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Zhu Y, Sun H, Wang H, Li N. Synaptic mechanisms underlying the elevated sympathetic outflow in fructose-induced hypertension. Front Physiol 2024; 15:1365594. [PMID: 38505704 PMCID: PMC10949223 DOI: 10.3389/fphys.2024.1365594] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2024] [Accepted: 02/05/2024] [Indexed: 03/21/2024] Open
Abstract
Metabolic syndrome is associated with cardiovascular dysfunction, including elevated sympathetic outflow. However, the underlying brain mechanisms are unclear. The nucleus tractus solitarius (NTS) critically regulates autonomic reflexes related to cardiovascular function and contains neurons projecting to the caudal ventrolateral medulla (CVLM). Nitric oxide (NO) is a diffusible free-radical messenger in the vascular, immune, and nervous systems. In this study, we determine if NO in the NTS is involved in the synaptic plasticity underlying the elevated sympathetic outflow in fructose-induced hypertension. We retrogradely labeled CVLM-projecting NTS neurons through the injection of FluoSpheres into the CVLM in a fructose-fed rat model to determine the cellular mechanism involved in increased sympathetic outflow. Fructose feeding increased the blood pressure and glucose levels, which represent metabolic syndrome. We found that fructose feeding reduces the NO precursor L-arginine-induced increase in the firing activity of CVLM-projecting NTS neurons. Furthermore, fructose feeding reduces the L-arginine-induced increase in presynaptic spontaneous glutamatergic synaptic inputs to NTS neurons, while NO donor DEA/NO produces an increase in glutamatergic synaptic inputs in fructose-fed rats similar to that in vehicle-treated rats. In addition, fructose feeding reduces the NO-induced depressor response and sympathoinhibition. These data suggested that fructose feeding reduced NO production and, thus, the subsequent NO-induced glutamate releases in the NTS and depressor response. The findings of this study provide new insights into the central mechanisms involved in the neural control of cardiovascular and autonomic functions in the NTS in metabolic syndrome.
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Affiliation(s)
- Yun Zhu
- Department of Otorhinolaryngology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Haiying Sun
- Department of Otorhinolaryngology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Hongjie Wang
- Department of Anesthesiology, Affiliated Hospital of Hebei University, Baoding, China
| | - Na Li
- Department of Physiology, School of Basic Medical Sciences, Hebei University, Baoding, China
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Poliacek I, Pitts T, Rose MJ, Davenport PW, Simera M, Veternik M, Kotmanova Z, Bolser DC. Microinjection of kynurenic acid in the rostral nucleus of the tractus solitarius disrupts spatiotemporal aspects of mechanically induced tracheobronchial cough. J Neurophysiol 2017; 117:2179-2187. [PMID: 28250153 DOI: 10.1152/jn.00935.2016] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Revised: 02/07/2017] [Accepted: 02/24/2017] [Indexed: 01/08/2023] Open
Abstract
The importance of neurons in the nucleus of the solitary tract (NTS) in the production of coughing was tested by microinjections of the nonspecific glutamate receptor antagonist kynurenic acid (kyn; 100 mM in artificial cerebrospinal fluid) in 15 adult spontaneously breathing anesthetized cats. Repetitive coughing was elicited by mechanical stimulation of the intrathoracic airway. Electromyograms (EMG) were recorded from inspiratory parasternal and expiratory transversus abdominis (ABD) muscles. Bilateral microinjections of kyn into the NTS rostral to obex [55 ± 4 nl total in 2 locations (n = 6) or 110 ± 4 nl total in 4 locations (n = 5)], primarily the ventrolateral subnucleus, reduced cough number and expiratory cough efforts (amplitudes of ABD EMG and maxima of esophageal pressure) compared with control. These microinjections also markedly prolonged the inspiratory phase, all cough-related EMG activation, and the total cough cycle duration as well as some other cough-related time intervals. In response to microinjections of kyn into the NTS rostral to the obex respiratory rate decreased, and there were increases in the durations of the inspiratory and postinspiratory phases and mean blood pressure. However, bilateral microinjections of kyn into the NTS caudal to obex as well as control vehicle microinjections in the NTS location rostral to obex had no effect on coughing or cardiorespiratory variables. These results are consistent with the existence of a critical component of the cough rhythmogenic circuit located in the rostral ventral and lateral NTS. Neuronal structures of the rostral NTS are significantly involved specifically in the regulation of cough magnitude and phase timing.NEW & NOTEWORTHY The nucleus of the solitary tract contains significant neuronal structures responsible for control of 1) cough excitability, 2) motor drive during cough, 3) cough phase timing, and 4) cough rhythmicity. Significant elimination of neurons in the solitary tract nucleus results in cough apraxia (incomplete and/or disordered cough pattern). The mechanism of the cough impairment is different from that for the concomitant changes in breathing.
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Affiliation(s)
- Ivan Poliacek
- Department of Physiological Sciences, College of Veterinary Medicine, University of Florida, Gainesville, Florida.,Institute of Medical Biophysics, Jessenius Faculty of Medicine in Martin, Comenius University in Bratislava, Martin, Slovak Republic; and
| | - Teresa Pitts
- Department of Physiological Sciences, College of Veterinary Medicine, University of Florida, Gainesville, Florida.,Kentucky Spinal Cord Injury Research Center, Department of Neurological Surgery, University of Louisville, Louisville, Kentucky
| | - Melanie J Rose
- Department of Physiological Sciences, College of Veterinary Medicine, University of Florida, Gainesville, Florida
| | - Paul W Davenport
- Department of Physiological Sciences, College of Veterinary Medicine, University of Florida, Gainesville, Florida
| | - Michal Simera
- Institute of Medical Biophysics, Jessenius Faculty of Medicine in Martin, Comenius University in Bratislava, Martin, Slovak Republic; and
| | - Marcel Veternik
- Institute of Medical Biophysics, Jessenius Faculty of Medicine in Martin, Comenius University in Bratislava, Martin, Slovak Republic; and
| | - Zuzana Kotmanova
- Institute of Medical Biophysics, Jessenius Faculty of Medicine in Martin, Comenius University in Bratislava, Martin, Slovak Republic; and
| | - Donald C Bolser
- Department of Physiological Sciences, College of Veterinary Medicine, University of Florida, Gainesville, Florida;
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Cutsforth-Gregory JK, Benarroch EE. Nucleus of the solitary tract, medullary reflexes, and clinical implications. Neurology 2017; 88:1187-1196. [PMID: 28202704 DOI: 10.1212/wnl.0000000000003751] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
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Romanenko SA, Perelman PL, Trifonov VA, Serdyukova NA, Li T, Fu B, O’Brien PCM, Ng BL, Nie W, Liehr T, Stanyon R, Graphodatsky AS, Yang F. A First Generation Comparative Chromosome Map between Guinea Pig (Cavia porcellus) and Humans. PLoS One 2015; 10:e0127937. [PMID: 26010445 PMCID: PMC4444286 DOI: 10.1371/journal.pone.0127937] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2015] [Accepted: 04/21/2015] [Indexed: 11/19/2022] Open
Abstract
The domesticated guinea pig, Cavia porcellus (Hystricomorpha, Rodentia), is an important laboratory species and a model for a number of human diseases. Nevertheless, genomic tools for this species are lacking; even its karyotype is poorly characterized. The guinea pig belongs to Hystricomorpha, a widespread and important group of rodents; so far the chromosomes of guinea pigs have not been compared with that of other hystricomorph species or with any other mammals. We generated full sets of chromosome-specific painting probes for the guinea pig by flow sorting and microdissection, and for the first time, mapped the chromosomal homologies between guinea pig and human by reciprocal chromosome painting. Our data demonstrate that the guinea pig karyotype has undergone extensive rearrangements: 78 synteny-conserved human autosomal segments were delimited in the guinea pig genome. The high rate of genome evolution in the guinea pig may explain why the HSA7/16 and HSA16/19 associations presumed ancestral for eutherians and the three syntenic associations (HSA1/10, 3/19, and 9/11) considered ancestral for rodents were not found in C. porcellus. The comparative chromosome map presented here is a starting point for further development of physical and genetic maps of the guinea pig as well as an aid for genome assembly assignment to specific chromosomes. Furthermore, the comparative mapping will allow a transfer of gene map data from other species. The probes developed here provide a genomic toolkit, which will make the guinea pig a key species to unravel the evolutionary biology of the Hystricomorph rodents.
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Affiliation(s)
- Svetlana A. Romanenko
- Institute of Molecular and Cellular Biology, SB RAS, Novosibirsk, Russia
- Novosibirsk State University, Novosibirsk, Russia
- * E-mail: (SAR); (FY)
| | - Polina L. Perelman
- Institute of Molecular and Cellular Biology, SB RAS, Novosibirsk, Russia
- Novosibirsk State University, Novosibirsk, Russia
| | - Vladimir A. Trifonov
- Institute of Molecular and Cellular Biology, SB RAS, Novosibirsk, Russia
- Novosibirsk State University, Novosibirsk, Russia
| | | | - Tangliang Li
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, PR China
| | - Beiyuan Fu
- Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SA, United Kingdom
| | - Patricia C. M. O’Brien
- Centre for Veterinary Science, Department of Veterinary Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Bee L. Ng
- Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SA, United Kingdom
| | - Wenhui Nie
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, PR China
| | - Thomas Liehr
- Jena University Hospital, Institute of Human Genetics and Anthropology, Jena, Germany
| | - Roscoe Stanyon
- Department of Biology, University of Florence, Florence, Italy
| | - Alexander S. Graphodatsky
- Institute of Molecular and Cellular Biology, SB RAS, Novosibirsk, Russia
- Novosibirsk State University, Novosibirsk, Russia
| | - Fengtang Yang
- Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SA, United Kingdom
- * E-mail: (SAR); (FY)
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