3 : 1. The subcutaneous pocket for the generator was located in the lateral third infraclavicular area through the axillary wrinkle. Our method was a modification of the standard VNS generator implantation in the mid-infraclavicular pocket through anterior axillary incision. Results : There were the excellent or good cosmetic satisfaction in 95% of the cases and fair in 5%. The generator was located outside the lung field in 15%, periphery of the lung field in 45%, and crossed over the lung field in 40%. Discomfort from shoulder motion occurred transiently in 35% of cases. Other complications were minimal. Conclusion : These results demonstrate that the lateral third infraclavicular apporach will offers cosmetic benefits and reduction of obscuration of the lung field without serious complications. Thus, this technique provides an attractive alternative among the surgical techniques for the vagal nerve stimulation.

• Korean Journal of Clinical Laboratory Science
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• v.38 no.2
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• pp.141-146
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• 2006

Vagal nerve stimulation (VNS) has been proposed as a possible way to improve the control of refractory epilepsy. We report the effects following VNS treatment in patients with refractory epilepsy. Seventeen patients with a mean age of 12.8 years, ranging from 5 to 29 years, underwent the implantation of vagal nerve stimulation (Cyberonics, Houston, TX). We reviewed the clinical findings before and after VNS in seizure frequency, number of antiepileptic drugs (AED), and quality of life (QOL). All of the patients had intractable seizures, eleven of the patients had additional medical complications, three had hippocampus atrophy, one had encephalomalacia, five had encephalitis, one had pachygyria, and one had schizencephaly. Thirteen patients had symptomatic partial epilepsies, three patients had Lennox-Gastaut syndrome and one had cryptogenic partial epilepsy. The mean follow up duration was 35 months. The mean reduction of seizure frequency compared with baseline before VNS was 26.1% after 3 months (p<0.005), 41.9% after 6 months (p<0.001), 46.9% after 1 year (p<0.001), and 53% at the latest follow-up (p<0.001). Twelve patients showed an improvement of QOL such as mood, language, alertness, expression, and motor function. The most common side effects were transient hoarseness or voice change or cough, which was detected in six patients (35%) and wound infection in one patient (5%). This study has shown a good anti-seizure effect of VNS, decrease in seizure frequency and improvements in QOL. We concluded that VNS is a beneficial therapy in refractory epilepsy with a non-resectable epileptic focus. Further studies should be focused on the prediction of unresponsiveness and the adjustment of VNS parameters for maximum efficacy in patients with various medical histories.

• The Journal of Internal Korean Medicine
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• v.29 no.3
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• pp.621-628
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• 2008

Objectives : The aim of this study was to investigate changes of gastric vagal nerve activity and pyloric valve function after execution of combination treatments of both electroacupuncture at Zusanli(ST36) and manual acupuncture at other acupoints in patient with functional dyspepsia. Methods : Bowel sounds of 49 patients (18 male, 31 female) were recorded and their % of bowel sound (%BS) and ratio of dominant frequency (DF) were analyzed. Postprandial %BS was used to indicate the gastric vagal activity after eating. Ratio of postprandial/fasting dominant frequency was used to present the degree of pyloric valve function. According to values of %BS and DF ratio, each patient was classified into normal or abnormal (<6 %BS, hypoactivity: <1 DF ratio, dysfunction) group. For 2 weeks, patients received a treatment consisting of both electroacupuncture stimulation at Zusanli (ST36) and acupuncture at other meridian points. Variation of parameters shifting normal to abnormal or abnormal to normal was observed, and total cure rate was calculated. Results : Total cure rate of %BS was 16%, and that of DF was 37%. Patients who improved to normal value from abnormal or aggravated to abnormal level showed both significant difference in both vagal nerve hypoactivity and pyloric valve dysfunction, respectively. Conclusions : Analysis of bowel sound might be useful to evaluate both gastric vagal nerve activity and pyloric valve function. Combination effects of Zusanli (ST36) electroacupuncture and manual acupuncture of other acupoints showed a bidirectional effect in which their activity and function were in general improved. sometimes from aggravated to abnormal level.

• Korean Journal of Clinical Laboratory Science
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• v.39 no.1
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• pp.56-62
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• 2007

Lennox-Gastaut syndrome(LGS) is a severe age-specific epilepsy syndrome that causes medication-resistant seizures in childhood. Vagal nerve stimulation (VNS) has been proposed as a possible way to improve the treatment of refractory epilepsy. We treated 9 patients with Lennox-Gastaut syndrome between the ages of 2 and 11 years (mean 5.8 years), by using the vagus nerve stimulation. The mean follow-up duration was 35 months. The mean reduction of seizure frequency compared with baseline before VNS was 52% after 6 months (range, 0% to 89%; P<0.011), and 58% after 1 year (range 0% to 89%; P<0.012). Seven patients showed improvements of quality of life (QOL) such as alertness, mood, and language skills. The most common side effects were transient hoarseness (6 patients) and drooling (1 patient). Our results suggest that the vagus nerve stimulation could be an effective and safe adjunct therapy for the treatment of Lennox-Gastaut syndrome.

• Archives of Pharmacal Research
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• v.11 no.1
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• pp.65-73
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• 1988

The effects of clonidine on the negative chronotropic response induced by stimulation of vagus nerve were studied in the presence of propranolol in reserpinized and anesthetized rats. When the heart rate was decreased by stimulation of the vagus nerve, clonidine significantly inhibited vagally induced heart rate decrease (negative chronotropic response) in dose dependent manner. This inhibitory effect of clonidine was virtually abolished by phentolamine, ${\alpha}_1-\;and\;{\alpha}_2-adrenoceptor$ antagonist, and partially antagonized by prazosin, ${\alpha}_1-adrenoceptor$ antagonist. On the other hand, when the heart rate was decreased by the infusion of bethanechol, a muscarinic parasympathetic stimulant, clonidine had no effect on the bethanechol-induced heart rate decrease. These results suggest that clonidine inhibits vagally induced negative chronotropic response by activation of presynaptic ${\alpha}-adrenoceptors$ located on the parasympathetic cholinergic nerve terminal in the heart and this effect of clonidine is more related to ${\alpha}_2-adrenoceptors$ than ${\alpha}_1-adrenoceptors$.

• Journal of Korean Medicine Rehabilitation
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• v.34 no.1
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• pp.65-81
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• 2024

Objectives This study aimed to understand the general research trends, applicated disease, and methodology of transcutaneous/percutaneous vagus nerve stimulation, contemplating its clinical use in traditional Korean medicine and future research directions. Methods A scoping review was conducted following Arksey and O'Malley Framework Stage and adhering to the PRISMA extension for scoping reviews: checklist and explanation. Papers published until October 30, 2023, were investigated across 10 databases (PubMed, Embase, Scopus, Web of Science, China National Knowledge Infrastructure, Oriental Medicine Advanced Searching Integrated System, Korean Studies Information Service System, KMbase, Science ON, Research Information Sharing Service. The search terms used were 'Transcutaneous/Percutaneous vagus nerve stimulation'. Results Since 2021, the application of transcutaneous/percutaneous vagus nerve stimulation for musculoskeletal symptoms has been actively researched, predominantly in Asia (37%), Europe (37%), and North America (21%). All 19 papers were part of clinical studies. Chronic pain was noted that most applied disease, it also was found to potentially aid in acute post-surgical pain relief. Major assessment tools include not only simple pain metrics but also pain perception, vagal nerve tension, quality of life, and inflammatory markers. Most procedures were carried out through the ear, which offers a favorable site for therapeutic stimulation without notable side effects. And parameter analysis, frequencies typically ranged around 25 Hz to 30 Hz, while pulse widths were commonly set at 250 ㎲ or 300 ㎲. Conclusions Transcutaneous/percutaneous vagus nerve stimulation is easily accessible through acupuncture in Korean medicine. Therefore, if future studies establish parameters and clinical significance, it could be utilized as a therapeutic modality.

• Journal of Acupuncture Research
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• v.20 no.1
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• pp.97-103
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• 2003

Objective : Auricular acupuncture is a method of treatment that involves needling the ear in order to produce relief of symptoms. This concept was first developed by P.Nogier, french doctor and referred to as somatotopic representation. Many authors have commented the fact that the vagus nerve supplies the external auditory and the concha. The aim of this randomised, single blind study was to investigate whether auricular acupuncture of the ear produced changes in the pulse rate, an indicator of vagal tone. Methods: 10 healthy man volunteers were divided into normal and epinephrine stimulation group. Then each group was divided into vagus area acupuncture and control area acupuncture group again. Epinephrine stimulation group was injected by epinephrine 0.3cc twice, first. All of them were needled in either the vagus area or control area of the ear, and pulse rate changes were measured by patient monitor over 1 hour. Results : In the epinephrine stimulation group, there was significant differences in the pulse rate change between vagus area acupuncture and control area acupuncture group. After injection of epinephrine, the basal pulse rate was increased 1.3~1.4 times in the control group. However, in the vagus area acupuncture group the basal pulse rate was increased only 1.1~1.2 times.

• The Korean Journal of Physiology
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• v.23 no.2
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• pp.393-399
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• 1989

Sixty-seven conscious rats prepared with chronic gastric fistula were studied to examine the effect of vagotomy on gastric secretory responses to medial amygdaloid stimulation. Gastric acid output was significantly increased by electrical stimulation of the medial amygdaloid nucleus, and the increases in acid secretion were completely eliminated by vagotomy. However, in rats subjected to stimulation of the medial amygdaloid nucleus plus vagotomy, acid output was almost same as that in only vagotomized rats. And vagotomy itself decreased the acid secretion significantly. These results indicate that the influence of electrical stimulaton of the medial amygdaloid nucleus on acid secretion is carried largely via vagus nerves. And also, without electrical stimulation of medial amygdaloid nucleus, acid secretion is controlled by way of vagus in rats. Plasma gastrin concentrations were measured following stimulation of the medial amygdaloid nucleus. Plasma levels of gastrin were not significantly altered by stimulation of the medial amygdaloid nucleus with or without vagotomy. It is therefore inferred from the above results that the facilitatory influence of the medial amygdaloid nucleus on the gastric acid secretion is mediated chiefly via vagal activity and that gastrin is not responsible for the increase in acid secretion in this process.

• Archives of Pharmacal Research
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• v.12 no.4
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• pp.243-248
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• 1989

Effects of B-HT 920 on the vagally stimulated gastric acid secretion were studied in anesthetized and gastric fistula rats. When the gastric acid secretion was increased by stimulation of the vagus nerve, B-HT 920 was partially attenuated by prazosin, $\alpha_1-$adrenoceptor antagonist and virtually abolished by yohimbine, $\alpha_2-$adrenoceptor antagonist. On the other hand, when the gastric acid secretion was increased by the infusion of bethanechol, a muscarinic parasympathetic stimulant, B-HT 920 had no effect on the bethanechol-induced gastric acid secretion. These results suggest that B-HT 920 inhibits vagally induced gastric acid secretion by activation of presynaptic $\alpha-$adrenoceptors located on the vagally stimulated pathways in the gastric wall and this effect of B-HT 920 is more related to $\alpha_2-$adrenoceptors than $\alpha_1-$adrenoceptors.