-
Neurogastroenterology and Motility Nov 2019We have shown previously that an attenuated rodent model of mild necrotizing enterocolitis (NEC) increases intestinal histopathological severity grade, prevents typical...
BACKGROUND
We have shown previously that an attenuated rodent model of mild necrotizing enterocolitis (NEC) increases intestinal histopathological severity grade, prevents typical developmental increases in the high-frequency spectrum of heart rate variability (HF-HRV), alters the nitrergic myenteric phenotype, and increases IL-6 and IL-1β when combined with anterior subdiaphragmatic vagotomy. The aims of the present study were to test the hypotheses that in mild NEC-induced pups, administration of the orexigenic hormone ghrelin (a) reduces the histopathological score, (b) increases the HF-HRV power, (c) improves the altered myenteric phenotype, and (d) subdiaphragmatic vagotomy prevents the effects of ghrelin.
METHODS
Newborn Sprague Dawley rats were subjected to seven days of brief periods of cold stress and hypoxia to induce mild NEC with or without anterior subdiaphragmatic vagotomy. HRV was measured at postnatal days one, five, and ten; intraperitoneal ghrelin (0.05 mg kg ) was administered postnatal days five through ten b.i.d. Pups were sacrificed at day 12, and whole brains, gastrointestinal tissues, and blood were collected for immunohistochemical, corticosterone, and cytokine analysis.
KEY RESULTS
Ghrelin treatment reduced the intestinal histopathological score, increased the HF-HRV power, improved the altered intestinal myenteric phenotype, and subdiaphragmatic vagotomy prevented the effects of ghrelin. There were no differences in serum cytokines or corticosterone between groups.
CONCLUSIONS AND INFERENCES
Our data suggest that ghrelin administration is able to recover the mild NEC-induced changes to the histology, HF-HRV, and myenteric phenotype in a vagally dependent manner.
Topics: Animals; Animals, Newborn; Enterocolitis, Necrotizing; Ghrelin; Heart Rate; Intestines; Myenteric Plexus; Phenotype; Rats; Rats, Sprague-Dawley
PubMed: 31386261
DOI: 10.1111/nmo.13682 -
Aging Nov 2020Light exerts critical non-visual effects on a multitude of physiological processes and behaviors, including sleep-wake behavior and cognitive function. In this study, we... (Comparative Study)
Comparative Study
Light exerts critical non-visual effects on a multitude of physiological processes and behaviors, including sleep-wake behavior and cognitive function. In this study, we investigated the effects of continued exposure to different colors of light on cognitive function after sepsis in old mice. We found that exposure to red light, but not green light, exaggerated learning impairments and anxiety-like behaviors after sepsis. Red light also induced remarkable splenomegaly and altered the diversity and composition of the fecal microbiota. Pseudo germ-free mice transplanted with fecal bacteria from septic mice exposed to red light developed the same behavioral defects and splenomegaly as their donors. Intriguingly, splenectomy and subdiaphragmatic vagotomy reversed the learning impairments and anxiety-like behaviors resulting from red light exposure after sepsis. After subdiaphragmatic vagotomy, no differences in behavior or spleen size were observed among pseudo germ-free mice transplanted with fecal bacteria from septic mice exposed to different colors of light. Our results suggested that red light exposure after sepsis in old mice causes gut microbiota dysfunction, thus stimulating signaling through the subdiaphragmatic vagus nerve that induces splenomegaly and aggravates learning impairments and anxiety-like behaviors.
Topics: Age Factors; Animals; Anxiety; Behavior, Animal; Disease Models, Animal; Dysbiosis; Feces; Gastrointestinal Microbiome; Intestines; Learning Disabilities; Light; Male; Maze Learning; Mice, Inbred C57BL; Open Field Test; Sepsis; Splenomegaly; Vagus Nerve
PubMed: 33197883
DOI: 10.18632/aging.103940 -
Acta Neurobiologiae Experimentalis 2023In the central nervous system, long‑term effects of a vagotomy include disturbance of monoaminergic activity of the limbic system. Since low vagal activity is observed...
In the central nervous system, long‑term effects of a vagotomy include disturbance of monoaminergic activity of the limbic system. Since low vagal activity is observed in major depression and autism spectrum disorder, the study aimed to determine whether animals fully recovered after subdiaphragmatic vagotomy demonstrates neurochemical indicators of altered well‑being and social component of sickness behavior. Bilateral vagotomy or sham surgery was performed in adult rats. After one month of recovery, rats were challenged with lipopolysaccharide or vehicle to determine the role of central signaling upon sickness. Striatal monoamines and met‑enkephalin concentrations were evaluated using HPLC and RIA methods. We also defined a concentration of immune‑derived plasma met‑enkephalin to establish a long‑term effect of vagotomy on peripheral analgesic mechanisms. The data indicate that 30 days after vagotomy procedure, striatal dopaminergic, serotoninergic, and enkephalinergic neurochemistry was altered, both under physiological and inflammatory conditions. Vagotomy prevented inflammation‑induced increases of plasma met‑enkephalin - an opioid analgesic. Our data suggest that in a long perspective, vagotomized rats may be more sensitive to pain and social stimuli during peripheral inflammation.
Topics: Rats; Animals; Enkephalin, Methionine; Autism Spectrum Disorder; Vagotomy; Vagus Nerve; Inflammation; Amines
PubMed: 37078817
DOI: 10.55782/ane-2023-009 -
Journal of Neuroinflammation Jul 2023Inflammation is a fundamental biological response to injury and infection, which if unregulated can contribute to the pathophysiology of many diseases. The vagus nerve,...
BACKGROUND
Inflammation is a fundamental biological response to injury and infection, which if unregulated can contribute to the pathophysiology of many diseases. The vagus nerve, which primarily originates from the dorsal motor nucleus (DMN), plays an important role in rapidly dampening inflammation by regulating splenic function. However, direct vagal innervation of the spleen, which houses the majority of immune and inflammatory cells, has not been established. As an alternative to direct innervation, an anti-inflammatory reflex pathway has been proposed which involves the vagus nerve, the sympathetic celiac ganglion, and the neurotransmitter norepinephrine. Although sympathetic regulation of inflammation has been shown, the interaction of the vagus nerve and the celiac ganglia requires a unique interaction of parasympathetic and sympathetic inputs, making this putative mechanism of brain-spleen interaction controversial. BODY: As neuropeptides can be expressed at relatively high levels in neurons, we reasoned that DMN neuropeptide immunoreactivity could be used to determine their target innervation. Employing immunohistochemistry, subdiaphragmatic vagotomy, viral tract tracing, CRISPR-mediated knock-down, and functional assays, we show that cocaine and amphetamine-regulated transcript (CART) peptide-expressing projection neurons in the caudal DMN directly innervate the spleen. In response to lipopolysaccharide (LPS) stimulation, CART acts to reduce inflammation, an effect that can be augmented by intrasplenic administration of a synthetic CART peptide. These in vivo effects could be recapitulated in cultured splenocytes, suggesting that these cells express the as yet unidentified CART receptor(s).
CONCLUSION
Our results provide evidence for direct connections between the caudal DMN and spleen. In addition to acetylcholine, these neurons express the neuropeptide CART that, once released, acts to suppress inflammation by acting directly upon splenocytes.
Topics: Humans; Spleen; Neurons; Neuropeptides; Vagus Nerve; Inflammation
PubMed: 37403174
DOI: 10.1186/s12974-023-02838-2 -
The Cochrane Database of Systematic... Mar 2016Refractory peptic ulcers are ulcers in the stomach or duodenum that do not heal after eight to 12 weeks of medical treatment or those that are associated with... (Review)
Review
BACKGROUND
Refractory peptic ulcers are ulcers in the stomach or duodenum that do not heal after eight to 12 weeks of medical treatment or those that are associated with complications despite medical treatment. Recurrent peptic ulcers are peptic ulcers that recur after healing of the ulcer. Given the number of deaths due to peptic ulcer-related complications and the long-term complications of medical treatment (increased incidence of fracture), it is unclear whether medical or surgical intervention is the better treatment option in people with recurrent or refractory peptic ulcers.
OBJECTIVES
To assess the benefits and harms of medical versus surgical treatment for people with recurrent or refractory peptic ulcer.
SEARCH METHODS
We searched the specialised register of the Cochrane Upper GI and Pancreatic Diseases group, the Cochrane Central Register of Controlled Trials (CENTRAL) in the Cochrane Library, MEDLINE, EMBASE, Science Citation Index Expanded, and trials registers until September 2015 to identify randomised trials and non-randomised studies, using search strategies. We also searched the references of included studies to identify further studies.
SELECTION CRITERIA
We considered randomised controlled trials and non-randomised studies comparing medical treatment with surgical treatment in people with refractory or recurrent peptic ulcer, irrespective of language, blinding, or publication status for inclusion in the review.
DATA COLLECTION AND ANALYSIS
Two review authors independently identified trials and extracted data. We planned to calculate the risk ratio, mean difference, standardised mean difference, or hazard ratio with 95% confidence intervals using both fixed-effect and random-effects models with Review Manager 5 based on intention-to-treat analysis.
MAIN RESULTS
We included only one non-randomised study published 30 years ago in the review. This study included 77 participants who had gastric ulcer and in whom medical therapy (histamine H2 receptor blockers, antacids, and diet) had failed after an average duration of treatment of 29 months. The authors do not state whether these were recurrent or refractory ulcers. It appears that the participants did not have previous complications such as bleeding or perforation. Of the 77 included participants, 37 participants continued to have medical therapy while 40 participants received surgical therapy (antrectomy with or without vagotomy; subtotal gastrectomy with or without vagotomy; vagotomy; pyloroplasty and suture of the ulcer; suture or closure of ulcer without vagotomy or excision of the ulcer; proximal gastric or parietal cell vagotomy alone; suture or closure of the ulcer with proximal gastric or parietal cell vagotomy). Whether to use medical or surgical treatment was determined by participant's or treating physician's preference.The study authors reported that two participants in the medical treatment group (2 out of 37; 5.4%) had gastric cancer, which was identified by repeated biopsy. They did not report the proportion of participants who had gastric cancer in the surgical treatment group. They also did not report the implications of the delayed diagnosis of gastric cancer in the medical treatment group. They did not report any other outcomes of interest for this review (that is health-related quality of life (using any validated scale), adverse events and serious adverse events, peptic ulcer bleeding, peptic ulcer perforation, abdominal pain, and long-term mortality).
AUTHORS' CONCLUSIONS
We found no studies that provide the relative benefits and harms of medical versus surgical treatment for recurrent or refractory peptic ulcers. Studies that evaluate the natural history of recurrent and refractory peptic ulcers are urgently required to determine whether randomised controlled trials comparing medical versus surgical management in patients with recurrent or refractory peptic ulcers or both are necessary. Such studies will also provide information for the design of such randomised controlled trials. A minimum follow-up of two to three years will allow the calculation of the incidence of complications and gastric cancer (in gastric ulcers only) in recurrent and refractory peptic ulcers. In addition to complications related to treatment and disease, health-related quality of life and loss of productivity should also be measured.
Topics: Antacids; Histamine H2 Antagonists; Humans; Peptic Ulcer; Recurrence; Stomach Neoplasms; Stomach Ulcer; Treatment Failure
PubMed: 27025289
DOI: 10.1002/14651858.CD011523.pub2 -
American Journal of Physiology.... Mar 2023The Bezold-Jarisch reflex is a powerful inhibitory reflex initiated by activation of cardiopulmonary vagal nerves during myocardial ischemia, hemorrhage, and orthostatic...
The Bezold-Jarisch reflex is a powerful inhibitory reflex initiated by activation of cardiopulmonary vagal nerves during myocardial ischemia, hemorrhage, and orthostatic stress leading to bradycardia, vasodilation, hypotension, and vasovagal syncope. This clinically relevant reflex has been studied by measuring heart rate (HR) and mean arterial pressure (MAP) responses to injections of a variety of chemical compounds. We hypothesized that reflex responses to different compounds vary due to differential activation of vagal afferent subtypes and/or variable coactivation of excitatory afferents. HR and MAP responses to intravenous injections of the transient receptor potential vanilloid-1 (TRPV1) agonist capsaicin and the serotonin 5-HT receptor agonist phenylbiguanide (PBG) were measured in anesthetized C57BL/6 mice before and after bilateral cervical vagotomy. Capsaicin and PBG evoked rapid dose-dependent decreases in HR and MAP followed by increases in HR and MAP above baseline. Bezold-Jarisch reflex responses were abolished after vagotomy, whereas the delayed tachycardic and pressor responses to capsaicin and PBG were differentially enhanced. The relative magnitude of bradycardic versus depressor responses (↓HR/↓MAP) in vagus-intact mice was greater with capsaicin. In contrast, after vagotomy, the magnitude of excitatory tachycardic versus pressor responses (↑HR/↑MAP) was greater with PBG. Although capsaicin-induced increases in MAP and HR postvagotomy were strongly attenuated or abolished after administration of the ganglionic blocker hexamethonium, PBG-induced increases in MAP and HR were mildly attenuated and unchanged, respectively. We conclude that responses to capsaicin and PBG differ in mice, with implications for delineating the role of endogenous agonists of TRPV1 and 5-HT receptors in evoking cardiopulmonary reflexes in pathophysiological states.
Topics: Mice; Animals; Capsaicin; Serotonin; Mice, Inbred C57BL; Bradycardia; Heart Rate; Reflex; Blood Pressure
PubMed: 36622083
DOI: 10.1152/ajpregu.00102.2022 -
American Journal of Physiology.... Apr 2021Impaired cardiac preload secondary to umbilical cord occlusion (UCO) has been hypothesized to contribute to intrapartum decelerations, brief falls in fetal heart rate...
Impaired cardiac preload secondary to umbilical cord occlusion (UCO) has been hypothesized to contribute to intrapartum decelerations, brief falls in fetal heart rate (FHR), through activation of the Bezold-Jarisch reflex. This cardioprotective reflex increases parasympathetic and inhibits sympathetic outflows triggering hypotension, bradycardia, and peripheral vasodilation, but its potential to contribute to intrapartum decelerations has never been systematically examined. In this study, we performed bilateral cervical vagotomy to remove the afferent arm and the efferent parasympathetic arm of the Bezold-Jarisch reflex. Twenty-two chronically instrumented fetal sheep at 0.85 of gestation received vagotomy ( = 7) or sham vagotomy (control, = 15), followed by three 1-min complete UCOs separated by 4-min reperfusion periods. UCOs in control fetuses were associated with a rapid fall in FHR and reduced femoral blood flow mediated by intense femoral vasoconstriction, leading to hypertension. Vagotomy abolished the rapid fall in FHR ( < 0.001) and, despite reduced diastolic filling time, increased both carotid ( < 0.001) and femoral ( < 0.05) blood flow during UCOs, secondary to carotid vasodilation ( < 0.01) and delayed femoral vasoconstriction ( < 0.05). Finally, vagotomy was associated with an attenuated rise in cortical impedance during UCOs ( < 0.05), consistent with improved cerebral substrate supply. In conclusion, increased carotid and femoral blood flows after vagotomy are consistent with increased left and right ventricular output, which is incompatible with the hypothesis that labor-like UCOs impair ventricular filling. Overall, the cardiovascular responses to vagotomy do not support the hypothesis that the Bezold-Jarisch reflex is activated by UCO. The Bezold-Jarisch reflex is therefore mechanistically unable to contribute to intrapartum decelerations.
Topics: Animals; Autonomic Nervous System; Blood Flow Velocity; Blood Pressure; Carotid Arteries; Constriction; Femoral Artery; Fetal Heart; Heart Rate, Fetal; Hemodynamics; Reflex; Sheep, Domestic; Time Factors; Umbilical Cord; Uterine Contraction; Vagotomy; Ventricular Function
PubMed: 33533313
DOI: 10.1152/ajpregu.00357.2020 -
Brazilian Journal of Medical and... May 2015The parasympathetic nervous system is important for β-cell secretion and mass regulation. Here, we characterized involvement of the vagus nerve in pancreatic β-cell...
The parasympathetic nervous system is important for β-cell secretion and mass regulation. Here, we characterized involvement of the vagus nerve in pancreatic β-cell morphofunctional regulation and body nutrient homeostasis in 90-day-old monosodium glutamate (MSG)-obese rats. Male newborn Wistar rats received MSG (4 g/kg body weight) or saline [control (CTL) group] during the first 5 days of life. At 30 days of age, both groups of rats were submitted to sham-surgery (CTL and MSG groups) or subdiaphragmatic vagotomy (Cvag and Mvag groups). The 90-day-old MSG rats presented obesity, hyperinsulinemia, insulin resistance, and hypertriglyceridemia. Their pancreatic islets hypersecreted insulin in response to glucose but did not increase insulin release upon carbachol (Cch) stimulus, despite a higher intracellular Ca(2+) mobilization. Furthermore, while the pancreas weight was 34% lower in MSG rats, no alteration in islet and β-cell mass was observed. However, in the MSG pancreas, increases of 51% and 55% were observed in the total islet and β-cell area/pancreas section, respectively. Also, the β-cell number per β-cell area was 19% higher in MSG rat pancreas than in CTL pancreas. Vagotomy prevented obesity, reducing 25% of body fat stores and ameliorated glucose homeostasis in Mvag rats. Mvag islets demonstrated partially reduced insulin secretion in response to 11.1 mM glucose and presented normalization of Cch-induced Ca(2+) mobilization and insulin release. All morphometric parameters were similar among Mvag and CTL rat pancreases. Therefore, the higher insulin release in MSG rats was associated with greater β-cell/islet numbers and not due to hypertrophy. Vagotomy improved whole body nutrient homeostasis and endocrine pancreatic morphofunction in Mvag rats.
Topics: Animals; Carbachol; Cell Count; Cholesterol; Cholinergic Agonists; Flavoring Agents; Glucose; Homeostasis; Hyperinsulinism; Insulin; Insulin Resistance; Insulin Secretion; Insulin-Secreting Cells; Islets of Langerhans; Male; Obesity; Pancreas; Rats, Wistar; Sodium Glutamate; Triglycerides; Vagotomy; Vagus Nerve
PubMed: 25714886
DOI: 10.1590/1414-431X20144340 -
BMC Cardiovascular Disorders Jul 2020The activity of autonomic nervous system and its association with organ damage have not been entirely elucidated in hemorrhagic shock. The aim of this study was to...
BACKGROUND
The activity of autonomic nervous system and its association with organ damage have not been entirely elucidated in hemorrhagic shock. The aim of this study was to investigate heart rate variability (HRV) and pulmonary gas exchange in hemorrhagic shock during unilateral subdiaphragmatic vagotomy.
METHODS
Male Sprague Dawley rats were randomly assigned into groups of Sham, vagotomized (Vag), hemorrhagic shock (HS) and Vag + HS. HS was induced in conscious animals by blood withdrawal until reaching to mean arterial blood pressure (MAP) of 40 ± 5 mmHg. Then, it was allowed to MAP returning toward the basal values. MAP and heart rate (HR) were recorded throughout the experiments, HRV components of low (LF, sympathetic index), high (LH, parasympathetic index), and very low (VLF, injury index) frequencies and the LF/HF ratio calculated, and the lung histological and blood gas parameters assessed.
RESULTS
In the initial phases of HS, the increase in HR with no change in MAP were observed in both HS and Vag + HS groups, while LF increased only in the HS group. In the second phase, HR and MAP decreased sharply in the HS group, whereas, only MAP decreased in the Vag + HS group. Meanwhile, LF and HF increased relative to their baselines in the HS and Vag + HS groups, even though the values were much pronounced in the HS group. In the third phase, HR, MAP, LF, HF, and the LF/HF ratio were returned back to their baselines in both HS and Vag + HS groups. In the Vag + HS group, the VLF was lower and HR was higher than those in the other groups. Furthermore, blood gas parameters and lung histology indicated the impairment of gas exchange in the Vag + HS group.
CONCLUSIONS
The sympathetic activity is predominant in the first phase, whereas the parasympathetic activity is dominant in the second and third phases of hemorrhagic shock. There is an inverse relationship between the level of VLF and lung injury in vagotomized animals subjected to hemorrhagic shock.
Topics: Animals; Arterial Pressure; Disease Models, Animal; Heart; Heart Rate; Lung; Lung Injury; Male; Pulmonary Gas Exchange; Rats, Sprague-Dawley; Shock, Hemorrhagic; Sympathetic Nervous System; Time Factors; Vagotomy; Vagus Nerve
PubMed: 32652932
DOI: 10.1186/s12872-020-01606-x -
BMB Reports Mar 2024The stomach has emerged as a crucial endocrine organ in the regulation of feeding since the discovery of ghrelin. Gut-derived hormones, such as ghrelin and...
The stomach has emerged as a crucial endocrine organ in the regulation of feeding since the discovery of ghrelin. Gut-derived hormones, such as ghrelin and cholecystokinin, can act through the vagus nerve. We previously reported the satiety effect of hypothalamic clusterin, but the impact of peripheral clusterin remains unknown. In this study, we administered clusterin intraperitoneally to mice and observed its ability to suppress fasting-driven food intake. Interestingly, we found its synergism with cholecystokinin and antagonism with ghrelin. These effects were accompanied by increased c-fos immunoreactivity in nucleus tractus solitarius, area postrema, and hypothalamic paraventricular nucleus. Notably, truncal vagotomy abolished this response. The stomach expressed clusterin at high levels among the organs, and gastric clusterin was detected in specific enteroendocrine cells and the submucosal plexus. Gastric clusterin expression decreased after fasting but recovered after 2 hours of refeeding. Furthermore, we confirmed that stomachspecific overexpression of clusterin reduced food intake after overnight fasting. These results suggest that gastric clusterin may function as a gut-derived peptide involved in the regulation of feeding through the gut-brain axis. [BMB Reports 2024; 57(3): 149-154].
Topics: Mice; Animals; Ghrelin; Eating; Clusterin; Cholecystokinin; Stomach; Feeding Behavior
PubMed: 37817436
DOI: 10.5483/BMBRep.2023-0117