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vagal reflex

Michal Behuliak, Michal Bencze, Anna Vavrinova, Ivana Vaneckova, Josef Zicha
OBJECTIVE: Voltage-dependent calcium channels (VDCCs) play an important role in two major abnormalities observed in spontaneously hypertensive rats (SHR) - hyperactivity of sympathetic nervous system (SNS) and enhanced Ca influx to vascular smooth muscle cells (VSMC). α2δ subunit of VDCC, which promotes surface trafficking and modulates the biophysical properties of VDCC, was identified as a critical component of increased L-type VDCC calcium currents in arterial myocytes of SHR. On the other hand, N-type VDCCs control a neurotransmitter release in the peripheral sympathetic nervous system and play an important role in sympathetic hyperactivity in SHR...
September 2016: Journal of Hypertension
Roisin Bartlam, Rajiv Mohanraj
BACKGROUND: Seizures can lead to cardiac arrhythmias by a number of mechanisms including activation/inhibition of cortical autonomic centers, increase in vagal tone through activation of brainstem reflex centers, and respiratory failure. Ictal asystole (IA) is a potential mechanism underlying sudden unexpected death in epilepsy (SUDEP). We analyzed the clinical features of 5 patients who developed IA requiring pacemaker implantation. METHODS: Patients with ictal arrhythmias were identified from the video-telemetry and ambulatory EEG database at Greater Manchester Neurosciences Centre, as well as an independent epilepsy residential care facility...
October 13, 2016: Epilepsy & Behavior: E&B
Hirotaka Ueda, Mayu Suga, Takakazu Yagi, Ikue Kusumoto-Yoshida, Hideki Kashiwadani, Tomoyuki Kuwaki, Shouichi Miyawaki
The aim of this study was to clarify the effect of vagal afferent activation on salivation and swallowing-like events. Salivation is part of a reflex induced by stimulation of the oral area during feeding or chewing. Recently, we reported that nausea induced by gastro-esophageal reflux (GER) activation produced salivation and swallowing in humans. Here, we investigated the ability of visceral sensation to enhance salivation and swallowing in rodents in order to inform the mechanism of GER-mediated stomatognathic activation...
October 5, 2016: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology
Kun-Ze Lee, Hsiang-Chun Kuo
The present study was designed to establish a midcervical contusion model that can simulate long-term respiratory deficits, and investigate the breathing pattern during vagal-mediated respiratory reflexes following midcervical contusion. Moderate and severe (impactor height: 6.25 or 12.5 mm) contusion was induced at midline C3-4 spinal cord in adult Sprague-Dawley rats. The ventilatory behaviors of unanesthetized were evaluated by whole body plethysmography at 1 day and 1, 2, 4, and 8 weeks post-injury. The tidal volume was decreased and frequency was increased in contused animals compared with uninjured animals at the acute injury state...
October 13, 2016: Journal of Neurotrauma
Takaaki Kamatani, Ayako Akizuki, Seiji Kondo, Tatsuo Shirota
Although cardiac arrhythmias are occasionally associated with dental extractions and dental anesthesia, atrioventricular block is rarely seen during dental procedures. We report a rare case of type I second-degree atrioventricular block (Wenckebach phenomenon) occurring after bilateral extraction of impacted mandibular third molars under general anesthesia in a 16-year-old Japanese girl. Under consultation with a cardiovascular physician, we carefully monitored the patient's vital signs postoperatively, including blood pressure, oxygen saturation, and electrocardiogram, using a bedside monitor...
2016: Anesthesia Progress
Colin Reardon
Communication between the nervous and immune systems can significantly alter immune cell function in a number of inflammatory diseases. Elegant studies have defined a basic functional circuit in a "cholinergic anti-inflammatory pathway" that highlights a unique role for the vagus nerve, and has brought about a resurgence in the field of neuro-immunology. This research has further identified that in addition to tonic signals that can restrain immune cell activation; the anti-inflammatory reflex arc is amiable to targeted stimulation as a therapeutic modality...
October 2016: Immunology Letters
Gintautas Grabauskas, Xiaoyin Wu, Il Song, Shi-Yi Zhou, Thomas Lanigan, Chung Owyang
BACKGROUND & AIMS: Patients with diabetes have defects in the vagal afferent pathway that result in abnormal gastrointestinal function. We investigated whether selective increased activation of the 2 pore domain potassium channel TRESK contributes to nodose ganglia (NG) malfunction, disrupting gastrointestinal function in diabetic rats. METHODS: We conducted whole-cell current-clamp and single-unit recordings in NG neurons from diabetes-prone BioBreeding/Worcester rats and streptozotocin-induced diabetic (STZ-D) rats and compared with control rats...
July 27, 2016: Gastroenterology
Ragini G Gupta, Claire Schafer, Yolande Ramaroson, Michael G Sciullo, Charles C Horn
The incidence of postoperative nausea and vomiting (PONV) can be as high as 80% in patients with risk factors (e.g., females, history of motion sickness). PONV delays postoperative recovery and costs several hundred million dollars annually. Cell-based assays show that halogenated ethers (e.g., isoflurane) activate 5-HT3 receptors, which are found on gastrointestinal vagal afferents and in the hindbrain - key pathways for producing nausea and vomiting. This project evaluated the role of the vagus and activation of the hindbrain in isoflurane-induced emesis in musk shrews, a small animal model with a vomiting reflex, which is lacking in rats and mice...
July 2, 2016: Autonomic Neuroscience: Basic & Clinical
D Martelli, D G S Farmer, S T Yao
What is the topic of this review? We review the current literature on the neural reflex termed the 'inflammatory reflex' that inhibits an excessive release of inflammatory mediators in response to an immune challenge. What advances does it highlight? The original model proposed that the inflammatory reflex is a vago-vagal reflex that controls immune function. We posit that, in the endotoxaemic animal model, the vagus nerves do not appear to play a role. The evidence suggests that the efferent motor pathway, termed here the 'splanchnic anti-inflammatory pathway', is purely sympathetic, travelling via the greater splanchnic nerves to regulate the ensuing inflammatory response to immune challenges...
October 1, 2016: Experimental Physiology
Chou-Ming Yeh, Ting Ruan, Yu-Jung Lin, Tien-Huan Hsu
BACKGROUND: Reactive oxygen species (ROS), including H2O2, have been shown to induce hypersensitivity of vagal lung C-fibers (VLCFs) mainly through receptor potential ankyrin 1 (TRPA1) and P2X receptors. Cannabinoids (CBs) exert antinociceptive effects by binding to specific CB receptors, designated CB1 and CB2 (type 2) for type 1 and type 2, respectively. We investigated whether activation of CB receptors can suppress ROS-mediated VLCF hypersensitivity and, if so, what type(s) of CB receptors are involved...
October 2016: Pulmonary Pharmacology & Therapeutics
Christopher A Lear, Robert Galinsky, Guido Wassink, Kyohei Yamaguchi, Joanne O Davidson, Jenny A Westgate, Laura Bennet, Alistair J Gunn
A distinctive pattern of recurrent rapid falls in fetal heart rate, called decelerations, are commonly associated with uterine contractions during labour. These brief decelerations are mediated by vagal activation. The reflex triggering this vagal response has been variably attributed to a mechanoreceptor response to fetal head compression, to baroreflex activation following increased blood pressure during umbilical cord compression, and/or a Bezold-Jarisch reflex response to reduced venous return from the placenta...
September 1, 2016: Journal of Physiology
Maylla Ronacher Simões, Silvio César Preti, Bruna Fernandes Azevedo, Jonaína Fiorim, David D Freire, Emilia Polaco Covre, Dalton Valentim Vassallo, Leonardo Dos Santos
Lead (Pb) induces adverse effects when it chronically accumulates in the body, including effects on the nervous and cardiovascular systems. Wistar rats were exposed to lead acetate for 30 days (first dose 4 µg/100 g followed by 0.05 µg/100 g/day, i.m.) to investigate the cardiovascular system impact on the autonomic control. The femoral artery and vein were catheterised to perform hemodynamic evaluations in awake rats: heart rate variability (HRV), baroreflex sensitivity, cardiopulmonary reflex and hemodynamic responses to vagal and sympathetic pharmacological blockade...
June 7, 2016: Cardiovascular Toxicology
Chang-Huan Yang, Wei-Ling Zhuang, Yan-Jhih Shen, Ching Jung Lai, Yu Ru Kou
Obstructive sleep apnea (OSA), manifested by exposure to chronic intermittent hypoxia (CIH) and excess production of reactive oxygen species (ROS) in the airways, is associated with hyperreactive airway diseases. ROS, particularly when created by NADPH oxidase, are known to sensitize lung vagal C fibers (LVCFs), which may contribute to airway hypersensitivity pathogenesis. We investigated whether CIH augments the reflex and afferent responses of LVCFs to chemical stimulants and the roles of ROS and NADPH oxidase in such airway hypersensitivity...
2016: Frontiers in Physiology
I Tonhajzerova, Z Visnovcova, A Mestanikova, A Jurko, M Mestanik
We aimed to study complex cardiovagal control using heart rate variability (HRV), linear and nonlinear analyses at rest and during negative emotional stress in healthy students with varying depressive symptoms. ECG recording in 20 students was performed at baseline, negative emotional stress, and recovery period. The HRV parameters evaluated were the following: RR interval, spectral power in high-frequency band (HF-HRV), and symbolic dynamics index 2LV%. The subjects were divided into two groups based on the score of the Beck Depression Inventory (BDI) - normal mood (BDI: 0...
2016: Advances in Experimental Medicine and Biology
Emilia D'Elia, Paolo Ferrero, Miriam Revera, Attilio Iacovoni, Edoardo Gandolfi, Michele Senni, Emilio Vanoli
AIMS: The aim is to investigate autonomic nervous system imbalance in hypertrophic cardiomyopathy (HCM) by combining echocardiographic morphological and functional parameters with the analysis of the autonomic responses to orthostatic stress. METHODS: A 10-min tilting test and a transthoracic echocardiogram focused on ventricular septal systolic (S wave) and diastolic function (isovolumic relaxation time) were performed. Low frequency on high frequency ratio (LF/HF) and RR variation (variation of beat to beat intervals) in response to passive orthostatism were used as measures of sympathetic reflex activation [delta LF/HF (D-LF/HF) and delta RR (DRR), respectively]...
May 24, 2016: Journal of Cardiovascular Medicine
John A Rudd, Eugene Nalivaiko, Norio Matsuki, Christina Wan, Paul Lr Andrews
Diverse transmitter systems (e.g. acetylcholine, dopamine, endocannabinoids, endorphins, glutamate, histamine, 5-hydroxytryptamine, substance P) have been implicated in the pathways by which nausea and vomiting are induced and are targets for anti-emetic drugs (e.g. 5-hydroxytryptamine3 and tachykinin NK1 antagonists). The involvement of TRPV1 in emesis was discovered in the early 1990s and may have been overlooked previously as TRPV1 pharmacology was studied in rodents (mice, rats) lacking an emetic reflex...
April 2015: Temperature: Multidisciplinary Biomedical Journal
Xin Cao, Yuji Nakamura, Takeshi Wada, Hiroko Izumi-Nakaseko, Kentaro Ando, Bingmei Zhu, Bin Xu, Akira Takahara, Masaki Saitoh, Atsushi Sugiyama
We assessed the anti-anginal effects of cilnidipine in comparison with those of nicardipine and nifedipine (1 and 10 µg/kg, n = 6 for each drug) or vehicle (n = 6) by using the vasopressin-induced angina model of rats. The administration of vasopressin (0.5 IU/kg, i.v.) to the rats depressed the S-wave level of the electrocardiogram reflecting the presence of subendocardial ischemia, whereas it significantly increased the mean blood pressure, resulting in the decrease of the heart rate and the prolongation of the PR interval possibly through a reflex-mediated increase in vagal tone...
May 18, 2016: Heart and Vessels
Michal Simera, Ivan Poliacek, Marcel Veternik, Lucia Babalova, Zuzana Kotmanova, Jan Jakus
Unilateral cooling of the vagus nerve (<5°C, blocking mainly conductivity of myelinated fibers) and unilateral vagotomy were employed to reduce cough afferent drive in order to evaluate the effects of these interventions on the temporal features of the cough reflex. Twenty pentobarbitone anesthetized, spontaneously breathing cats were used. Cough was induced by mechanical stimulation of the tracheobronchial airways. The number of coughs during vagal cooling was significantly decreased (p<0.001). Inspiratory cough efforts were reduced by approximately 30% (p<0...
August 2016: Respiratory Physiology & Neurobiology
Melanie Maya Kaelberer, Sven-Eric Jordt
Somatosensory nerves transduce thermal, mechanical, chemical, and noxious stimuli caused by both endogenous and environmental agents. The cell bodies of these afferent neurons are located within the sensory ganglia. Sensory ganglia innervate a specific organ or portion of the body. For instance, the dorsal root ganglia (DRG) are located in the vertebral column and extend processes throughout the body and limbs. The trigeminal ganglia are located in the skull and innervate the face, and upper airways. Vagal afferents of the nodose ganglia extend throughout the gut, heart, and lungs...
2016: Journal of Visualized Experiments: JoVE
Anthony M Downs, Hawa B Jalloh, Kayla J Prater, Santiago P Fregoso, Cherie E Bond, Thomas G Hampton, Donald B Hoover
The neurotrophic factor neurturin is required for normal cholinergic innervation of adult mouse heart and bradycardic responses to vagal stimulation. Our goals were to determine effects of neurturin deletion on development of cardiac chronotropic and dromotropic functions, vagal baroreflex response, and cholinergic nerve density in nodal regions of postnatal mice. Experiments were performed on postnatal C57BL/6 wild-type (WT) and neurturin knockout (KO) mice. Serial electrocardiograms were recorded noninvasively from conscious pups using an ECGenie apparatus...
May 2016: Physiological Reports
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