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Joseph DJ, Von Deimling M, Risbud R, McCoy AJ, Marsh ED. Loss of postnatal Arx transcriptional activity in parvalbumin interneurons reveals non-cell autonomous disturbances in CA1 pyramidal cells. Neuroscience 2024; 558:128-150. [PMID: 38788829 DOI: 10.1016/j.neuroscience.2024.05.020] [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: 07/19/2023] [Revised: 04/16/2024] [Accepted: 05/15/2024] [Indexed: 05/26/2024]
Abstract
Maintenance of proper electrophysiological and connectivity profiles in the adult brain may be a perturbation point in neurodevelopmental disorders (NDDs). How these profiles are maintained within mature circuits is unclear. We recently demonstrated that postnatal ablation of the Aristaless (Arx) homeobox gene in parvalbumin interneurons (PVIs) alone led to dysregulation of their transcriptome and alterations in their functional as well as network properties in the hippocampal cornu Ammoni first region (CA1). Here, we characterized CA1 pyramidal cells (PCs) responses in this conditional knockout (CKO) mouse to further understand the circuit mechanisms by which postnatal Arx expression regulates mature CA1 circuits. Field recordings of network excitability showed that CA1 PC ensembles were less excitable in response to unpaired stimulations but exhibited enhanced excitability in response to paired-pulse stimulations. Whole-cell voltage clamp recordings revealed a significant increase in the frequency of spontaneous inhibitory postsynaptic currents onto PCs. In contrast, excitatory drive from evoked synaptic transmission was reduced while that of inhibitory synaptic transmission was increased. Current clamp recordings showed increase excitability in several sub- and threshold membrane properties that correlated with an increase in voltage-gated Na+ current. Our data suggest that, in addition to cell-autonomous disruption in PVIs, loss of Arx postnatal transcriptional activity in PVIs led to complex dysfunctions in PCs in CA1 microcircuits. These non-cell autonomous effects are likely the product of breakdown in feedback and/or feedforward processes and should be considered as fundamental contributors to the circuit mechanisms of NDDs such as Arx-linked early-onset epileptic encephalopathies.
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Affiliation(s)
- Donald J Joseph
- Division of Child Neurology, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Markus Von Deimling
- Division of Child Neurology, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA; Department of Urology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Rashmi Risbud
- Division of Child Neurology, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Almedia J McCoy
- Division of Child Neurology, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Eric D Marsh
- Division of Child Neurology, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA; Departments of Neurology and Pediatrics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, 19104, USA.
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Maxion A, Kutafina E, Dohrn MF, Sacré P, Lampert A, Tigerholm J, Namer B. A modelling study to dissect the potential role of voltage-gated ion channels in activity-dependent conduction velocity changes as identified in small fiber neuropathy patients. Front Comput Neurosci 2023; 17:1265958. [PMID: 38156040 PMCID: PMC10752960 DOI: 10.3389/fncom.2023.1265958] [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: 07/24/2023] [Accepted: 10/25/2023] [Indexed: 12/30/2023] Open
Abstract
Objective Patients with small fiber neuropathy (SFN) suffer from neuropathic pain, which is still a therapeutic problem. Changed activation patterns of mechano-insensitive peripheral nerve fibers (CMi) could cause neuropathic pain. However, there is sparse knowledge about mechanisms leading to CMi dysfunction since it is difficult to dissect specific molecular mechanisms in humans. We used an in-silico model to elucidate molecular causes of CMi dysfunction as observed in single nerve fiber recordings (microneurography) of SFN patients. Approach We analyzed microneurography data from 97 CMi-fibers from healthy individuals and 34 of SFN patients to identify activity-dependent changes in conduction velocity. Using the NEURON environment, we adapted a biophysical realistic preexisting CMi-fiber model with ion channels described by Hodgkin-Huxley dynamics for identifying molecular mechanisms leading to those changes. Via a grid search optimization, we assessed the interplay between different ion channels, Na-K-pump, and resting membrane potential. Main results Changing a single ion channel conductance, Na-K-pump or membrane potential individually is not sufficient to reproduce in-silico CMi-fiber dysfunction of unchanged activity-dependent conduction velocity slowing and quicker normalization of conduction velocity after stimulation as observed in microneurography. We identified the best combination of mechanisms: increased conductance of potassium delayed-rectifier and decreased conductance of Na-K-pump and depolarized membrane potential. When the membrane potential is unchanged, opposite changes in Na-K-pump and ion channels generate the same effect. Significance Our study suggests that not one single mechanism accounts for pain-relevant changes in CMi-fibers, but a combination of mechanisms. A depolarized membrane potential, as previously observed in patients with neuropathic pain, leads to changes in the contribution of ion channels and the Na-K-pump. Thus, when searching for targets for the treatment of neuropathic pain, combinations of several molecules in interplay with the membrane potential should be regarded.
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Affiliation(s)
- Anna Maxion
- Research Group Neuroscience, Interdisciplinary Centre for Clinical Research within the Faculty of Medicine at the RWTH Aachen University, Aachen, Germany
| | - Ekaterina Kutafina
- Institute of Medical Informatics, Medical Faculty, RWTH Aachen University, Aachen, Germany
| | - Maike F. Dohrn
- Department of Neurology, Medical Faculty, RWTH Aachen University, Aachen, Germany
| | - Pierre Sacré
- Department of Electrical Engineering and Computer Science, University of Liège, Liège, Belgium
| | - Angelika Lampert
- Institute of Neurophysiology, Uniklinik RWTH Aachen University Aachen, Aachen, Germany
| | - Jenny Tigerholm
- Joint Research Center for Computational Biomedicine, RWTH Aachen, Aachen, Germany
| | - Barbara Namer
- Research Group Neuroscience, Interdisciplinary Centre for Clinical Research within the Faculty of Medicine at the RWTH Aachen University, Aachen, Germany
- Institute of Neurophysiology, RWTH Aachen University, Aachen, Germany
- Institute of Physiology and Pathophysiology, University of Erlangen-Nürnberg, Erlangen, Germany
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Wang X, Gan S, Zhang Z, Zhu P, Li CH, Luo F. HCN-Channel-Dependent Hyperexcitability of the Layer V Pyramidal Neurons in IL-mPFC Contributes to Fentanyl-Induced Hyperalgesia in Male Rats. Mol Neurobiol 2023; 60:2553-2571. [PMID: 36689134 DOI: 10.1007/s12035-023-03218-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Accepted: 01/04/2023] [Indexed: 01/24/2023]
Abstract
Opioids are often first-line analgesics in pain therapy. However, prolonged use of opioids causes paradoxical pain, termed "opioid-induced hyperalgesia (OIH)." The infralimbic medial prefrontal cortex (IL-mPFC) has been suggested to be critical in inflammatory and neuropathic pain processing through its dynamic output from layer V pyramidal neurons. Whether OIH condition induces excitability changes of these output neurons and what mechanisms underlie these changes remains elusive. Here, with combination of patch-clamp recording, immunohistochemistry, as well as optogenetics, we revealed that IL-mPFC layer V pyramidal neurons exhibited hyperexcitability together with higher input resistance. In line with this, optogenetic and chemogenetic activation of these neurons aggravates behavioral hyperalgesia in male OIH rats. Inhibition of these neurons alleviates hyperalgesia in male OIH rats but exerts an opposite effect in male control rats. Electrophysiological analysis of hyperpolarization-activated cation current (Ih) demonstrated that decreased Ih is a prerequisite for the hyperexcitability of IL-mPFC output neurons. This decreased Ih was accompanied by a decrease in HCN1, but not HCN2, immunolabeling, in these neurons. In contrast, the application of HCN channel blocker increased the hyperalgesia threshold of male OIH rats. Consequently, we identified an HCN-channel-dependent hyperexcitability of IL-mPFC output neurons, which governs the development and maintenance of OIH in male rats.
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Affiliation(s)
- Xixi Wang
- Department of Anesthesiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Sifei Gan
- Department of Anesthesiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Zeru Zhang
- Department of Anesthesiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Pengfei Zhu
- Department of Anesthesiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Chen Hong Li
- The Laboratory of Membrane Ion Channels and Medicine, Key Laboratory of Cognitive Science, State Ethnic Affairs Commission, College of Biomedical Engineering, South-Central University for Nationalities, Wuhan, Hubei, China
| | - Fang Luo
- Department of Anesthesiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China.
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Davis MJ, Earley S, Li YS, Chien S. Vascular mechanotransduction. Physiol Rev 2023; 103:1247-1421. [PMID: 36603156 PMCID: PMC9942936 DOI: 10.1152/physrev.00053.2021] [Citation(s) in RCA: 50] [Impact Index Per Article: 50.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Revised: 09/26/2022] [Accepted: 10/04/2022] [Indexed: 01/07/2023] Open
Abstract
This review aims to survey the current state of mechanotransduction in vascular smooth muscle cells (VSMCs) and endothelial cells (ECs), including their sensing of mechanical stimuli and transduction of mechanical signals that result in the acute functional modulation and longer-term transcriptomic and epigenetic regulation of blood vessels. The mechanosensors discussed include ion channels, plasma membrane-associated structures and receptors, and junction proteins. The mechanosignaling pathways presented include the cytoskeleton, integrins, extracellular matrix, and intracellular signaling molecules. These are followed by discussions on mechanical regulation of transcriptome and epigenetics, relevance of mechanotransduction to health and disease, and interactions between VSMCs and ECs. Throughout this review, we offer suggestions for specific topics that require further understanding. In the closing section on conclusions and perspectives, we summarize what is known and point out the need to treat the vasculature as a system, including not only VSMCs and ECs but also the extracellular matrix and other types of cells such as resident macrophages and pericytes, so that we can fully understand the physiology and pathophysiology of the blood vessel as a whole, thus enhancing the comprehension, diagnosis, treatment, and prevention of vascular diseases.
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Affiliation(s)
- Michael J Davis
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, Missouri
| | - Scott Earley
- Department of Pharmacology, University of Nevada, Reno, Nevada
| | - Yi-Shuan Li
- Department of Bioengineering, University of California, San Diego, California
- Institute of Engineering in Medicine, University of California, San Diego, California
| | - Shu Chien
- Department of Bioengineering, University of California, San Diego, California
- Institute of Engineering in Medicine, University of California, San Diego, California
- Department of Medicine, University of California, San Diego, California
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Ma T, Li L, Chen R, Yang L, Sun H, Du S, Xu X, Cao Z, Zhang X, Zhang L, Shi X, Liu JY. Protein arginine methyltransferase 7 modulates neuronal excitability by interacting with NaV1.9. Pain 2022; 163:753-764. [PMID: 34326297 PMCID: PMC8929296 DOI: 10.1097/j.pain.0000000000002421] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Revised: 07/09/2021] [Accepted: 07/13/2021] [Indexed: 11/26/2022]
Abstract
ABSTRACT Human NaV1.9 (hNaV1.9), encoded by SCN11A, is preferentially expressed in nociceptors, and its mutations have been linked to pain disorders. NaV1.9 could be a promising drug target for pain relief. However, the modulation of NaV1.9 activity has remained elusive. Here, we identified a new candidate NaV1.9-interacting partner, protein arginine methyltransferase 7 (PRMT7). Whole-cell voltage-clamp recordings showed that coelectroporation of human SCN11A and PRMT7 in dorsal root ganglion (DRG) neurons of Scn11a-/- mice increased the hNaV1.9 current density. By contrast, a PRMT7 inhibitor (DS-437) reduced mNaV1.9 currents in Scn11a+/+ mice. Using the reporter molecule CD4, we observed an increased distribution of hLoop1 on the cell surface of PRMT7-overexpressing HKE293T cells. Furthermore, we found that PRMT7 mainly binds to residues 563 to 566 within the first intracellular loop of hNaV1.9 (hLoop1) and methylates hLoop1 at arginine residue 519. Moreover, overexpression of PRMT7 increased the number of action potential fired in DRG neurons of Scn11a+/+ mice but not Scn11a-/- mice. However, DS-437 significantly inhibited the action potential frequency of DRG neurons and relieved pain hypersensitivity in Scn11aA796G/A796G mice. In summary, our observations revealed that PRMT7 modulates neuronal excitability by regulating NaV1.9 currents, which may provide a potential method for pain treatment.
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Affiliation(s)
- Tingbin Ma
- College of Life Science and Technology, Huazhong University of Science and Technology (HUST), Wuhan, China
| | - Lulu Li
- College of Life Science and Technology, Huazhong University of Science and Technology (HUST), Wuhan, China
| | - Rui Chen
- College of Life Science and Technology, Huazhong University of Science and Technology (HUST), Wuhan, China
| | - Luyao Yang
- College of Life Science and Technology, Huazhong University of Science and Technology (HUST), Wuhan, China
| | - Hao Sun
- College of Life Science and Technology, Huazhong University of Science and Technology (HUST), Wuhan, China
| | - Shiyue Du
- College of Life Science and Technology, Huazhong University of Science and Technology (HUST), Wuhan, China
| | - Xuan Xu
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, China
| | - Zhijian Cao
- College of Life Science and Technology, Huazhong University of Science and Technology (HUST), Wuhan, China
| | - Xianwei Zhang
- Department of Anesthesiology, Tongji Hospital of HUST, Wuhan, China
| | - Luoying Zhang
- College of Life Science and Technology, Huazhong University of Science and Technology (HUST), Wuhan, China
| | - Xiaoliu Shi
- Department of Medical Genetics, the Second Xiangya Hospital, Central South University, Changsha, China
| | - Jing Yu Liu
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, China
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Bernard Healey SA, Scholtes I, Abrahams M, McNaughton PA, Menon DK, Lee MC. Role of hyperpolarization-activated cyclic nucleotide-gated ion channels in neuropathic pain: a proof-of-concept study of ivabradine in patients with chronic peripheral neuropathic pain. Pain Rep 2021; 6:e967. [PMID: 34712888 PMCID: PMC8547924 DOI: 10.1097/pr9.0000000000000967] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Revised: 08/23/2021] [Accepted: 09/11/2021] [Indexed: 11/25/2022] Open
Abstract
Hyperpolarization-activated cyclic nucleotide-gated (HCN) channel receptors mediate neuropathic pain in preclinical models. Here, exploratory analysis reveals a dose-dependent reduction in pain with HCN blockade in patients with neuropathic pain. Introduction: Hyperpolarization-activated cyclic nucleotide-gated (HCN) ion channels mediate repetitive action potential firing in the heart and nervous system. The HCN2 isoform is expressed in nociceptors, and preclinical studies suggest a critical role in neuropathic pain. Ivabradine is a nonselective HCN blocker currently available for prescription for cardiac indications. Mouse data suggest that ivabradine in high concentrations is equianalgesic with gabapentin. We sought to translate these findings to patients with chronic peripheral neuropathic pain. Objectives: We sought to translate these findings to patients with chronic peripheral neuropathic pain. Methods: We adopted an open-label design, administering increasing doses of ivabradine to target a heart rate of 50 to 60 BPM, up to a maximum of 7.5 mg twice daily. All participants scored their pain on an 11-point numerical rating scale (NRS). Results: Seven (7) participants received the drug and completed the study. There was no significant treatment effect on the primary endpoint, the difference between the mean score at baseline and at maximum dosing (mean reduction = 0.878, 95% CI = −2.07 to 0.31, P = 0.1). Exploratory analysis using linear mixed models, however, revealed a highly significant correlation between ivabradine dose and pain scores (χ2(1) = 74.6, P < 0.001), with a reduction of 0.12 ± 0.01 (SEM) NRS points per milligram. The 2 participants with painful diabetic neuropathy responded particularly well. Conclusion: This suggests that ivabradine may be efficacious at higher doses, particularly in patients with diabetic neuropathic pain. Importantly, participants reported no adverse effects. These data suggest that ivabradine, a peripherally restricted drug (devoid of central nervous system side effects), is well tolerated in patients with chronic neuropathic pain. Ivabradine is now off-patent, and its analgesic potential merits further investigation in clinical trials.
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Affiliation(s)
| | - Ingrid Scholtes
- Division of Anaesthesia, University of Cambridge, Cambridge, United Kingdom
| | - Mark Abrahams
- Pain Service, Cambridge University Hospitals NHS Trust, Cambridge, United Kingdom
| | - Peter A McNaughton
- Wolfson Centre for Age-Related Diseases, King's College London, London, United Kingdom
| | - David K Menon
- Division of Anaesthesia, University of Cambridge, Cambridge, United Kingdom
| | - Michael C Lee
- Division of Anaesthesia, University of Cambridge, Cambridge, United Kingdom
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7
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Martin CA, Vorn R, Schrieber M, Lai C, Yun S, Kim HS, Gill J. Identification of DNA Methylation Changes That Predict Onset of Post-traumatic Stress Disorder and Depression Following Physical Trauma. Front Neurosci 2021; 15:738347. [PMID: 34630024 PMCID: PMC8498101 DOI: 10.3389/fnins.2021.738347] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Accepted: 09/06/2021] [Indexed: 11/13/2022] Open
Abstract
Post-traumatic stress disorder (PTSD) and major depressive disorder (MDD) are commonly experienced after exposure to highly stressful events, including physical trauma, yet, biological predictors remain elusive. Methylation of DNA may provide key insights, as it likely is reflective of factors that may increase the risk in trauma patients, as DNA methylation is altered by previous stressors. Here, we compared DNA methylation patterns using bisulfite sequencing in patients with a physical trauma that required more than a 24-h hospitalization (n = 33). We then compared DNA methylation in patients who developed and compared the following groups (1) PTSD and MDD; n = 12), (2) MDD (patients with MDD only; n = 12), and (3) control (patients who did not have PTSD or MDD; n = 9), determined by the PTSD Checklist (PCL-5) and Quick Inventory of Depressive Symptomatology (QIDS) at 6-months follow-up. We identified 17 genes with hypermethylated cytosine sites and 2 genes with hypomethylated sites in comparison between PTSD and control group. In comparison between MDD and control group, we identified 12 genes with hypermethylated cytosine sites and 6 genes with hypomethylated sites. Demethylation of these genes altered the CREB signaling pathway in neurons and may represent a promising therapeutic development target for PTSD and MDD. Our findings suggest that epigenetic changes in these gene regions potentially relate to the onset and symptomology of PTSD and MDD and could be used as potential biomarkers in predicting the onset of PTSD or MDD following traumatic events.
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Affiliation(s)
- Carina A. Martin
- National Institute of Nursing Research, National Institutes of Health, Bethesda, MD, United States
| | - Rany Vorn
- National Institute of Nursing Research, National Institutes of Health, Bethesda, MD, United States
| | - Martin Schrieber
- Division of Trauma, Critical Care and Acute Care Surgery, Oregon Health and Sciences University, Portland, OR, United States
| | - Chen Lai
- National Institute of Nursing Research, National Institutes of Health, Bethesda, MD, United States
| | - Sijung Yun
- Yotta Biomed, Bethesda, MD, United States
| | - Hyung-Suk Kim
- National Institute of Nursing Research, National Institutes of Health, Bethesda, MD, United States
| | - Jessica Gill
- National Institute of Nursing Research, National Institutes of Health, Bethesda, MD, United States
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Barravecchia I, Demontis GC. HCN1 channels: A versatile tool for signal processing by primary sensory neurons. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2021; 166:133-146. [PMID: 34197835 DOI: 10.1016/j.pbiomolbio.2021.06.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Revised: 06/11/2021] [Accepted: 06/25/2021] [Indexed: 12/20/2022]
Abstract
Most primary sensory neurons (PSNs) generate a slowly-activating inward current in response to membrane hyperpolarization (Ih) and express HCN1 along with additional isoforms coding for hyperpolarization-activated channels (HCN). Changes in HCN expression may affect the excitability and firing patterns of PSNs, but retinal and inner ear PSNs do not fire action potentials, suggesting HCN channel roles may extend beyond excitability and cell firing control. In patients taking Ih blockers, photopsia triggered in response to abrupt changes in luminance correlates with impaired visual signal processing via parallel rod and cone pathways. Furthermore, in a mouse model of inherited retinal degeneration, HCN blockers or Hcn1 genetic ablation may worsen photoreceptors' demise. PSN's use of HCN channels to adjust either their firing rate or process signals generated by sensory transduction in non-spiking PSNs indicates HCN1 channels as a versatile tool with a novel role in sensory processing beyond firing control.
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Affiliation(s)
- Ivana Barravecchia
- Department of Pharmacy, Università di Pisa, Italy, Via Bonanno, 6, 56126, Pisa, Italy; Istitute of Life Science, Scuola Superiore Sant' Anna, 56127, Pisa, Italy.
| | - Gian Carlo Demontis
- Department of Pharmacy, Università di Pisa, Italy, Via Bonanno, 6, 56126, Pisa, Italy.
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Characterization of the HCN Interaction Partner TRIP8b/PEX5R in the Intracardiac Nervous System of TRIP8b-Deficient and Wild-Type Mice. Int J Mol Sci 2021; 22:ijms22094772. [PMID: 33946275 PMCID: PMC8125662 DOI: 10.3390/ijms22094772] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 04/21/2021] [Accepted: 04/28/2021] [Indexed: 12/25/2022] Open
Abstract
The tetratricopeptide repeat-containing Rab8b-interacting protein (TRIP8b/PEX5R) is an interaction partner and auxiliary subunit of hyperpolarization-activated cyclic nucleotide-gated (HCN) channels, which are key for rhythm generation in the brain and in the heart. Since TRIP8b is expressed in central neurons but not in cardiomyocytes, the TRIP8b-HCN interaction has been studied intensely in the brain, but is deemed irrelevant in the cardiac conduction system. Still, to date, TRIP8b has not been studied in the intrinsic cardiac nervous system (ICNS), a neuronal network located within epicardial fat pads. In vitro electrophysiological studies revealed that TRIP8b-deficient mouse hearts exhibit increased atrial refractory and atrioventricular nodal refractory periods, compared to hearts of wild-type littermates. Meanwhile, heart rate, sino-nodal recovery time, and ventricular refractory period did not differ between genotypes. Trip8b mRNA was detected in the ICNS by quantitative polymerase chain reaction. RNAscope in situ hybridization confirmed Trip8b localization in neuronal somata and nerve fibers. Additionally, we found a very low amount of mRNAs in the sinus node and atrioventricular node, most likely attributable to the delicate fibers innervating the conduction system. In contrast, TRIP8b protein was not detectable. Our data suggest that TRIP8b in the ICNS may play a role in the modulation of atrial electrophysiology beyond HCN-mediated sino-nodal control of the heart.
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Zhong W, Darmani NA. The HCN Channel Blocker ZD7288 Induces Emesis in the Least Shrew ( Cryptotis parva). Front Pharmacol 2021; 12:647021. [PMID: 33995059 PMCID: PMC8117105 DOI: 10.3389/fphar.2021.647021] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Accepted: 04/12/2021] [Indexed: 12/02/2022] Open
Abstract
Subtypes (1-4) of the hyperpolarization-activated cyclic nucleotide-gated (HCN) channels are widely expressed in the central and peripheral nervous systems, as well as the cells of smooth muscles in many organs. They mainly serve to regulate cellular excitability in these tissues. The HCN channel blocker ZD7288 has been shown to reduce apomorphine-induced conditioned taste aversion on saccharin preference in rats suggesting potential antinausea/antiemetic effects. Currently, in the least shew model of emesis we find that ZD7288 induces vomiting in a dose-dependent manner, with maximal efficacies of 100% at 1 mg/kg (i.p.) and 83.3% at 10 µg (i.c.v.). HCN channel subtype (1-4) expression was assessed using immunohistochemistry in the least shrew brainstem dorsal vagal complex (DVC) containing the emetic nuclei (area postrema (AP), nucleus tractus solitarius and dorsal motor nucleus of the vagus). Highly enriched HCN1 and HCN4 subtypes are present in the AP. A 1 mg/kg (i.p.) dose of ZD7288 strongly evoked c-Fos expression and ERK1/2 phosphorylation in the shrew brainstem DVC, but not in the in the enteric nervous system in the jejunum, suggesting a central contribution to the evoked vomiting. The ZD7288-evoked c-Fos expression exclusively occurred in tryptophan hydroxylase 2-positive serotonin neurons of the dorsal vagal complex, indicating activation of serotonin neurons may contribute to ZD7288-induced vomiting. To reveal its mechanism(s) of emetic action, we evaluated the efficacy of diverse antiemetics against ZD7288-evoked vomiting including the antagonists/inhibitors of: ERK1/2 (U0126), L-type Ca2+ channel (nifedipine); store-operated Ca2+ entry (MRS 1845); T-type Ca2+ channel (Z944), IP3R (2-APB), RyR receptor (dantrolene); the serotoninergic type 3 receptor (palonosetron); neurokinin 1 receptor (netupitant), dopamine type 2 receptor (sulpride), and the transient receptor potential vanilloid 1 receptor agonist, resiniferatoxin. All tested antiemetics except sulpride attenuated ZD7288-evoked vomiting to varying degrees. In sum, ZD7288 has emetic potential mainly via central mechanisms, a process which involves Ca2+ signaling and several emetic receptors. HCN channel blockers have been reported to have emetic potential in the clinic since they are currently used/investigated as therapeutic candidates for cancer therapy related- or unrelated-heart failure, pain, and cognitive impairment.
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Affiliation(s)
| | - N. A. Darmani
- Department of Basic Medical Sciences, College of Osteopathic Medicine of the Pacific, Western University of Health Sciences, Pomona, CA, United States
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Lu HJ, Nguyen TL, Hong GS, Pak S, Kim H, Kim H, Kim DY, Kim SY, Shen Y, Ryu PD, Lee MO, Oh U. Tentonin 3/TMEM150C senses blood pressure changes in the aortic arch. J Clin Invest 2021; 130:3671-3683. [PMID: 32484458 DOI: 10.1172/jci133798] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Accepted: 03/24/2020] [Indexed: 01/09/2023] Open
Abstract
The baroreceptor reflex is a powerful neural feedback that regulates arterial pressure (AP). Mechanosensitive channels transduce pulsatile AP to electrical signals in baroreceptors. Here we show that tentonin 3 (TTN3/TMEM150C), a cation channel activated by mechanical strokes, is essential for detecting AP changes in the aortic arch. TTN3 was expressed in nerve terminals in the aortic arch and nodose ganglion (NG) neurons. Genetic ablation of Ttn3 induced ambient hypertension, tachycardia, AP fluctuations, and impaired baroreflex sensitivity. Chemogenetic silencing or activation of Ttn3+ neurons in the NG resulted in an increase in AP and heart rate, or vice versa. More important, overexpression of Ttn3 in the NG of Ttn3-/- mice reversed the cardiovascular changes observed in Ttn3-/- mice. We conclude that TTN3 is a molecular component contributing to the sensing of dynamic AP changes in baroreceptors.
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Affiliation(s)
- Huan-Jun Lu
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, Korea.,College of Pharmacy
| | - Thien-Luan Nguyen
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, Korea.,College of Pharmacy
| | - Gyu-Sang Hong
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, Korea
| | - Sungmin Pak
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, Korea
| | - Hyesu Kim
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, Korea
| | - Hyungsup Kim
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, Korea
| | | | - Sung-Yon Kim
- Institute of Molecular Biology and Genetics, and
| | - Yiming Shen
- College of Veterinary Medicine, Seoul National University, Seoul, Korea
| | - Pan Dong Ryu
- College of Veterinary Medicine, Seoul National University, Seoul, Korea
| | | | - Uhtaek Oh
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, Korea
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12
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Gur S, Alzweri L, Yilmaz-Oral D, Kaya-Sezginer E, Abdel-Mageed AB, Sikka SC, Hellstrom WJG. Ivabradine, the hyperpolarization-activated cyclic nucleotide-gated channel blocker, elicits relaxation of the human corpus cavernosum: a potential option for erectile dysfunction treatment. Aging Male 2020; 23:1088-1097. [PMID: 31741421 DOI: 10.1080/13685538.2019.1678125] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
OBJECTIVE To evaluate the effect of the If channel inhibitor, ivabradine on human corpus cavernosum (HCC) smooth muscle tone. METHODS HCC samples were obtained from erectile dysfunction(ED) patients (n = 12) undergoing penile prosthesis surgery. Concentration-response curves for ivabradine were exposed to various inhibitory and stimulatory agents. The relaxant and contractile responses to electrical field stimulation (EFS, 10 Hz and 80 Hz) were examined in the presence or absence of ivabradine (10 μM). HCN3 and HCN4 channel expression and localization were determined by Western blot and immunohistochemical analyses of HCC tissues. RESULTS Increasing ivabradine concentrations dependently reduced the maximal contractile responses of isolated HCC strips induced by KCl (59.5 ± 2.5%) and phenylephrine (84.0 ± 9.8%), which was not affected by nitric oxide synthase and soluble guanylyl cyclase inhibitors after phenylephrine-induced contraction. Nifedipine and tetraethylammonium inhibited the maximum relaxation to ivabradine by 75% and 39.3%, respectively. Fasudil and sildenafil increased the relaxation response to ivabradine without altering the maximum response. Pre-incubation with ivabradine significantly increased relaxant responses to EFS (p < 0.01) and reduced the contractile tension evoked by EFS (72.3%) (p < 0.001). Ivabradine incubation did not affect the expression and localization of HCN3 and HCN4 channels in the HCC smooth muscle cells. CONCLUSIONS Ivabradine exhibits a relaxant effect on HCC tissues, which is likely to be attributed to the blocking of L-type Ca2+ channels and the opening of K+ channels, independent of changes in the activation of the nitric oxide/cyclic guanosine monophosphate system. Inhibition of HCN channels localized in cavernosal smooth muscle cells may offer pharmacological benefits for patients with cardiovascular risk factors.
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Affiliation(s)
- Serap Gur
- Departments of Urology, Tulane University Health Sciences Center, New Orleans, LA, USA
- Department of Pharmacology and Biochemistry, Faculty of Pharmacy, Ankara University, Ankara, Turkey
| | - Laith Alzweri
- Departments of Urology, Tulane University Health Sciences Center, New Orleans, LA, USA
| | - Didem Yilmaz-Oral
- Department of Pharmacology, Faculty of Pharmacy, Cukurova University, Adana, Turkey
| | - Ecem Kaya-Sezginer
- Department of Pharmacology and Biochemistry, Faculty of Pharmacy, Ankara University, Ankara, Turkey
| | - Asim B Abdel-Mageed
- Departments of Urology, Tulane University Health Sciences Center, New Orleans, LA, USA
| | - Suresh C Sikka
- Departments of Urology, Tulane University Health Sciences Center, New Orleans, LA, USA
| | - Wayne J G Hellstrom
- Departments of Urology, Tulane University Health Sciences Center, New Orleans, LA, USA
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13
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Kawada T, Yamamoto H, Uemura K, Hayama Y, Nishikawa T, Sugimachi M. Intravenous ivabradine augments the dynamic heart rate response to moderate vagal nerve stimulation in anesthetized rats. Am J Physiol Heart Circ Physiol 2019; 317:H597-H606. [DOI: 10.1152/ajpheart.00288.2019] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Ivabradine is a selective bradycardic agent that reduces the heart rate (HR) by inhibiting the hyperpolarization-activated cyclic nucleotide-gated channels. Although its cardiovascular effect is thought to be minimal except for inducing bradycardia, ivabradine could interact with cardiovascular regulation by the autonomic nervous system. We tested whether ivabradine modifies dynamic characteristics of peripheral vagal HR control. In anesthetized Wistar-Kyoto rats ( n = 7), the right vagal nerve was sectioned and stimulated for 10 min according to a binary white noise sequence with a switching interval of 500 ms. The efferent vagal nerve stimulation (VNS) trials were performed using three different rates (10, 20, and 40 Hz), and were designated as V0–10, V0–20, and V0–40, respectively. The transfer function from the VNS to the HR was estimated before and after the intravenous administration of ivabradine (2 mg/kg). Ivabradine increased the asymptotic dynamic gain in V0–20 [from 3.88 (1.78–5.79) to 6.62 (3.12–8.31) beats·min−1·Hz−1, P < 0.01, median (range)] but not in V0–10 or V0–40. Ivabradine increased the corner frequency in V0–10 [from 0.032 (0.026–0.041) to 0.064 (0.029–0.090) Hz, P < 0.01] and V0–20 [from 0.040 (0.037–0.056) to 0.068 (0.051–0.100) Hz, P < 0.01] but not in V0–40. In conclusion, ivabradine augmented the dynamic HR response to moderate VNS. At high VNS, however, ivabradine did not significantly augment the dynamic HR response, possibly because ivabradine reduced the baseline HR and limited the range for the bradycardic response to high VNS. NEW & NOTEWORTHY Ivabradine is considered to be a pure bradycardic agent that has little effect on cardiovascular function except inducing bradycardia. The present study demonstrated that ivabradine interacts with the dynamic vagal heart rate control in a manner that augments the heart rate response to moderate-intensity efferent vagal nerve stimulation.
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Affiliation(s)
- Toru Kawada
- Department of Cardiovascular Dynamics, National Cerebral and Cardiovascular Center, Osaka, Japan
| | - Hiromi Yamamoto
- Division of Cardiology, Department of Medicine, Faculty of Medicine, Kindai University, Osaka, Japan
| | - Kazunori Uemura
- Department of Cardiovascular Dynamics, National Cerebral and Cardiovascular Center, Osaka, Japan
| | - Yohsuke Hayama
- Department of Cardiovascular Dynamics, National Cerebral and Cardiovascular Center, Osaka, Japan
| | - Takuya Nishikawa
- Department of Cardiovascular Dynamics, National Cerebral and Cardiovascular Center, Osaka, Japan
| | - Masaru Sugimachi
- Department of Cardiovascular Dynamics, National Cerebral and Cardiovascular Center, Osaka, Japan
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14
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A randomised, double-blind, placebo-controlled crossover trial of the influence of the HCN channel blocker ivabradine in a healthy volunteer pain model: an enriched population trial. Pain 2019; 160:2554-2565. [DOI: 10.1097/j.pain.0000000000001638] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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15
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Marmoy OR, Furlong PL, Moore CEG. Upper and lower limb motor axons demonstrate differential excitability and accommodation to strong hyperpolarizing currents during induced hyperthermia. J Neurophysiol 2019; 121:2061-2070. [PMID: 30917073 DOI: 10.1152/jn.00464.2018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Length-dependent peripheral neuropathy typically involves the insidious onset of sensory loss in the lower limbs before later progressing proximally. Recent evidence proposes hyperpolarization-activated cyclic nucleotide-gated (HCN) channels as dysfunctional in rodent models of peripheral neuropathy, and therefore differential expression of HCN channels in the lower limbs was hypothesized as a pathophysiological mechanism accounting for the pattern of symptomatology within this study. We studied six healthy participants, using motor axon excitability including strong and long [-70% and -100% hyperpolarizing threshold electrotonus (TEh)] hyperpolarizing currents to preferably study HCN channel function from the median and tibial nerves from high (40%) and low (20%) threshold. This was recorded at normothermia (~32°C) and then repeated during hyperthermia (~40°C) as an artificial hyperpolarizing axon stress. Significant differences between recovery cycle, superexcitability, accommodation to small depolarizing currents, and alterations in late stages of the inward-rectifying currents of strongest (-70% and -100% TEh) currents were observed in the lower limbs during hyperthermia. We demonstrate differences in late IH current flow, which implies higher expression of HCN channel isoforms. The findings also indicate their potential inference in the symptomatology of length-dependent peripheral neuropathies and may be a unique target for minimizing symptomatology and pathogenesis in acquired disease. NEW & NOTEWORTHY This study demonstrates nerve excitability differences between the upper and lower limbs during hyperthermia, an experimentally induced axonal stress. The findings indicate that there is differential expression of slow hyperpolarization-activated cyclic nucleotide-gated (HCN) channel isoforms between the upper and lower limbs, which was demonstrated through strong, long hyperpolarizing currents during hyperthermia. Such mechanisms may underlie postural control but render the lower limbs susceptible to dysfunction in disease states.
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Affiliation(s)
- Oliver R Marmoy
- Department of Clinical Neurophysiology, Portsmouth Hospitals NHS Trust, Portsmouth , United Kingdom.,Aston University , Birmingham , United Kingdom
| | | | - Christopher E G Moore
- Department of Clinical Neurophysiology, Portsmouth Hospitals NHS Trust, Portsmouth , United Kingdom
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16
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Kawada T, Shimizu S, Uemura K, Hayama Y, Yamamoto H, Shishido T, Nishikawa T, Sugimachi M. Ivabradine preserves dynamic sympathetic control of heart rate despite inducing significant bradycardia in rats. J Physiol Sci 2019; 69:211-222. [PMID: 30191411 PMCID: PMC10718044 DOI: 10.1007/s12576-018-0636-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Accepted: 08/28/2018] [Indexed: 10/28/2022]
Abstract
Ivabradine is a selective bradycardic agent that inhibits hyperpolarization-activated cyclic nucleotide-gated (HCN) channels. HCN channels play a key role in mediating the positive chronotropic response to sympathetic nerve stimulation (SNS). We examined whether ivabradine would interfere with dynamic sympathetic control of heart rate (HR). The effect of intravenous ivabradine (2 mg/kg, n = 7) or metoprolol (10 mg/kg, n = 6) on the transfer function from SNS to HR was examined in anesthetized rats. Ivabradine preserved the asymptotic dynamic gain of the HR transfer function and nearly doubled the asymptotic dynamic gain of the transfer function from SNS to the R-R interval. In contrast, metoprolol abolished dynamic sympathetic control of HR. Preserved dynamic sympathetic control of HR, with coexisting bradycardia, may contribute to some of the beneficial effects of ivabradine previously reported in clinical application.
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Affiliation(s)
- Toru Kawada
- Department of Cardiovascular Dynamics, National Cerebral and Cardiovascular Center, Osaka, 565-8565, Japan.
| | - Shuji Shimizu
- Department of Cardiovascular Dynamics, National Cerebral and Cardiovascular Center, Osaka, 565-8565, Japan
| | - Kazunori Uemura
- Department of Cardiovascular Dynamics, National Cerebral and Cardiovascular Center, Osaka, 565-8565, Japan
| | - Yohsuke Hayama
- Department of Cardiovascular Dynamics, National Cerebral and Cardiovascular Center, Osaka, 565-8565, Japan
| | - Hiromi Yamamoto
- Division of Cardiology, Department of Medicine, Faculty of Medicine, Kindai University, Osaka, 589-8511, Japan
| | - Toshiaki Shishido
- Department of Research Promotion, National Cerebral and Cardiovascular Center, Osaka, 565-8565, Japan
| | - Takuya Nishikawa
- Department of Cardiovascular Dynamics, National Cerebral and Cardiovascular Center, Osaka, 565-8565, Japan
| | - Masaru Sugimachi
- Department of Cardiovascular Dynamics, National Cerebral and Cardiovascular Center, Osaka, 565-8565, Japan
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17
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Tu H, Zhang D, Li YL. Cellular and Molecular Mechanisms Underlying Arterial Baroreceptor Remodeling in Cardiovascular Diseases and Diabetes. Neurosci Bull 2018; 35:98-112. [PMID: 30146675 DOI: 10.1007/s12264-018-0274-y] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Accepted: 05/31/2018] [Indexed: 01/23/2023] Open
Abstract
Clinical trials and animal experimental studies have demonstrated an association of arterial baroreflex impairment with the prognosis and mortality of cardiovascular diseases and diabetes. As a primary part of the arterial baroreflex arc, the pressure sensitivity of arterial baroreceptors is blunted and involved in arterial baroreflex dysfunction in cardiovascular diseases and diabetes. Changes in the arterial vascular walls, mechanosensitive ion channels, and voltage-gated ion channels contribute to the attenuation of arterial baroreceptor sensitivity. Some endogenous substances (such as angiotensin II and superoxide anion) can modulate these morphological and functional alterations through intracellular signaling pathways in impaired arterial baroreceptors. Arterial baroreceptors can be considered as a potential therapeutic target to improve the prognosis of patients with cardiovascular diseases and diabetes.
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Affiliation(s)
- Huiyin Tu
- Department of Emergency Medicine, University of Nebraska Medical Center, Omaha, NE, 68198, USA
| | - Dongze Zhang
- Department of Emergency Medicine, University of Nebraska Medical Center, Omaha, NE, 68198, USA
| | - Yu-Long Li
- Department of Emergency Medicine, University of Nebraska Medical Center, Omaha, NE, 68198, USA.
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18
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Yamamoto H, Kawada T, Shimizu S, Uemura K, Inagaki M, Kakehi K, Iwanaga Y, Fukuda K, Miyamoto T, Miyazaki S, Sugimachi M. Ivabradine does not acutely affect open-loop baroreflex static characteristics and spares sympathetic heart rate control in rats. Int J Cardiol 2018; 257:255-261. [DOI: 10.1016/j.ijcard.2017.11.115] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/07/2017] [Revised: 11/29/2017] [Accepted: 11/30/2017] [Indexed: 11/26/2022]
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19
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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] [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.
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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
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20
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Cordeiro Matos S, Zamfir M, Longo G, Ribeiro-da-Silva A, Séguéla P. Noradrenergic fiber sprouting and altered transduction in neuropathic prefrontal cortex. Brain Struct Funct 2017; 223:1149-1164. [PMID: 29094305 DOI: 10.1007/s00429-017-1543-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Accepted: 10/19/2017] [Indexed: 12/22/2022]
Abstract
Functional changes in hyperpolarization-activated and cyclic nucleotide-gated (HCN) channels have been shown to contribute to medial prefrontal (mPFC) hyperexcitability after peripheral nerve injury. A reduction in the open probability of these neuronal channels might be relevant since this can enhance membrane input resistance and synaptic summation. However, the molecular mechanisms underlying neuropathy-associated alterations in HCN channel activity remain elusive. Using the spared nerve injury model of neuropathic pain in Long-Evans rats, we first discovered a significant increase in noradrenergic innervation within the mPFC of nerve-injured compared to control animals. Patch-clamp recordings in layer II/III pyramidal neurons of the mPFC revealed that adrenoceptors, primarily the α2 subtype, can modulate the voltage-dependent activation of HCN channels and the abnormal prefrontal excitability following peripheral neuropathy. Additionally, microinfusions of the α2 adrenoceptor agonist clonidine in the mPFC of neuropathic rats provided analgesic effects, indicating the behavioral significance for this noradrenergic pathway in manifestations of the chronic pain state. Taken together, our results provide insights into the role of cortical catecholaminergic neuromodulation in neuropathic pain and suggest that altered noradrenergic transduction may play a major role in the HCN channel dysfunction and pyramidal hyperactivity observed in several chronic pain conditions.
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Affiliation(s)
- Steven Cordeiro Matos
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, 3801 University, Montreal, QC, H3A 2B4, Canada.,Alan Edwards Centre for Research on Pain, McGill University, Montreal, QC, H3A 0G1, Canada
| | - Maria Zamfir
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, 3801 University, Montreal, QC, H3A 2B4, Canada.,Alan Edwards Centre for Research on Pain, McGill University, Montreal, QC, H3A 0G1, Canada
| | - Geraldine Longo
- Alan Edwards Centre for Research on Pain, McGill University, Montreal, QC, H3A 0G1, Canada.,Department of Pharmacology and Therapeutics, McGill University, Montreal, QC, H3G 1Y6, Canada
| | - Alfredo Ribeiro-da-Silva
- Alan Edwards Centre for Research on Pain, McGill University, Montreal, QC, H3A 0G1, Canada.,Department of Pharmacology and Therapeutics, McGill University, Montreal, QC, H3G 1Y6, Canada
| | - Philippe Séguéla
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, 3801 University, Montreal, QC, H3A 2B4, Canada. .,Alan Edwards Centre for Research on Pain, McGill University, Montreal, QC, H3A 0G1, Canada.
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21
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Zhang M, Vollmer C, Nurse CA. Adenosine and dopamine oppositely modulate a hyperpolarization-activated current I h in chemosensory neurons of the rat carotid body in co-culture. J Physiol 2017; 596:3101-3117. [PMID: 28801916 DOI: 10.1113/jp274743] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Accepted: 08/08/2017] [Indexed: 12/24/2022] Open
Abstract
KEY POINTS Adenosine and dopamine (DA) are neuromodulators in the carotid body (CB) chemoafferent pathway, but their mechanisms of action are incompletely understood. Using functional co-cultures of rat CB chemoreceptor (type I) cells and sensory petrosal neurons (PNs), we show that adenosine enhanced a hyperpolarization-activated cation current Ih in chemosensory PNs via A2a receptors, whereas DA had the opposite effect via D2 receptors. Adenosine caused a depolarizing shift in the Ih activation curve and increased firing frequency, whereas DA caused a hyperpolarizing shift in the curve and decreased firing frequency. Acute hypoxia and isohydric hypercapnia depolarized type I cells concomitant with increased excitation of adjacent PNs; the A2a receptor blocker SCH58261 inhibited both type I and PN responses during hypoxia, but only the PN response during isohydric hypercapnia. We propose that adenosine and DA control firing frequency in chemosensory PNs via their opposing actions on Ih . ABSTRACT Adenosine and dopamine (DA) act as neurotransmitters or neuromodulators at the carotid body (CB) chemosensory synapse, but their mechanisms of action are not fully understood. Using a functional co-culture model of rat CB chemoreceptor (type I) cell clusters and juxtaposed afferent petrosal neurons (PNs), we tested the hypothesis that adenosine and DA act postsynaptically to modulate a hyperpolarization-activated, cyclic nucleotide-gated (HCN) cation current (Ih ). In whole-cell recordings from hypoxia-responsive PNs, cAMP mimetics enhanced Ih whereas the HCN blocker ZD7288 (2 μm) reversibly inhibited Ih . Adenosine caused a potentiation of Ih (EC50 ∼ 35 nm) that was sensitive to the A2a blocker SCH58261 (5 nm), and an ∼16 mV depolarizing shift in V½ for voltage dependence of Ih activation. By contrast, DA (10 μm) caused an inhibition of Ih that was sensitive to the D2 blocker sulpiride (1-10 μm), and an ∼11 mV hyperpolarizing shift in V½ . Sulpiride potentiated Ih in neurons adjacent to, but not distant from, type I cell clusters. DA also decreased PN action potential frequency whereas adenosine had the opposite effect. During simultaneous paired recordings, SCH58261 inhibited both the presynaptic hypoxia-induced receptor potential in type I cells and the postsynaptic PN response. By contrast, SCH58261 inhibited only the postsynaptic PN response induced by isohydric hypercapnia. Confocal immunofluorescence confirmed the localization of HCN4 subunits in tyrosine hydroxylase-positive chemoafferent neurons in tissue sections of rat petrosal ganglia. These data suggest that adenosine and DA, acting through A2a and D2 receptors respectively, regulate PN excitability via their opposing actions on Ih .
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Affiliation(s)
- Min Zhang
- Department of Biology, McMaster University, 1280 Main St. West, Hamilton, Ontario, L8S 4K1, Canada
| | - Cathy Vollmer
- Department of Biology, McMaster University, 1280 Main St. West, Hamilton, Ontario, L8S 4K1, Canada
| | - Colin A Nurse
- Department of Biology, McMaster University, 1280 Main St. West, Hamilton, Ontario, L8S 4K1, Canada
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22
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Weerasinghe D, Menon P, Vucic S. Hyperpolarization-activated cyclic-nucleotide-gated channels potentially modulate axonal excitability at different thresholds. J Neurophysiol 2017; 118:3044-3050. [PMID: 28904107 DOI: 10.1152/jn.00576.2017] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Revised: 09/06/2017] [Accepted: 09/12/2017] [Indexed: 11/22/2022] Open
Abstract
Hyperpolarization-activated cyclic-nucleotide-gated (HCN) channels mediate differences in sensory and motor axonal excitability at different thresholds in animal models. Importantly, HCN channels are responsible for voltage-gated inward rectifying (Ih) currents activated during hyperpolarization. The Ih currents exert a crucial role in determining the resting membrane potential and have been implicated in a variety of neurological disorders, including neuropathic pain. In humans, differences in biophysical properties of motor and sensory axons at different thresholds remain to be elucidated and could provide crucial pathophysiological insights in peripheral neurological diseases. Consequently, the aim of this study was to characterize sensory and motor axonal function at different threshold. Median nerve motor and sensory axonal excitability studies were undertaken in 15 healthy subjects (45 studies in total). Tracking targets were set to 20, 40, and 60% of maximum for sensory and motor axons. Hyperpolarizing threshold electrotonus (TEh) at 90-100 ms was significantly increased in lower threshold sensory axons times (F = 11.195, P < 0.001). In motor axons, the hyperpolarizing current/threshold (I/V) gradient was significantly increased in lower threshold axons (F = 3.191, P < 0.05). The minimum I/V gradient was increased in lower threshold motor and sensory axons. In conclusion, variation in the kinetics of HCN isoforms could account for the findings in motor and sensory axons. Importantly, assessing the function of HCN channels in sensory and motor axons of different thresholds may provide insights into the pathophysiological processes underlying peripheral neurological diseases in humans, particularly focusing on the role of HCN channels with the potential of identifying novel treatment targets.NEW & NOTEWORTHY Hyperpolarization-activated cyclic-nucleotide-gated (HCN) channels, which underlie inward rectifying currents (Ih), appear to mediate differences in sensory and motor axonal properties. Inward rectifying currents are increased in lower threshold motor and sensory axons, although different HCN channel isoforms appear to underlie these changes. While faster activating HCN channels seem to underlie Ih changes in sensory axons, slower activating HCN isoforms appear to be mediating the differences in Ih conductances in motor axons of different thresholds. The differences in HCN gating properties could explain the predilection for dysfunction of sensory and motor axons in specific neurological diseases.
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Affiliation(s)
| | - Parvathi Menon
- Department of Neurology, Westmead Hospital, Sydney, Australia; and.,Westmead Clinical School, The University of Sydney, Sydney, Australia
| | - Steve Vucic
- Department of Neurology, Westmead Hospital, Sydney, Australia; and .,Westmead Clinical School, The University of Sydney, Sydney, Australia
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23
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Pietak A, Levin M. Bioelectric gene and reaction networks: computational modelling of genetic, biochemical and bioelectrical dynamics in pattern regulation. J R Soc Interface 2017; 14:20170425. [PMID: 28954851 PMCID: PMC5636277 DOI: 10.1098/rsif.2017.0425] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Accepted: 08/31/2017] [Indexed: 12/17/2022] Open
Abstract
Gene regulatory networks (GRNs) describe interactions between gene products and transcription factors that control gene expression. In combination with reaction-diffusion models, GRNs have enhanced comprehension of biological pattern formation. However, although it is well known that biological systems exploit an interplay of genetic and physical mechanisms, instructive factors such as transmembrane potential (Vmem) have not been integrated into full GRN models. Here we extend regulatory networks to include bioelectric signalling, developing a novel synthesis: the bioelectricity-integrated gene and reaction (BIGR) network. Using in silico simulations, we highlight the capacity for Vmem to alter steady-state concentrations of key signalling molecules inside and out of cells. We characterize fundamental feedbacks where Vmem both controls, and is in turn regulated by, biochemical signals and thereby demonstrate Vmem homeostatic control, Vmem memory and Vmem controlled state switching. BIGR networks demonstrating hysteresis are identified as a mechanisms through which more complex patterns of stable Vmem spots and stripes, along with correlated concentration patterns, can spontaneously emerge. As further proof of principle, we present and analyse a BIGR network model that mechanistically explains key aspects of the remarkable regenerative powers of creatures such as planarian flatworms. The functional properties of BIGR networks generate the first testable, quantitative hypotheses for biophysical mechanisms underlying the stability and adaptive regulation of anatomical bioelectric pattern.
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Affiliation(s)
- Alexis Pietak
- Allen Discovery Center, Tufts University, Medford, MA, USA
| | - Michael Levin
- Allen Discovery Center, Tufts University, Medford, MA, USA
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Sturdy J, Ottesen JT, Olufsen MS. Modeling the differentiation of A- and C-type baroreceptor firing patterns. J Comput Neurosci 2016; 42:11-30. [PMID: 27704337 DOI: 10.1007/s10827-016-0624-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Revised: 08/30/2016] [Accepted: 09/04/2016] [Indexed: 12/17/2022]
Abstract
The baroreceptor neurons serve as the primary transducers of blood pressure for the autonomic nervous system and are thus critical in enabling the body to respond effectively to changes in blood pressure. These neurons can be separated into two types (A and C) based on the myelination of their axons and their distinct firing patterns elicited in response to specific pressure stimuli. This study has developed a comprehensive model of the afferent baroreceptor discharge built on physiological knowledge of arterial wall mechanics, firing rate responses to controlled pressure stimuli, and ion channel dynamics within the baroreceptor neurons. With this model, we were able to predict firing rates observed in previously published experiments in both A- and C-type neurons. These results were obtained by adjusting model parameters determining the maximal ion-channel conductances. The observed variation in the model parameters are hypothesized to correspond to physiological differences between A- and C-type neurons. In agreement with published experimental observations, our simulations suggest that a twofold lower potassium conductance in C-type neurons is responsible for the observed sustained basal firing, where as a tenfold higher mechanosensitive conductance is responsible for the greater firing rate observed in A-type neurons. A better understanding of the difference between the two neuron types can potentially be used to gain more insight about pathophysiology and treatment of diseases related to baroreflex function, e.g. in patients with autonomic failure, a syndrome that is difficult to diagnose in terms of its pathophysiology.
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Affiliation(s)
- Jacob Sturdy
- Department of Structural Engineering, Norwegian University of Science and Technology, Richard Birkelandsvei 1A, 7491, Trondheim, Norway
| | - Johnny T Ottesen
- Department of Science and Environment, Roskilde University, Universitetsvej 1, 4000, Roskilde, Denmark
| | - Mette S Olufsen
- Department of Mathematics, North Carolina State University, Campus Box 8205, Raleigh, NC, 27695-8205, USA.
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McGovern AE, Robusto J, Rakoczy J, Simmons DG, Phipps S, Mazzone SB. The effect of hyperpolarization-activated cyclic nucleotide-gated ion channel inhibitors on the vagal control of guinea pig airway smooth muscle tone. Br J Pharmacol 2016; 171:3633-50. [PMID: 24762027 DOI: 10.1111/bph.12745] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2013] [Revised: 02/10/2014] [Accepted: 02/14/2014] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND AND PURPOSE Subtypes of the hyperpolarization-activated cyclic nucleotide-gated (HCN) family of cation channels are widely expressed on nerves and smooth muscle cells in many organ systems, where they serve to regulate membrane excitability. Here we have assessed whether HCN channel inhibitors alter the function of airway smooth muscle or the neurons that regulate airway smooth muscle tone. EXPERIMENTAL APPROACH The effects of the HCN channel inhibitors ZD7288, zatebradine and Cs(+) were assessed on agonist and nerve stimulation-evoked changes in guinea pig airway smooth muscle tone using tracheal strips in vitro, an innervated tracheal tube preparation ex vivo or in anaesthetized mechanically ventilated guinea pigs in vivo. HCN channel expression in airway nerves was assessed using immunohistochemistry, PCR and in situ hybridization. KEY RESULTS HCN channel inhibition did not alter airway smooth muscle reactivity in vitro to exogenously administered smooth muscle spasmogens, but significantly potentiated smooth muscle contraction evoked by the sensory nerve stimulant capsaicin and electrical field stimulation of parasympathetic cholinergic postganglionic neurons. Sensory nerve hyperresponsiveness was also evident in in vivo following HCN channel blockade. Cs(+) , but not ZD7288, potentiated preganglionic nerve-dependent airway contractions and over time induced autorhythmic preganglionic nerve activity, which was not mimicked by inhibitors of potassium channels. HCN channel expression was most evident in vagal sensory ganglia and airway nerve fibres. CONCLUSIONS AND IMPLICATIONS HCN channel inhibitors had a previously unrecognized effect on the neural regulation of airway smooth muscle tone, which may have implications for some patients receiving HCN channel inhibitors for therapeutic purposes.
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Affiliation(s)
- Alice E McGovern
- School of Biomedical Sciences, University of Queensland, St Lucia, Qld, Australia
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Heusser K, Tank J, Brinkmann J, Schroeder C, May M, Großhennig A, Wenzel D, Diedrich A, Sweep FCGJ, Mehling H, Luft FC, Jordan J. Preserved Autonomic Cardiovascular Regulation With Cardiac Pacemaker Inhibition: A Crossover Trial Using High-Fidelity Cardiovascular Phenotyping. J Am Heart Assoc 2016; 5:e002674. [PMID: 26764413 PMCID: PMC4859385 DOI: 10.1161/jaha.115.002674] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/17/2015] [Accepted: 12/03/2015] [Indexed: 12/29/2022]
Abstract
BACKGROUND Sympathetic and parasympathetic influences on heart rate (HR), which are governed by baroreflex mechanisms, are integrated at the cardiac sinus node through hyperpolarization-activated cyclic nucleotide-gated channels (HCN4). We hypothesized that HCN4 blockade with ivabradine selectively attenuates HR and baroreflex HR regulation, leaving baroreflex control of muscle sympathetic nerve activity intact. METHODS AND RESULTS We treated 21 healthy men with 2×7.5 mg ivabradine or placebo in a randomized crossover fashion. We recorded electrocardiogram, blood pressure, and muscle sympathetic nerve activity at rest and during pharmacological baroreflex testing. Ivabradine reduced normalized HR from 65.9±8.1 to 58.4±6.2 beats per minute (P<0.001) with unaffected blood pressure and muscle sympathetic nerve activity. On ivabradine, cardiac and sympathetic baroreflex gains and blood pressure responses to vasoactive drugs were unchanged. Ivabradine aggravated bradycardia during baroreflex loading. CONCLUSIONS HCN4 blockade with ivabradine reduced HR, leaving physiological regulation of HR and muscle sympathetic nerve activity as well as baroreflex blood pressure buffering intact. Ivabradine could aggravate bradycardia during parasympathetic activation. CLINICAL TRIAL REGISTRATION URL: http://www.clinicaltrials.gov. Unique identifier: NCT00865917.
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Affiliation(s)
- Karsten Heusser
- Institute of Clinical PharmacologyHannover Medical SchoolHannoverGermany
| | - Jens Tank
- Institute of Clinical PharmacologyHannover Medical SchoolHannoverGermany
| | - Julia Brinkmann
- Institute of Clinical PharmacologyHannover Medical SchoolHannoverGermany
| | | | - Marcus May
- Institute of Clinical PharmacologyHannover Medical SchoolHannoverGermany
| | - Anika Großhennig
- Institute of BiostatisticsHannover Medical SchoolHannoverGermany
| | - Daniela Wenzel
- Institute of BiostatisticsHannover Medical SchoolHannoverGermany
| | - André Diedrich
- Division of Clinical PharmacologyDepartment of MedicineAutonomic Dysfunction ServiceVanderbilt UniversityNashvilleTN
| | - Fred C. G. J. Sweep
- Department of Laboratory MedicineRadboud University Medical CentreNijmegenThe Netherlands
| | - Heidrun Mehling
- Experimental Clinical Research CenterCharité Medical Faculty and Max Delbrück Center for Molecular MedicineBerlinGermany
| | - Friedrich C. Luft
- Experimental Clinical Research CenterCharité Medical Faculty and Max Delbrück Center for Molecular MedicineBerlinGermany
| | - Jens Jordan
- Institute of Clinical PharmacologyHannover Medical SchoolHannoverGermany
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Electrical resonance with voltage-gated ion channels: perspectives from biophysical mechanisms and neural electrophysiology. Acta Pharmacol Sin 2016; 37:67-74. [PMID: 26725736 DOI: 10.1038/aps.2015.140] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2015] [Accepted: 10/28/2015] [Indexed: 12/12/2022] Open
Abstract
Electrical resonance, providing selective signal amplification at preferred frequencies, is a unique phenomenon of excitable membranes, which has been observed in the nervous system at the cellular, circuit and system levels. The mechanisms underlying electrical resonance have not been fully elucidated. Prevailing hypotheses attribute the resonance to voltage-gated ion channels on the membrane of single neurons. In this review, we follow this line of thinking to summarize and analyze the biophysical/molecular mechanisms, and also the physiological relevance of channel-mediated electrical resonance.
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Novella Romanelli M, Sartiani L, Masi A, Mannaioni G, Manetti D, Mugelli A, Cerbai E. HCN Channels Modulators: The Need for Selectivity. Curr Top Med Chem 2016; 16:1764-91. [PMID: 26975509 PMCID: PMC5374843 DOI: 10.2174/1568026616999160315130832] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2015] [Revised: 08/04/2015] [Accepted: 08/05/2015] [Indexed: 12/27/2022]
Abstract
Hyperpolarization-activated, cyclic nucleotide-gated (HCN) channels, the molecular correlate of the hyperpolarization-activated current (If/Ih), are membrane proteins which play an important role in several physiological processes and various pathological conditions. In the Sino Atrial Node (SAN) HCN4 is the target of ivabradine, a bradycardic agent that is, at the moment, the only drug which specifically blocks If. Nevertheless, several other pharmacological agents have been shown to modulate HCN channels, a property that may contribute to their therapeutic activity and/or to their side effects. HCN channels are considered potential targets for developing drugs to treat several important pathologies, but a major issue in this field is the discovery of isoform-selective compounds, owing to the wide distribution of these proteins into the central and peripheral nervous systems, heart and other peripheral tissues. This survey is focused on the compounds that have been shown, or have been designed, to interact with HCN channels and on their binding sites, with the aim to summarize current knowledge and possibly to unveil useful information to design new potent and selective modulators.
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Affiliation(s)
- Maria Novella Romanelli
- University of Florence, Department of Neurosciences, Psychology, Drug Research and Child's Health, Section of Pharmaceutical and Nutraceutical Sciences, via Ugo Schiff 6, 50019 Sesto Fiorentino, Italy.
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Cordeiro Matos S, Zhang Z, Séguéla P. Peripheral Neuropathy Induces HCN Channel Dysfunction in Pyramidal Neurons of the Medial Prefrontal Cortex. J Neurosci 2015; 35:13244-56. [PMID: 26400952 PMCID: PMC6605438 DOI: 10.1523/jneurosci.0799-15.2015] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Revised: 08/21/2015] [Accepted: 08/22/2015] [Indexed: 01/28/2023] Open
Abstract
Neuropathic pain is a debilitating condition for which the development of effective treatments has been limited by an incomplete understanding of its molecular basis. The cationic current Ih mediated by hyperpolarization-activated cyclic nucleotide-gated (HCN) channels plays an important role in pain by facilitating ectopic firing and hyperexcitability in DRG neurons, however little is known regarding the role of Ih in supraspinal pain pathways. The medial prefrontal cortex (mPFC), which is reported to be involved in the affective aspects of pain, exhibits high HCN channel expression. Using the spared nerve injury (SNI) model of neuropathic pain in Long-Evans rats and patch-clamp recordings in layer II/III pyramidal neurons of the contralateral mPFC, we observed a hyperpolarizing shift in the voltage-dependent activation of Ih in SNI neurons, whereas maximal Ih remained unchanged. Accordingly, SNI mPFC pyramidal neurons exhibited increased input resistance and excitability, as well as facilitated glutamatergic mGluR5-mediated persistent firing, compared with sham neurons. Moreover, intracellular application of bromo-cAMP abolished the hyperpolarizing shift in the voltage-dependent activation of Ih observed in SNI neurons, whereas protein kinase A (PKA) inhibition further promoted this shift in both SNI and sham neurons. Behaviorally, acute HCN channel blockade by local injection of ZD7288 in the mPFC of SNI rats induced a decrease in cold allodynia. These findings suggest that changes in the cAMP/PKA axis in mPFC neurons underlie alterations to HCN channel function, which can influence descending inhibition of pain pathways in neuropathic conditions. Significance statement: Recent studies investigating the role of the medial prefrontal cortex (mPFC) in neuropathic pain have led to an increased awareness of how affective and cognitive factors can influence pain perception. It is therefore imperative that we advance our understanding of the involvement of supraspinal pain pathways. Our electrophysiological and behavioral results support an important role for hyperpolarization-activated cyclic nucleotide-gated channels and the cAMP/protein kinase A signaling axis in promoting hyperexcitability and persistent firing in pyramidal neurons of the mPFC in neuropathic animals. These findings offer novel insights, with potential therapeutic implications, into pathophysiological mechanisms underlying the abnormal contribution of layer II/III prefrontal pyramidal neurons to chronic pain states.
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Affiliation(s)
- Steven Cordeiro Matos
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, Alan Edwards Centre for Research on Pain, McGill University, Montreal, Quebec H3A 2B4, Canada
| | - Zizhen Zhang
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, Alan Edwards Centre for Research on Pain, McGill University, Montreal, Quebec H3A 2B4, Canada
| | - Philippe Séguéla
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, Alan Edwards Centre for Research on Pain, McGill University, Montreal, Quebec H3A 2B4, Canada
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Turner MJ, Kawada T, Shimizu S, Fukumitsu M, Sugimachi M. Open-loop characteristics of the arterial baroreflex after blockade of unmyelinated baroreceptors with resiniferatoxin. Auton Neurosci 2015; 193:38-43. [PMID: 26049262 DOI: 10.1016/j.autneu.2015.05.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2015] [Revised: 05/25/2015] [Accepted: 05/26/2015] [Indexed: 02/01/2023]
Abstract
Arterial baroreceptors can be divided into two categories dependent on whether their axons are myelinated (A-fiber) or unmyelinated (C-fiber). We investigated the effect of periaxonal resiniferatoxin (RTX), a blocker of C-fiber baroreceptor activity, on the open-loop static characteristics of the arterial baroreflex. The baroreceptor region of the right aortic depressor nerve was isolated, and intra-baroreceptor region pressure (BRP) was changed from 60 to 180 mm Hg in 10 anesthetized Sprague-Dawley rats. Open-loop static characteristics of the neural arc from BRP to efferent sympathetic nerve activity (SNA), peripheral arc from SNA to arterial pressure (AP), and total reflex arc from BRP to AP were estimated. Although blocking C-fiber activity with RTX resulted in a lower response range (33.7±4.6% and 49.4±4.8%, P<0.01) and higher minimum SNA (78.0±4.7% and 53.6±5.0%, P<0.001) of the steady-state neural arc, the peak SNA response to BRP was greater at a BRP of 160 mm Hg (-37.87±5.83% and -26.28±4.90%, P=0.01). RTX also resulted in a lower response range (27.8±5.0 mm Hg and 40.9±5.2 mm Hg, P<0.01) and higher minimum AP (92.4±4.7 mm Hg and 79.1±4.9 mm Hg, P<0.001) of the total reflex arc. Despite these changes, the maximum slope of the neural arc and the maximum gain of the total reflex arc did not differ significantly after RTX. These data suggest that A-fiber baroreceptors can regulate AP and maintain the maximum gain when systemic AP is around the normal operating range. In contrast, C-fiber baroreceptors are critically important for reductions in SNA and AP when systemic AP is raised above the normal operating range.
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Affiliation(s)
- Michael J Turner
- Department of Cardiovascular Dynamics, National Cerebral and Cardiovascular Center, Osaka 565-8565, Japan.
| | - Toru Kawada
- Department of Cardiovascular Dynamics, National Cerebral and Cardiovascular Center, Osaka 565-8565, Japan
| | - Shuji Shimizu
- Department of Cardiovascular Dynamics, National Cerebral and Cardiovascular Center, Osaka 565-8565, Japan
| | - Masafumi Fukumitsu
- Department of Cardiovascular Dynamics, National Cerebral and Cardiovascular Center, Osaka 565-8565, Japan; Department of Artificial Organ Medicine, Faculty of Medicine, Osaka University Graduate School of Medicine, Osaka 565-0871, Japan
| | - Masaru Sugimachi
- Department of Cardiovascular Dynamics, National Cerebral and Cardiovascular Center, Osaka 565-8565, Japan; Department of Artificial Organ Medicine, Faculty of Medicine, Osaka University Graduate School of Medicine, Osaka 565-0871, Japan
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Hyperpolarization-activated cyclic nucleotide-gated channels may contribute to regional anesthetic effects of lidocaine. Anesthesiology 2015; 122:606-18. [PMID: 25485469 DOI: 10.1097/aln.0000000000000557] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
BACKGROUND Local anesthetics (e.g., lidocaine) have been found to inhibit hyperpolarization-activated cyclic nucleotide-gated (HCN) channels besides sodium channels. However, the exact role of HCN channels in regional anesthesia in vivo is still elusive. METHODS Sciatic nerve block and intrathecal anesthesia were performed using lidocaine in wild-type and HCN1 channel knockout (HCN1) mice. EC50 of lidocaine and durations of 1% lidocaine were determined. In electrophysiologic recordings, effects of lidocaine on HCN channel currents, voltage-gated sodium channel currents, and neural membrane properties were recorded on dorsal root ganglia neurons. RESULTS In both sciatic nerve block and intrathecal anesthesia, EC50 of lidocaine for tactile sensory blockade (2 g von Frey fiber) was significantly increased in HCN1 mice, whereas EC50 of lidocaine for pinprick blockade was unaffected. Durations of 1% lidocaine were significantly shorter in HCN1 mice for both sciatic nerve block and intrathecal anesthesia (n = 10). ZD7288 (HCN blocker) could significantly prolong durations of 1% lidocaine including pinprick blockade in sciatic nerve block (n = 10). Forskolin (raising cyclic adenosine monophosphate to enhance HCN2) could significantly shorten duration of pinprick blockade of 1% lidocaine in sciatic nerve block (n = 10). In electrophysiologic recordings, lidocaine could nonselectively inhibit HCN channel and sodium channel currents both in large and in small dorsal root ganglia neurons (n = 5 to 6). Meanwhile, lidocaine caused neural membrane hyperpolarization and increased input resistance of dorsal root ganglia neurons but not in large dorsal root ganglia neurons from HCN1 mice (n = 5-7). CONCLUSIONS These data indicate that HCN channels may contribute to regional anesthetic effects of lidocaine. By inhibiting HCN channels, lidocaine could alter membrane properties of neurons.
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Liu N, Zhang D, Zhu M, Luo S, Liu T. Minocycline inhibits hyperpolarization-activated currents in rat substantia gelatinosa neurons. Neuropharmacology 2015; 95:110-20. [PMID: 25777286 DOI: 10.1016/j.neuropharm.2015.03.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2015] [Revised: 03/04/2015] [Accepted: 03/05/2015] [Indexed: 12/30/2022]
Abstract
Minocycline is a widely used glial activation inhibitor that could suppress pain-related behaviors in a number of different pain animal models, yet, its analgesic mechanisms are not fully understood. Hyperpolarization-activated cation channel-induced Ih current plays an important role in neuronal excitability and pathological pain. In this study, we investigated the possible effect of minocycline on Ih of substantia gelatinosa neuron in superficial spinal dorsal horn by using whole-cell patch-clamp recording. We found that extracellular minocycline rapidly decreases Ih amplitude in a reversible and concentration-dependent manner (IC50 = 41 μM). By contrast, intracellular minocycline had no effect. Minocycline-induced inhibition of Ih was not affected by Na(+) channel blocker tetrodotoxin, glutamate-receptor antagonists (CNQX and D-APV), GABAA receptor antagonist (bicuculine methiodide), or glycine receptor antagonist (strychnine). Minocycline also caused a negative shift in the activation curve of Ih, but did not alter the reversal potential. Moreover, minocycline slowed down the inter-spike depolarizing slope and produced a robust decrease in the rate of action potential firing. Together, these results illustrate a novel cellular mechanism underlying minocycline's analgesic effect by inhibiting Ih currents of spinal dorsal horn neurons.
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Affiliation(s)
- Nana Liu
- Department of Pediatrics, the First Affiliated Hospital of Nanchang University, Nanchang, 330006, China
| | - Daying Zhang
- Department of Pain Clinic, the First Affiliated Hospital of Nanchang University, Nanchang, 330006, China
| | - Mengye Zhu
- Department of Pain Clinic, the First Affiliated Hospital of Nanchang University, Nanchang, 330006, China
| | - Shiwen Luo
- Center for Laboratory Medicine, the First Affiliated Hospital of Nanchang University, Nanchang, 330006, China
| | - Tao Liu
- Department of Pediatrics, the First Affiliated Hospital of Nanchang University, Nanchang, 330006, China; Center for Laboratory Medicine, the First Affiliated Hospital of Nanchang University, Nanchang, 330006, China.
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Calik MW, Carley DW. Cannabinoid type 1 and type 2 receptor antagonists prevent attenuation of serotonin-induced reflex apneas by dronabinol in Sprague-Dawley rats. PLoS One 2014; 9:e111412. [PMID: 25350456 PMCID: PMC4211887 DOI: 10.1371/journal.pone.0111412] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2014] [Accepted: 10/02/2014] [Indexed: 01/31/2023] Open
Abstract
The prevalence of obstructive sleep apnea (OSA) in Americans is 9% and increasing. Increased afferent vagal activation may predispose to OSA by reducing upper airway muscle activation/patency and disrupting respiratory rhythmogenesis. Vagal afferent neurons are inhibited by cannabinoid type 1 (CB1) or cannabinoid type 2 (CB2) receptors in animal models of vagally-mediated behaviors. Injections of dronabinol, a non-selective CB1/CB2 receptor agonist, into the nodose ganglia reduced serotonin (5-HT)-induced reflex apneas. It is unknown what role CB1 and/or CB2 receptors play in reflex apnea. Here, to determine the independent and combined effects of activating CB1 and/or CB2 receptors on dronabinol’s attenuating effect, rats were pre-treated with CB1 (AM251) and/or CB2 (AM630) receptor antagonists. Adult male Sprague-Dawley rats were anesthetized, instrumented with bilateral electrodes to monitor genioglossus electromyogram (EMGgg) and a piezoelectric strain gauge to monitor respiratory pattern. Following intraperitoneal treatment with AM251 and/or AM630, or with vehicle, serotonin was intravenously infused into a femoral vein to induce reflex apnea. After baseline recordings, the nodose ganglia were exposed and 5-HT-induced reflex apneas were again recorded to confirm that the nerves remained functionally intact. Dronabinol was injected into each nodose ganglion and 5-HT infusion was repeated. Prior to dronabinol injection, there were no significant differences in 5-HT-induced reflex apneas or phasic and tonic EMGgg before or after surgery in the CB1, CB2, combined CB1/CB2 antagonist, and vehicle groups. In the vehicle group, dronabinol injections reduced 5-HT-induced reflex apnea duration. In contrast, dronabinol injections into nodose ganglia of the CB1, CB2, and combined CB1/CB2 groups did not attenuate 5-HT-induced reflex apnea duration. However, the CB1 and CB2 antagonists had no effect on dronabinol’s ability to increase phasic EMGgg. These findings underscore the therapeutic potential of dronabinol in the treatment of OSA and implicate participation of both cannabinoid receptors in dronabinol’s apnea suppression effect.
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Affiliation(s)
- Michael W. Calik
- Center for Narcolepsy, Sleep and Health Research, University of Illinois at Chicago, Chicago, Illinois, United States of America
- Department of Biobehavioral Health Science, University of Illinois at Chicago, Chicago, Illinois, United States of America
- * E-mail:
| | - David W. Carley
- Center for Narcolepsy, Sleep and Health Research, University of Illinois at Chicago, Chicago, Illinois, United States of America
- Department of Biobehavioral Health Science, University of Illinois at Chicago, Chicago, Illinois, United States of America
- Department of Medicine, University of Illinois at Chicago, Chicago, Illinois, United States of America
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Kentish SJ, O'Donnell TA, Wittert GA, Page AJ. Diet-dependent modulation of gastro-oesphageal vagal afferent mechanosensitivity by endogenous nitric oxide. J Physiol 2014; 592:3287-301. [PMID: 24879868 DOI: 10.1113/jphysiol.2014.272674] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Neuronal nitric oxide (NO) plays an important role in gastric motor activity and modulates the mechanosensitivity of gastro-oesophageal vagal afferents. Effects of NO on food intake are dependent on feeding status. We sought to determine the effect of NO on gastro-oesophageal vagal afferent activity in the normally fed and food-restricted states and the second messenger pathways mediating these effects. Eight week old female C56BL/6 mice were fed ad libitum or food restricted for 14 h. An in vitro preparation was used to determine the functional effects of NO and the second messenger pathways involved. Expression of NO signal transduction molecules in vagal afferents was determined by reverse-transcription polymerase chain reaction (RT-PCR). Endogenous NO and the NO donor S-nitroso-N-acetylpenicillamine (SNAP) inhibited vagal mucosal afferent responses to tactile stimuli in mice fed ad libitum. After a 14 h fast endogenous NO and SNAP potentiated tension and mucosal afferent responses to mechanical stimulation. The excitatory effect of NO was blocked by the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase inhibitor apocynin. After a 14 h fast expression of NADPH oxidase 2 (NOX2) mRNA in whole nodose ganglia was significantly reduced and the excitatory effect of NO on gastro-oesophageal vagal afferents was lost. Under fasting conditions the inhibitory effect of NO was blocked with the hyperpolarisation-activated cyclic nucleotide-gated (HCN) channel blocker ivabradine and mRNA expression of HCN3 in the nodose ganglia was elevated. In conclusion, the role of NO in the peripheral modulation of gastro-oesophageal vagal afferents is dynamic and dependent on feeding status.
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Affiliation(s)
- Stephen J Kentish
- Nerve-Gut Research Laboratory, Department of Medicine, University of Adelaide, Adelaide, Australia
| | - Tracey A O'Donnell
- Nerve-Gut Research Laboratory, Department of Medicine, University of Adelaide, Adelaide, Australia
| | - Gary A Wittert
- Nerve-Gut Research Laboratory, Department of Medicine, University of Adelaide, Adelaide, Australia
| | - Amanda J Page
- Nerve-Gut Research Laboratory, Department of Medicine, University of Adelaide, Adelaide, Australia Royal Adelaide Hospital, Adelaide, Australia
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Li YL. Angiotensin II-Superoxide Signaling and Arterial Baroreceptor Function in Type-1 Diabetes Mellitus. JOURNAL OF DIABETES & METABOLISM 2014; Suppl 12:1-6. [PMID: 24567847 DOI: 10.4172/2155-6156.s12-001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Diabetes is a major world health problem. Growing evidence from both clinical trials and animal experiments has clearly confirmed that arterial baroreflex dysfunction is a feature of type 1 diabetes, which links to prognosis and mortality of the type 1 diabetic patients. The arterial baroreflex normally regulates the blood pressure and heart rate through sensing changes of arterial vascular tension by the arterial baroreceptors in the aortic arch and carotid sinus. The aortic baroreceptor neuron located in the nodose ganglia is a primary afferent component of the arterial baroreflex. The functional changes of these neurons are involved in the arterial baroreflex dysfunction in the type 1 diabetes. Type 1 diabetes causes the overexpression and hyperactivation of hyperpolarization-activated cyclic nucleotide-gated (HCN) channels and further reduces cell excitability of the aortic baroreceptor neurons. The alterations of the HCN channels are regulated by angiotensin II-NADPH oxidase-superoxide signaling in the aortic baroreceptor neurons. From the present review, we can understand the possible mechanisms responsible for the attenuated arterial baroreflex in the type 1 diabetes. These findings are beneficial for improving quality of life and prognosis in patients with the type 1 diabetes mellitus.
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Affiliation(s)
- Yu-Long Li
- Department of Emergency Medicine, University of Nebraska Medical Center, USA
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He C, Chen F, Li B, Hu Z. Neurophysiology of HCN channels: From cellular functions to multiple regulations. Prog Neurobiol 2014; 112:1-23. [DOI: 10.1016/j.pneurobio.2013.10.001] [Citation(s) in RCA: 230] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2012] [Revised: 10/01/2013] [Accepted: 10/07/2013] [Indexed: 12/18/2022]
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Qiao GF, Qian Z, Sun HL, Xu WX, Yan ZY, Liu Y, Zhou JY, Zhang HC, Wang LJ, Pan XD, Fu Y. Remodeling of hyperpolarization-activated current, Ih, in Ah-type visceral ganglion neurons following ovariectomy in adult rats. PLoS One 2013; 8:e71184. [PMID: 23951107 PMCID: PMC3741359 DOI: 10.1371/journal.pone.0071184] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2013] [Accepted: 06/27/2013] [Indexed: 12/21/2022] Open
Abstract
Hyperpolarization-activated currents (Ih) mediated by hyperpolarization-activated cyclic nucleotide-gated (HCN) channels modulate excitability of myelinated A− and Ah-type visceral ganglion neurons (VGN). Whether alterations in Ih underlie the previously reported reduction of excitability of myelinated Ah-type VGNs following ovariectomy (OVX) has remained unclear. Here we used the intact nodose ganglion preparation in conjunction with electrophysiological approaches to examine the role of Ih remodeling in altering Ah-type neuron excitability following ovariectomy in adult rats. Ah-type neurons were identified based on their afferent conduction velocity. Ah-type neurons in nodose ganglia from non-OVX rats exhibited a voltage ‘sag’ as well as ‘rebound’ action potentials immediately following hyperpolarizing current injections, which both were suppressed by the Ih blocker ZD7288. Repetitive spike activity induced afterhyperpolarizations lasting several hundreds of milliseconds (termed post-excitatory membrane hyperpolarizations, PEMHs), which were significantly reduced by ZD7288, suggesting that they resulted from transient deactivation of Ih during the preceding spike trains. Ovariectomy reduced whole-cell Ih density, caused a hyperpolarizing shift of the voltage-dependence of Ih activation, and slowed Ih activation. OVX-induced Ih remodeling was accompanied by a flattening of the stimulus frequency/response curve and loss of PEMHs. Also, HCN1 mRNA levels were reduced by ∼30% in nodose ganglia from OVX rats compared with their non-OVX counterparts. Acute exposure of nodose ganglia to 17beta-estradiol partly restored Ih density and accelerated Ih activation in Ah-type cells. In conclusion, Ih plays a significant role in modulating the excitability of myelinated Ah-type VGNs in adult female rats.
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Affiliation(s)
- Guo-Fen Qiao
- State Key Laboratory of Robotics and System, Harbin Institute of Technology, Harbin, Heilongjiang, China
- Department of Pharmacology, Harbin Medical University, Harbin, Heilongjiang, China
| | - Zhao Qian
- Department of Pharmacology, Harbin Medical University, Harbin, Heilongjiang, China
| | - Hong-Li Sun
- Department of Pharmacology, Da-Qing Campus of Harbin Medical University, Da-Qing, Heilongjiang, China
| | - Wen-Xiao Xu
- Department of Orthopedics, the First Affiliated Hospital, Harbin Medical University, Harbin, Heilongjiang, China
| | - Zhen-Yu Yan
- Department of Pharmacology, Harbin Medical University, Harbin, Heilongjiang, China
| | - Yang Liu
- Department of Pharmacology, Harbin Medical University, Harbin, Heilongjiang, China
| | - Jia-Ying Zhou
- Department of Pharmacology, Harbin Medical University, Harbin, Heilongjiang, China
| | - Hao-Cheng Zhang
- Department of Pharmacology, Harbin Medical University, Harbin, Heilongjiang, China
| | - Li-Juan Wang
- Department of Pharmacology, Harbin Medical University, Harbin, Heilongjiang, China
| | - Xiao-Dong Pan
- Department of Pharmacology, Harbin Medical University, Harbin, Heilongjiang, China
| | - Yili Fu
- State Key Laboratory of Robotics and System, Harbin Institute of Technology, Harbin, Heilongjiang, China
- * E-mail:
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Hatch RJ, Jennings EA, Ivanusic JJ. Peripheral hyperpolarization-activated cyclic nucleotide-gated channels contribute to inflammation-induced hypersensitivity of the rat temporomandibular joint. Eur J Pain 2012; 17:972-82. [PMID: 23255289 DOI: 10.1002/j.1532-2149.2012.00261.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/12/2012] [Indexed: 01/09/2023]
Abstract
BACKGROUND Hyperpolarization-activated cyclic nucleotide-gated (HCN) channels conduct an inward cation current (Ih ) that contributes to the maintenance of neuronal membrane potential and have been implicated in a number of animal models of neuropathic and inflammatory pain. In the current study, we investigated HCN channel involvement in inflammatory pain of the temporomandibular joint (TMJ). METHODS The contribution of HCN channels to inflammation (complete Freund's adjuvant; CFA)-induced mechanical hypersensitivity of the rat TMJ was tested with injections of the HCN channel blocker ZD7288. Retrograde labelling and immunohistochemistry was used to explore HCN channel expression in sensory neurons that innervate the TMJ. RESULTS Injection of CFA into the TMJ (n = 7) resulted in a significantly increased mechanical sensitivity relative to vehicle injection (n = 7) (p < 0.05). The mechanical hypersensitivity generated by CFA injection was blocked by co-injection of ZD7288 with the CFA (n = 7). Retrograde labelling and immunohistochemistry experiments revealed expression predominantly of HCN1 and HCN2 channel subunits in trigeminal ganglion neurons that innervate the TMJ (n = 3). No change in the proportion or intensity of HCN channel expression was found in inflamed (n = 6) versus control (n = 5) animals at the time point tested. CONCLUSIONS Our findings suggest a role for peripheral HCN channels in inflammation-induced pain of the TMJ. Peripheral application of a HCN channel blocker could provide therapeutic benefit for inflammatory TMJ pain and avoid side effects associated with activation of HCN channels in the central nervous system.
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Affiliation(s)
- R J Hatch
- Department of Anatomy and Neuroscience, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Australia
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Andresen MC, Hofmann ME, Fawley JA. The unsilent majority-TRPV1 drives "spontaneous" transmission of unmyelinated primary afferents within cardiorespiratory NTS. Am J Physiol Regul Integr Comp Physiol 2012; 303:R1207-16. [PMID: 23076872 PMCID: PMC3532589 DOI: 10.1152/ajpregu.00398.2012] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2012] [Accepted: 10/11/2012] [Indexed: 01/29/2023]
Abstract
Cranial primary afferent sensory neurons figure importantly in homeostatic control of visceral organ systems. Of the two broad classes of visceral afferents, the role of unmyelinated or C-type class remains poorly understood. This review contrasts key aspects of peripheral discharge properties of C-fiber afferents and their glutamate transmission mechanisms within the solitary tract nucleus (NTS). During normal prevailing conditions, most information arrives at the NTS through myelinated A-type nerves. However, most of visceral afferent axons (75-90%) in NTS are unmyelinated, C-type axons. Centrally, C-type solitary tract (ST) afferent terminals have presynaptic transient receptor potential vanilloid type 1 (TRPV1) receptors. Capsaicin activation of TRPV1 blocks phasic or synchronous release of glutamate but facilitates release of glutamate from a separate pool of vesicles. This TRPV1-operated pool of vesicles is active at normal temperatures and is responsible for actively driving a 10-fold higher release of glutamate at TRPV1 compared with TRPV1- terminals even in the absence of afferent action potentials. This novel TRPV1 mechanism is responsible for an additional asynchronous release of glutamate that is not present in myelinated terminals. The NTS is rich with presynaptic G protein-coupled receptors, and the implications of TRPV1-operated glutamate offer unique targets for signaling in C-type sensory afferent terminals from neuropeptides, inflammatory mediators, lipid metabolites, cytokines, and cannabinoids. From a homeostatic view, this combination could have broad implications for integration in chronic pathological disturbances in which the numeric dominance of C-type endings and TRPV1 would broadly disturb multisystem control mechanisms.
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Affiliation(s)
- Michael C Andresen
- Department of Physiology and Pharmacology, Oregon Health and Science University, Portland, OR 97239-3098, USA.
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Acosta C, McMullan S, Djouhri L, Gao L, Watkins R, Berry C, Dempsey K, Lawson SN. HCN1 and HCN2 in Rat DRG neurons: levels in nociceptors and non-nociceptors, NT3-dependence and influence of CFA-induced skin inflammation on HCN2 and NT3 expression. PLoS One 2012; 7:e50442. [PMID: 23236374 PMCID: PMC3517619 DOI: 10.1371/journal.pone.0050442] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2012] [Accepted: 10/22/2012] [Indexed: 11/26/2022] Open
Abstract
Ih, which influences neuronal excitability, has recently been measured in vivo in sensory neuron subtypes in dorsal root ganglia (DRGs). However, expression levels of HCN (hyperpolarization-activated cyclic nucleotide-gated) channel proteins that underlie Ih were unknown. We therefore examined immunostaining of the most abundant isoforms in DRGs, HCN1 and HCN2 in these neuron subtypes. This immunostaining was cytoplasmic and membrane-associated (ring). Ring-staining for both isoforms was in neurofilament-rich A-fiber neurons, but not in small neurofilament-poor C-fiber neurons, although some C-neurons showed cytoplasmic HCN2 staining. We recorded intracellularly from DRG neurons in vivo, determined their sensory properties (nociceptive or low-threshold-mechanoreceptive, LTM) and conduction velocities (CVs). We then injected fluorescent dye enabling subsequent immunostaining. For each dye-injected neuron, ring- and cytoplasmic-immunointensities were determined relative to maximum ring-immunointensity. Both HCN1- and HCN2-ring-immunointensities were positively correlated with CV in both nociceptors and LTMs; they were high in Aβ-nociceptors and Aα/β-LTMs. High HCN1 and HCN2 levels in Aα/β-neurons may, via Ih, influence normal non-painful (e.g. touch and proprioceptive) sensations as well as nociception and pain. HCN2-, not HCN1-, ring-intensities were higher in muscle spindle afferents (MSAs) than in all other neurons. The previously reported very high Ih in MSAs may relate to their very high HCN2. In normal C-nociceptors, low HCN1 and HCN2 were consistent with their low/undetectable Ih. In some C-LTMs HCN2-intensities were higher than in C-nociceptors. Together, HCN1 and HCN2 expressions reflect previously reported Ih magnitudes and properties in neuronal subgroups, suggesting these isoforms underlie Ih in DRG neurons. Expression of both isoforms was NT3-dependent in cultured DRG neurons. HCN2-immunostaining in small neurons increased 1 day after cutaneous inflammation (CFA-induced) and recovered by 4 days. This could contribute to acute inflammatory pain. HCN2-immunostaining in large neurons decreased 4 days after CFA, when NT3 was decreased in the DRG. Thus HCN2-expression control differs between large and small neurons.
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Affiliation(s)
- Cristian Acosta
- School of Physiology and Pharmacology, University of Bristol, Bristol, United Kingdom
| | - Simon McMullan
- Australian School of Advanced Medicine, Macquarie University, Sydney, Australia
| | - Laiche Djouhri
- Department of Biomedical Sciences, Faculty of Medicine, King Faisal University, Al-Ahssa, Saudi Arabia
| | - Linlin Gao
- School of Physiology and Pharmacology, University of Bristol, Bristol, United Kingdom
- Department of Physiology, Tongji Medical School, Huazhong University of Science and Technology, Wuhan, China
| | - Roger Watkins
- School of Physiology and Pharmacology, University of Bristol, Bristol, United Kingdom
| | - Carol Berry
- School of Physiology and Pharmacology, University of Bristol, Bristol, United Kingdom
| | - Katherine Dempsey
- School of Physiology and Pharmacology, University of Bristol, Bristol, United Kingdom
| | - Sally N. Lawson
- School of Physiology and Pharmacology, University of Bristol, Bristol, United Kingdom
- * E-mail:
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Orio P, Parra A, Madrid R, González O, Belmonte C, Viana F. Role of Ih in the firing pattern of mammalian cold thermoreceptor endings. J Neurophysiol 2012; 108:3009-23. [DOI: 10.1152/jn.01033.2011] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Mammalian peripheral cold thermoreceptors respond to cooling of their sensory endings with an increase in firing rate and modification of their discharge pattern. We recently showed that cultured trigeminal cold-sensitive (CS) neurons express a prominent hyperpolarization-activated current ( Ih), mainly carried by HCN1 channels, supporting subthreshold resonance in the soma without participating in the response to acute cooling. However, peripheral pharmacological blockade of Ih, or characterization of HCN1−/− mice, reveals a deficit in acute cold detection. Here we investigated the role of Ih in CS nerve endings, where cold sensory transduction actually takes place. Corneal CS nerve endings in mice show a rhythmic spiking activity at neutral skin temperature that switches to bursting mode when the temperature is lowered. Ih blockers ZD7288 and ivabradine alter firing patterns of CS nerve endings, lengthening interspike intervals and inducing bursts at neutral skin temperature. We characterized the CS nerve endings from HCN1−/− mouse corneas and found that they behave similar to wild type, although with a lower slope in the firing frequency vs. temperature relationship, thus explaining the deficit in cold perception of HCN1−/− mice. The firing pattern of nerve endings from HCN1−/− mice was also affected by ZD7288, which we attribute to the presence of HCN2 channels in the place of HCN1. Mathematical modeling shows that the firing phenotype of CS nerve endings from HCN1−/− mice can be reproduced by replacing HCN1 channels with the slower HCN2 channels rather than by abolishing Ih. We propose that Ih carried by HCN1 channels helps tune the frequency of the oscillation and the length of bursts underlying regular spiking in cold thermoreceptors, having important implications for neural coding of cold sensation.
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Affiliation(s)
- Patricio Orio
- Centro Interdisciplinario de Neurociencia de Valparaíso (CINV) and Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
| | - Andrés Parra
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández-CSIC, Alicante, Spain
| | - Rodolfo Madrid
- Departamento de Biología, Facultad de Química y Biología, Universidad de Santiago de Chile, Santiago, Chile; and
| | - Omar González
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández-CSIC, Alicante, Spain
- Fundación de Investigación Oftalmológica, Instituto Fernandez-Vega, Oviedo, Spain
| | - Carlos Belmonte
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández-CSIC, Alicante, Spain
| | - Félix Viana
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández-CSIC, Alicante, Spain
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Schild JH, Kunze DL. Differential distribution of voltage-gated channels in myelinated and unmyelinated baroreceptor afferents. Auton Neurosci 2012; 172:4-12. [DOI: 10.1016/j.autneu.2012.10.014] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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McDougall SJ, Andresen MC. Independent transmission of convergent visceral primary afferents in the solitary tract nucleus. J Neurophysiol 2012; 109:507-17. [PMID: 23114206 DOI: 10.1152/jn.00726.2012] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Cranial primary afferents from the viscera enter the brain at the solitary tract nucleus (NTS), where their information is integrated for homeostatic reflexes. The organization of sensory inputs is poorly understood, despite its critical impact on overall reflex performance characteristics. Single afferents from the solitary tract (ST) branch within NTS and make multiple contacts onto individual neurons. Many neurons receive more than one ST input. To assess the potential interaction between converging afferents and proximal branching near to second-order neurons, we probed near the recorded soma in horizontal slices from rats with focal electrodes and minimal shocks. Remote ST shocks evoked monosynaptic excitatory postsynaptic currents (EPSCs), and nearby focal shocks also activated monosynaptic EPSCs. We tested the timing and order of stimulation to determine whether focal shocks influenced ST responses and vice versa in single neurons. Focal-evoked EPSC response profiles closely resembled ST-EPSC characteristics. Mean synaptic jitters, failure rates, depression, and phenotypic segregation by capsaicin responsiveness were indistinguishable between focal and ST-evoked EPSCs. ST-EPSCs failed to affect focal-EPSCs within neurons, indicating that release sites and synaptic terminals were functionally independent and isolated from cross talk or neurotransmitter overflow. In only one instance, focal shocks intercepted and depleted the ST axon generating evoked EPSCs. Despite large numbers of functional contacts, multiple afferents do not appear to interact, and ST axon branches may be limited to close to the soma. Thus single or multiple primary afferents and their presynaptic active release sites act independently when they contact single second-order NTS neurons.
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Affiliation(s)
- Stuart J McDougall
- Department of Physiology and Pharmacology, Oregon Health and Science University, Portland, Oregon, USA.
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Nodera H, Rutkove SB. Accommodation to hyperpolarizing currents: Differences between motor and sensory nerves in mice. Neurosci Lett 2012; 518:111-6. [DOI: 10.1016/j.neulet.2012.04.065] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2012] [Revised: 04/12/2012] [Accepted: 04/25/2012] [Indexed: 12/22/2022]
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Tatalovic M, Glazebrook PA, Kunze DL. Expression of the P/Q (Cav2.1) calcium channel in nodose sensory neurons and arterial baroreceptors. Neurosci Lett 2012; 520:38-42. [PMID: 22617008 DOI: 10.1016/j.neulet.2012.05.026] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2012] [Revised: 04/23/2012] [Accepted: 05/07/2012] [Indexed: 10/28/2022]
Abstract
The predominant calcium current in nodose sensory neurons, including the subpopulation of baroreceptor neurons, is the N-type channel, Cav2.2. It is also the primary calcium channel responsible for transmitter release at their presynaptic terminals in the nucleus of the solitary tract in the brainstem. The P/Q channel, Cav2.1, the other major calcium channel responsible for transmitter release at mammalian synapses, represents only 15-20% of total calcium current in the general population of sensory neurons and makes a minor contribution to transmitter release at the presynaptic terminal. In the present study we identified a subpopulation of the largest nodose neurons (capacitance>50pF) in which, surprisingly, Cav2.1 represents over 50% of the total calcium current, differing from the remainder of the population. Consistent with these electrophysiological data, anti-Cav2.1 antibody labeling was more membrane delimited in a subgroup of the large neurons in slices of nodose ganglia. Data reported in other synapses in the central nervous system assign different roles in synaptic information transfer to the P/Q-type versus N-type calcium channels. The study raises the possibility that the P/Q channel which has been associated with high fidelity transmission at other central synapses serves a similar function in this group of large myelinated sensory afferents, including arterial baroreceptors where a high frequency regular discharge pattern signals the pressure pulse. This contrasts to the irregular lower frequency discharge of the unmyelinated fibers that make up the majority of the sensory population and that utilize the N-type channel in synaptic transmission.
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Affiliation(s)
- Milos Tatalovic
- Rammelkamp Center for Education and Research, Case Western Reserve University, 2500 MetroHealth Drive, Cleveland, OH 44109, United States
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Liu J, Zhang L, Tu H, Li YL. Angiotensin II induces protein overexpression of hyperpolarization-activated cyclic nucleotide-gated channels in primary cultured nodose neurons. Neurosci Lett 2012; 515:168-73. [PMID: 22465246 DOI: 10.1016/j.neulet.2012.03.046] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2012] [Accepted: 03/16/2012] [Indexed: 11/25/2022]
Abstract
Modulating ion channel function includes acutely affecting the kinetics of the ion channels and chronically changing the expression of ion channels. Our previous study showed that angiotensin II (Ang II) acutely increased hyperpolarization-activated cyclic nucleotide-gated (HCN) currents in nodose ganglion (NG) neurons via NADPH oxidase-superoxide signaling. Therefore, the present study was to measure chronic treatment with Ang II on protein expression of the HCN channels in the primary cultured rat NG neurons. Immunofluorescent staining data showed that HCN1 was expressed in the A-type NG neurons, and HCN2 was expressed in the C-type NG neurons. Chronic treatment of Ang II (100 nM, 12 h) induced the protein expression of HCN2 besides the overexpression of HCN1 in the A-type NG neurons; and the overexpression of HCN2 in the C-type NG neurons. An Ang II type I receptor antagonist (1 μM losartan), a NADPH oxidase inhibitor (100 μM apocynin), or a superoxide dismutase mimetic (1mM tempol) attenuated the effect of Ang II to increase the protein expression of the HCN channels in rat nodose neurons. Whole cell patch-clamp data further confirmed that chronic treatment of Ang II (100 nM, 12 h) significantly enhanced the density of HCN currents in A- and C-type NG neurons. Above three inhibitors significantly inhibited the Ang II-induced increase of the HCN channel density in rat NG neurons. These findings suggest that Ang II-NADPH oxidase-superoxide signaling chronically regulates the protein expression of the HCN channels in rat nodose neurons.
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Affiliation(s)
- Jinxu Liu
- Department of Emergency Medicine, University of Nebraska Medical Center, Omaha, NE 68198, USA
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Evoked bursting in injured Aβ dorsal root ganglion neurons: A mechanism underlying tactile allodynia. Pain 2012; 153:657-665. [DOI: 10.1016/j.pain.2011.11.030] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2011] [Revised: 11/28/2011] [Accepted: 11/29/2011] [Indexed: 11/17/2022]
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Wang YP, Sun BY, Li Q, Dong L, Zhang GH, Grundy D, Rong WF. Hyperpolarization-activated cyclic nucleotide-gated cation channel subtypes differentially modulate the excitability of murine small intestinal afferents. World J Gastroenterol 2012; 18:522-31. [PMID: 22363118 PMCID: PMC3280397 DOI: 10.3748/wjg.v18.i6.522] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/02/2011] [Revised: 06/21/2011] [Accepted: 06/28/2011] [Indexed: 02/06/2023] Open
Abstract
AIM: To assess the role of hyperpolarization-activated cyclic nucleotide-gated cation (HCN) channels in regulating the excitability of vagal and spinal gut afferents.
METHODS: The mechanosensory response of mesenteric afferent activity was measured in an ex vivo murine jejunum preparation. HCN channel activity was recorded through voltage and current clamp in acutely dissociated dorsal root ganglia (DRG) and nodose ganglia (NG) neurons retrogradely labeled from the small intestine through injection of a fluorescent marker (DiI). The isoforms of HCN channels expressed in DRG and NG neurons were examined by immunohistochemistry.
RESULTS: Ramp distension of the small intestine evoked biphasic increases in the afferent nerve activity, reflecting the activation of low- and high-threshold fibers. HCN blocker CsCl (5 mmol/L) preferentially inhibited the responses of low-threshold fibers to distension and showed no significant effects on the high-threshold responses. The effect of CsCl was mimicked by the more selective HCN blocker ZD7288 (10 μmol/L). In 71.4% of DiI labeled DRG neurons (n = 20) and 90.9% of DiI labeled NG neurons (n = 10), an inward current (Ih current) was evoked by hyperpolarization pulses which was fully eliminated by extracellular CsCl. In neurons expressing Ih current, a typical “sag” was observed upon injection of hyperpolarizing current pulses in current-clamp recordings. CsCl abolished the sag entirely. In some DiI labeled DRG neurons, the Ih current was potentiated by 8-Br-cAMP, which had no effect on the Ih current of DiI labeled NG neurons. Immunohistochemistry revealed differential expression of HCN isoforms in vagal and spinal afferents, and HCN2 and HCN3 seemed to be the dominant isoform in DRG and NG, respectively.
CONCLUSION: HCNs differentially regulate the excitability of vagal and spinal afferent of murine small intestine.
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Abstract
Hyperpolarization-activated cyclic nucleotide-gated (HCN) channels have a key role in the control of heart rate and neuronal excitability. Ivabradine is the first compound acting on HCN channels to be clinically approved for the treatment of angina pectoris. HCN channels may offer excellent opportunities for the development of novel anticonvulsant, anaesthetic and analgesic drugs. In support of this idea, some well-established drugs that act on the central nervous system - including lamotrigine, gabapentin and propofol - have been found to modulate HCN channel function. This Review gives an up-to-date summary of compounds acting on HCN channels, and discusses strategies to further explore the potential of these channels for therapeutic intervention.
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Emery EC, Young GT, Berrocoso EM, Chen L, McNaughton PA. HCN2 ion channels play a central role in inflammatory and neuropathic pain. Science 2011; 333:1462-6. [PMID: 21903816 DOI: 10.1126/science.1206243] [Citation(s) in RCA: 250] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The rate of action potential firing in nociceptors is a major determinant of the intensity of pain. Possible modulators of action potential firing include the HCN ion channels, which generate an inward current, I(h), after hyperpolarization of the membrane. We found that genetic deletion of HCN2 removed the cyclic adenosine monophosphate (cAMP)-sensitive component of I(h) and abolished action potential firing caused by an elevation of cAMP in nociceptors. Mice in which HCN2 was specifically deleted in nociceptors expressing Na(V)1.8 had normal pain thresholds, but inflammation did not cause hyperalgesia to heat stimuli. After a nerve lesion, these mice showed no neuropathic pain in response to thermal or mechanical stimuli. Neuropathic pain is therefore initiated by HCN2-driven action potential firing in Na(V)1.8-expressing nociceptors.
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Affiliation(s)
- Edward C Emery
- Department of Pharmacology, University of Cambridge, Cambridge CB2 1PD, UK
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