1
|
Habecker BA. Identifying vagal sensory neurons driving the Bezold-Jarisch reflex. Trends Neurosci 2024; 47:90-91. [PMID: 38030510 PMCID: PMC10922441 DOI: 10.1016/j.tins.2023.11.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Accepted: 11/22/2023] [Indexed: 12/01/2023]
Abstract
Homeostatic reflexes are crucial for life, but the subpopulations of sensory neurons that stimulate these reflexes are largely unknown. A recent paper from Lovelace, Ma, and colleagues identified a population of sensory neurons in the cardiac ventricle that underlies the Bezold-Jarisch reflex and triggers syncope (fainting).
Collapse
Affiliation(s)
- Beth A Habecker
- Department of Chemical Physiology and Biochemistry, Oregon Health & Science University, Portland, OR 97239, USA; Department of Medicine, Knight Cardiovascular Institute, Oregon Health & Science University, Portland, OR 97239, USA.
| |
Collapse
|
2
|
Kim H, Park KT, Jo H, Shin Y, Chung G, Ko SG, Jin YH, Kim W. The effect of ginger extract on cisplatin-induced acute anorexia in rats. Front Pharmacol 2023; 14:1267254. [PMID: 38026983 PMCID: PMC10665510 DOI: 10.3389/fphar.2023.1267254] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Accepted: 10/30/2023] [Indexed: 12/01/2023] Open
Abstract
Cisplatin is a platinum-based chemotherapeutic agent widely used to treat various cancers. However, several side effects have been reported in treated patients. Among these, acute anorexia is one of the most severe secondary effects. In this study, a single oral administration of 100 or 500 mg/kg ginger extract (GE) significantly alleviated the cisplatin-induced decrease in food intake in rats. However, these body weight and water intake decreases were reversed in the 100 mg/kg group rats. To elucidate the underlying mechanism of action, serotonin (5-HT) and 5-HT2C, 3A, and 4 receptors in the nodose ganglion of the vagus nerve were investigated. The results showed that cisplatin-induced increases in serotonin levels in both the blood and nodose ganglion tissues were significantly decreased by100 and 500 mg/kg of GE administration. On 5-HT receptors, 5-HT3A and 4, but not 2C receptors, were affected by cisplatin, and GE 100 and 500 mg/kg succeeded in downregulating the evoked upregulated gene of these receptors. Protein expression of 5-HT3A and 4 receptors were also reduced in the 100 mg/kg group. Furthermore, the injection of 5-HT3A, and 4 receptors antagonists (palonostron, 0.1 mg/kg, i.p.; piboserod, 1 mg/kg, i.p., respectively) in cisplatin treated rats prevented the decrease in food intake. Using high-performance liquid chromatography (HPLC) analysis, [6]-gingerol and [6]-shogaol were identified and quantified as the major components of GE, comprising 4.12% and 2.15% of the GE, respectively. Although [6]-gingerol or [6]-shogaol alone failed to alleviate the evoked anorexia, when treated together, the effect was significant on the cisplatin-induced decrease in food intake. These results show that GE can be considered a treatment option to alleviate cisplatin-induced anorexia.
Collapse
Affiliation(s)
- Hyeonah Kim
- Department of Physiology, College of Korean Medicine, Kyung Hee University, Seoul, Republic of Korea
| | - Keun-Tae Park
- Department of Physiology, College of Korean Medicine, Kyung Hee University, Seoul, Republic of Korea
| | - Heejoon Jo
- Department of Physiology, College of Korean Medicine, Kyung Hee University, Seoul, Republic of Korea
| | - Yuchan Shin
- Department of Physiology, College of Korean Medicine, Kyung Hee University, Seoul, Republic of Korea
| | - Geehoon Chung
- Department of Physiology, College of Korean Medicine, Kyung Hee University, Seoul, Republic of Korea
| | - Seong-Gyu Ko
- Korean Medicine-Based Drug Repositioning Cancer Research Center, College of Korean Medicine, Kyung Hee University, Seoul, Republic of Korea
| | - Young-Ho Jin
- Department of Physiology, College of Medicine, Kyung Hee University, Seoul, Republic of Korea
| | - Woojin Kim
- Department of Physiology, College of Korean Medicine, Kyung Hee University, Seoul, Republic of Korea
- Korean Medicine-Based Drug Repositioning Cancer Research Center, College of Korean Medicine, Kyung Hee University, Seoul, Republic of Korea
| |
Collapse
|
3
|
Zhang L, Bang S, He Q, Matsuda M, Luo X, Jiang YH, Ji RR. SHANK3 in vagal sensory neurons regulates body temperature, systemic inflammation, and sepsis. Front Immunol 2023; 14:1124356. [PMID: 36845137 PMCID: PMC9944123 DOI: 10.3389/fimmu.2023.1124356] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Accepted: 01/25/2023] [Indexed: 02/11/2023] Open
Abstract
Excessive inflammation has been implicated in autism spectrum disorder (ASD), but the underlying mechanisms have not been fully studied. SHANK3 is a synaptic scaffolding protein and mutations of SHANK3 are involved in ASD. Shank3 expression in dorsal root ganglion sensory neurons also regulates heat pain and touch. However, the role of Shank3 in the vagus system remains unknown. We induced systemic inflammation by lipopolysaccharide (LPS) and measured body temperature and serum IL-6 levels in mice. We found that homozygous and heterozygous Shank3 deficiency, but not Shank2 and Trpv1 deficiency, aggravates hypothermia, systemic inflammation (serum IL-6 levels), and sepsis mortality in mice, induced by lipopolysaccharide (LPS). Furthermore, these deficits can be recapitulated by specific deletion of Shank3 in Nav1.8-expressing sensory neurons in conditional knockout (CKO) mice or by selective knockdown of Shank3 or Trpm2 in vagal sensory neurons in nodose ganglion (NG). Mice with Shank3 deficiency have normal basal core temperature but fail to adjust body temperature after perturbations with lower or higher body temperatures or auricular vagus nerve stimulation. In situ hybridization with RNAscope revealed that Shank3 is broadly expressed by vagal sensory neurons and this expression was largely lost in Shank3 cKO mice. Mechanistically, Shank3 regulates the expression of Trpm2 in NG, as Trpm2 but not Trpv1 mRNA levels in NG were significantly reduced in Shank3 KO mice. Our findings demonstrated a novel molecular mechanism by which Shank3 in vagal sensory neurons regulates body temperature, inflammation, and sepsis. We also provided new insights into inflammation dysregulation in ASD.
Collapse
Affiliation(s)
- Linlin Zhang
- Center for Translational Pain Medicine, Department of Anesthesiology, Duke University Medical Center, Durham, NC, United States
| | - Sangsu Bang
- Center for Translational Pain Medicine, Department of Anesthesiology, Duke University Medical Center, Durham, NC, United States
| | - Qianru He
- Center for Translational Pain Medicine, Department of Anesthesiology, Duke University Medical Center, Durham, NC, United States
| | - Megumi Matsuda
- Center for Translational Pain Medicine, Department of Anesthesiology, Duke University Medical Center, Durham, NC, United States
| | - Xin Luo
- Center for Translational Pain Medicine, Department of Anesthesiology, Duke University Medical Center, Durham, NC, United States
| | - Yong-Hui Jiang
- Department of Genetics, Pediatrics and Neuroscience, Yale University School of Medicine, New Haven, CT, United States
| | - Ru-Rong Ji
- Center for Translational Pain Medicine, Department of Anesthesiology, Duke University Medical Center, Durham, NC, United States
- Department of Neurobiology, Duke University Medical Center, Durham, NC, United States
- Department of Cell Biology, Duke University Medical Center, Durham, NC, United States
| |
Collapse
|
4
|
Ning Y, Noebels JL, Aiba I. Emx1-Cre Is Expressed in Peripheral Autonomic Ganglia That Regulate Central Cardiorespiratory Functions. eNeuro 2022; 9:ENEURO. [PMID: 36192157 DOI: 10.1523/ENEURO.0093-22.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Revised: 08/02/2022] [Accepted: 08/05/2022] [Indexed: 12/15/2022] Open
Abstract
The Emx1-IRES-Cre transgenic mouse is commonly used to direct genetic recombination in forebrain excitatory neurons. However, the original study reported that Emx1-Cre is also expressed embryonically in peripheral autonomic ganglia, which could potentially affect the interpretation of targeted circuitry contributing to systemic phenotypes. Here, we report that Emx1-Cre is expressed in the afferent vagus nerve system involved in autonomic cardiorespiratory regulatory pathways. Our imaging studies revealed expression of Emx1-Cre driven tdtomato fluorescence in the afferent vagus nerve innervating the dorsal medulla of brainstem, cell bodies in the nodose ganglion, and their potential target structures at the carotid bifurcation such as the carotid sinus and the superior cervical ganglion (SCG). Photostimulation of the afferent terminals in the nucleus tractus solitarius (NTS) in vitro using Emx1-Cre driven ChR2 reliably evoked EPSCs in the postsynaptic neurons with electrophysiological characteristics consistent with the vagus afferent nerves. In addition, optogenetic stimulation targeting the Emx1-Cre expressing structures identified in this study, such as vagus nerve, carotid bifurcation, and the dorsal medulla surface transiently depressed cardiorespiratory rate in urethane anesthetized mice in vivo Together, our study demonstrates that Emx1-IRES-Cre is expressed in the key peripheral autonomic nerve system and can modulate cardiorespiratory function independently of forebrain expression. These results raise caution when interpreting systemic phenotypes of Emx1-IRES-Cre conditional recombinant mice, and also suggest the utility of this line to investigate modulators of the afferent vagal system.
Collapse
|
5
|
Nakamura U, Nohmi T, Sagane R, Hai J, Ohbayashi K, Miyazaki M, Yamatsu A, Kim M, Iwasaki Y. Dietary Gamma-Aminobutyric Acid (GABA) Induces Satiation by Enhancing the Postprandial Activation of Vagal Afferent Nerves. Nutrients 2022; 14:2492. [PMID: 35745222 DOI: 10.3390/nu14122492] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Revised: 06/06/2022] [Accepted: 06/13/2022] [Indexed: 12/07/2022] Open
Abstract
Gamma-aminobutyric acid (GABA) is present in the mammalian brain as the main inhibitory neurotransmitter and in foods. It is widely used as a supplement that regulates brain function through stress-reducing and sleep-enhancing effects. However, its underlying mechanisms remain poorly understood, as it is reportedly unable to cross the blood–brain barrier. Here, we explored whether a single peroral administration of GABA affects feeding behavior as an evaluation of brain function and the involvement of vagal afferent nerves. Peroral GABA at 20 and 200 mg/kg immediately before refeeding suppressed short-term food intake without aversive behaviors in mice. However, GABA administration 30 min before refeeding demonstrated no effects. A rise in circulating GABA concentrations by the peroral administration of 200 mg/kg GABA was similar to that by the intraperitoneal injection of 20 mg/kg GABA, which did not alter feeding. The feeding suppression by peroral GABA was blunted by the denervation of vagal afferents. Unexpectedly, peroral GABA alone did not alter vagal afferent activities histologically. The coadministration of a liquid diet and GABA potentiated the postprandial activation of vagal afferents, thereby enhancing postprandial satiation. In conclusion, dietary GABA activates vagal afferents in collaboration with meals or meal-evoked factors and regulates brain function including feeding behavior.
Collapse
|
6
|
Jawaid S, Herring AI, Getsy PM, Lewis SJ, Watanabe M, Kolesova H. Differential immunostaining patterns of transient receptor potential (TRP) ion channels in the rat nodose ganglion. J Anat 2022; 241:230-244. [PMID: 35396708 DOI: 10.1111/joa.13656] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Revised: 01/26/2022] [Accepted: 03/07/2022] [Indexed: 11/27/2022] Open
Abstract
Vagal afferents regulate numerous physiological functions including arterial blood pressure, heart rate, breathing, and nociception. Cell bodies of vagal afferents reside in the inferior vagal (nodose) ganglia and their stimulation by various means is being considered as a way to regulate cardiorespiratory responses and control pain sensations. Stimulation of the nodose by exposure to infrared light is recently being considered as a precise way to elicit responses. These responses would likely involve the activity of temperature-sensitive membrane-bound channels. While papers have been published to track the expression of these transient receptor potential ion channels (TRPs), further studies are warranted to determine the in situ expression of the endogenous TRP proteins in the nodose ganglia to fully understand their pattern of expression, subcellular locations, and functions in this animal model. TRP ion channels are a superfamily of Na+ /Ca2+ -channels whose members are temperature- and/or mechano-sensitive and therefore represent a potential set of proteins that will be activated directly or indirectly by infrared light. Here, we report the spatial localization of six TRP channels, TRPV1, TRPV4, TRPM3, TRPM8, TRPA1, and TRPC1, from nodose ganglia taken from juvenile male Sprague-Dawley rats. The channels were detected using immunohistology with fluorescent tags on cryosections and imaged using confocal microscopy. All six TRP channels were detected with different levels of intensity in neuronal cell bodies and some were also detected in axonal fibers and blood vessels. The TRP receptors differed in their prevalence, in their patterns of expression, and in subcellular expression/localization. More specifically, TRPV1, TRPV4, TRPA1, TRPM8, TRPC1, and TRPM3 were found in vagal afferent cell bodies with a wide range of immunostaining intensity from neuron to neuron. Immunostaining for TRPV1, TRPV4, and TRPA1 appeared as fine particles scattered throughout the cytoplasm of the cell body. Intense TRPV1 immunostaining was also evident in a subset of axonal fibers. TRPM8 and TRPC1 were expressed in courser particles suggesting different subcellular compartments than for TRPV1. The localization of TRPM3 differed markedly from the other TRP channels with an immunostaining pattern that was localized to the periphery of a subset of cell bodies, whereas a scattering or no immunostaining was detected within the bulk of the cytoplasm. TRPV4 and TRPC1 were also expressed on the walls of blood vessels. The finding that all six TRP channels (representing four subfamilies) were present in the nodose ganglia provides the basis for studies designed to understand the roles of these channels in sensory transmission within vagal afferent fibers and in the responses elicited by exposure of nodose ganglia to infrared light and other stimuli. Depending on the location and functionality of the TRP channels, they may regulate the flux of Na+ /Ca2+ -across the membranes of cell bodies and axons of sensory afferents, efferent (motor) fibers coursing through the ganglia, and in vascular smooth muscle.
Collapse
Affiliation(s)
- Safdar Jawaid
- Divisions of Pediatric Cardiology, Case Western Reserve University School of Medicine, Cleveland, OH, USA
| | - Amanda I Herring
- Divisions of Pediatric Cardiology, Case Western Reserve University School of Medicine, Cleveland, OH, USA
| | - Paulina M Getsy
- Pediatric Pulmonology, Department of Pediatrics, Case Western Reserve University School of Medicine, Cleveland, OH, USA
| | - Stephen J Lewis
- Pediatric Pulmonology, Department of Pediatrics, Case Western Reserve University School of Medicine, Cleveland, OH, USA
| | - Michiko Watanabe
- Divisions of Pediatric Cardiology, Case Western Reserve University School of Medicine, Cleveland, OH, USA
| | - Hana Kolesova
- Department of Anatomy, First Faculty of Medicine, Charles University, Prague, Czech Republic
| |
Collapse
|
7
|
Abstract
Internal human body normal temperature fluctuates between 36.5 and 37.5°C and it is generally measured in the oral cavity. Interestingly, most electrophysiological studies on the functioning of ion channels and their role in neuronal behavior are carried out at room temperature, which usually oscillates between 22 and 24°C, even when thermosensitive channels are studied. We very often forget that if the core of the body reached that temperature, the probability of death from cardiorespiratory arrest would be extremely high. Does this mean that we are studying ion channels in dying neurons? Thousands of electrophysiological experiments carried out at these low temperatures suggest that most neurons tolerate this aggression quite well, at least for the duration of the experiments. This also seems to happen with ion channels, although studies at different temperatures indicate large changes in both, neuron and channel behavior. It is known that many chemical, physical and therefore physiological processes, depend to a great extent on body temperature. Temperature clearly affects the kinetics of numerous events such as chemical reactions or conformational changes in proteins but, what if these proteins constitute ion channels and these channels are specifically designed to detect changes in temperature? In this review, we discuss the importance of the potassium channels of the TREK subfamily, belonging to the recently discovered family of two-pore domain channels, in the transduction of thermal sensitivity in different cell types.
Collapse
Affiliation(s)
- Lola Rueda-Ruzafa
- CINBIO, Laboratory of Neuroscience, University of Vigo, Vigo, Spain.,Laboratory of Neuroscience, Galicia Sur Health Research Institute (IISGS), Vigo, Spain
| | - Salvador Herrera-Pérez
- CINBIO, Laboratory of Neuroscience, University of Vigo, Vigo, Spain.,Grupo de Neurofisiología Experimental y Circuitos Neuronales, Hospital Nacional de Parapléjicos, SESCAM, Toledo, Spain
| | - Ana Campos-Ríos
- CINBIO, Laboratory of Neuroscience, University of Vigo, Vigo, Spain.,Laboratory of Neuroscience, Galicia Sur Health Research Institute (IISGS), Vigo, Spain
| | - J A Lamas
- CINBIO, Laboratory of Neuroscience, University of Vigo, Vigo, Spain.,Laboratory of Neuroscience, Galicia Sur Health Research Institute (IISGS), Vigo, Spain
| |
Collapse
|
8
|
Lewis THJ, Getsy PM, Peroni JF, Ryan RM, Jenkins MW, Lewis SJ. Characterization of endothelium-dependent and -independent processes in occipital artery of the rat: Relevance to control of blood flow to nodose sensory cells. J Appl Physiol (1985) 2021; 131:1067-1079. [PMID: 34323595 DOI: 10.1152/japplphysiol.00221.2021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Circulating factors access cell bodies of vagal afferents in nodose ganglia (NG) via the occipital artery (OA). Constrictor responses of OA segments closer in origin from the external carotid artery (ECA) differ from segments closer to NG. Our objective was to determine the role of endothelium in this differential vasoreactivity in rat OA segments. Vasoreactivity of OA segments (proximal segments closer to ECA, distal segments closer to NG) were examined in wire myographs. We evaluated (a) vasoconstrictor effects of 5-hydroxytryptamine (5-HT) in intact and endothelium-denuded OA segments in absence/presence of soluble guanylate cyclase (SGC) inhibitor ODQ, (b) vasodilator responses elicited by NO-donor MAHMA NONOate in intact or endothelium-denuded OA segments in absence/presence of ODQ, and (c) vasodilator responses elicited by endothelium-dependent vasodilator, acetylcholine (ACh), in intact OA segments in absence/presence of ODQ. Intact distal OA responded more to 5-HT than intact proximal OA. Endothelium denudation increased 5-HT potency in both OA segments, especially proximal OA. ODQ increased maximal responses of 5HT in both segments, particularly proximal OA. ACh similarly relaxed both OA segments, effects abolished by endothelial denudation and attenuated by ODQ. MAHMA NONOate elicited transient vasodilation in both segments. Effects of ODQ against ACh were segment-dependent whereas those against MAHMA NONOate were not. The endothelium regulates OA responsiveness in a segment-dependently fashion. Endothelial cells at the OA-ECA junction more strongly influence vascular tone than those closer to NG. Differential endothelial regulation of OA tone may play a role in controlling blood flow and access of circulating factors to NG.
Collapse
Affiliation(s)
- Tristan H J Lewis
- Department of Biology, Case Western Reserve University, Cleveland, OH, United States
| | - Paulina M Getsy
- Department of Pediatrics, Case Western Reserve University, Cleveland, OH, United States
| | - John F Peroni
- Department of Large Animal Medicine, University of Georgia, Athens, Georgia, United States
| | - Rita M Ryan
- Department of Pediatrics, Case Western Reserve University, Cleveland, OH, United States
| | - Michael W Jenkins
- Department of Pediatrics, Case Western Reserve University, Cleveland, OH, United States.,Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, United States
| | - Stephen John Lewis
- Department of Pediatrics, Case Western Reserve University, Cleveland, OH, United States.,Department of Pharmacology, Case Western Reserve University, Cleveland, OH, United States.,Functional Electrical Stimulation Center, Case Western Reserve University, Cleveland, OH, United States
| |
Collapse
|
9
|
Borgmann D, Ciglieri E, Biglari N, Brandt C, Cremer AL, Backes H, Tittgemeyer M, Wunderlich FT, Brüning JC, Fenselau H. Gut-brain communication by distinct sensory neurons differently controls feeding and glucose metabolism. Cell Metab 2021; 33:1466-1482.e7. [PMID: 34043943 PMCID: PMC8280952 DOI: 10.1016/j.cmet.2021.05.002] [Citation(s) in RCA: 67] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Revised: 02/23/2021] [Accepted: 05/03/2021] [Indexed: 01/26/2023]
Abstract
Sensory neurons relay gut-derived signals to the brain, yet the molecular and functional organization of distinct populations remains unclear. Here, we employed intersectional genetic manipulations to probe the feeding and glucoregulatory function of distinct sensory neurons. We reconstruct the gut innervation patterns of numerous molecularly defined vagal and spinal afferents and identify their downstream brain targets. Bidirectional chemogenetic manipulations, coupled with behavioral and circuit mapping analysis, demonstrated that gut-innervating, glucagon-like peptide 1 receptor (GLP1R)-expressing vagal afferents relay anorexigenic signals to parabrachial nucleus neurons that control meal termination. Moreover, GLP1R vagal afferent activation improves glucose tolerance, and their inhibition elevates blood glucose levels independent of food intake. In contrast, gut-innervating, GPR65-expressing vagal afferent stimulation increases hepatic glucose production and activates parabrachial neurons that control normoglycemia, but they are dispensable for feeding regulation. Thus, distinct gut-innervating sensory neurons differentially control feeding and glucoregulatory neurocircuits and may provide specific targets for metabolic control.
Collapse
Affiliation(s)
- Diba Borgmann
- Synaptic Transmission in Energy Homeostasis Group, Max Planck Institute for Metabolism Research, Gleueler Strasse 50, 50931 Cologne, Germany; Translational Neurocircuitry Group, Max Planck Institute for Metabolism Research, Gleueler Strasse 50, 50931 Cologne, Germany; Center for Anatomy II, Neuroanatomy, University Hospital Cologne, Joseph-Stelzmann Str. 9, 50937 Cologne, Germany
| | - Elisa Ciglieri
- Synaptic Transmission in Energy Homeostasis Group, Max Planck Institute for Metabolism Research, Gleueler Strasse 50, 50931 Cologne, Germany; Center for Endocrinology, Diabetes and Preventive Medicine (CEDP), University Hospital Cologne, Kerpener Strasse 26, 50937 Cologne, Germany
| | - Nasim Biglari
- Max Planck Institute for Metabolism Research, Department of Neuronal Control of Metabolism, Gleueler Strasse 50, 50931 Cologne, Germany
| | - Claus Brandt
- Max Planck Institute for Metabolism Research, Department of Neuronal Control of Metabolism, Gleueler Strasse 50, 50931 Cologne, Germany
| | - Anna Lena Cremer
- Max Planck Institute for Metabolism Research, Department of Neuronal Control of Metabolism, Gleueler Strasse 50, 50931 Cologne, Germany
| | - Heiko Backes
- Max Planck Institute for Metabolism Research, Department of Neuronal Control of Metabolism, Gleueler Strasse 50, 50931 Cologne, Germany
| | - Marc Tittgemeyer
- Translational Neurocircuitry Group, Max Planck Institute for Metabolism Research, Gleueler Strasse 50, 50931 Cologne, Germany; Excellence Cluster on Cellular Stress Responses in Aging Associated Diseases (CECAD), University of Cologne, Joseph-Stelzmann-Straße 26, Cologne 50931, Germany
| | - F Thomas Wunderlich
- Center for Endocrinology, Diabetes and Preventive Medicine (CEDP), University Hospital Cologne, Kerpener Strasse 26, 50937 Cologne, Germany; Max Planck Institute for Metabolism Research, Department of Neuronal Control of Metabolism, Gleueler Strasse 50, 50931 Cologne, Germany; Excellence Cluster on Cellular Stress Responses in Aging Associated Diseases (CECAD), University of Cologne, Joseph-Stelzmann-Straße 26, Cologne 50931, Germany; Center of Molecular Medicine Cologne (CMMC), University of Cologne, Robert-Koch-Straße 21, 50931 Cologne, Germany
| | - Jens C Brüning
- Center for Endocrinology, Diabetes and Preventive Medicine (CEDP), University Hospital Cologne, Kerpener Strasse 26, 50937 Cologne, Germany; Max Planck Institute for Metabolism Research, Department of Neuronal Control of Metabolism, Gleueler Strasse 50, 50931 Cologne, Germany; Excellence Cluster on Cellular Stress Responses in Aging Associated Diseases (CECAD), University of Cologne, Joseph-Stelzmann-Straße 26, Cologne 50931, Germany; Center of Molecular Medicine Cologne (CMMC), University of Cologne, Robert-Koch-Straße 21, 50931 Cologne, Germany
| | - Henning Fenselau
- Synaptic Transmission in Energy Homeostasis Group, Max Planck Institute for Metabolism Research, Gleueler Strasse 50, 50931 Cologne, Germany; Center for Endocrinology, Diabetes and Preventive Medicine (CEDP), University Hospital Cologne, Kerpener Strasse 26, 50937 Cologne, Germany; Excellence Cluster on Cellular Stress Responses in Aging Associated Diseases (CECAD), University of Cologne, Joseph-Stelzmann-Straße 26, Cologne 50931, Germany.
| |
Collapse
|
10
|
Navickaite I, Pauziene N, Pauza DH. Anatomical evidence of non-parasympathetic cardiac nitrergic nerve fibres in rat. J Anat 2021; 238:20-35. [PMID: 32790077 PMCID: PMC7755078 DOI: 10.1111/joa.13291] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2020] [Revised: 07/09/2020] [Accepted: 07/13/2020] [Indexed: 01/03/2023] Open
Abstract
Neuronal nitric oxide synthase (nNOS)-derived nitric oxide (NO) plays a major role in the neural control of circulation and in many cardiovascular diseases. However, the exact mechanism of how NO regulates these processes is still not fully understood. This study was designed to determine the possible sources of nitrergic nerve fibres supplying the heart attempting to imply their role in the cardiac neural control. Sections of medulla oblongata, vagal nerve, its rootlets and nodose ganglia, vagal cardiac branches, Th1 -Th5 spinal cord segments, dorsal root ganglia of C8 -Th5 spinal nerves, and stellate ganglia from 28 Wistar rats were examined applying double immunohistochemical staining for nNOS combined with choline acetyltransferase (ChAT), peripherin, substance P, calcitonin gene-related peptide, tyrosine hydroxylase or myelin basic protein. Our findings show that the most abundant population of purely nNOS-immunoreactive (IR) neuronal somata (NS) was observed in the nodose ganglia (37.4 ± 1.3%). A high number of nitrergic NFs spread along the vagal nerve and entered its cardiac branches. All nitrergic neuronal somata (NS) in the nucleus ambiguus were simultaneously immunoreactive (IR) to ChAT and composed only a small subset of neurons (6%). In the dorsal nucleus of vagal nerve, biphenotypic nNOS-IR/ChAT-IR neurons composed 7.0 ± 1.0%, while small purely nNOS-IR neurons were scarce. Nitrergic NS were plentifully distributed within the nuclei of solitary tract. In the examined dorsal root and stellate ganglia, a few nitrergic NS were sporadically present. The majority of sympathetic NS in the intermediolateral nucleus were simultaneously immunoreactive for nNOS and ChAT. In conclusion, an abundant population of nitrergic NS in the nodose ganglion implies that neuronal NO is involved in afferent cardiac innervation. Nevertheless, nNOS-IR neurons identified within vagal nuclei may play a role in the transmission of preganglionic parasympathetic nerve impulses.
Collapse
Affiliation(s)
- Ieva Navickaite
- Faculty of MedicineInstitute of AnatomyLithuanian University of Health SciencesKaunasLithuania
| | - Neringa Pauziene
- Faculty of MedicineInstitute of AnatomyLithuanian University of Health SciencesKaunasLithuania
| | - Dainius H. Pauza
- Faculty of MedicineInstitute of AnatomyLithuanian University of Health SciencesKaunasLithuania
| |
Collapse
|
11
|
Min S, Chang RB, Prescott SL, Beeler B, Joshi NR, Strochlic DE, Liberles SD. Arterial Baroreceptors Sense Blood Pressure through Decorated Aortic Claws. Cell Rep 2020; 29:2192-2201.e3. [PMID: 31747594 PMCID: PMC6893869 DOI: 10.1016/j.celrep.2019.10.040] [Citation(s) in RCA: 63] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Revised: 09/13/2019] [Accepted: 10/10/2019] [Indexed: 01/30/2023] Open
Abstract
Mechanosensory neurons across physiological systems sense force using diverse terminal morphologies. Arterial baroreceptors are sensory neurons that monitor blood pressure for real-time stabilization of cardiovascular output. Various aortic sensory terminals have been described, but those that sense blood pressure are unclear because of a lack of selective genetic tools. Here, we find that all baroreceptor neurons are marked in Piezo2-ires-Cre mice and then use genetic approaches to visualize the architecture of mechanosensory endings. Cre-guided ablation of vagal and glossopharyngeal PIEZO2 neurons eliminates the baroreceptor reflex and aortic depressor nerve effects on blood pressure and heart rate. Genetic mapping reveals that PIEZO2 neurons form a distinctive mechanosensory structure: macroscopic claws that surround the aortic arch and exude fine end-net endings. Other arterial sensory neurons that form flower-spray terminals are dispensable for baroreception. Together, these findings provide structural insights into how blood pressure is sensed in the aortic vessel wall. Min et al. use genetic approaches to reveal how neurons sense blood pressure. Elevated blood pressure evokes a classic neuronal reflex (the baroreceptor reflex), found here to require PIEZO2 neurons. To sense blood pressure, PIEZO2 neurons form large claws that surround the aorta and are decorated with mechanosensory endings.
Collapse
Affiliation(s)
- Soohong Min
- Howard Hughes Medical Institute, Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Rui B Chang
- Howard Hughes Medical Institute, Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Sara L Prescott
- Howard Hughes Medical Institute, Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Brennan Beeler
- Howard Hughes Medical Institute, Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Narendra R Joshi
- Howard Hughes Medical Institute, Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA
| | - David E Strochlic
- Howard Hughes Medical Institute, Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Stephen D Liberles
- Howard Hughes Medical Institute, Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA.
| |
Collapse
|
12
|
Davis EA, Wald HS, Suarez AN, Zubcevic J, Liu CM, Cortella AM, Kamitakahara AK, Polson JW, Arnold M, Grill HJ, de Lartigue G, Kanoski SE. Ghrelin Signaling Affects Feeding Behavior, Metabolism, and Memory through the Vagus Nerve. Curr Biol 2020; 30:4510-4518.e6. [PMID: 32946754 PMCID: PMC7674191 DOI: 10.1016/j.cub.2020.08.069] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Revised: 07/10/2020] [Accepted: 08/20/2020] [Indexed: 02/07/2023]
Abstract
Vagal afferent neuron (VAN) signaling sends information from the gut to the brain and is fundamental in the control of feeding behavior and metabolism [1]. Recent findings reveal that VAN signaling also plays a critical role in cognitive processes, including affective motivational behaviors and hippocampus (HPC)-dependent memory [2-5]. VANs, located in nodose ganglia, express receptors for various gut-derived peptide signals; however, the function of these receptors with regard to feeding behavior, metabolism, and memory control is poorly understood. We hypothesized that VAN-mediated processes are influenced by ghrelin, a stomach-derived orexigenic hormone, via communication to its receptor (GHSR) expressed on gut-innervating VANs. To examine this hypothesis, rats received nodose ganglia injections of an adeno-associated virus (AAV) expressing short hairpin RNAs targeting GHSR (or a control AAV) for RNAi-mediated VAN-specific GHSR knockdown. Results reveal that VAN GHSR knockdown induced various feeding and metabolic disturbances, including increased meal frequency, impaired glucose tolerance, delayed gastric emptying, and increased body weight compared to controls. Additionally, VAN-specific GHSR knockdown impaired HPC-dependent contextual episodic memory and reduced HPC brain-derived neurotrophic factor expression, but did not affect anxiety-like behavior or general activity levels. A functional role for endogenous VAN GHSR signaling was further confirmed by results revealing that VAN signaling is required for the hyperphagic effects of ghrelin administered at dark onset, and that gut-restricted ghrelin-induced increases in VAN firing rate require intact VAN GHSR expression. Collective results reveal that VAN GHSR signaling is required for both normal feeding and metabolic function as well as HPC-dependent memory.
Collapse
Affiliation(s)
- Elizabeth A Davis
- Department of Biological Sciences, Human and Evolutionary Biology Section, Dornsife College of Letters, Arts and Sciences, University of Southern California, Los Angeles, CA 90089, USA
| | - Hallie S Wald
- Institute of Diabetes, Obesity and Metabolism, Graduate Groups of Psychology and Neuroscience, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Andrea N Suarez
- Department of Biological Sciences, Human and Evolutionary Biology Section, Dornsife College of Letters, Arts and Sciences, University of Southern California, Los Angeles, CA 90089, USA
| | - Jasenka Zubcevic
- Department of Physiological Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL 32610, USA
| | - Clarissa M Liu
- Neuroscience Graduate Program, University of Southern California, Los Angeles, CA, USA
| | - Alyssa M Cortella
- Department of Biological Sciences, Human and Evolutionary Biology Section, Dornsife College of Letters, Arts and Sciences, University of Southern California, Los Angeles, CA 90089, USA
| | | | - Jaimie W Polson
- School of Medical Sciences & Bosch Institute, The University of Sydney, Sydney 2006, Australia
| | - Myrtha Arnold
- Department of Health Sciences and Technology, ETH Zurich, Zurich 8092, Switzerland
| | - Harvey J Grill
- Institute of Diabetes, Obesity and Metabolism, Graduate Groups of Psychology and Neuroscience, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Guillaume de Lartigue
- Pharmacodynamics Department, College of Pharmacy, University of Florida, Gainesville, FL 32610, USA; Center for Integrative Cardiovascular and Metabolic Disease, University of Florida, Gainesville, FL 32610, USA.
| | - Scott E Kanoski
- Department of Biological Sciences, Human and Evolutionary Biology Section, Dornsife College of Letters, Arts and Sciences, University of Southern California, Los Angeles, CA 90089, USA; Neuroscience Graduate Program, University of Southern California, Los Angeles, CA, USA.
| |
Collapse
|
13
|
Yılmaz O, Soygüder Z, Keleş ÖF, Yaman T, Yener Z, Uyar A, Çakır T. An Immunohistochemical Study on the Presence of Nitric Oxide Synthase Isoforms (nNOS, iNOS, eNOS) in the Spinal Cord and Nodose Ganglion of Rats Receiving Ionising Gamma Radiation to their Liver. J Vet Res 2020; 64:445-53. [PMID: 32984637 DOI: 10.2478/jvetres-2020-0059] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Accepted: 08/25/2020] [Indexed: 11/20/2022] Open
Abstract
Introduction This study determined the presence of nitric oxide synthesis isoforms (nNOS, iNOS, and eNOS) in thoracic spinal cord segments and nodose ganglia of rats with gamma-irradiated livers. Material and Methods Male rats (n = 32) were divided into equal groups A, B, C, and D. In group A, the controls, no radiation was applied, while groups B, C, and D received 10 Gy of ionising gamma radiation. The rats of group B were euthanized at the end of the first day (d1), those of group C on the second day (d2), and those of group D on the third day (d3). The liver, spinal cord segments, and nodose ganglion tissues were dissected and fixed, and the liver sections were examined histopathologically. The other tissues were observed through a light microscope. Results Regeneration occurred at the end of d3 in hepatocytes which were radiation-damaged at the end of d1 and d2. On d1, some nNOS-positive staining was found in the neuronal cells of laminae I–III of the spinal cord and in neurons of the nodose ganglion, and on d3, some staining was observed in lamina X of the spinal cord, while none of note was in the nodose ganglion. Dense iNOS-positive staining was seen on d1 in the ependymal cells of the spinal cord and in the glial cells of the nodose ganglion, and on d3, there was still considerable iNOS staining in both tissues. There was clear eNOS-positive staining in the capillary endothelial cells of the spinal cord and light diffuse cytoplasmic staining in the neurons of the nodose ganglion on d1, and on d3, intense eNOS-positive staining was visible in several endothelial cells of the spinal cord, while light nuclear staining was recognised in the neurons of the nodose ganglion. Conclusion The nNOS, iNOS, and eNOS isoforms are activated in the spinal cord and nodose ganglion of rats after ionising radiation insult to the liver.
Collapse
|
14
|
Chen J, Cheng M, Wang L, Zhang L, Xu D, Cao P, Wang F, Herzog H, Song S, Zhan C. A Vagal-NTS Neural Pathway that Stimulates Feeding. Curr Biol 2020; 30:3986-3998.e5. [PMID: 32822608 DOI: 10.1016/j.cub.2020.07.084] [Citation(s) in RCA: 62] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Revised: 07/01/2020] [Accepted: 07/28/2020] [Indexed: 10/23/2022]
Abstract
A fundamental question of physiology is how gut-brain signaling stimulates appetite. While many studies have emphasized the importance of vagal afferents to the brain in inducing satiation, little is known about whether and how the vagal-mediated gut-brain pathway senses orexigenic signals and stimulates feeding. Here, we identified a previously uncharacterized population of fasting-activated catecholaminergic neurons in the nucleus of the solitary tract (NTS). After characterizing the anatomical complexity among NTS catecholaminergic neurons, we surprisingly found that activation of NTS epinephrine (ENTS) neurons co-expressing neuropeptide Y (NPY) stimulated feeding, whereas activation of NTS norepinephrine (NENTS) neurons suppressed feeding. Monosynaptic tracing/activation experiments then showed that these NTS neurons receive direct vagal afferents from nodose neurons. Moreover, activation of the vagal→NPY/ENTS neural circuit stimulated feeding. Our study reveals an orexigenic role of the vagal→NTS pathway in controlling feeding, thereby providing important insights about how gut-brain signaling regulates feeding behavior.
Collapse
Affiliation(s)
- Jing Chen
- Department of Biomedical Engineering and Laboratory for Brain and Intelligence, IDG/McGovern Institute for Brain Research, Center for Brain-Inspired Computing Research, Tsinghua University, Beijing 100084, China; National Institute of Biological Sciences, Beijing 102206, China
| | - Mingxiu Cheng
- National Institute of Biological Sciences, Beijing 102206, China; TIMBR Graduate Program, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Liang Wang
- National Institute of Biological Sciences, Beijing 102206, China
| | - Lei Zhang
- Neuroscience Division, Garvan Institute of Medical Research, Sydney, NSW 2010, Australia
| | - Dan Xu
- National Institute of Biological Sciences, Beijing 102206, China
| | - Peng Cao
- National Institute of Biological Sciences, Beijing 102206, China; Tsinghua Institute of Multidisciplinary Biomedical Research, Tsinghua University, Beijing 100084, China
| | - Fengchao Wang
- National Institute of Biological Sciences, Beijing 102206, China; Tsinghua Institute of Multidisciplinary Biomedical Research, Tsinghua University, Beijing 100084, China
| | - Herbert Herzog
- Neuroscience Division, Garvan Institute of Medical Research, Sydney, NSW 2010, Australia
| | - Sen Song
- Department of Biomedical Engineering and Laboratory for Brain and Intelligence, IDG/McGovern Institute for Brain Research, Center for Brain-Inspired Computing Research, Tsinghua University, Beijing 100084, China
| | - Cheng Zhan
- National Institute of Biological Sciences, Beijing 102206, China; Tsinghua Institute of Multidisciplinary Biomedical Research, Tsinghua University, Beijing 100084, China.
| |
Collapse
|
15
|
Kupari J, Häring M, Agirre E, Castelo-Branco G, Ernfors P. An Atlas of Vagal Sensory Neurons and Their Molecular Specialization. Cell Rep 2020; 27:2508-2523.e4. [PMID: 31116992 PMCID: PMC6533201 DOI: 10.1016/j.celrep.2019.04.096] [Citation(s) in RCA: 206] [Impact Index Per Article: 51.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Revised: 03/25/2019] [Accepted: 04/22/2019] [Indexed: 12/31/2022] Open
Abstract
Sensory functions of the vagus nerve are critical for conscious perceptions and for monitoring visceral functions in the cardio-pulmonary and gastrointestinal systems. Here, we present a comprehensive identification, classification, and validation of the neuron types in the neural crest (jugular) and placode (nodose) derived vagal ganglia by single-cell RNA sequencing (scRNA-seq) transcriptomic analysis. Our results reveal major differences between neurons derived from different embryonic origins. Jugular neurons exhibit fundamental similarities to the somatosensory spinal neurons, including major types, such as C-low threshold mechanoreceptors (C-LTMRs), A-LTMRs, Aδ-nociceptors, and cold-, and mechano-heat C-nociceptors. In contrast, the nodose ganglion contains 18 distinct types dedicated to surveying the physiological state of the internal body. Our results reveal a vast diversity of vagal neuron types, including many previously unanticipated types, as well as proposed types that are consistent with chemoreceptors, nutrient detectors, baroreceptors, and stretch and volume mechanoreceptors of the respiratory, gastrointestinal, and cardiovascular systems. A comprehensive molecular identification of neuronal types in vagal ganglion complex Prdm12+ jugular ganglion neurons share features with spinal somatosensory neurons Phox2b+ viscerosensory nodose neurons are molecularly versatile and highly specialized Nodose neuron types are consistent with chemo-, baro-, stretch-, tension-, and volume-sensors
Collapse
Affiliation(s)
- Jussi Kupari
- Division of Molecular Neurobiology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, 17177 Stockholm, Sweden
| | - Martin Häring
- Division of Molecular Neurobiology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, 17177 Stockholm, Sweden
| | - Eneritz Agirre
- Division of Molecular Neurobiology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, 17177 Stockholm, Sweden
| | - Gonçalo Castelo-Branco
- Division of Molecular Neurobiology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, 17177 Stockholm, Sweden; Ming Wai Lau Centre for Reparative Medicine, Stockholm node, Karolinska Institutet, Stockholm, Sweden
| | - Patrik Ernfors
- Division of Molecular Neurobiology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, 17177 Stockholm, Sweden.
| |
Collapse
|
16
|
Prescott SL, Umans BD, Williams EK, Brust RD, Liberles SD. An Airway Protection Program Revealed by Sweeping Genetic Control of Vagal Afferents. Cell 2020; 181:574-589.e14. [PMID: 32259485 PMCID: PMC7197391 DOI: 10.1016/j.cell.2020.03.004] [Citation(s) in RCA: 98] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Revised: 02/08/2020] [Accepted: 03/04/2020] [Indexed: 12/22/2022]
Abstract
Sensory neurons initiate defensive reflexes that ensure airway integrity. Dysfunction of laryngeal neurons is life-threatening, causing pulmonary aspiration, dysphagia, and choking, yet relevant sensory pathways remain poorly understood. Here, we discover rare throat-innervating neurons (∼100 neurons/mouse) that guard the airways against assault. We used genetic tools that broadly cover a vagal/glossopharyngeal sensory neuron atlas to map, ablate, and control specific afferent populations. Optogenetic activation of vagal P2RY1 neurons evokes a coordinated airway defense program-apnea, vocal fold adduction, swallowing, and expiratory reflexes. Ablation of vagal P2RY1 neurons eliminates protective responses to laryngeal water and acid challenge. Anatomical mapping revealed numerous laryngeal terminal types, with P2RY1 neurons forming corpuscular endings that appose laryngeal taste buds. Epithelial cells are primary airway sentinels that communicate with second-order P2RY1 neurons through ATP. These findings provide mechanistic insights into airway defense and a general molecular/genetic roadmap for internal organ sensation by the vagus nerve.
Collapse
Affiliation(s)
- Sara L Prescott
- Howard Hughes Medical Institute, Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Benjamin D Umans
- Howard Hughes Medical Institute, Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Erika K Williams
- Howard Hughes Medical Institute, Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Rachael D Brust
- Howard Hughes Medical Institute, Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Stephen D Liberles
- Howard Hughes Medical Institute, Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA.
| |
Collapse
|
17
|
Holt MK, Pomeranz LE, Beier KT, Reimann F, Gribble FM, Rinaman L. Synaptic Inputs to the Mouse Dorsal Vagal Complex and Its Resident Preproglucagon Neurons. J Neurosci 2019; 39:9767-81. [PMID: 31666353 DOI: 10.1523/JNEUROSCI.2145-19.2019] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Revised: 10/07/2019] [Accepted: 10/13/2019] [Indexed: 12/17/2022] Open
Abstract
Stress responses are coordinated by widespread neural circuits. Homeostatic and psychogenic stressors activate preproglucagon (PPG) neurons in the caudal nucleus of the solitary tract (cNTS) that produce glucagon-like peptide-1; published work in rodents indicates that these neurons play a crucial role in stress responses. While the axonal targets of PPG neurons are well established, their afferent inputs are unknown. Stress responses are coordinated by widespread neural circuits. Homeostatic and psychogenic stressors activate preproglucagon (PPG) neurons in the caudal nucleus of the solitary tract (cNTS) that produce glucagon-like peptide-1; published work in rodents indicates that these neurons play a crucial role in stress responses. While the axonal targets of PPG neurons are well established, their afferent inputs are unknown. Here we use retrograde tracing with cholera toxin subunit b to show that the cNTS in male and female mice receives axonal inputs similar to those reported in rats. Monosynaptic and polysynaptic inputs specific to cNTS PPG neurons were revealed using Cre-conditional pseudorabies and rabies viruses. The most prominent sources of PPG monosynaptic input include the lateral (LH) and paraventricular (PVN) nuclei of the hypothalamus, parasubthalamic nucleus, lateral division of the central amygdala, and Barrington's nucleus (Bar). Additionally, PPG neurons receive monosynaptic vagal sensory input from the nodose ganglia and spinal sensory input from the dorsal horn. Sources of polysynaptic input to cNTS PPG neurons include the hippocampal formation, paraventricular thalamus, and prefrontal cortex. Finally, cNTS-projecting neurons within PVN, LH, and Bar express the activation marker cFOS in mice after restraint stress, identifying them as potential sources of neurogenic stress-induced recruitment of PPG neurons. In summary, cNTS PPG neurons in mice receive widespread monosynaptic and polysynaptic input from brain regions implicated in coordinating behavioral and physiological stress responses, as well as from vagal and spinal sensory neurons. Thus, PPG neurons are optimally positioned to integrate signals of homeostatic and psychogenic stress. SIGNIFICANCE STATEMENT Recent research has indicated a crucial role for glucagon-like peptide-1-producing preproglucagon (PPG) neurons in regulating both appetite and behavioral and autonomic responses to acute stress. Intriguingly, the central glucagon-like peptide-1 system defined in rodents is conserved in humans, highlighting the translational importance of understanding its anatomical organization. Findings reported here indicate that PPG neurons receive significant monosynaptic and polysynaptic input from brain regions implicated in autonomic and behavioral responses to stress, as well as direct input from vagal and spinal sensory neurons. Improved understanding of the neural pathways underlying the recruitment of PPG neurons may facilitate the development of novel therapies for the treatment of stress-related disorders.
Collapse
|
18
|
Minaya DM, Di Lorenzo PM, Hajnal A, Czaja K. Roux‑en‑Y gastric bypass surgery triggers rapid DNA fragmentation in vagal afferent neurons in rats. Acta Neurobiol Exp (Wars) 2019; 79:432-444. [PMID: 31885399 PMCID: PMC7033620] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Previous studies have shown that Roux‑en‑Y gastric bypass (RYGB), one of the most effective weight loss treatments for obesity, results in neurodegenerative responses in vagal afferent gut‑brain connection reflected by microglia activation and reduced sensory input to the nucleus tractus solitarius (NTS). However, it is not known whether RYGB‑induced microglia activation is the cause or an effect of the reported neuronal damage. Therefore, the aim of this study was to establish the order of neurodegenerative responses in vagal afferents after RYGB in the nodose ganglia (NG) and NTS in male and female rats. Sprague‑Dawley rats were fed regular chow or an energy‑dense diet for two weeks followed by RYGB or sham surgery. Twenty‑four hours later, animals were sacrificed and NG and NTS were collected. Neuronal cell damage was determined by TUNEL assay. Microglia activation was determined by quantifying the fluorescent staining against the ionizing calcium adapter‑binding molecule 1. Reorganization of vagal afferents was evaluated by fluorescent staining against isolectin 4. Results of the study revealed significantly increased DNA fragmentation in vagal neurons in the NG when observed at 24 h after RYGB. The surgery did not produce rapid changes in the density of vagal afferents and microglia activation in the NTS. These data indicate that decreased density of vagal afferents and increased microglia activation in the NTS likely ensue as a res ult of RYGB‑induced neuronal damage.
Collapse
Affiliation(s)
- Dulce M Minaya
- Department of Veterinary Biosciences and Diagnostic Imaging, University of Georgia, Athens, USA
| | | | - Andras Hajnal
- Department of Neural and Behavioral Sciences, Pennsylvania State University, College of Medicine, Hershey, USA
| | - Krzysztof Czaja
- Department of Veterinary Biosciences and Diagnostic Imaging, University of Georgia, Athens, USA;
| |
Collapse
|
19
|
Liu Y, Wu D, Qu MY, He JL, Yuan M, Zhao M, Wang JX, He J, Wang LQ, Guo XJ, Zuo M, Zhao SY, Ma MN, Li JN, Shou W, Qiao GF, Li BY. Neuropeptide Y-mediated sex- and afferent-specific neurotransmissions contribute to sexual dimorphism of baroreflex afferent function. Oncotarget 2018; 7:66135-66148. [PMID: 27623075 PMCID: PMC5323221 DOI: 10.18632/oncotarget.11880] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Accepted: 07/16/2016] [Indexed: 01/19/2023] Open
Abstract
Background Molecular and cellular mechanisms of neuropeptide-Y (NPY)-mediated gender-difference in blood pressure (BP) regulation are largely unknown. Methods Baroreceptor sensitivity (BRS) was evaluated by measuring the response of BP to phenylephrine/nitroprusside. Serum NPY concentration was determined using ELISA. The mRNA and protein expression of NPY receptors were assessed in tissue and single-cell by RT-PCR, immunoblot, and immunohistochemistry. NPY was injected into the nodose while arterial pressure was monitored. Electrophysiological recordings were performed on nodose neurons from rats by patch-clamp technique. Results The BRS was higher in female than male and ovariectomized rats, while serum NPY concentration was similar among groups. The sex-difference was detected in Y1R, not Y2R protein expression, however, both were upregulated upon ovariectomy and canceled by estrogen replacement. Immunostaining confirmed Y1R and Y2R expression in myelinated and unmyelinated afferents. Single-cell PCR demonstrated that Y1R expression/distribution was identical between A- and C-types, whereas, expressed level of Y2R was ∼15 and ∼7 folds higher in Ah- and C-types than A-types despite similar distribution. Activation of Y1R in nodose elevated BP, while activation of Y2R did the opposite. Activation of Y1R did not alter action potential duration (APD) of A-types, but activation of Y2R- and Y1R/Y2R in Ah- and C-types frequency-dependently prolonged APD. N-type ICa was reduced in A-, Ah- and C-types when either Y1R, Y2R, or both were activated. The sex-difference in Y1R expression was also observed in NTS. Conclusions Sex- and afferent-specific expression of Neuropeptide-Y receptors in baroreflex afferent pathway may contribute to sexual-dimorphic neurocontrol of BP regulation.
Collapse
Affiliation(s)
- Yang Liu
- Department of Pharmacology, Harbin Medical University, Harbin, China
| | - Di Wu
- Key Laboratory of Cardiovascular Research of Ministry of Education, Harbin Medical University, Harbin, China
| | - Mei-Yu Qu
- Key Laboratory of Cardiovascular Research of Ministry of Education, Harbin Medical University, Harbin, China
| | - Jian-Li He
- Key Laboratory of Cardiovascular Research of Ministry of Education, Harbin Medical University, Harbin, China
| | - Mei Yuan
- Department of Pharmacology, Harbin Medical University, Harbin, China
| | - Miao Zhao
- Key Laboratory of Cardiovascular Research of Ministry of Education, Harbin Medical University, Harbin, China
| | - Jian-Xin Wang
- Key Laboratory of Cardiovascular Research of Ministry of Education, Harbin Medical University, Harbin, China
| | - Jian He
- Key Laboratory of Cardiovascular Research of Ministry of Education, Harbin Medical University, Harbin, China
| | - Lu-Qi Wang
- Key Laboratory of Cardiovascular Research of Ministry of Education, Harbin Medical University, Harbin, China
| | - Xin-Jing Guo
- Department of Pharmacology, Harbin Medical University, Harbin, China
| | - Meng Zuo
- Department of Pharmacology, Harbin Medical University, Harbin, China
| | - Shu-Yang Zhao
- Key Laboratory of Cardiovascular Research of Ministry of Education, Harbin Medical University, Harbin, China
| | - Mei-Na Ma
- Key Laboratory of Cardiovascular Research of Ministry of Education, Harbin Medical University, Harbin, China
| | - Jun-Nan Li
- Department of Pharmacology, Harbin Medical University, Harbin, China
| | - Weinian Shou
- Riley Heart Research Center, Division of Pediatric Cardiology, Herman B. Wells Center for Pediatric Research, Department of Pediatrics, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Guo-Fen Qiao
- Department of Pharmacology, Harbin Medical University, Harbin, China.,Key Laboratory of Cardiovascular Research of Ministry of Education, Harbin Medical University, Harbin, China
| | - Bai-Yan Li
- Department of Pharmacology, Harbin Medical University, Harbin, China
| |
Collapse
|
20
|
Kameda Y. Morphological and molecular evolution of the ultimobranchial gland of nonmammalian vertebrates, with special reference to the chicken C cells. Dev Dyn 2017; 246:719-739. [PMID: 28608500 DOI: 10.1002/dvdy.24534] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Revised: 04/30/2017] [Accepted: 04/30/2017] [Indexed: 12/14/2022] Open
Abstract
This review summarizes the current understanding of the nonmammalian ultimobranchial gland from morphological and molecular perspectives. Ultimobranchial anlage of all animal species develops from the last pharyngeal pouch. The genes involved in the development of pharyngeal pouches are well conserved across vertebrates. The ultimobranchial anlage of nonmammalian vertebrates and monotremes does not merge with the thyroid, remaining as an independent organ throughout adulthood. Although C cells of all animal species secrete calcitonin, the shape, cellular components and location of the ultimobranchial gland vary from species to species. Avian ultimobranchial gland is unique in several phylogenic aspects; the organ is located between the vagus and recurrent laryngeal nerves at the upper thorax and is densely innervated by branches emanating from them. In chick embryos, TuJ1-, HNK-1-, and PGP 9.5-immunoreactive cells that originate from the distal vagal (nodose) ganglion, colonize the ultimobranchial anlage and differentiate into C cells; neuronal cells give rise to C cells. Like C cells of mammals, the cells of fishes, amphibians, reptiles, and also a subset of C cells of birds, appear to be derived from the endodermal epithelium forming ultimobranchial anlage. Thus, the avian ultimobranchial C cells may have dual origins, neural progenitors and endodermal epithelium. Developmental Dynamics 246:719-739, 2017. © 2017 Wiley Periodicals, Inc.
Collapse
Affiliation(s)
- Yoko Kameda
- Department of Anatomy, Kitasato University School of Medicine, Sagamihara, Kanagawa, Japan
| |
Collapse
|
21
|
Kaczyńska K, Jampolska M, Szereda-Przestaszewska M. The role of vagal pathway and NK1 and NK2 receptors in cardiovascular and respiratory effects of neurokinin A. Clin Exp Pharmacol Physiol 2017; 43:818-24. [PMID: 27199181 DOI: 10.1111/1440-1681.12594] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Revised: 05/06/2016] [Accepted: 05/15/2016] [Indexed: 11/29/2022]
Abstract
Neurokinin A (NKA) is a peptide neurotransmitter that participates in the regulation of breathing and the cardiovascular system. The purpose of the current study was to determine the cardiorespiratory pattern exerted by the systemic injection of NKA, to look at the contribution of neurokinin NK1 and NK2 receptors, and to establish the engagement of the vagal pathway in mediation of these responses. The effects of intravenous injections of NKA (50 μg/kg) were studied in anaesthetized, spontaneously breathing rats in the following experimental schemes: in neurally intact rats; and vagotomized at either midcervical or supranodosal level. Intravenous injections of NKA in the intact rats evoked sudden and short-lived increase in the respiratory rate concomitant with drop in tidal volume, followed by a prolonged depression, coupled with continuous augmentation of the tidal volume. Respiratory alterations were accompanied by transient tachycardia and prolonged hypotension. Midcervical vagotomy eliminated respiratory rate response and augmentation of tidal volume. Section of supranodosal vagi abrogated all respiratory reactions. NK2 receptor blockade abolished respiratory changes without affecting cardiovascular effects, whereas NK1 receptor blockade significantly reduced hypotension and increase in heart rate with no impact on the respiratory system. These results indicate that NKA induced changes in the breathing resulting from an excitation of the NK2 receptors on the vagal endings. A fall in blood pressure triggered by NKA occurs outside of the vagus nerve and is probably mediated via its direct action on vascular smooth muscles supplied with NK1 receptors.
Collapse
Affiliation(s)
- Katarzyna Kaczyńska
- Laboratory of Respiration Physiology, Mossakowski Medical Research Centre, Polish Academy of Sciences, Warsaw, Poland
| | - Monika Jampolska
- Laboratory of Respiration Physiology, Mossakowski Medical Research Centre, Polish Academy of Sciences, Warsaw, Poland
| | | |
Collapse
|
22
|
Barbe M, Gomez-Amaya S, Braverman A, Brown J, Lamarre N, Massicotte V, Lewis J, Dachert S, Ruggieri M. Evidence of vagus nerve sprouting to innervate the urinary bladder and clitoris in a canine model of lower motoneuron lesioned bladder. Neurourol Urodyn 2017; 36:91-97. [PMID: 26452068 PMCID: PMC4826634 DOI: 10.1002/nau.22904] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2015] [Accepted: 09/25/2015] [Indexed: 12/18/2022]
Abstract
AIMS Complete spinal cord injury does not block perceptual responses or inferior solitary nucleus activation after genital self-stimulation, even though the vagus is not thought to innervate pelvic structures. We tested if vagus nerve endings sprout after bladder decentralization to innervate genitourinary structures in canines with decentralized bladders. METHODS Four reinnervation surgeries were performed in female hounds: bilateral genitofemoral nerve transfer to pelvic nerve with vesicostomy (GNF-V) or without (GFN-NV); and left femoral nerve transfer (FNT-V and FNT-NV). After 8 months, retrograde dyes were injected into genitourinary structures. Three weeks later, at euthanasia, reinnervation was evaluated as increased detrusor pressure induced by functional electrical stimulation (FES). Controls included un-operated, sham-operated, and decentralized animals. RESULTS Increased detrusor pressure was seen in 8/12 GFNT-V, 4/5 GFNT-NV, 5/5 FNT-V, and 4/5 FNT-NV animals after FES, but not decentralized controls. Lumbar cord segments contained cells labeled from the bladder in all nerve transfer animals with FES-induced increased detrusor pressure. Nodose ganglia cells labeled from the bladder were observed in 5/7 nerve transfer animals (1/2 GNT-NV; 4/5 FNT-V), and from the clitoris were in 6/7 nerve transfer animals (2/2 GFNT-NV; 4/5 FNT-V). Dorsal motor nucleus vagus cells labeled from the bladder were observed in 3/5 nerve transfer animals (1/2 GFNT-NV; 2/3 FNT-V), and from the clitoris in 4/5 nerve transfer animals (1/2 GFNT-NV; 3/3 FNT-V). Controls lacked this labeling. CONCLUSIONS Evidence of vagal nerve sprouting to the bladder and clitoris was observed in canines with lower motoneuron lesioned bladders. Neurourol. Urodynam. 36:91-97, 2017. © 2015 Wiley Periodicals, Inc.
Collapse
Affiliation(s)
- M.F. Barbe
- Department of Anatomy and Cell Biology, Temple University School of Medicine, 3500 North Broad Street, Philadelphia, PA 19140
| | - S. Gomez-Amaya
- CAIF A1224, University of Pittsburgh, School of Medicine, 200 Lothrop St, Pittsburgh PA. 15213
| | - A.S. Braverman
- Department of Anatomy and Cell Biology, Temple University School of Medicine, 3500 North Broad Street, Philadelphia, PA 19140
| | - J.M. Brown
- Division of Neurosurgery, UCSD Medical Center, San Diego, CA 92103-8897
| | - N. Lamarre
- CAIF A1224, University of Pittsburgh, School of Medicine, 200 Lothrop St, Pittsburgh PA. 15213
| | - V.S. Massicotte
- Department of Anatomy and Cell Biology, Temple University School of Medicine, 3500 North Broad Street, Philadelphia, PA 19140
| | - J.K.S. Lewis
- Department of Anatomy and Cell Biology, Temple University School of Medicine, 3500 North Broad Street, Philadelphia, PA 19140
| | - S.R. Dachert
- Department of Anatomy and Cell Biology, Temple University School of Medicine, 3500 North Broad Street, Philadelphia, PA 19140
| | - M.R. Ruggieri
- Department of Anatomy and Cell Biology, Temple University School of Medicine, 3500 North Broad Street, Philadelphia, PA 19140
- Shriners Hospital of Philadelphia, Philadelphia, PA 19140
| |
Collapse
|
23
|
Wu SW, Lindberg JEM, Peters JH. Genetic and pharmacological evidence for low-abundance TRPV3 expression in primary vagal afferent neurons. Am J Physiol Regul Integr Comp Physiol 2016; 310:R794-805. [PMID: 26843581 DOI: 10.1152/ajpregu.00366.2015] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Accepted: 01/28/2016] [Indexed: 01/11/2023]
Abstract
Primary vagal afferent neurons express a multitude of thermosensitive ion channels. Within this family of ion channels, the heat-sensitive capsaicin receptor (TRPV1) greatly influences vagal afferent signaling by determining the threshold for action-potential initiation at the peripheral endings, while controlling temperature-sensitive forms of glutamate release at central vagal terminals. Genetic deletion of TRPV1 does not completely eliminate these temperature-dependent effects, suggesting involvement of additional thermosensitive ion channels. The warm-sensitive, calcium-permeable, ion channel TRPV3 is commonly expressed with TRPV1; however, the extent to which TRPV3 is found in vagal afferent neurons is unknown. Here, we begin to characterize the genetic and functional expression of TRPV3 in vagal afferent neurons using molecular biology (RT-PCR and RT-quantitative PCR) in whole nodose and isolated neurons and fluorescent calcium imaging on primary cultures of nodose ganglia neurons. We confirmed low-level TRPV3 expression in vagal afferent neurons and observed direct activation with putative TRPV3 agonists eugenol, ethyl vanillin (EVA), and farnesyl pyrophosphate (FPP). Agonist activation stimulated neurons also containing TRPV1 and was blocked by ruthenium red. FPP sensitivity overlapped with EVA and eugenol but represented the smallest percentage of vagal afferent neurons, and it was the only agonist that did not stimulate neurons from TRPV3(-/-1) mice, suggesting FPP has the highest selectivity. Further, FPP was predictive of enhanced responses to capsaicin, EVA, and eugenol in rats. From our results, we conclude TRPV3 is expressed in a discrete subpopulation of vagal afferent neurons and may contribute to vagal afferent signaling either directly or in combination with TRPV1.
Collapse
Affiliation(s)
- Shaw-Wen Wu
- Department of Integrative Physiology and Neuroscience, Washington State University, Pullman, Washington
| | - Jonathan E M Lindberg
- Department of Integrative Physiology and Neuroscience, Washington State University, Pullman, Washington
| | - James H Peters
- Department of Integrative Physiology and Neuroscience, Washington State University, Pullman, Washington
| |
Collapse
|
24
|
Zhang D, Muelleman RL, Li YL. Angiotensin II-superoxide-NFκB signaling and aortic baroreceptor dysfunction in chronic heart failure. Front Neurosci 2015; 9:382. [PMID: 26528122 PMCID: PMC4607814 DOI: 10.3389/fnins.2015.00382] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Accepted: 10/02/2015] [Indexed: 11/13/2022] Open
Abstract
Chronic heart failure (CHF) affects approximately 5.7 million people in the United States. Increasing evidence from both clinical and experimental studies indicates that the sensitivity of arterial baroreflex is blunted in the CHF state, which is a predictive risk factor for sudden cardiac death. Normally, the arterial baroreflex regulates blood pressure and heart rate through sensing mechanical alteration of arterial vascular walls by baroreceptor terminals in the aortic arch and carotid sinus. There are aortic baroreceptor neurons in the nodose ganglion (NG), which serve as the main afferent component of the arterial baroreflex. Functional changes of baroreceptor neurons are involved in the arterial baroreflex dysfunction in CHF. In the CHF state, circulating angiotensin II (Ang II) and local Ang II concentration in the NG are elevated, and AT1R mRNA and protein are overexpressed in the NG. Additionally, Ang II-superoxide-NFκB signaling pathway regulates the neuronal excitability of aortic baroreceptors through influencing the expression and activation of Nav channels in aortic baroreceptors, and subsequently causes the impairment of the arterial baroreflex in CHF. These new findings provide a basis for potential pharmacological interventions for the improvement of the arterial baroreflex sensitivity in the CHF state. This review summarizes the mechanisms responsible for the arterial baroreflex dysfunction in CHF.
Collapse
Affiliation(s)
- Dongze Zhang
- Department of Emergency Medicine, University of Nebraska Medical Center Omaha, NE, USA
| | - Robert L Muelleman
- Department of Emergency Medicine, University of Nebraska Medical Center Omaha, NE, USA
| | - Yu-Long Li
- Department of Emergency Medicine, University of Nebraska Medical Center Omaha, NE, USA
| |
Collapse
|
25
|
Vermehren-Schmaedick A, Khanjian RA, Balkowiec A. Cellular mechanisms of activity-dependent BDNF expression in primary sensory neurons. Neuroscience 2015; 310:665-73. [PMID: 26459016 DOI: 10.1016/j.neuroscience.2015.10.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Revised: 09/11/2015] [Accepted: 10/03/2015] [Indexed: 12/16/2022]
Abstract
Brain-derived neurotrophic factor (BDNF) is abundantly expressed by both developing and adult rat visceral sensory neurons from the nodose ganglion (NG) in vivo and in vitro. We have previously shown that BDNF is released from neonatal NG neurons by activity and regulates dendritic development in their postsynaptic targets in the brainstem. The current study was carried out to examine the cellular and molecular mechanisms of activity-dependent BDNF expression in neonatal rat NG neurons, using our established in vitro model of neuronal activation by electrical field stimulation with patterns that mimic neuronal activity in vivo. We show that BDNF mRNA (transcript 4) increases over threefold in response to a 4-h tonic or bursting pattern delivered at the frequency of 6 Hz, which corresponds to the normal heart rate of a newborn rat. No significant increase in BDNF expression was observed following stimulation at 1 Hz. The latter effect suggests a frequency-dependent mechanism of regulated BDNF expression. In addition to BDNF transcript 4, which is known to be regulated by activity, transcript 1 also showed significant upregulation. The increases in BDNF mRNA were followed by BDNF protein upregulation of a similar magnitude after 24h of stimulation at 6 Hz. Electrical stimulation-evoked BDNF expression was inhibited by pretreating neurons with the blocker of voltage-gated sodium channels tetrodotoxin and by removing extracellular calcium. Moreover, our data show that repetitive stimulation-evoked BDNF expression requires calcium influx through N-, but not L-type, channels. Together, our study reveals novel mechanisms through which electrical activity stimulates de novo synthesis of BDNF in sensory neurons, and points to the role of N-type calcium channels in regulating BDNF expression in sensory neurons in response to repetitive stimulation.
Collapse
|
26
|
Lu VB, Ikeda SR, Puhl HL 3rd. A 3.7 kb fragment of the mouse Scn10a gene promoter directs neural crest but not placodal lineage EGFP expression in a transgenic animal. J Neurosci 2015; 35:8021-34. [PMID: 25995484 DOI: 10.1523/JNEUROSCI.0214-15.2015] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Under physiological conditions, the voltage-gated sodium channel Nav1.8 is expressed almost exclusively in primary sensory neurons. The mechanism restricting Nav1.8 expression is not entirely clear, but we have previously described a 3.7 kb fragment of the Scn10a promoter capable of recapitulating the tissue-specific expression of Nav1.8 in transfected neurons and cell lines (Puhl and Ikeda, 2008). To validate these studies in vivo, a transgenic mouse encoding EGFP under the control of this putative sensory neuron specific promoter was generated and characterized in this study. Approximately 45% of dorsal root ganglion neurons of transgenic mice were EGFP-positive (mean diameter = 26.5 μm). The majority of EGFP-positive neurons bound isolectin B4, although a small percentage (∼10%) colabeled with markers of A-fiber neurons. EGFP expression correlated well with the presence of Nav1.8 transcript (95%), Nav1.8-immunoreactivity (70%), and TTX-R INa (100%), although not all Nav1.8-expressing neurons expressed EGFP. Several cranial sensory ganglia originating from neurogenic placodes, such as the nodose ganglion, failed to express EGFP, suggesting that additional regulatory elements dictate Scn10a expression in placodal-derived sensory neurons. EGFP was also detected in discrete brain regions of transgenic mice. Quantitative PCR and Nav1.8-immunoreactivity confirmed Nav1.8 expression in the amygdala, brainstem, globus pallidus, lateral and paraventricular hypothalamus, and olfactory tubercle. TTX-R INa recorded from EGFP-positive hypothalamic neurons demonstrate the usefulness of this transgenic line to study novel roles of Nav1.8 beyond sensory neurons. Overall, Scn10a-EGFP transgenic mice recapitulate the majority of the Nav1.8 expression pattern in neural crest-derived sensory neurons.
Collapse
|
27
|
Naznin F, Toshinai K, Waise TMZ, NamKoong C, Md Moin AS, Sakoda H, Nakazato M. Diet-induced obesity causes peripheral and central ghrelin resistance by promoting inflammation. J Endocrinol 2015; 226:81-92. [PMID: 26016745 PMCID: PMC4485401 DOI: 10.1530/joe-15-0139] [Citation(s) in RCA: 73] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 05/26/2015] [Indexed: 12/30/2022]
Abstract
Ghrelin, a stomach-derived orexigenic peptide, transmits starvation signals to the hypothalamus via the vagus afferent nerve. Peripheral administration of ghrelin does not induce food intake in high fat diet (HFD)-induced obese mice. We investigated whether this ghrelin resistance was caused by dysfunction of the vagus afferent pathway. Administration (s.c.) of ghrelin did not induce food intake, suppression of oxygen consumption, electrical activity of the vagal afferent nerve, phosphorylation of ERK2 and AMP-activated protein kinase alpha in the nodose ganglion, or Fos expression in hypothalamic arcuate nucleus of mice fed a HFD for 12 weeks. Administration of anti-ghrelin IgG did not induce suppression of food intake in HFD-fed mice. Expression levels of ghrelin receptor mRNA in the nodose ganglion and hypothalamus of HFD-fed mice were reduced. Inflammatory responses, including upregulation of macrophage/microglia markers and inflammatory cytokines, occurred in the nodose ganglion and hypothalamus of HFD-fed mice. A HFD blunted ghrelin signaling in the nodose ganglion via a mechanism involving in situ activation of inflammation. These results indicate that ghrelin resistance in the obese state may be caused by dysregulation of ghrelin signaling via the vagal afferent.
Collapse
Affiliation(s)
- Farhana Naznin
- Division of NeurologyRespirology, Endocrinology and Metabolism, Department of Internal Medicine, Faculty of Medicine, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki 889-1692, JapanDepartment of Sports and FitnessFaculty of Wellness, Shigakkan University, 55 Nakoyama, Yokone, Obu 474-8651, JapanAMED-CRESTAgency for Medical Research and Development, 1-7-1 Otemachi, Chiyoda-ku, Tokyo 100-0004, Japan
| | - Koji Toshinai
- Division of NeurologyRespirology, Endocrinology and Metabolism, Department of Internal Medicine, Faculty of Medicine, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki 889-1692, JapanDepartment of Sports and FitnessFaculty of Wellness, Shigakkan University, 55 Nakoyama, Yokone, Obu 474-8651, JapanAMED-CRESTAgency for Medical Research and Development, 1-7-1 Otemachi, Chiyoda-ku, Tokyo 100-0004, Japan Division of NeurologyRespirology, Endocrinology and Metabolism, Department of Internal Medicine, Faculty of Medicine, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki 889-1692, JapanDepartment of Sports and FitnessFaculty of Wellness, Shigakkan University, 55 Nakoyama, Yokone, Obu 474-8651, JapanAMED-CRESTAgency for Medical Research and Development, 1-7-1 Otemachi, Chiyoda-ku, Tokyo 100-0004, Japan
| | - T M Zaved Waise
- Division of NeurologyRespirology, Endocrinology and Metabolism, Department of Internal Medicine, Faculty of Medicine, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki 889-1692, JapanDepartment of Sports and FitnessFaculty of Wellness, Shigakkan University, 55 Nakoyama, Yokone, Obu 474-8651, JapanAMED-CRESTAgency for Medical Research and Development, 1-7-1 Otemachi, Chiyoda-ku, Tokyo 100-0004, Japan
| | - Cherl NamKoong
- Division of NeurologyRespirology, Endocrinology and Metabolism, Department of Internal Medicine, Faculty of Medicine, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki 889-1692, JapanDepartment of Sports and FitnessFaculty of Wellness, Shigakkan University, 55 Nakoyama, Yokone, Obu 474-8651, JapanAMED-CRESTAgency for Medical Research and Development, 1-7-1 Otemachi, Chiyoda-ku, Tokyo 100-0004, Japan
| | - Abu Saleh Md Moin
- Division of NeurologyRespirology, Endocrinology and Metabolism, Department of Internal Medicine, Faculty of Medicine, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki 889-1692, JapanDepartment of Sports and FitnessFaculty of Wellness, Shigakkan University, 55 Nakoyama, Yokone, Obu 474-8651, JapanAMED-CRESTAgency for Medical Research and Development, 1-7-1 Otemachi, Chiyoda-ku, Tokyo 100-0004, Japan
| | - Hideyuki Sakoda
- Division of NeurologyRespirology, Endocrinology and Metabolism, Department of Internal Medicine, Faculty of Medicine, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki 889-1692, JapanDepartment of Sports and FitnessFaculty of Wellness, Shigakkan University, 55 Nakoyama, Yokone, Obu 474-8651, JapanAMED-CRESTAgency for Medical Research and Development, 1-7-1 Otemachi, Chiyoda-ku, Tokyo 100-0004, Japan
| | - Masamitsu Nakazato
- Division of NeurologyRespirology, Endocrinology and Metabolism, Department of Internal Medicine, Faculty of Medicine, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki 889-1692, JapanDepartment of Sports and FitnessFaculty of Wellness, Shigakkan University, 55 Nakoyama, Yokone, Obu 474-8651, JapanAMED-CRESTAgency for Medical Research and Development, 1-7-1 Otemachi, Chiyoda-ku, Tokyo 100-0004, Japan Division of NeurologyRespirology, Endocrinology and Metabolism, Department of Internal Medicine, Faculty of Medicine, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki 889-1692, JapanDepartment of Sports and FitnessFaculty of Wellness, Shigakkan University, 55 Nakoyama, Yokone, Obu 474-8651, JapanAMED-CRESTAgency for Medical Research and Development, 1-7-1 Otemachi, Chiyoda-ku, Tokyo 100-0004, Japan
| |
Collapse
|
28
|
Herrity AN, Petruska JC, Stirling DP, Rau KK, Hubscher CH. The effect of spinal cord injury on the neurochemical properties of vagal sensory neurons. Am J Physiol Regul Integr Comp Physiol 2015; 308:R1021-33. [PMID: 25855310 DOI: 10.1152/ajpregu.00445.2014] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2014] [Accepted: 04/01/2015] [Indexed: 12/29/2022]
Abstract
The vagus nerve is composed primarily of nonmyelinated sensory neurons whose cell bodies are located in the nodose ganglion (NG). The vagus has widespread projections that supply most visceral organs, including the bladder. Because of its nonspinal route, the vagus nerve itself is not directly damaged from spinal cord injury (SCI). Because most viscera, including bladder, are dually innervated by spinal and vagal sensory neurons, an impact of SCI on the sensory component of vagal circuitry may contribute to post-SCI visceral pathologies. To determine whether SCI, in male Wistar rats, might impact neurochemical characteristics of NG neurons, immunohistochemical assessments were performed for P2X3 receptor expression, isolectin B4 (IB4) binding, and substance P expression, three known injury-responsive markers in sensory neuronal subpopulations. In addition to examining the overall population of NG neurons, those innervating the urinary bladder also were assessed separately. All three of the molecular markers were represented in the NG from noninjured animals, with the majority of the neurons binding IB4. In the chronically injured rats, there was a significant increase in the number of NG neurons expressing P2X3 and a significant decrease in the number binding IB4 compared with noninjured animals, a finding that held true also for the bladder-innervating population. Overall, these results indicate that vagal afferents, including those innervating the bladder, display neurochemical plasticity post-SCI that may have implications for visceral homeostatic mechanisms and nociceptive signaling.
Collapse
Affiliation(s)
- April N Herrity
- Department of Anatomical Sciences & Neurobiology, University of Louisville School of Medicine, Louisville, Kentucky; Kentucky Spinal Cord Injury Research Center, University of Louisville, Louisville, Kentucky
| | - Jeffrey C Petruska
- Department of Anatomical Sciences & Neurobiology, University of Louisville School of Medicine, Louisville, Kentucky; Kentucky Spinal Cord Injury Research Center, University of Louisville, Louisville, Kentucky; Department of Neurological Surgery, University of Louisville, Louisville, Kentucky
| | - David P Stirling
- Kentucky Spinal Cord Injury Research Center, University of Louisville, Louisville, Kentucky; Department of Neurological Surgery, University of Louisville, Louisville, Kentucky; Department of Microbiology & Immunology, University of Louisville School of Medicine, Louisville, Kentucky; and
| | - Kristofer K Rau
- Department of Anatomical Sciences & Neurobiology, University of Louisville School of Medicine, Louisville, Kentucky; Kentucky Spinal Cord Injury Research Center, University of Louisville, Louisville, Kentucky; Department of Anesthesiology, University of Louisville, Louisville, Kentucky
| | - Charles H Hubscher
- Department of Anatomical Sciences & Neurobiology, University of Louisville School of Medicine, Louisville, Kentucky; Kentucky Spinal Cord Injury Research Center, University of Louisville, Louisville, Kentucky;
| |
Collapse
|
29
|
Biddinger JE, Fox EA. Reduced intestinal brain-derived neurotrophic factor increases vagal sensory innervation of the intestine and enhances satiation. J Neurosci. 2014;34:10379-10393. [PMID: 25080597 DOI: 10.1523/JNEUROSCI.1042-14.2014] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Brain-derived neurotrophic factor (BDNF) is produced by developing and mature gastrointestinal (GI) tissues that are heavily innervated by autonomic neurons and may therefore control their development or function. To begin investigating this hypothesis, we compared the morphology, distribution, and density of intraganglionic laminar endings (IGLEs), the predominant vagal GI afferent, in mice with reduced intestinal BDNF (INT-BDNF(-/-)) and controls. Contrary to expectations of reduced development, IGLE density and longitudinal axon bundle number in the intestine of INT-BDNF(-/-) mice were increased, but stomach IGLEs were normal. INT-BDNF(-/-) mice also exhibited increased vagal sensory neuron numbers, suggesting that their survival was enhanced. To determine whether increased intestinal IGLE density or other changes to gut innervation in INT-BDNF(-/-) mice altered feeding behavior, meal pattern and microstructural analyses were performed. INT-BDNF(-/-) mice ate meals of much shorter duration than controls, resulting in reduced meal size. Increased suppression of feeding in INT-BDNF(-/-) mice during the late phase of a scheduled meal suggested that increased satiation signaling contributed to reduced meal duration and size. Furthermore, INT-BDNF(-/-) mice demonstrated increases in total daily intermeal interval and satiety ratio, suggesting that satiety signaling was augmented. Compensatory responses maintained normal daily food intake and body weight in INT-BDNF(-/-) mice. These findings suggest a target organ-derived neurotrophin suppresses development of that organ's sensory innervation and sensory neuron survival and demonstrate a role for BDNF produced by peripheral tissues in short-term controls of feeding, likely through its regulation of development or function of gut innervation, possibly including augmented intestinal IGLE innervation.
Collapse
|
30
|
Darling RA, Zhao H, Kinch D, Li AJ, Simasko SM, Ritter S. Mercaptoacetate and fatty acids exert direct and antagonistic effects on nodose neurons via GPR40 fatty acid receptors. Am J Physiol Regul Integr Comp Physiol 2014; 307:R35-43. [PMID: 24760994 DOI: 10.1152/ajpregu.00536.2013] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
β-mercaptoacetate (MA) is a drug known to block mitochondrial oxidation of medium- and long-chain fatty acids (FAs) and to stimulate feeding. Because MA-induced feeding is vagally dependent, it has been assumed that the feeding response is mediated by MA's antimetabolic action at a peripheral, vagally innervated site. However, MA's site of action has not yet been identified. Therefore, we used fluorescent calcium measurements in isolated neurons from rat nodose ganglia to determine whether MA has direct effects on vagal sensory neurons. We found that MA alone did not alter cytosolic calcium concentrations in nodose neurons. However, MA (60 μM to 6 mM) significantly decreased calcium responses to both linoleic acid (LA; 10 μM) and caprylic acid (C8; 10 μM) in all neurons responsive to LA and C8. GW9508 (40 μM), an agonist of the FA receptor, G protein-coupled receptor 40 (GPR40), also increased calcium levels almost exclusively in FA-responsive neurons. MA significantly inhibited this response to GW9508. MA did not inhibit calcium responses to serotonin, high K(+), or capsaicin, which do not utilize GPRs, or to CCK, which acts on a different GPR. GPR40 was detected in nodose ganglia by RT-PCR. Results suggest that FAs directly activate vagal sensory neurons via GPR40 and that MA antagonizes this effect. Thus, we propose that MA's nonmetabolic actions on GPR40 membrane receptors, expressed by multiple peripheral tissues in addition to the vagus nerve, may contribute to or mediate MA-induced stimulation of feeding.
Collapse
Affiliation(s)
- Rebecca A Darling
- Program in Neuroscience, Washington State University, Pullman, Washington
| | - Huan Zhao
- Program in Neuroscience, Washington State University, Pullman, Washington
| | - Dallas Kinch
- Program in Neuroscience, Washington State University, Pullman, Washington
| | - Ai-Jun Li
- Program in Neuroscience, Washington State University, Pullman, Washington
| | - Steven M Simasko
- Program in Neuroscience, Washington State University, Pullman, Washington
| | - Sue Ritter
- Program in Neuroscience, Washington State University, Pullman, Washington
| |
Collapse
|
31
|
Avau B, De Smet B, Thijs T, Geuzens A, Tack J, Vanden Berghe P, Depoortere I. Ghrelin is involved in the paracrine communication between neurons and glial cells. Neurogastroenterol Motil 2013; 25:e599-608. [PMID: 23781841 DOI: 10.1111/nmo.12171] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/12/2012] [Accepted: 05/20/2013] [Indexed: 02/08/2023]
Abstract
BACKGROUND Ghrelin is the only known peripherally active orexigenic hormone produced by the stomach that activates vagal afferents to stimulate food intake and to accelerate gastric emptying. Vagal sensory neurons within the nodose ganglia are surrounded by glial cells, which are able to receive and transmit chemical signals. We aimed to investigate whether ghrelin activates or influences the interaction between both types of cells. The effect of ghrelin was compared with that of leptin and cholecystokinin (CCK). METHODS Cultures of rat nodose ganglia were characterized by immunohistochemistry and the functional effects of peptides, neurotransmitters, and pharmacological blockers were measured by Ca(2+) imaging using Fluo-4-AM as an indicator. KEY RESULTS Neurons responded to KCl and were immunoreactive for PGP-9.5 whereas glial cells responded to lysophosphatidic acid and had the typical SOX-10-positive nuclear staining. Neurons were only responsive to CCK (31 ± 5%) whereas glial cells responded equally to the applied stimuli: ghrelin (27 ± 2%), leptin (21 ± 2%), and CCK (30 ± 2%). In contrast, neurons stained more intensively for the ghrelin receptor than glial cells. ATP induced [Ca(2+) ]i rises in 90% of the neurons whereas ACh and the NO donor, SIN-1, mainly induced [Ca(2+) ]i changes in glial cells (41 and 51%, respectively). The percentage of ghrelin-responsive glial cells was not affected by pretreatment with suramin, atropine, hexamethonium or 1400 W, but was reduced by l-NAME and by tetrodotoxin. Neurons were shown to be immunoreactive for neuronal NO-synthase (nNOS). CONCLUSIONS & INFERENCES Our data show that ghrelin induces Ca(2+) signaling in glial cells of the nodose ganglion via the release of NO originating from the neurons.
Collapse
Affiliation(s)
- B Avau
- Translational Research Center for Gastrointestinal Disorders, University of Leuven, Leuven, Belgium
| | | | | | | | | | | | | |
Collapse
|
32
|
Hübsch M, Neuhuber WL, Raab M. Muscarinic acetylcholine receptors in the mouse esophagus: focus on intraganglionic laminar endings (IGLEs). Neurogastroenterol Motil 2013; 25:e560-73. [PMID: 23742744 DOI: 10.1111/nmo.12161] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/05/2012] [Accepted: 05/04/2013] [Indexed: 02/08/2023]
Abstract
BACKGROUND IGLEs represent the only low-threshold vagal mechanosensory terminals in the tunica muscularis of the esophagus. Previously, close relationships of vesicular glutamate transporter 2 (VGLUT2) immunopositive IGLEs and cholinergic varicosities suggestive for direct contacts were described in almost all mouse esophageal myenteric ganglia. Possible cholinergic influence on IGLEs requires specific acetylcholine receptors. In particular, the occurrence and location of neuronal muscarinic acetylcholine receptors (mAChR) in the esophagus were not yet characterized. METHODS This study aimed at specifying relationships of VGLUT2 immunopositive IGLEs and vesicular acetylcholine transporter (VAChT)-immunopositive varicosities using pre-embedding electron microscopy and the location of mAChR1-3 (M1-3) within esophagus and nodose ganglia using multilabel immunofluorescence and retrograde tracing. KEY RESULTS Electron microscopy confirmed synaptic contacts between cholinergic varicosities and IGLEs. M1- and M2-immunoreactivities (-iry; -iries) were colocalized with VGLUT2-iry in subpopulations of IGLEs. Retrograde Fast Blue tracing from the esophagus showed nodose ganglion neurons colocalizing tracer and M2-iry. M1-3-iries were detected in about 80% of myenteric ganglia and in about 67% of myenteric neurons. M1- and M2-iry were present in many fibers and varicosities within myenteric ganglia. Presynaptic M2-iry was detected in all, presynaptic M3-iry in one-fifth of motor endplates of striated esophageal muscles. M1-iry could not be detected in motor endplates of the esophagus, but in sternomastoid muscle. CONCLUSIONS & INFERENCES Acetylcholine probably released from varicosities of both extrinsic and intrinsic origin may influence a subpopulation of esophageal IGLEs via M2 and M1-receptors.
Collapse
Affiliation(s)
- M Hübsch
- Institute of Anatomy I, University of Erlangen-Nuremberg, Erlangen, Germany
| | | | | |
Collapse
|
33
|
Goldberg D, Borojevic R, Anderson M, Chen JJ, Gershon MD, Ratcliffe EM. Slit/Robo-mediated chemorepulsion of vagal sensory axons in the fetal gut. Dev Dyn 2013; 242:9-15. [PMID: 23161783 PMCID: PMC3688041 DOI: 10.1002/dvdy.23898] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/17/2012] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND The vagus nerve descends from the brain to the gut during fetal life to reach specific targets in the bowel wall. Vagal sensory axons have been shown to respond to the axon guidance molecule netrin and to its receptor, deleted in colorectal cancer (DCC). As there are regions of the gut wall into which vagal axons do and do not extend, it is likely that a combination of attractive and repellent cues are involved in how vagal axons reach specific targets. We tested the hypothesis that Slit/Robo chemorepulsion can contribute to the restriction of vagal sensory axons to specific targets in the gut wall. RESULTS Transcripts encoding Robo1 and Robo2 were expressed in the nodose ganglia throughout development and mRNA encoding the Robo ligands Slit1, Slit2, and Slit3 were all found in the fetal and adult bowel. Slit2 protein was located in the outer gut mesenchyme in regions that partially overlap with the secretion of netrin-1. Neurites extending from explanted nodose ganglia were repelled by Slit2. CONCLUSIONS These observations suggest that vagal sensory axons are responsive to Slit proteins and are thus repelled by Slits secreted in the gut wall and prevented from reaching inappropriate targets.
Collapse
Affiliation(s)
- David Goldberg
- School of Dentistry, University of Western Ontario, London, Ontario, Canada
| | - Rajka Borojevic
- Department of Pediatrics, McMaster University, Hamilton, Ontario, Canada
- Farncombe Family Digestive Health Research Institute, McMaster University, Hamilton, Ontario, Canada
| | - Monique Anderson
- School of Medicine, University of Virginia, Charlottesville, Virginia
| | - Jason J. Chen
- Department of Pathology and Cell Biology, Columbia University, New York, New York
| | - Michael D. Gershon
- Department of Pathology and Cell Biology, Columbia University, New York, New York
| | - Elyanne M. Ratcliffe
- Department of Pediatrics, McMaster University, Hamilton, Ontario, Canada
- Farncombe Family Digestive Health Research Institute, McMaster University, Hamilton, Ontario, Canada
| |
Collapse
|
34
|
Andrei F, Didilescu AC, Rusu MC. Evidence of nNOS and ChAT positive phenotypes in nervous ganglia of the retrostyloid space. J Med Life 2012; 5:482-5. [PMID: 23346255 PMCID: PMC3539831] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2012] [Accepted: 12/06/2012] [Indexed: 11/16/2022] Open
Abstract
The cholinergic and nitrergic phenotypes in human fetal ganglia (inferior) of the glossopharyngeal and vagus nerves were overlooked in basic research. Lack of a positive neuronal NO synthase (nNOS) phenotype in the inferior vagal fetal ganglion was recently suggested to be an individually variable phenotype. Choline acetyltransferase (ChAT) was not evaluated previously in ontogenesis. We aimed to evaluate these phenotypes in human midterm fetuses. Samples from five specimens with gestational ages varying from 4 to 6 months were used. Immunohistochemistry for nNOS, ChAT, neurofilaments, and S100 protein was performed. Neuronal somata were positively stained for nNOS, ChAT and neurofilaments in the inferior glossopharyngeal and vagal ganglia. S100 protein distinctively labelled the satellite glial cells ensheating the respective neurons. In human midterm fetuses vagal and glossopharyngeal inferior ganglia are nitrergic and cholinergic. To evaluate a functional role of these phenotypes in ontogenesis, the specific anatomic circuits should be further checked. Differences in immune labelling should be evaluated by use of similar antibodies from different manufacturers.
Collapse
Affiliation(s)
- F Andrei
- Department of Anatomy, Faculty of Medicine, "Victor Babeş" University of Medicine and Pharmacy, Timişoara, Romania
| | - AC Didilescu
- Discipline of Embryology, Faculty of Dental Medicine, “Carol Davila" University of Medicine and Pharmacy, Bucharest, Romania
| | - MC Rusu
- Discipline of Anatomy, Faculty of Dental Medicine, “Carol Davila" University of Medicine and Pharmacy, Bucharest, Romania,MEDCENTER – Center of Excellence in Laboratory Medicine and Pathology
| |
Collapse
|
35
|
Burdyga G, Varro A, Dimaline R, Thompson DG, Dockray GJ. Expression of cannabinoid CB1 receptors by vagal afferent neurons: kinetics and role in influencing neurochemical phenotype. Am J Physiol Gastrointest Liver Physiol 2010; 299:G63-9. [PMID: 20430875 PMCID: PMC2904113 DOI: 10.1152/ajpgi.00059.2010] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The intestinal hormone cholecystokinin (CCK) inhibits food intake via stimulation of vagal afferent neurons (VAN). Recent studies suggest that CCK also regulates the expression of some G protein-coupled receptors and neuropeptide transmitters in these neurons. The aim of the present study was to characterize the expression of cannabinoid (CB)1 receptors in VAN and to determine whether stimulation of these receptors plays a role in regulating neurochemical phenotype. Expression of CB1 in rat VAN was detectable by in situ hybridization or immunohistochemistry after 6 h of fasting and increased to a maximum after 24 h when approximately 50% of neurons in the mid and caudal regions expressed the receptor. Melanin-concentrating hormone (MCH)1 receptors also increased with fasting, but the changes were delayed compared with CB1; in contrast Y2 receptors (Y2R) exhibited reciprocal changes in expression to CB1. Administration of CCK8s (10 nmol ip) to fasted rats decreased expression of CB1 with a t(1/2) of approximately 1 h compared with 3 h for MCH1. The action of CCK8s was inhibited by ghrelin and orexin-A. The CB1 agonist anandamide (intraperitoneally) reversed the effect of CCK8s on CB1, MCH1, and Y2 receptor expression. In contrast, in rats fasted for 18 h, administration of a CB1 antagonist/inverse agonist (AM281 ip) downregulated CB1 expression and increased Y2 receptor expression. Activation of vagal CB1 receptors therefore influences the neurochemical phenotype of these neurons, indicating a new and hitherto unrecognized role for endocannabinoids in gut-brain signaling.
Collapse
Affiliation(s)
- Galina Burdyga
- 1Physiological Laboratory, School of Biomedical Sciences, University of Liverpool, Liverpool;
| | - Andrea Varro
- 1Physiological Laboratory, School of Biomedical Sciences, University of Liverpool, Liverpool;
| | - Rod Dimaline
- 1Physiological Laboratory, School of Biomedical Sciences, University of Liverpool, Liverpool;
| | - David G. Thompson
- 2Division of Gastroenterology, Hope University Hospital, Salford, United Kingdom
| | - Graham J. Dockray
- 1Physiological Laboratory, School of Biomedical Sciences, University of Liverpool, Liverpool;
| |
Collapse
|
36
|
Jia Y, Wang X, Aponte SI, Rivelli MA, Yang R, Rizzo CA, Corboz MR, Priestley T, Hey JA. Nociceptin/orphanin FQ inhibits capsaicin-induced guinea-pig airway contraction through an inward-rectifier potassium channel. Br J Pharmacol 2002; 135:764-70. [PMID: 11834624 PMCID: PMC1573179 DOI: 10.1038/sj.bjp.0704515] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2001] [Revised: 10/02/2001] [Accepted: 11/16/2001] [Indexed: 11/08/2022] Open
Abstract
Nociceptin/orphanin FQ (N/OFQ), an endogenous opioid-like orphan receptor (NOP receptor, previously termed ORL1 receptor) agonist, has been found to inhibit capsaicin-induced bronchoconstriction in isolated guinea-pig lungs and in vivo. The underlying mechanisms are not clear. In the present studies, we tested the effect of N/OFQ on VR1 channel function in isolated guinea-pig nodose ganglia cells. Capsaicin increased intracellular Ca(2+) concentration in these cells through activation of vanilloid receptors. Capsaicin-induced Ca(2+) responses were attenuated by pretreatment of nodose neurons with N/OFQ (1 microM). N/OFQ inhibitory effect on the Ca(2+) response in nodose ganglia cells was antagonized by tertiapin (0.5 microM), an inhibitor of inward-rectifier K(+) channels, but not by verapamil, a voltage gated Ca(2+) channel blocker, indicating that an inward-rectifier K(+) channel is involved in N/OFQ inhibitory effect. In isolated guinea-pig bronchus, N/OFQ (1 microM) inhibited capsaicin-induced airway contraction. Tertiapin (0.5 microM) abolished the N/OFQ inhibition of capsaicin-induced bronchial contraction. Capsaicin (10 microg) increased pulmonary inflation pressure in the isolated perfused guinea-pig lungs. This response was significantly attenuated by pretreatment with N/OFQ (1 microM). Tertiapin also abolished the N/OFQ inhibitory effect on capsaicin-induced bronchoconstriction in perfused lungs. Capsaicin increased the release of substance P and neurokinin A from isolated lungs. N/OFQ (1 microM) blocked the capsaicin-induced tachykinin release. These results indicate that N/OFQ-induced hyperpolarization of tachykinin containing airway sensory nerves, through an inward-rectifier K(+) channel activation, accounts for the inhibition of capsaicin-evoked broncoconstriction.
Collapse
Affiliation(s)
- Yanlin Jia
- Allergy, Schering-Plough Research Institute, Kenilworth, New Jersey 07033, USA.
| | | | | | | | | | | | | | | | | |
Collapse
|
37
|
Abstract
1. The aim of this study was to investigate a role for Epithelial Sodium Channels (ENaCs) in the mechanical activation of low-threshold vagal afferent nerve terminals in the guinea-pig trachea/bronchus. 2. Using extracellular single-unit recording techniques, we found that the ENaC blocker amiloride, and its analogues dimethylamiloride and benzamil caused a reduction in the mechanical activation of guinea-pig airway afferent fibres. 3. Amiloride and it analogues also reduced the sensitivity of afferent fibres to electrical stimulation such that greater stimulation voltages were required to induce action potentials from their peripheral terminals within the trachea/bronchus. 4. The relative potencies of these compounds for inhibiting electrical excitability of afferent nerves were similar to that observed for inhibition of mechanical stimulation (dimethylamiloride approximately benzamil > amiloride). This rank order of potency is incompatible with the known rank order of potency for blockade of ENaCs (benzamil > amiloride >> dimethylamiloride). 5. As voltage-gated sodium channels play an important role in determining the electrical excitability of neurons, we used whole-cell patch recordings of nodose neuron cell bodies to investigate the possibility that amiloride analogues caused blockade of these channels. At the concentration required to inhibit mechanical activation of vagal nodose afferent fibres (100 microM), benzamil caused significant inhibition of voltage-gated sodium currents in neuronal cell bodies acutely isolated from guinea-pig nodose ganglia. 6. Combined, our findings suggest that amiloride and its analogues did not selectively block mechanotransduction in airway afferent neurons, but rather they reduced neuronal excitability, possibly by inhibiting voltage-gated sodium currents.
Collapse
Affiliation(s)
- Michael J Carr
- Johns Hopkins Asthma and Allergy Center, 5501 Hopkins Bayview Circle, Baltimore, Maryland, MD 21224, U.S.A
| | - Tony D Gover
- Department of Pharmacology and Experimental Therapeutics, University of Maryland School of Medicine, 655 West Baltimore Street, Baltimore, Maryland, MD 21201, U.S.A
| | - Daniel Weinreich
- Department of Pharmacology and Experimental Therapeutics, University of Maryland School of Medicine, 655 West Baltimore Street, Baltimore, Maryland, MD 21201, U.S.A
| | - Bradley J Undem
- Johns Hopkins Asthma and Allergy Center, 5501 Hopkins Bayview Circle, Baltimore, Maryland, MD 21224, U.S.A
- Author for correspondence:
| |
Collapse
|
38
|
Erickson JT, Brosenitsch TA, Katz DM. Brain-derived neurotrophic factor and glial cell line-derived neurotrophic factor are required simultaneously for survival of dopaminergic primary sensory neurons in vivo. J Neurosci 2001; 21:581-9. [PMID: 11160437 PMCID: PMC6763821] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/18/2023] Open
Abstract
Null mutations affecting members of the transforming growth factor-beta and neurotrophin families result in overlapping patterns of neuronal cell death. This is particularly striking in the cranial sensory nodose-petrosal ganglion complex (NPG), in which loss of either glial cell line-derived neurotrophic factor (GDNF), brain-derived neurotrophic factor (BDNF), neurotrophin-3 (NT-3), or neurotrophin-4 (NT-4) results in a 30-50% reduction in neuronal survival. It is unknown, however, whether GDNF and any single neurotrophin support survival of the same cells, and if so, whether they are required simultaneously or sequentially during development. To approach these issues we defined survival requirements of nodose and petrosal neurons for GDNF in vitro and in bdnf, gdnf, and bdnf/gdnf null mutant mice, as well as the distribution of GDNF in NPG target tissues. Our analyses focused on the total population of ganglion cells as well as the subset of NPG neurons that are dopaminergic. Neuron losses in bdnf/gdnf double mutants are not additive of the losses in single bdnf or gdnf null mutants, indicating that many cells, including dopaminergic neurons, require both GDNF and BDNF for survival in vivo. Moreover, both factors are required during the same period of development, between embryonic day (E) 15.5 and E17.5. In addition, GDNF, like BDNF is expressed in target tissues at the time of initial target innervation and coincident with GDNF dependence of the innervating neurons. Together, these findings demonstrate that both GDNF and BDNF can act as target-derived trophic factors and are required simultaneously for survival of some primary sensory neurons.
Collapse
Affiliation(s)
- J T Erickson
- Department of Neurosciences, Case Western Reserve University School of Medicine, Cleveland, Ohio 44106, USA
| | | | | |
Collapse
|
39
|
Dunn PM, Liu M, Zhong Y, King BF, Burnstock G. Diinosine pentaphosphate: an antagonist which discriminates between recombinant P2X(3) and P2X(2/3) receptors and between two P2X receptors in rat sensory neurones. Br J Pharmacol 2000; 130:1378-84. [PMID: 10903979 PMCID: PMC1572177 DOI: 10.1038/sj.bjp.0703404] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
1. We have compared the antagonist activity of trinitrophenyl-ATP (TNP-ATP) and diinosine pentaphosphate (Ip(5)I) on recombinant P2X receptors expressed in Xenopus oocytes with their actions at native P2X receptors in sensory neurones from dorsal root and nodose ganglia. 2. Slowly-desensitizing responses to alpha,beta-methylene ATP (alpha,beta-meATP) recorded from oocytes expressing P2X(2/3) receptors were inhibited by TNP-ATP at sub-micromolar concentrations. However, Ip(5)I at concentrations up to 30 microM was without effect. 3. Nodose ganglion neurones responded to alpha,beta-meATP with slowly-desensitizing inward currents. These were inhibited by TNP-ATP (IC(50), 20 nM), but not by Ip(5)I at concentrations up to 30 microM. 4. In DRG neurones that responded to ATP with a rapidly-desensitizing inward current, the response was inhibited by TNP-ATP with an IC(50) of 0.8 nM. These responses were also inhibited by Ip(5)I with an IC(50) of 0.1 microM. Both antagonists are known to inhibit homomeric P2X(3) receptors. 5. Some DRG neurones responded to alpha,beta-meATP with a biphasic inward current, consisting of transient and sustained components. While the transient current was abolished by 1 microM Ip(5)I, the sustained component remained unaffected. 6. In conclusion, Ip(5)I is a potent antagonist at homomeric P2X(3) receptors but not at heteromeric P2X(2/3) receptors, and therefore should be a useful tool for elucidating the subunit composition of native P2X receptors.
Collapse
MESH Headings
- Adenosine Triphosphate/analogs & derivatives
- Adenosine Triphosphate/pharmacology
- Animals
- Animals, Newborn
- DNA, Complementary/administration & dosage
- DNA, Complementary/genetics
- DNA, Recombinant/administration & dosage
- DNA, Recombinant/genetics
- Dinucleoside Phosphates/pharmacology
- Dose-Response Relationship, Drug
- Female
- Ganglia, Spinal/cytology
- Ganglia, Spinal/drug effects
- Ganglia, Spinal/physiology
- Membrane Potentials/drug effects
- Neurons, Afferent/cytology
- Neurons, Afferent/drug effects
- Neurons, Afferent/physiology
- Nodose Ganglion/cytology
- Nodose Ganglion/drug effects
- Nodose Ganglion/physiology
- Oocytes
- Rats
- Receptors, Purinergic P2/genetics
- Receptors, Purinergic P2/physiology
- Receptors, Purinergic P2X2
- Receptors, Purinergic P2X3
- Xenopus
Collapse
Affiliation(s)
- P M Dunn
- Autonomic Neuroscience Institute, Royal Free and University College Medical School, London.
| | | | | | | | | |
Collapse
|
40
|
Broberger C, Holmberg K, Kuhar MJ, Hökfelt T. Cocaine- and amphetamine-regulated transcript in the rat vagus nerve: A putative mediator of cholecystokinin-induced satiety. Proc Natl Acad Sci U S A 1999; 96:13506-11. [PMID: 10557351 PMCID: PMC23978 DOI: 10.1073/pnas.96.23.13506] [Citation(s) in RCA: 109] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Cocaine- and amphetamine-regulated transcript (CART) is widely expressed in the central nervous system. Recent studies have pointed to a role for CART-derived peptides in inhibiting feeding behavior. Although these actions have generally been attributed to hypothalamic CART, it remains to be determined whether additional CART pathways exist that link signals from the gastrointestinal tract to the central control of food intake. In the present study, we have investigated the presence of CART in the rat vagus nerve and nodose ganglion. In the viscerosensory nodose ganglion, half of the neuron profiles expressed CART and its predicted peptide, as determined by in situ hybridization and immunohistochemistry. CART expression was markedly attenuated after vagotomy, but no modulation was observed after food restriction or high-fat regimes. A large proportion of CART-labeled neuron profiles also expressed cholecystokinin A receptor mRNA. CART-peptide-like immunoreactivity was transported in the vagus nerve and found in a dense fiber plexus in the nucleus tractus solitarii. Studies on CART in the spinal somatosensory system revealed strong immunostaining of the dorsal horn but only a small number of stained cell bodies in dorsal root ganglia. The present results suggest that CART-derived peptides are present in vagal afferent neurons sensitive to cholecystokinin, suggesting that the role of these peptides in feeding may be explained partly by mediating postprandial satiety effects of cholecystokinin.
Collapse
Affiliation(s)
- C Broberger
- Department of Neuroscience, Karolinska Institutet, 171 77 Stockholm, Sweden.
| | | | | | | |
Collapse
|
41
|
Brady R, Zaidi SI, Mayer C, Katz DM. BDNF is a target-derived survival factor for arterial baroreceptor and chemoafferent primary sensory neurons. J Neurosci 1999; 19:2131-42. [PMID: 10066266 PMCID: PMC6782548] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/1998] [Accepted: 01/04/1999] [Indexed: 02/11/2023] Open
Abstract
Brain-derived neurotrophic factor (BDNF) supports survival of 50% of visceral afferent neurons in the nodose/petrosal sensory ganglion complex (NPG; Ernfors et al., 1994a; Jones et al., 1994; Conover et al., 1995; Liu et al., 1995; Erickson et al., 1996), including arterial chemoafferents that innervate the carotid body and are required for development of normal breathing (Erickson et al., 1996). However, the relationship between BDNF dependence of visceral afferents and the location and timing of BDNF expression in visceral tissues is unknown. The present study demonstrates that BDNF mRNA and protein are transiently expressed in NPG targets in the fetal cardiac outflow tract, including baroreceptor regions in the aortic arch, carotid sinus, and right subclavian artery, as well as in the carotid body. The period of BDNF expression corresponds to the onset of sensory innervation and to the time at which fetal NPG neurons are BDNF-dependent in vitro. Moreover, baroreceptor innervation is absent in newborn mice lacking BDNF. In addition to vascular targets, vascular afferents themselves express high levels of BDNF, both during and after the time they are BDNF-dependent. However, endogenous BDNF supports survival of fetal NPG neurons in vitro only under depolarizing conditions. Together, these data indicate two roles for BDNF during vascular afferent pathway development; initially, as a target-derived survival factor, and subsequently, as a signaling molecule produced by the afferents themselves. Furthermore, the fact that BDNF is required for survival of functionally distinct populations of vascular afferents demonstrates that trophic requirements of NPG neurons are not modality-specific but may instead be associated with innervation of particular organ systems.
Collapse
Affiliation(s)
- R Brady
- Department of Neurosciences, Case Western Reserve University School of Medicine, Cleveland, Ohio 44106-4975, USA
| | | | | | | |
Collapse
|
42
|
Ek M, Kurosawa M, Lundeberg T, Ericsson A. Activation of vagal afferents after intravenous injection of interleukin-1beta: role of endogenous prostaglandins. J Neurosci 1998; 18:9471-9. [PMID: 9801384 PMCID: PMC6792875] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023] Open
Abstract
Intravenous administration of interleukin-1 (IL-1) activates central autonomic neuronal circuitries originating in the nucleus of the solitary tract (NTS). The mechanism(s) by which blood-borne IL-1 regulates brain functions, whether by operating across the blood-brain barrier and/or by activating peripheral sensory afferents, remains to be characterized. It has been proposed that vagal afferents originating in the periphery may monitor circulating IL-1 levels, because neurons within the NTS are primary recipients of sensory information from the vagus nerve and also exhibit exquisite sensitivity to blood-borne IL-1. In this study, we present evidence that viscerosensory afferents of the vagus nerve respond to intravenously administered IL-1beta. Specific labeling for mRNAs encoding the type 1 IL-1 receptor and the EP3 subtype of the prostaglandin E2 receptor was detected in situ over neuronal cell bodies in the rat nodose ganglion. Moreover, intravenously applied IL-1 increased the number of sensory neurons in the nodose ganglion that express the cellular activation marker c-Fos, which was matched by an increase in discharge activity of vagal afferents arising from gastric compartments. This response to IL-1 administration was attenuated in animals pretreated with the cyclooxygenase inhibitor indomethacin, suggesting partial mediation by prostaglandins. In conclusion, these results demonstrate that somata and/or fibers of sensory neurons of the vagus nerve express receptors to IL-1 and prostaglandin E2 and that circulating IL-1 stimulates vagal sensory activity via both prostaglandin-dependent and -independent mechanisms.
Collapse
Affiliation(s)
- M Ek
- Department of Medicine, Unit of Rheumatology, The Karolinska Institute, Stockholm, Sweden
| | | | | | | |
Collapse
|
43
|
Abstract
1. In the present study, in vitro electrophysiology and receptor autoradiography were used to determine whether rat vagal afferent neurones possess gamma-aminobutyric acid (GABA)A receptors. 2. GABA (1-100 microM) and isoguvacine (3-100 microM) caused a concentration-dependent depolarization of the rat isolated nodose ganglion preparation at room temperature. When applied to the tissue 20 min before the agonist, SR95531 (3 microM) and bicuculline (3 microM) caused a parallel shift to the right of the GABA and isoguvacine concentration-response curves, yielding shifts of 81 fold and 117 fold for SR95531 and 4 fold and 12 fold for bicuculline, respectively. 3. Baclofen (10 nM-100 microM) was unable to elicit a depolarization of the rat isolated nodose ganglion preparation at either room temperature or at 36 degrees C, whilst 5-aminovaleric acid (10 microM), a GABAB receptor antagonist, was unable to antagonize significantly the GABA-induced depolarization at either room temperature or at 36 degrees C. 4. [3H]-SR95531 (7.2 nM), a GABAA receptor-selective antagonist, bound topographically to sections of rat brainstem. Specific binding was highest in the medial nucleus tractus solitarius (NTS) and dorsal motor nucleus of the vagus nerve (DMVN). Binding was also observed in certain medullary reticular nuclei, in particular the parvocellular reticular nucleus. 5. Unilateral nodose ganglionectomy caused a reduction in GABAA binding site density in the medial NTS from 93 +/- 7 to 68 +/- 6 d.p.m./mm2. This procedure also caused a reduction in GABAA binding site density in the side of the NTS contralateral to the lesion, from 151 +/- 12 to 93 +/- 7 d.p.m./mm2. Sham surgery had no effect on the binding of [3H]-SR95531 in rat brainstem. 6. The present data provide evidence for the presence of GABAA receptors located on the soma and central terminals of rat vagal afferent neurones. Additionally, a population of GABAA receptors is evidenced postsynaptically in the rat NTS with respect to vagal afferent terminals. These data are discussed in relation to the functional pharmacology of GABA in this region of the NTS.
Collapse
Affiliation(s)
- M Ashworth-Preece
- Department of Pharmacology, Monash University, Clayton, Victoria, Australia
| | | | | | | |
Collapse
|