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Lale N, Ditting T, Hilgers KF, Linz P, Ott C, Schmieder RE, Schiffer M, Amann K, Veelken R, Rodionova K. Afferent neurons of the kidney with impaired firing pattern in inflammation - role of sodium currents? Pflugers Arch 2023; 475:1329-1342. [PMID: 37672108 PMCID: PMC10567872 DOI: 10.1007/s00424-023-02852-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2023] [Revised: 08/15/2023] [Accepted: 08/16/2023] [Indexed: 09/07/2023]
Abstract
Peripheral neurons with renal afferents exhibit a predominantly tonic firing pattern of higher frequency that is reduced to low frequencies (phasic firing pattern) in renal inflammation. We wanted to test the hypothesis that the reduction in firing activity during inflammation is due to high-activity tonic neurons switching from higher to low frequencies depending on altered sodium currents. We identified and cultivated afferent sensory neurons with renal projections from the dorsal root ganglia (Th11-L2). Cultivated neurons were incubated with the chemokine CXCL1 (1,5 nmol/ml) for 12 h. We characterized neurons as "tonic," i.e., sustained action potential (AP) firing, or "phasic," i.e., < 5 APs upon stimulation in the current clamp. Their membrane currents were investigated in a voltage clamp. Data analyzed: renal vs. non-renal and tonic vs. phasic neurons. Renal afferent neurons exposed to CXCL1 showed a decrease in tonic firing pattern (CXCL1: 35,6% vs. control: 57%, P < 0.05). Na+ and K+ currents were not different between control renal and non-renal DRG neurons. Phasic neurons exhibited higher Na+ and K+ currents than tonic resulting in shorter APs (3.7 ± 0.3 vs. 6.1 ± 0.6 ms, P < 0.01). In neurons incubated with CXCL1, Na+ and K+ peak current density increased in phasic (Na+: - 969 ± 47 vs. - 758 ± 47 nA/pF, P < 0.01; K+: 707 ± 22 vs. 558 ± 31 nA/pF, P < 0.01), but were unchanged in tonic neurons. Phasic neurons exposed to CXCL1 showed a broader range of Na+ currents ([- 365- - 1429 nA] vs. [- 412- - 4273 nA]; P < 0.05) similar to tonic neurons. After CXCL1 exposure, significant changes in phasic neurons were observed in sodium activation/inactivation as well as a wider distribution of Na+ currents characteristic of tonic neurons. These findings indicate a subgroup of tonic neurons besides mere tonic or phasic neurons exists able to exhibit a phasic activity pattern under pathological conditions.
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Affiliation(s)
- Nena Lale
- Department of Internal Medicine 4 Nephrology and Hypertension, Friedrich-Alexander University Erlangen, 91054, Erlangen, Germany
| | - Tilmann Ditting
- Department of Internal Medicine 4 Nephrology and Hypertension, Friedrich-Alexander University Erlangen, 91054, Erlangen, Germany
- Department of Internal Medicine 4 - Nephrology and Hypertension, Paracelsus Private Medical School Nuremberg, Nuremberg, Germany
| | - Karl F Hilgers
- Department of Internal Medicine 4 Nephrology and Hypertension, Friedrich-Alexander University Erlangen, 91054, Erlangen, Germany
| | - Peter Linz
- Department of Radiology, Friedrich-Alexander University Erlangen, 91054, Erlangen, Germany
| | - Christian Ott
- Department of Internal Medicine 4 Nephrology and Hypertension, Friedrich-Alexander University Erlangen, 91054, Erlangen, Germany
- Department of Internal Medicine 4 - Nephrology and Hypertension, Paracelsus Private Medical School Nuremberg, Nuremberg, Germany
| | - Roland E Schmieder
- Department of Internal Medicine 4 Nephrology and Hypertension, Friedrich-Alexander University Erlangen, 91054, Erlangen, Germany
| | - Mario Schiffer
- Department of Internal Medicine 4 Nephrology and Hypertension, Friedrich-Alexander University Erlangen, 91054, Erlangen, Germany
| | - Kerstin Amann
- Department of Nephropathology, Friedrich-Alexander University Erlangen, 91054, Erlangen, Germany
| | - Roland Veelken
- Department of Internal Medicine 4 Nephrology and Hypertension, Friedrich-Alexander University Erlangen, 91054, Erlangen, Germany.
- Department of Internal Medicine 4 - Nephrology and Hypertension, Paracelsus Private Medical School Nuremberg, Nuremberg, Germany.
| | - Kristina Rodionova
- Department of Internal Medicine 4 Nephrology and Hypertension, Friedrich-Alexander University Erlangen, 91054, Erlangen, Germany
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Pickny L, Hindermann M, Ditting T, Hilgers KF, Linz P, Ott C, Schmieder RE, Schiffer M, Amann K, Veelken R, Rodionova K. Myocardial infarction with a preserved ejection fraction-the impaired function of the cardio-renal baroreflex. Front Physiol 2023; 14:1144620. [PMID: 37082237 PMCID: PMC10110856 DOI: 10.3389/fphys.2023.1144620] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2023] [Accepted: 03/14/2023] [Indexed: 04/22/2023] Open
Abstract
Introduction: In experimental myocardial infarction with reduced ejection fraction causing overt congestive heart failure, the control of renal sympathetic nerve activity (RSNA) by the cardio-renal baroreflex was impaired. The afferent vagal nerve activity under these experimental conditions had a lower frequency at saturation than that in controls. Hence, by investigating respective first neurons in the nodose ganglion (NG), we wanted to test the hypothesis that after myocardial infarction with still-preserved ejection fraction, the cardiac afferent nerve pathway is also already impaired. Material and methods: A myocardial infarction was induced by coronary artery ligature. After 21 days, nodose ganglion neurons with cardiac afferents from rats with myocardial infarction were cultured. A current clamp was used to characterize neurons as "tonic," i.e., sustained action potential (AP) firing, or "phasic," i.e., <5 APs upon current injection. Cardiac ejection fraction was measured using echocardiography; RSNA was recorded to evaluate the sensitivity of the cardiopulmonary baroreflex. Renal and cardiac histology was studied for inflammation and fibrosis markers. Results: A total of 192 neurons were investigated. In rats, after myocardial infarction, the number of neurons with a tonic response pattern increased compared to that in the controls (infarction vs. control: 78.6% vs. 48.5%; z-test, *p < 0.05), with augmented production of APs (23.7 ± 2.86 vs. 15.5 ± 1.86 APs/600 ms; mean ± SEM, t-test, *p < 0.05). The baseline activity of RSNA was subtly increased, and its control by the cardiopulmonary baroreflex was impaired following myocardial infarction: the fibrosis marker collagen I augmented in the renal interstitium. Discussion: After myocardial infarction with still-preserved ejection fraction, a complex impairment of the afferent limb of the cardio-renal baroreflex caused dysregulation of renal sympathetic nerve activity with signs of renal fibrosis.
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Affiliation(s)
- Lisa Pickny
- Department of Internal Medicine 4—Nephrology and Hypertension, Friedrich-Alexander University Erlangen, Erlangen, Germany
| | - Martin Hindermann
- Department of Internal Medicine 4—Nephrology and Hypertension, Friedrich-Alexander University Erlangen, Erlangen, Germany
| | - Tilmann Ditting
- Department of Internal Medicine 4—Nephrology and Hypertension, Friedrich-Alexander University Erlangen, Erlangen, Germany
- Department of Internal Medicine 4—Nephrology and Hypertension, Paracelsus Private Medical School Nuremberg, Nuremberg, Germany
| | - Karl F. Hilgers
- Department of Internal Medicine 4—Nephrology and Hypertension, Friedrich-Alexander University Erlangen, Erlangen, Germany
| | - Peter Linz
- Department of Radiology, Friedrich-Alexander University Erlangen, Erlangen, Germany
| | - Christian Ott
- Department of Internal Medicine 4—Nephrology and Hypertension, Friedrich-Alexander University Erlangen, Erlangen, Germany
- Department of Internal Medicine 4—Nephrology and Hypertension, Paracelsus Private Medical School Nuremberg, Nuremberg, Germany
| | - Roland E. Schmieder
- Department of Internal Medicine 4—Nephrology and Hypertension, Friedrich-Alexander University Erlangen, Erlangen, Germany
| | - Mario Schiffer
- Department of Internal Medicine 4—Nephrology and Hypertension, Friedrich-Alexander University Erlangen, Erlangen, Germany
| | - Kerstin Amann
- Department of Nephropathology, Friedrich-Alexander University Erlangen, Erlangen, Germany
| | - Roland Veelken
- Department of Internal Medicine 4—Nephrology and Hypertension, Friedrich-Alexander University Erlangen, Erlangen, Germany
- Department of Internal Medicine 4—Nephrology and Hypertension, Paracelsus Private Medical School Nuremberg, Nuremberg, Germany
- *Correspondence: Roland Veelken,
| | - Kristina Rodionova
- Department of Internal Medicine 4—Nephrology and Hypertension, Friedrich-Alexander University Erlangen, Erlangen, Germany
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Rodionova K, Hilgers KF, Rafii-Tabrizi S, Doellner J, Cordasic N, Linz P, Karl AL, Ott C, Schmieder RE, Schiffer M, Amann K, Veelken R, Ditting T. Responsiveness of afferent renal nerve units in renovascular hypertension in rats. Pflugers Arch 2021; 473:1617-1629. [PMID: 34232378 PMCID: PMC8433106 DOI: 10.1007/s00424-021-02591-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Revised: 05/12/2021] [Accepted: 06/03/2021] [Indexed: 12/01/2022]
Abstract
Previous data suggest that renal afferent nerve activity is increased in hypertension exerting sympathoexcitatory effects. Hence, we wanted to test the hypothesis that in renovascular hypertension, the activity of dorsal root ganglion (DRG) neurons with afferent projections from the kidneys is augmented depending on the degree of intrarenal inflammation. For comparison, a nonhypertensive model of mesangioproliferative nephritis was investigated. Renovascular hypertension (2-kidney, 1-clip [2K1C]) was induced by unilateral clipping of the left renal artery and mesangioproliferative glomerulonephritis (anti-Thy1.1) by IV injection of a 1.75-mg/kg BW OX-7 antibody. Neuronal labeling (dicarbocyanine dye [DiI]) in all rats allowed identification of renal afferent dorsal root ganglion (DRG) neurons. A current clamp was used to characterize neurons as tonic (sustained action potential [AP] firing) or phasic (1–4 AP) upon stimulation by current injection. All kidneys were investigated using standard morphological techniques. DRG neurons exhibited less often tonic response if in vivo axonal input from clipped kidneys was received (30.4% vs. 61.2% control, p < 0.05). However, if the nerves to the left clipped kidneys were cut 7 days prior to investigation, the number of tonic renal neurons completely recovered to well above control levels. Interestingly, electrophysiological properties of neurons that had in vivo axons from the right non-clipped kidneys were not distinguishable from controls. Renal DRG neurons from nephritic rats also showed less often tonic activity upon current injection (43.4% vs. 64.8% control, p < 0.05). Putative sympathoexcitatory and impaired sympathoinhibitory renal afferent nerve fibers probably contribute to increased sympathetic activity in 2K1C hypertension.
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Affiliation(s)
- Kristina Rodionova
- Department of Internal Medicine 4 - Nephrology and Hypertension, Friedrich-Alexander University Erlangen, Erlangen, Germany
| | - Karl F Hilgers
- Department of Internal Medicine 4 - Nephrology and Hypertension, Friedrich-Alexander University Erlangen, Erlangen, Germany
| | - Salman Rafii-Tabrizi
- Department of Internal Medicine 4 - Nephrology and Hypertension, Friedrich-Alexander University Erlangen, Erlangen, Germany
| | - Johannes Doellner
- Department of Internal Medicine 4 - Nephrology and Hypertension, Friedrich-Alexander University Erlangen, Erlangen, Germany
| | - Nada Cordasic
- Department of Internal Medicine 4 - Nephrology and Hypertension, Friedrich-Alexander University Erlangen, Erlangen, Germany
| | - Peter Linz
- Department of Radiology, Friedrich-Alexander University Erlangen, Erlangen, Germany
| | - Anna-Lena Karl
- Department of Internal Medicine 4 - Nephrology and Hypertension, Friedrich-Alexander University Erlangen, Erlangen, Germany
| | - Christian Ott
- Department of Internal Medicine 4 - Nephrology and Hypertension, Friedrich-Alexander University Erlangen, Erlangen, Germany.,Department of Internal Medicine 4 - Nephrology and Hypertension, Paracelsus Private Medical School Nuremberg, Nuremberg, Germany
| | - Roland E Schmieder
- Department of Internal Medicine 4 - Nephrology and Hypertension, Friedrich-Alexander University Erlangen, Erlangen, Germany
| | - Mario Schiffer
- Department of Internal Medicine 4 - Nephrology and Hypertension, Friedrich-Alexander University Erlangen, Erlangen, Germany
| | - Kerstin Amann
- Department of Nephropathology, Friedrich-Alexander University Erlangen, Erlangen, Germany
| | - Roland Veelken
- Department of Internal Medicine 4 - Nephrology and Hypertension, Friedrich-Alexander University Erlangen, Erlangen, Germany. .,Department of Radiology, Friedrich-Alexander University Erlangen, Erlangen, Germany.
| | - Tilmann Ditting
- Department of Internal Medicine 4 - Nephrology and Hypertension, Friedrich-Alexander University Erlangen, Erlangen, Germany.,Department of Internal Medicine 4 - Nephrology and Hypertension, Paracelsus Private Medical School Nuremberg, Nuremberg, Germany
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Singh SK, Muthu MS, Revand R, Mandal MB. Intra-arterial Instillation of a Nociceptive Agent Modulates Cardiorespiratory Parameters Involving 5-HT3 and TRPV1 Receptors in Anesthetized Rats. Cardiovasc Hematol Disord Drug Targets 2021; 21:46-54. [PMID: 33829976 DOI: 10.2174/1871529x21666210408101442] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Revised: 01/23/2021] [Accepted: 03/01/2021] [Indexed: 11/22/2022]
Abstract
BACKGROUND Since long back, it has been a matter of discussion regarding the role of peripheral blood vessels in the regulation of cardiorespiratory (CVR) system. OBJECTIVE The role of 5-HT3 and TRPV1 receptors present on perivascular nerves in elicitation of CVR reflexes was examined after intra-arterial instillation of bradykinin in urethane anesthetized rats. MATERIALS AND METHODS Femoral artery was cannulated retrogradely and was utilized for the instillation of saline/agonist/antagonist and recording of blood pressure (BP), using a double ported 24G cannula. BP, respiration and ECG were recorded for 30 min after bradykinin (1 μM) in the absence or presence of antagonists. RESULTS Instillation of bradykinin produced immediate hypotensive (40%), bradycardiac (17%), tachypnoeic (45%) and hyperventilatory (96%) responses of shorter latencies (5-8 s) favoring the neural mechanisms in producing the responses. In lignocaine (2%) pretreated animals, bradykinin- induced hypotensive (10%), bradycardiac (1.7%), tachypnoeic (13%) and hyperventilatory (13%) responses attenuated significantly. Pretreatment with ondansetron (100 μg/kg), 5-HT3-antagonist attenuated the hypotensive (10%), bradycardiac (1.7%), tachypnoeic (11%) and hyperventilatory (11%) responses significantly. Pretreatment with capsazepine (1 mg/kg), transient receptor potential vanilloid 1- antagonist blocked the hypotensive (5%), bradycardiac (1.2%), tachypnoeic (6%) and hyperventilatory (6%) responses significantly. CONCLUSION In conclusion, presence of a nociceptive agent in the local segment of an artery evokes vasosensory reflex responses modulating CVR parameters involving TRPV1 and 5-HT3 receptors present on the perivascular sensory nerve terminals in anesthetized rats.
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Affiliation(s)
- Sanjeev K Singh
- Department of Physiology, Institute of Medical Sciences, Banaras Hindu University, Varanasi, UP-221005, India
| | - M S Muthu
- Department of Pharmaceutical Engineering and Technology, Indian Institute of Technology (BHU), Varanasi, UP- -221005, India
| | - Ravindran Revand
- Department of Physiology, Institute of Medical Sciences, Banaras Hindu University, Varanasi, UP-221005, India
| | - Maloy B Mandal
- Department of Physiology, Institute of Medical Sciences, Banaras Hindu University, Varanasi, UP-221005, India
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Neurogenic substance P-influences on action potential production in afferent neurons of the kidney? Pflugers Arch 2021; 473:633-646. [PMID: 33786667 PMCID: PMC8049925 DOI: 10.1007/s00424-021-02552-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Revised: 03/01/2021] [Accepted: 03/03/2021] [Indexed: 12/23/2022]
Abstract
We recently showed that a substance P (SP)–dependent sympatho-inhibitory mechanism via afferent renal nerves is impaired in mesangioproliferative nephritis. Therefore, we tested the hypothesis that SP released from renal afferents inhibits the action potential (AP) production in their dorsal root ganglion (DRG) neurons. Cultured DRG neurons (Th11-L2) were investigated in current clamp mode to assess AP generation during both TRPV1 stimulation by protons (pH 6) and current injections with and without exposure to SP (0.5 µmol) or CGRP (0.5 µmol). Neurons were classified as tonic (sustained AP generation) or phasic (≤ 4 APs) upon current injection; voltage clamp experiments were performed for the investigation of TRPV1-mediated inward currents due to proton stimulation. Superfusion of renal neurons with protons and SP increased the number of action potentials in tonic neurons (9.6 ± 5 APs/10 s vs. 16.9 ± 6.1 APs/10 s, P < 0.05, mean ± SD, n = 7), while current injections with SP decreased it (15.2 ± 6 APs/600 ms vs. 10.2 ± 8 APs/600 ms, P < 0.05, mean ± SD, n = 29). Addition of SP significantly reduced acid-induced TRPV1-mediated currents in renal tonic neurons (− 518 ± 743 pA due to pH 6 superfusion vs. − 82 ± 50 pA due to pH 6 with SP superfusion). In conclusion, SP increased action potential production via a TRPV1-dependent mechanism in acid-sensitive renal neurons. On the other hand, current injection in the presence of SP led to decreased action potential production. Thus, the peptide SP modulates signaling pathways in renal neurons in an unexpected manner leading to both stimulation and inhibition of renal neuronal activity in different (e.g., acidic) environmental contexts.
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6
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Rodionova K, Veelken R, Hilgers KF, Paulus EM, Linz P, Fischer MJM, Schenker M, Reeh P, Tiegs G, Ott C, Schmieder R, Schiffer M, Amann K, Ditting T. Afferent renal innervation in anti-Thy1.1 nephritis in rats. Am J Physiol Renal Physiol 2020; 319:F822-F832. [PMID: 33017188 DOI: 10.1152/ajprenal.00063.2020] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Afferent renal nerves exhibit a dual function controlling central sympathetic outflow via afferent electrical activity and influencing intrarenal immunological processes by releasing peptides such as calcitonin gene-related peptide (CGRP). We tested the hypothesis that increased afferent and efferent renal nerve activity occur with augmented release of CGRP in anti-Thy1.1 nephritis, in which enhanced CGRP release exacerbates inflammation. Nephritis was induced in Sprague-Dawley rats by intravenous injection of OX-7 antibody (1.75 mg/kg), and animals were investigated neurophysiologically, electrophysiologically, and pathomorphologically 6 days later. Nephritic rats exhibited proteinuria (169.3 ± 10.2 mg/24 h) with increased efferent renal nerve activity (14.7 ± 0.9 bursts/s vs. control 11.5 ± 0.9 bursts/s, n = 11, P < 0.05). However, afferent renal nerve activity (in spikes/s) decreased in nephritis (8.0 ± 1.8 Hz vs. control 27.4 ± 4.1 Hz, n = 11, P < 0.05). In patch-clamp recordings, neurons with renal afferents from nephritic rats showed a lower frequency of high activity following electrical stimulation (43.4% vs. 66.4% in controls, P < 0.05). In vitro assays showed that renal tissue from nephritic rats exhibited increased CGRP release via spontaneous (14 ± 3 pg/mL vs. 6.8 ± 2.8 pg/ml in controls, n = 7, P < 0.05) and stimulated mechanisms. In nephritic animals, marked infiltration of macrophages in the interstitium (26 ± 4 cells/mm2) and glomeruli (3.7 ± 0.6 cells/glomerular cross-section) occurred. Pretreatment with the CGRP receptor antagonist CGRP8-37 reduced proteinuria, infiltration, and proliferation. In nephritic rats, it can be speculated that afferent renal nerves lose their ability to properly control efferent sympathetic nerve activity while influencing renal inflammation through increased CGRP release.
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Affiliation(s)
- Kristina Rodionova
- Department of Internal Medicine 4 (Nephrology und Hypertension), University of Erlangen, Erlangen, Germany
| | - Roland Veelken
- Department of Internal Medicine 4 (Nephrology und Hypertension), University of Erlangen, Erlangen, Germany.,Department of Internal Medicine 4 (Nephrology und Hypertension), Paracelsus Private Medical School, Klinikum Nuremberg, Nuremberg, Germany
| | - Karl F Hilgers
- Department of Internal Medicine 4 (Nephrology und Hypertension), University of Erlangen, Erlangen, Germany
| | - Eva-Maria Paulus
- Department of Internal Medicine 4 (Nephrology und Hypertension), University of Erlangen, Erlangen, Germany
| | - Peter Linz
- Department of Radiology, University of Erlangen, Erlangen, Germany
| | - Michael J M Fischer
- Center of Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Martina Schenker
- Department of Internal Medicine 4 (Nephrology und Hypertension), University of Erlangen, Erlangen, Germany.,Department of Physiology and Pathophysiology, University Erlangen, Erlangen, Germany
| | - Peter Reeh
- Department of Physiology and Pathophysiology, University Erlangen, Erlangen, Germany
| | - Gisa Tiegs
- Center of Internal Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Christian Ott
- Department of Internal Medicine 4 (Nephrology und Hypertension), University of Erlangen, Erlangen, Germany.,Department of Internal Medicine 4 (Nephrology und Hypertension), Paracelsus Private Medical School, Klinikum Nuremberg, Nuremberg, Germany
| | - Roland Schmieder
- Department of Internal Medicine 4 (Nephrology und Hypertension), University of Erlangen, Erlangen, Germany
| | - Mario Schiffer
- Department of Internal Medicine 4 (Nephrology und Hypertension), University of Erlangen, Erlangen, Germany
| | - Kerstin Amann
- Department of Nephropathology, University of Erlangen, Erlangen, Germany
| | - Tilmann Ditting
- Department of Internal Medicine 4 (Nephrology und Hypertension), University of Erlangen, Erlangen, Germany.,Department of Internal Medicine 4 (Nephrology und Hypertension), Paracelsus Private Medical School, Klinikum Nuremberg, Nuremberg, Germany
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7
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Ditting T, Freisinger W, Rodionova K, Schatz J, Lale N, Heinlein S, Linz P, Ott C, Schmieder RE, Scrogin KE, Veelken R. Impaired excitability of renal afferent innervation after exposure to the inflammatory chemokine CXCL1. Am J Physiol Renal Physiol 2015; 310:F364-71. [PMID: 26697980 DOI: 10.1152/ajprenal.00189.2015] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2015] [Accepted: 12/15/2015] [Indexed: 01/06/2023] Open
Abstract
Recently, we showed that renal afferent neurons exhibit a unique firing pattern, i.e., predominantly sustained firing, upon stimulation. Pathological conditions such as renal inflammation likely alter excitability of renal afferent neurons. Here, we tested whether the proinflammatory chemokine CXCL1 alters the firing pattern of renal afferent neurons. Rat dorsal root ganglion neurons (Th11-L2), retrogradely labeled with dicarbocyanine dye, were incubated with CXCL1 (20 h) or vehicle before patch-clamp recording. The firing pattern of neurons was characterized as tonic, i.e., sustained action potential (AP) firing, or phasic, i.e., <5 APs following current injection. Of the labeled renal afferents treated with vehicle, 58.9% exhibited a tonic firing pattern vs. 7.8%, in unlabeled, nonrenal neurons (P < 0.05). However, after exposure to CXCL1, significantly more phasic neurons were found among labeled renal neurons; hence the occurrence of tonic neurons with sustained firing upon electrical stimulation decreased (35.6 vs. 58.9%, P < 0.05). The firing frequency among tonic neurons was not statistically different between control and CXCL1-treated neurons. However, the lower firing frequency of phasic neurons was even further decreased with CXCL1 exposure [control: 1 AP/600 ms (1-2) vs. CXCL1: 1 AP/600 ms (1-1); P < 0.05; median (25th-75th percentile)]. Hence, CXCL1 shifted the firing pattern of renal afferents from a predominantly tonic to a more phasic firing pattern, suggesting that CXCL1 reduced the sensitivity of renal afferent units upon stimulation.
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Affiliation(s)
- Tilmann Ditting
- Department of Internal Medicine 4, Nephrology and Hypertension, Friedrich-Alexander University, Erlangen, Germany
| | - Wolfgang Freisinger
- Department of Internal Medicine 1, Nephrology Johannes-Guttenberg University, Mainz, Germany
| | - Kristina Rodionova
- Department of Internal Medicine 4, Nephrology and Hypertension, Friedrich-Alexander University, Erlangen, Germany
| | - Johannes Schatz
- Department of Internal Medicine 4, Nephrology and Hypertension, Friedrich-Alexander University, Erlangen, Germany
| | - Nena Lale
- Department of Internal Medicine 4, Nephrology and Hypertension, Friedrich-Alexander University, Erlangen, Germany
| | - Sonja Heinlein
- Department of Internal Medicine 4, Nephrology and Hypertension, Friedrich-Alexander University, Erlangen, Germany
| | - Peter Linz
- Department of Internal Medicine 4, Nephrology and Hypertension, Friedrich-Alexander University, Erlangen, Germany
| | - Christian Ott
- Department of Internal Medicine 4, Nephrology and Hypertension, Friedrich-Alexander University, Erlangen, Germany
| | - Roland E Schmieder
- Department of Internal Medicine 4, Nephrology and Hypertension, Friedrich-Alexander University, Erlangen, Germany
| | - Karie E Scrogin
- Department of Molecular Pharmacology and Therapeutics, Loyola University Chicago Stritch School of Medicine, Chicago, Illinois
| | - Roland Veelken
- Department of Internal Medicine 4, Nephrology and Hypertension, Friedrich-Alexander University, Erlangen, Germany;
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Liu Y, Liu Y, Liu X, Chen J, Zhang K, Huang F, Wang JF, Tang W, Huang H. Apocynin Attenuates Cardiac Injury in Type 4 Cardiorenal Syndrome via Suppressing Cardiac Fibroblast Growth Factor-2 With Oxidative Stress Inhibition. J Am Heart Assoc 2015; 4:JAHA.114.001598. [PMID: 26109504 PMCID: PMC4608061 DOI: 10.1161/jaha.114.001598] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Background Type 4 cardiorenal syndrome (CRS) refers to the cardiac injury induced by chronic kidney disease. We aimed to assess oxidative stress and cardiac injury in patients with type 4 CRS, determine whether the antioxidant apocynin attenuated cardiac injury in rats with type 4 CRS, and explore potential mechanisms. Methods and Results A cross-sectional study was conducted among patients with type 4 CRS (n=17) and controls (n=16). Compared with controls, patients with type 4 CRS showed elevated oxidative stress, which was significantly correlated with cardiac hypertrophy and decreased ejection fraction. In vivo study, male Sprague-Dawley rats underwent 5/6 subtotal nephrectomy and sham surgery, followed with apocynin or vehicle treatment for 8 weeks. Eight weeks after surgery, the 5/6 subtotal nephrectomy rats mimicked type 4 CRS, showing increased serum creatinine, cardiac hypertrophy and fibrosis, and decreased ejection fraction compared with sham-operated animals. Cardiac malondialdehyde, NADPH oxidase activity, fibroblast growth factor-2, and extracellular signal-regulated kinase 1/2 (ERK1/2) phosphorylation increased significantly in the 5/6 subtotal nephrectomy rats. These changes were significantly attenuated by apocynin. In vitro study showed that apocynin reduced angiotensin II–induced NADPH oxidase–dependent oxidative stress, upregulation of fibroblast growth factor-2 and fibrosis biomarkers, and ERK1/2 phosphorylation in cardiac fibroblasts. Importantly, the ERK1/2 inhibitor U0126 reduced the upregulation of fibroblast growth factor-2 and fibrosis biomarkers in angiotensin II–treated fibroblasts. Conclusions Oxidative stress is a candidate mediator for type 4 CRS. Apocynin attenuated cardiac injury in type 4 CRS rats via inhibiting NADPH oxidase–dependent oxidative stress-activated ERK1/2 pathway and subsequent fibroblast growth factor-2 upregulation. Our study added evidence to the beneficial effect of apocynin in type 4 CRS.
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Affiliation(s)
- Yang Liu
- Sun Yat-sen Memorial Hospital of Sun Yat-sen University, Guangzhou, China (Y.L., J.C., K.Z., F.H., J.F.W., W.T., H.H.) Guangdong Province Key Laboratory of Arrhythmia and Electrophysiology, Guangzhou, China (Y.L., Y.L., J.C., K.Z., F.H., J.F.W., H.H.)
| | - Yu Liu
- Guangdong Province Key Laboratory of Arrhythmia and Electrophysiology, Guangzhou, China (Y.L., Y.L., J.C., K.Z., F.H., J.F.W., H.H.) Department of Cardiology, People's Hospital of Guangxi Zhuang Autonomous Region, Nanning, China (Y.L.)
| | - Xun Liu
- Division of Nephrology, Department of Internal Medicine, The Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, China (X.L.)
| | - Jie Chen
- Sun Yat-sen Memorial Hospital of Sun Yat-sen University, Guangzhou, China (Y.L., J.C., K.Z., F.H., J.F.W., W.T., H.H.) Guangdong Province Key Laboratory of Arrhythmia and Electrophysiology, Guangzhou, China (Y.L., Y.L., J.C., K.Z., F.H., J.F.W., H.H.)
| | - Kun Zhang
- Sun Yat-sen Memorial Hospital of Sun Yat-sen University, Guangzhou, China (Y.L., J.C., K.Z., F.H., J.F.W., W.T., H.H.) Guangdong Province Key Laboratory of Arrhythmia and Electrophysiology, Guangzhou, China (Y.L., Y.L., J.C., K.Z., F.H., J.F.W., H.H.)
| | - Feifei Huang
- Sun Yat-sen Memorial Hospital of Sun Yat-sen University, Guangzhou, China (Y.L., J.C., K.Z., F.H., J.F.W., W.T., H.H.) Guangdong Province Key Laboratory of Arrhythmia and Electrophysiology, Guangzhou, China (Y.L., Y.L., J.C., K.Z., F.H., J.F.W., H.H.)
| | - Jing-Feng Wang
- Sun Yat-sen Memorial Hospital of Sun Yat-sen University, Guangzhou, China (Y.L., J.C., K.Z., F.H., J.F.W., W.T., H.H.) Guangdong Province Key Laboratory of Arrhythmia and Electrophysiology, Guangzhou, China (Y.L., Y.L., J.C., K.Z., F.H., J.F.W., H.H.)
| | - Wanchun Tang
- Sun Yat-sen Memorial Hospital of Sun Yat-sen University, Guangzhou, China (Y.L., J.C., K.Z., F.H., J.F.W., W.T., H.H.) Weil Institute of Critical Care Medicine, Rancho Mirage, CA (W.T.)
| | - Hui Huang
- Sun Yat-sen Memorial Hospital of Sun Yat-sen University, Guangzhou, China (Y.L., J.C., K.Z., F.H., J.F.W., W.T., H.H.) Guangdong Province Key Laboratory of Arrhythmia and Electrophysiology, Guangzhou, China (Y.L., Y.L., J.C., K.Z., F.H., J.F.W., H.H.)
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9
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Freisinger W, Schatz J, Ditting T, Lampert A, Heinlein S, Lale N, Schmieder R, Veelken R. Sensory renal innervation: a kidney-specific firing activity due to a unique expression pattern of voltage-gated sodium channels? Am J Physiol Renal Physiol 2013; 304:F491-7. [PMID: 23283993 DOI: 10.1152/ajprenal.00011.2012] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Sensory neurons with afferent axons from the kidney are extraordinary in their response to electrical stimulation. More than 50% exhibit a tonic firing pattern, i.e., sustained action potential firing throughout depolarizing, pointing to an increased excitability, whereas nonrenal neurons show mainly a phasic response, i.e., less than five action potentials. Here we investigated whether these peculiar firing characteristics of renal afferent neurons are due to differences in the expression of voltage-gated sodium channels (Navs). Dorsal root ganglion (DRG) neurons from rats (Th11-L2) were recorded by the current-clamp technique and distinguished as "tonic" or "phasic." In voltage-clamp recordings, Navs were characterized by their tetrodotoxoxin (TTX) sensitivity, and their molecular identity was revealed by RT-PCR. The firing pattern of 66 DRG neurons (41 renal and 25 nonrenal) was investigated. Renal neurons exhibited more often a tonic firing pattern (56.1 vs. 12%). Tonic neurons showed a more positive threshold (-21.75 ± 1.43 vs.-29.33 ± 1.63 mV; P < 0.05), a higher overshoot (56.74 [53.6-60.96] vs. 46.79 mV [38.63-54.75]; P < 0.05) and longer action potential duration (4.61 [4.15-5.85] vs. 3.35 ms [2.12-5.67]; P < 0.05). These findings point to an increased presence of the TTX-resistant Navs 1.8 and 1.9. Furthermore, tonic neurons exhibited a relatively higher portion of TTX-resistant sodium currents. Interestingly, mRNA expression of TTX-resistant sodium channels was significantly increased in renal, predominantly tonic, DRG neurons. Hence, under physiological conditions, renal sensory neurons exhibit predominantly a firing pattern associated with higher excitability. Our findings support that this is due to an increased expression and activation of TTX-resistant Navs.
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Affiliation(s)
- Wolfgang Freisinger
- Dept. of Medicine 4, Univ. of Erlangen-Nürnberg, Loschgestraβe 8, 91054 Erlangen, Germany.
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10
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Ditting T, Linz P, Freisinger W, Heinlein S, Reeh PW, Fiedler C, Siegel K, Scrogin KE, Neuhuber W, Veelken R. Norepinephrine reduces ω-conotoxin-sensitive Ca2+ currents in renal afferent neurons in rats. Am J Physiol Renal Physiol 2011; 302:F350-7. [PMID: 22049399 DOI: 10.1152/ajprenal.00681.2010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Sympathetic efferent and peptidergic afferent renal nerves likely influence hypertensive and inflammatory kidney disease. Our recent investigation with confocal microscopy revealed that in the kidney sympathetic nerve endings are colocalized with afferent nerve fibers (Ditting T, Tiegs G, Rodionova K, Reeh PW, Neuhuber W, Freisinger W, Veelken R. Am J Physiol Renal Physiol 297: F1427-F1434, 2009; Veelken R, Vogel EM, Hilgers K, Amman K, Hartner A, Sass G, Neuhuber W, Tiegs G. J Am Soc Nephrol 19: 1371-1378, 2008). However, it is not known whether renal afferent nerves are influenced by sympathetic nerve activity. We tested the hypothesis that norepinephrine (NE) influences voltage-gated Ca(2+) channel currents in cultured renal dorsal root ganglion (DRG) neurons, i.e., the first-order neuron of the renal afferent pathway. DRG neurons (T11-L2) retrogradely labeled from the kidney and subsequently cultured, were investigated by whole-cell patch clamp. Voltage-gated calcium channels (VGCC) were investigated by voltage ramps (-100 to +80 mV, 300 ms, every 20 s). NE and appropriate adrenergic receptor antagonists were administered by microperfusion. NE (20 μM) reduced VGCC-mediated currents by 10.4 ± 3.0% (P < 0.01). This reduction was abolished by the α-adrenoreceptor inhibitor phentolamine and the α(2)-adrenoceptor antagonist yohimbine. The β-adrenoreceptor antagonist propranolol and the α(1)-adrenoceptor antagonist prazosin had no effect. The inhibitory effect of NE was abolished when N-type currents were blocked by ω-conotoxin GVIA, but was unaffected by other specific Ca(2+) channel inhibitors (ω-agatoxin IVA; nimodipine). Confocal microscopy revealed sympathetic innervation of DRGs and confirmed colocalization of afferent and efferent fibers within in the kidney. Hence NE released from intrarenal sympathetic nerve endings, or sympathetic fibers within the DRGs, or even circulating catecholamines, may influence the activity of peptidergic afferent nerve fibers through N-type Ca(2+) channels via an α(2)-adrenoceptor-dependent mechanism. However, the exact site and the functional role of this interaction remains to be elucidated.
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Affiliation(s)
- Tilmann Ditting
- Dept. of Internal Medicine 4, Nephrology and Hypertension, Erlangen, Germany.
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11
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Ditting T, Tiegs G, Rodionova K, Reeh PW, Neuhuber W, Freisinger W, Veelken R. Do distinct populations of dorsal root ganglion neurons account for the sensory peptidergic innervation of the kidney? Am J Physiol Renal Physiol 2009; 297:F1427-34. [DOI: 10.1152/ajprenal.90599.2008] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Peptidergic afferent renal nerves (PARN) have been linked to kidney damage in hypertension and nephritis. Neither the receptors nor the signals controlling local release of neurokinines [calcitonin gene-related peptide (CGRP) and substance P (SP)] and signal transmission to the brain are well-understood. We tested the hypothesis that PARN, compared with nonrenal afferents (Non-RN), are more sensitive to acidic stimulation via transient receptor potential vanilloid type 1 (TRPV1) channels and exhibit a distinctive firing pattern. PARN were distinguished from Non-RN by fluorescent labeling (DiI) and studied by in vitro patch-clamp techniques in dorsal root ganglion neurons (DRG; T11-L2). Acid-induced currents or firing due to current injection or acidic superfusion were studied in 252 neurons, harvested from 12 Sprague-Dawley rats. PARN showed higher acid-induced currents than Non-RN (transient: 15.9 ± 5.1 vs. 0.4 ± 0.2* pA/pF at pH 6; sustained: 20.0 ± 4.5 vs. 6.2 ± 1.2* pA/pF at pH 5; * P < 0.05). The TRPV1 antagonist capsazepine inhibited sustained, amiloride-transient currents. Forty-eight percent of PARN were classified as tonic neurons (TN = sustained firing during current injection), and 52% were phasic (PN = transient firing). Non-RN were rarely tonic (15%), but more frequently phasic (85%), than PARN ( P < 0.001). TN were more frequently acid-sensitive than PN (50–70 vs. 2–20%, P < 0.01). Furthermore, renal PN were more frequently acid-sensitive than nonrenal PN (20 vs. 2%, P < 0.01). Confocal microscopy revealed innervation of renal vessels, tubules, and glomeruli by CGRP- and partly SP-positive fibers coexpressing TRPV1. Our data show that PARN are represented by a very distinct population of small-to-medium sized DRG neurons exhibiting more frequently tonic firing and TRPV1-mediated acid sensitivity. These very distinct DRG neurons might play a pivotal role in renal physiology and disease.
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Affiliation(s)
- Tilmann Ditting
- Department of Internal Medicine 4, Nephrology, and Hypertension,
| | - Gisa Tiegs
- Division of Experimental Immunology and Hepatology, Center of Internal Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | | | | | | | | | - Roland Veelken
- Department of Internal Medicine 4, Nephrology, and Hypertension,
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12
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Autonomous innervation in renal inflammatory disease—innocent bystander or active modulator? J Mol Med (Berl) 2009; 87:865-70. [DOI: 10.1007/s00109-009-0498-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2009] [Revised: 06/15/2009] [Accepted: 06/24/2009] [Indexed: 01/18/2023]
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13
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Singh SK, Deshpande SB. Nociceptive vascular reflexes evoked by scorpion venom modulate cardiorespiratory parameters involving vanilloid receptor 1 in anaesthetised rats. Neurosci Lett 2009; 451:194-8. [DOI: 10.1016/j.neulet.2009.01.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2008] [Revised: 01/03/2009] [Accepted: 01/07/2009] [Indexed: 10/21/2022]
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