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Weng HR. Emerging Molecular and Synaptic Targets for the Management of Chronic Pain Caused by Systemic Lupus Erythematosus. Int J Mol Sci 2024; 25:3602. [PMID: 38612414 PMCID: PMC11011483 DOI: 10.3390/ijms25073602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2024] [Revised: 03/13/2024] [Accepted: 03/19/2024] [Indexed: 04/14/2024] Open
Abstract
Patients with systemic lupus erythematosus (SLE) frequently experience chronic pain due to the limited effectiveness and safety profiles of current analgesics. Understanding the molecular and synaptic mechanisms underlying abnormal neuronal activation along the pain signaling pathway is essential for developing new analgesics to address SLE-induced chronic pain. Recent studies, including those conducted by our team and others using the SLE animal model (MRL/lpr lupus-prone mice), have unveiled heightened excitability in nociceptive primary sensory neurons within the dorsal root ganglia and increased glutamatergic synaptic activity in spinal dorsal horn neurons, contributing to the development of chronic pain in mice with SLE. Nociceptive primary sensory neurons in lupus animals exhibit elevated resting membrane potentials, and reduced thresholds and rheobases of action potentials. These changes coincide with the elevated production of TNFα and IL-1β, as well as increased ERK activity in the dorsal root ganglion, coupled with decreased AMPK activity in the same region. Dysregulated AMPK activity is linked to heightened excitability in nociceptive sensory neurons in lupus animals. Additionally, the increased glutamatergic synaptic activity in the spinal dorsal horn in lupus mice with chronic pain is characterized by enhanced presynaptic glutamate release and postsynaptic AMPA receptor activation, alongside the reduced activity of glial glutamate transporters. These alterations are caused by the elevated activities of IL-1β, IL-18, CSF-1, and thrombin, and reduced AMPK activities in the dorsal horn. Furthermore, the pharmacological activation of spinal GPR109A receptors in microglia in lupus mice suppresses chronic pain by inhibiting p38 MAPK activity and the production of both IL-1β and IL-18, as well as reducing glutamatergic synaptic activity in the spinal dorsal horn. These findings collectively unveil crucial signaling molecular and synaptic targets for modulating abnormal neuronal activation in both the periphery and spinal dorsal horn, offering insights into the development of analgesics for managing SLE-induced chronic pain.
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Affiliation(s)
- Han-Rong Weng
- Department of Basic Sciences, California Northstate University College of Medicine, Elk Grove, CA 95757, USA
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Pissas KP, Schilling M, Korkmaz A, Tian Y, Gründer S. Melatonin alters the excitability of mouse cerebellar granule neurons by inhibiting voltage-gated sodium, potassium, and calcium channels. J Pineal Res 2024; 76:e12919. [PMID: 37794846 DOI: 10.1111/jpi.12919] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/08/2023] [Revised: 09/01/2023] [Accepted: 09/19/2023] [Indexed: 10/06/2023]
Abstract
Besides its role in the circadian rhythm, the pineal gland hormone melatonin (MLT) also possesses antiepileptogenic, antineoplastic, and cardioprotective properties, among others. The dosages necessary to elicit beneficial effects in these diseases often far surpass physiological concentrations. Although even high doses of MLT are considered to be largely harmless to humans, the possible side effects of pharmacological concentrations are so far not well investigated. In the present study, we report that pharmacological doses of MLT (3 mM) strongly altered the electrophysiological characteristics of cultured primary mouse cerebellar granule cells (CGCs). Using whole-cell patch clamp and ratiometric Ca2+ imaging, we observed that pharmacological concentrations of MLT inhibited several types of voltage-gated Na+ , K+ , and Ca2+ channels in CGCs independently of known MLT-receptors, altering the character and pattern of elicited action potentials (APs) significantly, quickly and reversibly. Specifically, MLT reduced AP frequency, afterhyperpolarization, and rheobase, whereas AP amplitude and threshold potential remained unchanged. The altered biophysical profile of the cells could constitute a possible mechanism underlying the proposed beneficial effects of MLT in brain-related disorders, such as epilepsy. On the other hand, it suggests potential adverse effects of pharmacological MLT concentrations on neurons, which should be considered when using MLT as a pharmacological compound.
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Affiliation(s)
| | - Maria Schilling
- Medical faculty, Institute of Physiology, RWTH Aachen University, Aachen, Germany
| | - Ahmet Korkmaz
- Medical faculty, Institute of Physiology, RWTH Aachen University, Aachen, Germany
| | - Yuemin Tian
- Medical faculty, Institute of Physiology, RWTH Aachen University, Aachen, Germany
| | - Stefan Gründer
- Medical faculty, Institute of Physiology, RWTH Aachen University, Aachen, Germany
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Vazquez JI, Gascue V, Quintana L, Migliaro A. Understanding daily rhythms in weakly electric fish: the role of melatonin on the electric behavior of Brachyhypopomus gauderio. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2024; 210:7-18. [PMID: 37002418 DOI: 10.1007/s00359-023-01626-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Revised: 03/16/2023] [Accepted: 03/20/2023] [Indexed: 04/03/2023]
Abstract
Living organisms display molecular, physiological and behavioral rhythms synchronized with natural environmental cycles. Understanding the interaction between environment, physiology and behavior requires taking into account the complexity of natural habitats and the diversity of behavioral and physiological adaptations. Brachyhypopomus gauderio is characterized by the emission of electric organ discharges (EOD), with a very stable rate modulated by social and environmental cues. The nocturnal arousal in B. gauderio coincides with a melatonin-dependent EOD rate increase. Here, we first show a daily cycle in both the EOD basal rate (EOD-BR) and EOD-BR variability of B. gauderio in nature. We approached the understanding of the role of melatonin in this natural behavior through both behavioral pharmacology and in vitro assays. We report, for the first time in gymnotiformes, a direct effect of melatonin on the pacemaker nucleus (PN) in in vitro preparation. Melatonin treatment lowered EOD-BR in freely moving fish and PN basal rate, while increasing the variability of both. These results show that melatonin plays a key role in modulating the electric behavior of B. gauderio through its effect on rate and variability, both of which must be under a tight temporal regulation to prepare the animal for the challenging nocturnal environment.
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Affiliation(s)
- Juan I Vazquez
- Dpto de Neurofisiología Celular y Molecular, Instituto de Investigaciones Biológicas Clemente Estable, MEC, Montevideo, Uruguay
| | - Valentina Gascue
- Laboratorio de Neurociencias, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay
| | - Laura Quintana
- Dpto de Neurofisiología Celular y Molecular, Instituto de Investigaciones Biológicas Clemente Estable, MEC, Montevideo, Uruguay
| | - Adriana Migliaro
- Laboratorio de Neurociencias, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay.
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Viatchenko-Karpinski V, Kong L, Weng HR. Deficient AMPK activity contributes to hyperexcitability in peripheral nociceptive sensory neurons and thermal hyperalgesia in lupus mice. PLoS One 2023; 18:e0288356. [PMID: 37440542 PMCID: PMC10343046 DOI: 10.1371/journal.pone.0288356] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Accepted: 06/23/2023] [Indexed: 07/15/2023] Open
Abstract
Patients with systemic lupus erythematosus (SLE) often suffer from chronic pain. Little is known about the peripheral mechanisms underlying the genesis of chronic pain induced by SLE. The aim of this study was to investigate whether and how membrane properties in nociceptive neurons in the dorsal root ganglions (DRGs) are altered by SLE. We found elevation of resting membrane potentials, smaller capacitances, lower action potential thresholds and rheobases in nociceptive neurons in the DRGs from MRL/lpr mice (an SLE mouse model) with thermal hyperalgesia. DRGs from MRL/lpr mice had increased protein expressions in TNFα, IL-1β, and phosphorylated ERK but suppressed AMPK activity, and no changes in sodium channel 1.7 protein expression. We showed that intraplantar injection of Compound C (an AMPK inhibitor) induced thermal hyperalgesia in normal mice while intraplantar injection of AICAR (an AMPK activator) reduced thermal hyperalgesia in MRL/Lpr mice. Upon inhibition of AMPK membrane properties in nociceptive neurons from normal control mice could be rapidly switched to those found in SLE mice with thermal hyperalgesia. Our study indicates that increased excitability in peripheral nociceptive sensory neurons contributes to the genesis of thermal hyperalgesia in mice with SLE, and AMPK regulates membrane properties in nociceptive sensory neurons as well as thermal hyperalgesia in mice with SLE. Our study provides a basis for targeting signaling pathways regulating membrane properties of peripheral nociceptive neurons as a means for conquering chronic pain caused by SLE.
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Affiliation(s)
| | - Lingwei Kong
- Department of Biomedical Sciences, Mercer University School of Medicine, Macon, GA, United States of America
| | - Han-Rong Weng
- Department of Biomedical Sciences, Mercer University School of Medicine, Macon, GA, United States of America
- Department of Basic Sciences, California Northstate University College of Medicine, Elk Grove, CA, United States of America
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Ertik O, Sener G, Yanardag R. The effect of melatonin on glycoprotein levels and oxidative liver injury in experimental diabetes. J Biochem Mol Toxicol 2023; 37:e23268. [PMID: 36527249 DOI: 10.1002/jbt.23268] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Revised: 09/23/2022] [Accepted: 12/01/2022] [Indexed: 12/23/2022]
Abstract
In this present study, the duration of melatonin (Mel) administered to diabetic rats was prolonged so as to examine its effects on the biochemical liver parameters of diabetic rats. In the experiment, Male Sprague Dawley rats were divided randomly into five groups; the control, diabetic + Mel, diabetic, diabetic + insulin, and diabetic + Mel + insulin. Diabetes mellitus was induced by administration of a single dose of streptozotocin (60 mg/kg) intraperitoneally and rats were given vehicle as a solvent for Mel every day for 12 weeks. In the diabetic + Mel group, diabetic rats were administered Mel (10 mg/kg/day) for 12 weeks to treat diabetes. The diabetic + insulin group were diabetic rats given insulin (6 U/kg) subcutaneously for 12 weeks. The diabetic + Mel + insulin rats received insulin and Mel at the same dose and time. At the end of the experiment, the animals were decapitated and liver tissues were taken. The protective effect of Mel on liver tissue of diabetic rats was investigated, total antioxidant status, total oxidant status, reactive oxygen species, oxidative stress index, adenosine deaminase, xanthine oxidase, paraoxonase 1, sodium/potassium ATPase, myeloperoxidase, γ-glutamyl transferase, sorbitol dehydrogenase, tumor necrosis factor-alpha, homocysteine, nitric oxide, glucose-6-phosphate dehydrogenase, and glycoprotein levels were determined in liver tissues. Treatment with Mel and/or insulin has been found to have a protective effect on biochemical parameters. The results showed that administration of Mel to diabetic rats prevented the distortion of the studied biochemical parameters of liver tissues.
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Affiliation(s)
- Onur Ertik
- Department of Chemistry, Faculty of Engineering, Istanbul University-Cerrahpasa, Istanbul, Turkey
| | - Goksel Sener
- Department of Pharmacology, Faculty of Pharmacy, Fenerbahce University, Istanbul, Turkey
| | - Refiye Yanardag
- Department of Chemistry, Faculty of Engineering, Istanbul University-Cerrahpasa, Istanbul, Turkey
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da Silva‐Alves KS, Ferreira‐da‐Silva FW, Coelho‐de‐Souza AN, Weinreich D, Leal‐Cardoso JH. Diabetes mellitus differently affects electrical membrane properties of vagal afferent neurons of rats. Physiol Rep 2023; 11:e15605. [PMID: 36807809 PMCID: PMC9938008 DOI: 10.14814/phy2.15605] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Revised: 01/24/2023] [Accepted: 01/26/2023] [Indexed: 02/20/2023] Open
Abstract
To study whether diabetes mellitus (DM) would cause electrophysiological alterations in nodose ganglion (NG) neurons, we used patch clamp and intracellular recording for voltage and current clamp configuration, respectively, on cell bodies of NG from rats with DM. Intracellular microelectrodes recording, according to the waveform of the first derivative of the action potential, revealed three neuronal groups (A0 , Ainf , and Cinf ), which were differently affected. Diabetes only depolarized the resting potential of A0 (from -55 to -44 mV) and Cinf (from -49 to -45 mV) somas. In Ainf neurons, diabetes increased action potential and the after-hyperpolarization durations (from 1.9 and 18 to 2.3 and 32 ms, respectively) and reduced dV/dtdesc (from -63 to -52 V s-1 ). Diabetes reduced the action potential amplitude while increasing the after-hyperpolarization amplitude of Cinf neurons (from 83 and -14 mV to 75 and -16 mV, respectively). Using whole cell patch clamp recording, we observed that diabetes produced an increase in peak amplitude of sodium current density (from -68 to -176 pA pF-1 ) and displacement of steady-state inactivation to more negative values of transmembrane potential only in a group of neurons from diabetic animals (DB2). In the other group (DB1), diabetes did not change this parameter (-58 pA pF-1 ). This change in sodium current did not cause an increase in membrane excitability, probably explainable by the alterations in sodium current kinetics, which are also induced by diabetes. Our data demonstrate that diabetes differently affects membrane properties of different nodose neuron subpopulations, which likely have pathophysiological implications for diabetes mellitus.
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Affiliation(s)
- Kerly Shamyra da Silva‐Alves
- Laboratory of Electrophysiology, Superior Institute of Biomedical SciencesState University of CearáFortalezaBrazil
| | - Francisco Walber Ferreira‐da‐Silva
- Laboratory of Electrophysiology, Superior Institute of Biomedical SciencesState University of CearáFortalezaBrazil,Technological and Exact Science CenterState University Vale do AcaraúSobralBrazil
| | - Andrelina Noronha Coelho‐de‐Souza
- Laboratory of Electrophysiology, Superior Institute of Biomedical SciencesState University of CearáFortalezaBrazil,Laboratory of Experimental Physiology, Superior Institute of Biomedical SciencesState University of CearáFortalezaBrazil
| | - Daniel Weinreich
- Department of PharmacologyUniversity of Maryland, School of MedicineBaltimoreMarylandUSA
| | - José Henrique Leal‐Cardoso
- Laboratory of Electrophysiology, Superior Institute of Biomedical SciencesState University of CearáFortalezaBrazil
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Oliveira-Abreu K, Cipolla-Neto J, Leal-Cardoso JH. Effects of Melatonin on Diabetic Neuropathy and Retinopathy. Int J Mol Sci 2021; 23:ijms23010100. [PMID: 35008523 PMCID: PMC8744787 DOI: 10.3390/ijms23010100] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Revised: 12/14/2021] [Accepted: 12/16/2021] [Indexed: 12/18/2022] Open
Abstract
Diabetes mellitus (DM) leads to complications, the majority of which are nephropathy, retinopathy, and neuropathy. Redox imbalance and inflammation are important components of the pathophysiology of these complications. Many studies have been conducted to find a specific treatment for these neural complications, and some of them have investigated the therapeutic potential of melatonin (MEL), an anti-inflammatory agent and powerful antioxidant. In the present article, we review studies published over the past 21 years on the therapeutic efficacy of MEL in the treatment of DM-induced neural complications. Reports suggest that there is a real prospect of using MEL as an adjuvant treatment for hypoglycemic agents. However, analysis shows that there is a wide range of approaches regarding the doses used, duration of treatment, and treatment times in relation to the temporal course of DM. This wide range hinders an objective analysis of advances and prospective vision of the paths to be followed for the unequivocal establishment of parameters to be used in an eventual therapeutic validation of MEL in neural complications of DM.
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Affiliation(s)
- Klausen Oliveira-Abreu
- Laboratório de Eletrofisiologia, Instituto Superior de Ciências Biomédicas, Universidade Estadual do Ceará, Fortaleza 60714-903, CE, Brazil;
| | - José Cipolla-Neto
- Laboratório de Neurobiologia, Instituto de Ciências Biomédicas 1, Universidade de São Paulo, Sao Paulo 05508-000, SP, Brazil;
| | - Jose Henrique Leal-Cardoso
- Laboratório de Eletrofisiologia, Instituto Superior de Ciências Biomédicas, Universidade Estadual do Ceará, Fortaleza 60714-903, CE, Brazil;
- Correspondence: ; Tel.: +55-85-3101-9814
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Chang HM, Lin HC, Cheng HL, Liao CK, Tseng TJ, Renn TY, Lan CT, Chen LY. Melatonin Successfully Rescues the Hippocampal Molecular Machinery and Enhances Anti-oxidative Activity Following Early-Life Sleep Deprivation Injury. Antioxidants (Basel) 2021; 10:antiox10050774. [PMID: 34068192 PMCID: PMC8153000 DOI: 10.3390/antiox10050774] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Revised: 05/07/2021] [Accepted: 05/10/2021] [Indexed: 01/01/2023] Open
Abstract
Early-life sleep deprivation (ESD) is a serious condition with severe cognitive sequelae. Considering hippocampus plays an essential role in cognitive regulation, the present study aims to determine whether melatonin, a neuroendocrine beard with significant anti-oxidative activity, would greatly depress the hippocampal oxidative stress, improves the molecular machinery, and consequently exerts the neuro-protective effects following ESD. Male weanling Wistar rats (postnatal day 21) were subjected to ESD for three weeks. During this period, the animals were administered normal saline or melatonin (10 mg/kg) via intraperitoneal injection between 09:00 and 09:30 daily. After three cycles of ESD, the animals were kept under normal sleep/wake cycle until they reached adulthood and were sacrificed. The results indicated that ESD causes long-term effects, such as impairment of ionic distribution, interruption of the expressions of neurotransmitters and receptors, decreases in the levels of several antioxidant enzymes, and impairment of several signaling pathways, which contribute to neuronal death in hippocampal regions. Melatonin administration during ESD prevented these effects. Quantitative evaluation of cells also revealed a higher number of neurons in the melatonin-treated animals when compared with the saline-treated animals. As the hippocampus is critical to cognitive activity, preserving or even improving the hippocampal molecular machinery by melatonin during ESD not only helps us to better understand the underlying mechanisms of ESD-induced neuronal dysfunction, but also the therapeutic use of melatonin to counteract ESD-induced neuronal deficiency.
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Affiliation(s)
- Hung-Ming Chang
- Department of Anatomy and Cell Biology, School of Medicine, College of Medicine, Taipei Medical University, Taipei 11031, Taiwan; (H.-M.C.); (T.-Y.R.)
| | - Hsing-Chun Lin
- Department of Nutrition, Chung Shan Medical University, Taichung 40201, Taiwan; (H.-C.L.); (H.-L.C.)
- Department of Nutrition, Chung Shan Medical University Hospital, Taichung 40201, Taiwan
| | - Hsin-Lin Cheng
- Department of Nutrition, Chung Shan Medical University, Taichung 40201, Taiwan; (H.-C.L.); (H.-L.C.)
| | - Chih-Kai Liao
- Department of Anatomy, School of Medicine, College of Medicine, Chung Shan Medical University, Taichung 40201, Taiwan; (C.-K.L.); (T.-J.T.); (C.-T.L.)
| | - To-Jung Tseng
- Department of Anatomy, School of Medicine, College of Medicine, Chung Shan Medical University, Taichung 40201, Taiwan; (C.-K.L.); (T.-J.T.); (C.-T.L.)
| | - Ting-Yi Renn
- Department of Anatomy and Cell Biology, School of Medicine, College of Medicine, Taipei Medical University, Taipei 11031, Taiwan; (H.-M.C.); (T.-Y.R.)
| | - Chyn-Tair Lan
- Department of Anatomy, School of Medicine, College of Medicine, Chung Shan Medical University, Taichung 40201, Taiwan; (C.-K.L.); (T.-J.T.); (C.-T.L.)
| | - Li-You Chen
- Department of Anatomy, School of Medicine, College of Medicine, Chung Shan Medical University, Taichung 40201, Taiwan; (C.-K.L.); (T.-J.T.); (C.-T.L.)
- Department of Medical Education, Chung Shan Medical University Hospital, Taichung 40201, Taiwan
- Correspondence: ; Tel.: +886-4-2473-0022 (ext. 11602)
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Mayo JC, Sainz RM. Melatonin from an Antioxidant to a Classic Hormone or a Tissue Factor: Experimental and Clinical Aspects 2019. Int J Mol Sci 2020; 21:ijms21103645. [PMID: 32455655 PMCID: PMC7279336 DOI: 10.3390/ijms21103645] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Accepted: 05/16/2020] [Indexed: 12/11/2022] Open
Abstract
During the last 25 years we have accomplished great advances in melatonin research, regarding antioxidant or anti-inflammatory functions, oncostatic actions, glucose metabolism regulation or plant physiology, among others. Of course, we should not forget the classical, circadian-related functions of the indole, which has recently brought up new and important findings. All together these new discoveries will likely lead the way in the next decade in terms of melatonin research. This special issue collects some of these new advances focused on different aspects of the indole
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Affiliation(s)
- Juan C. Mayo
- Departamento de Morfología y Biología Celular, Redox Biology Group, Instituto Universitario Oncológico del Principado de Asturias (IUOPA), School of Medicine, University of Oviedo. C/ Julián Clavería 6, 33006 Oviedo, Spain;
- Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), Avda. Roma s/n, 33011 Oviedo, Spain
- Correspondence: ; Tel.: +34-985103000 (ext. 2730)
| | - Rosa M. Sainz
- Departamento de Morfología y Biología Celular, Redox Biology Group, Instituto Universitario Oncológico del Principado de Asturias (IUOPA), School of Medicine, University of Oviedo. C/ Julián Clavería 6, 33006 Oviedo, Spain;
- Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), Avda. Roma s/n, 33011 Oviedo, Spain
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Silva-Dos-Santos NM, Oliveira-Abreu K, Moreira-Junior L, Santos-Nascimento TD, Silva-Alves KSD, Coelho-de-Souza AN, Ferreira-da-Silva FW, Leal-Cardoso JH. Diabetes mellitus alters electrophysiological properties in neurons of superior cervical ganglion of rats. Brain Res 2020; 1729:146599. [PMID: 31843626 DOI: 10.1016/j.brainres.2019.146599] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Revised: 11/22/2019] [Accepted: 12/11/2019] [Indexed: 01/08/2023]
Abstract
Diabetic neuropathy is the most prevalent complication associated with diabetes mellitus (DM). The superior cervical ganglion (SCG) is an important sympathetic component of the autonomic nervous system. We investigated the changes in cellular electrophysiological properties and on Na+K+-ATPase activity of SCG neurons of rats with DM induced by streptozotocin (STZ). Three types of action potentials (AP) firing pattern were observed in response to a long (1 s) depolarizing pulse. Whilst some neurons fired a single AP (single firing phasic, SFP), others fired few APs (multiple firing phasic, MFP). A third type fired APs during more than 80% of the stimulus duration (tonic-like, TL). The occurrence of SFP, MFP and TL was 84.5, 13.8, and 1.7%, respectively. SFP and MFP differed significantly in their membrane input resistance (Rin). At the end of the 4th week of its time course, DM differently affected most types of neurons: DM induced depolarization of resting membrane potential (RMP), decreased AP amplitude in SFP, and decreased Rin in MFP. DM decreased spike after-hyperpolarization amplitude in MFP and the duration in SFP. Based on the RMP depolarization, we investigated the Na+K+-ATPase action and observed that DM caused a significant decrease in Na+K+-ATPase activity of SCG. In conclusion, we have demonstrated that DM affects several parameters of SCG physiology in a manner likely to have pathophysiological relevance.
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Affiliation(s)
- Nathalia Maria Silva-Dos-Santos
- Laboratório de Eletrofisiologia, Instituto Superior de Ciências Biomédicas, Universidade Estadual do Ceará, Fortaleza 60714-903, CE, Brazil
| | - Klausen Oliveira-Abreu
- Laboratório de Eletrofisiologia, Instituto Superior de Ciências Biomédicas, Universidade Estadual do Ceará, Fortaleza 60714-903, CE, Brazil
| | | | | | - Kerly Shamyra da Silva-Alves
- Laboratório de Eletrofisiologia, Instituto Superior de Ciências Biomédicas, Universidade Estadual do Ceará, Fortaleza 60714-903, CE, Brazil
| | - Andrelina Noronha Coelho-de-Souza
- Laboratório de Eletrofisiologia, Instituto Superior de Ciências Biomédicas, Universidade Estadual do Ceará, Fortaleza 60714-903, CE, Brazil
| | - Francisco Walber Ferreira-da-Silva
- Laboratório de Eletrofisiologia, Instituto Superior de Ciências Biomédicas, Universidade Estadual do Ceará, Fortaleza 60714-903, CE, Brazil
| | - José Henrique Leal-Cardoso
- Laboratório de Eletrofisiologia, Instituto Superior de Ciências Biomédicas, Universidade Estadual do Ceará, Fortaleza 60714-903, CE, Brazil.
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