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Dwaib H, Michel MC. Adrenoceptor Expression and Function in the Endocrine Pancreas. Handb Exp Pharmacol 2024. [PMID: 38872059 DOI: 10.1007/164_2024_717] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2024]
Abstract
The sympathetic nervous system plays an important role in the regulation of endocrine pancreatic function, most importantly insulin release. Among the nine adrenoceptor (AR) subtypes, the α2A-AR appears to be the subtype most abundantly expressed in the human pancreas. While α2- and β-AR have opposing effects, the net response to sympathetic stimulation is inhibition of insulin secretion mediated by α2-AR located in the plasma membrane of pancreatic β cells. This inhibition may be present physiologically as evidenced by increased insulin secretion in healthy and diabetic humans and animals in response to α2-AR antagonists, a finding that was confirmed in all studies. Based on such data and on an association of an α2A-AR polymorphism, that increases receptor expression levels, with an elevated risk for diabetes, increased α2A-AR signaling in the pancreatic β cells has been proposed as a risk factor for the development of type 2 diabetes. Thus, the α2A-AR was proposed as a drug target for the treatment of some forms of type 2 diabetes. Drug research and development programs leveraging this mechanism have reached the clinical stage, but none have resulted in an approved medicine due to a limited efficacy. While β-AR agonists can increase circulating insulin levels in vivo, it remains controversial whether this includes a direct effect on β cells or occurs secondary to general metabolic effects. Therefore, the regulation of endocrine pancreatic function is physiologically interesting but may be of limited therapeutic relevance.
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Affiliation(s)
- Haneen Dwaib
- Department of Clinical Nutrition and Dietetics, Palestine Ahliya University, Bethlehem, Palestine.
| | - Martin C Michel
- Department of Pharmacology, University Medical Center, Johannes Gutenberg University, Mainz, Germany
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2
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Michel MC. Introduction: A Short History of Adrenoceptor Research. Handb Exp Pharmacol 2024. [PMID: 38797750 DOI: 10.1007/164_2024_718] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/29/2024]
Abstract
This chapter provides a short history of adrenoceptor research starting from the initial discovery of adrenaline. It covers the evolving classification of adrenoceptor subtypes, the cloning of these subtypes from multiple species, and factors such as adrenoceptor regulation, inverse agonism and biased agonism. More details on many of these aspects are provided in other chapters of this volume of Handbook of Experimental Pharmacology.
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Affiliation(s)
- Martin C Michel
- Department of Pharmacology, University Medical Center, Johannes Gutenberg University, Mainz, Germany.
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3
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Taddei S, Tsabedze N, Tan RS. β-blockers are not all the same: pharmacologic similarities and differences, potential combinations and clinical implications. Curr Med Res Opin 2024; 40:15-23. [PMID: 38597065 DOI: 10.1080/03007995.2024.2318058] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Accepted: 02/07/2024] [Indexed: 04/11/2024]
Abstract
β-blockers are a heterogeneous class, with individual agents distinguished by selectivity for β1- vs. β2- and α-adrenoceptors, presence or absence of partial agonist activity at one of more β-receptor subtype, presence or absence of additional vasodilatory properties, and lipophilicity, which determines the ease of entry the drug into the central nervous system. Cardioselectivity (β1-adrenoceptor selectivity) helps to reduce the potential for adverse effects mediated by blockade of β2-adrenoceptors outside the myocardium, such as cold extremities, erectile dysfunction, or exacerbation of asthma or chronic obstructive pulmonary disease. According to recently updated guidelines from the European Society of Hypertension, β-blockers are included within the five major drug classes recommended as the basis of antihypertensive treatment strategies. Adding a β-blocker to another agent with a complementary mechanism may provide a rational antihypertensive combination that minimizes the adverse impact of induced sympathetic overactivity for optimal blood pressure-lowering efficacy and clinical outcomes benefit.
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Affiliation(s)
- Stefano Taddei
- Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - Nqoba Tsabedze
- Division of Cardiology, Department of Internal Medicine, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Ru-San Tan
- Department of Cardiology, National Heart Centre Singapore, Singapore
- Cardiovascular Sciences, Duke NUS Medical School, Singapore
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Watts SW, Townsend RR, Neubig RR. How New Developments in Pharmacology Receptor Theory Are Changing (Our Understanding of) Hypertension Therapy. Am J Hypertens 2024; 37:248-260. [PMID: 38150382 PMCID: PMC10941088 DOI: 10.1093/ajh/hpad121] [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: 10/24/2023] [Accepted: 12/21/2023] [Indexed: 12/29/2023] Open
Abstract
BACKGROUND Many hypertension therapeutics were developed prior to major advances in drug receptor theory. Moreover, newer drugs may take advantage of some of the newly understood modalities of receptor function. GOAL The goal of this review is to provide an up-to-date summary of drug receptor theory. This is followed by a discussion of the drug classes recognized for treating hypertension to which new concepts in receptor theory apply. RESULTS We raise ideas for mechanisms of potential new antihypertensive drugs and whether they may take advantage of new theories in drug-receptor interaction.
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Affiliation(s)
- Stephanie W Watts
- Department of Pharmacology and Toxicology, College of Osteopathic Medicine, Michigan State University, East Lansing, Michigan 48824-131, USA
| | - Raymond R Townsend
- Department of Nephrology and Hypertension, University of Pennsylvania Medical Center, Philadelphia, Pennsylvania 19104, USA
| | - Richard R Neubig
- Department of Pharmacology and Toxicology, College of Osteopathic Medicine, Michigan State University, East Lansing, Michigan 48824-131, USA
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5
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Miller WE, O'Connor CM. CMV-encoded GPCRs in infection, disease, and pathogenesis. Adv Virus Res 2024; 118:1-75. [PMID: 38461029 DOI: 10.1016/bs.aivir.2024.01.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/11/2024]
Abstract
G protein coupled receptors (GPCRs) are seven-transmembrane domain proteins that modulate cellular processes in response to external stimuli. These receptors represent the largest family of membrane proteins, and in mammals, their signaling regulates important physiological functions, such as vision, taste, and olfaction. Many organisms, including yeast, slime molds, and viruses encode GPCRs. Cytomegaloviruses (CMVs) are large, betaherpesviruses, that encode viral GPCRs (vGPCRs). Human CMV (HCMV) encodes four vGPCRs, including UL33, UL78, US27, and US28. Each of these vGPCRs, as well as their rodent and primate orthologues, have been investigated for their contributions to viral infection and disease. Herein, we discuss how the CMV vGPCRs function during lytic and latent infection, as well as our understanding of how they impact viral pathogenesis.
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Affiliation(s)
- William E Miller
- Department of Molecular and Cellular Bioscience, University of Cincinnati College of Medicine, Cincinnati, OH, United States
| | - Christine M O'Connor
- Infection Biology, Sheikha Fatima bint Mubarak Global Center for Pathogen and Human Health Research, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, United States; Molecular Medicine, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland Clinic, Cleveland, OH, United States; Case Comprehensive Cancer Center, Cleveland, OH, United States.
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6
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Amato R, Lucchesi M, Marracci S, Filippi L, Dal Monte M. β-Adrenoceptors in Cancer: Old Players and New Perspectives. Handb Exp Pharmacol 2023. [PMID: 37982890 DOI: 10.1007/164_2023_701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2023]
Abstract
Distress, or negative stress, is known to considerably increase the incidence of several diseases, including cancer. There is indeed evidence from pre-clinical models that distress causes a catecholaminergic overdrive that, mainly through the activation of β-adrenoceptors (β-ARs), results in cancer cell growth and cancer progression. In addition, clinical studies have evidenced a role of negative stress in cancer progression. Moreover, plenty of data demonstrates that β-blockers have positive effects in reducing the pro-tumorigenic activity of catecholamines, correlating with better outcomes in some type of cancers as evidenced by several clinical trials. Among β-ARs, β2-AR seems to be the main β-AR subtype involved in tumor development and progression. However, there are data indicating that also β1-AR and β3-AR may be involved in certain tumors. In this chapter, we will review current knowledge on the role of the three β-AR isoforms in carcinogenesis as well as in cancer growth and progression, with particular emphasis on recent studies that are opening new avenues in the use of β-ARs as therapeutic targets in treating tumors.
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Affiliation(s)
- Rosario Amato
- Department of Biology, University of Pisa, Pisa, Italy
| | | | | | - Luca Filippi
- Department of Clinical and Experimental Medicine, Neonatology and Neonatal Intensive Care Unit, University of Pisa, Pisa, Italy
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Baumann C, Chiang W, Valsecchi R, Jurt S, Deluigi M, Schuster M, Rosengren KJ, Plückthun A, Zerbe O. Side-chain dynamics of the α 1B -adrenergic receptor determined by NMR via methyl relaxation. Protein Sci 2023; 32:e4801. [PMID: 37805830 PMCID: PMC10593183 DOI: 10.1002/pro.4801] [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: 05/03/2023] [Revised: 08/17/2023] [Accepted: 10/04/2023] [Indexed: 10/09/2023]
Abstract
G protein-coupled receptors (GPCRs) are medically important membrane proteins that sample inactive, intermediate, and active conformational states characterized by relatively slow interconversions (~μs-ms). On a faster timescale (~ps-ns), the conformational landscape of GPCRs is governed by the rapid dynamics of amino acid side chains. Such dynamics are essential for protein functions such as ligand recognition and allostery. Unfortunately, technical challenges have almost entirely precluded the study of side-chain dynamics for GPCRs. Here, we investigate the rapid side-chain dynamics of a thermostabilized α1B -adrenergic receptor (α1B -AR) as probed by methyl relaxation. We determined order parameters for Ile, Leu, and Val methyl groups in the presence of inverse agonists that bind orthosterically (prazosin, tamsulosin) or allosterically (conopeptide ρ-TIA). Despite the differences in the ligands, the receptor's overall side-chain dynamics are very similar, including those of the apo form. However, ρ-TIA increases the flexibility of Ile1764×56 and possibly of Ile2145×49 , adjacent to Pro2155×50 of the highly conserved P5×50 I3×40 F6×44 motif crucial for receptor activation, suggesting differences in the mechanisms for orthosteric and allosteric receptor inactivation. Overall, increased Ile side-chain rigidity was found for residues closer to the center of the membrane bilayer, correlating with denser packing and lower protein surface exposure. In contrast to two microbial membrane proteins, in α1B -AR Leu exhibited higher flexibility than Ile side chains on average, correlating with the presence of Leu in less densely packed areas and with higher protein-surface exposure than Ile. Our findings demonstrate the feasibility of studying receptor-wide side-chain dynamics in GPCRs to gain functional insights.
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Affiliation(s)
| | - Wan‐Chin Chiang
- Department of ChemistryUniversity of ZurichZurichSwitzerland
| | | | - Simon Jurt
- Department of ChemistryUniversity of ZurichZurichSwitzerland
| | - Mattia Deluigi
- Department of BiochemistryUniversity of ZurichZurichSwitzerland
| | | | | | | | - Oliver Zerbe
- Department of ChemistryUniversity of ZurichZurichSwitzerland
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8
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Chen J, Wang J, Zeng Q, Wang W, Sun H, Wei B. Exploring the deactivation mechanism of human β2 adrenergic receptor by accelerated molecular dynamic simulations. Front Mol Biosci 2022; 9:972463. [PMID: 36111136 PMCID: PMC9468641 DOI: 10.3389/fmolb.2022.972463] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2022] [Accepted: 08/05/2022] [Indexed: 11/13/2022] Open
Abstract
The β2 adrenergic receptor (β2AR), one of important members of the G protein coupled receptors (GPCRs), has been suggested as an important target for cardiac and asthma drugs. Two replicas of Gaussian accelerated molecular dynamics (GaMD) simulations are performed to explore the deactivation mechanism of the active β2AR bound by three different substrates, including the agonist (P0G), antagonist (JTZ) and inverse agonist (JRZ). The simulation results indicate that the Gs protein is needed to stabilize the active state of the β2AR. Without the Gs protein, the receptor could transit from the active state toward the inactive state. During the transition process, helix TM6 moves toward TM3 and TM5 in geometric space and TM5 shrinks upwards. The intermediate state is captured during the transition process of the active β2AR toward the inactive one, moreover the changes in hydrophobic interaction networks between helixes TM3, TM5, and TM6 and the formation of a salt bridge between residues Arg3.50 and Glu6.30 drive the transition process. We expect that this finding can provide energetic basis and molecular mechanism for further understanding the function and target roles of the β2AR.
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Affiliation(s)
- Jianzhong Chen
- School of Science, Shandong Jiaotong University, Jinan, China
- *Correspondence: Jianzhong Chen, ; Benzheng Wei,
| | - Jian Wang
- School of Science, Shandong Jiaotong University, Jinan, China
| | - Qingkai Zeng
- School of Science, Shandong Jiaotong University, Jinan, China
| | - Wei Wang
- School of Science, Shandong Jiaotong University, Jinan, China
| | - Haibo Sun
- School of Science, Shandong Jiaotong University, Jinan, China
| | - Benzheng Wei
- Center for Medical Artificial Intelligence, Shandong University of Traditional Chinese Medicine, Qingdao, China
- *Correspondence: Jianzhong Chen, ; Benzheng Wei,
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Chmielarz P, Kuśmierczyk J, Rafa-Zabłocka K, Chorązka K, Kowalska M, Satała G, Nalepa I. Antidepressants Differentially Regulate Intracellular Signaling from α1-Adrenergic Receptor Subtypes In Vitro. Int J Mol Sci 2021; 22:ijms22094817. [PMID: 34062902 PMCID: PMC8124549 DOI: 10.3390/ijms22094817] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Revised: 04/28/2021] [Accepted: 04/29/2021] [Indexed: 11/16/2022] Open
Abstract
Currently utilized antidepressants have limited effectiveness and frequently incur undesired effects. Most antidepressants are thought to act via the inhibition of monoamine reuptake; however, direct binding to monoaminergic receptors has been proposed to contribute to both their clinical effectiveness and their side effects, or lack thereof. Among the target receptors of antidepressants, α1‑adrenergic receptors (ARs) have been implicated in depression etiology, antidepressant action, and side effects. However, differences in the direct effects of antidepressants on signaling from the three subtypes of α1-ARs, namely, α1A-, α1B- and α1D‑ARs, have been little explored. We utilized cell lines overexpressing α1A-, α1B- or α1D-ARs to investigate the effects of the antidepressants imipramine (IMI), desipramine (DMI), mianserin (MIA), reboxetine (REB), citalopram (CIT) and fluoxetine (FLU) on noradrenaline-induced second messenger generation by those receptors. We found similar orders of inhibition at α1A-AR (IMI < DMI < CIT < MIA < REB) and α1D‑AR (IMI = DMI < CIT < MIA), while the α1B-AR subtype was the least engaged subtype and was inhibited with low potency by three drugs (MIA < IMI = DMI). In contrast to their direct antagonistic effects, prolonged incubation with IMI and DMI increased the maximal response of the α1B-AR subtype, and the CIT of both the α1A- and the α1B-ARs. Our data demonstrate a complex, subtype-specific modulation of α1-ARs by antidepressants of different groups.
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Affiliation(s)
- Piotr Chmielarz
- Department of Brain Biochemistry, Maj Institute of Pharmacology, Polish Academy of Sciences, Smętna 12, 31-343 Kraków, Poland; (P.C.); (J.K.); (K.R.-Z.); (K.C.); (M.K.)
| | - Justyna Kuśmierczyk
- Department of Brain Biochemistry, Maj Institute of Pharmacology, Polish Academy of Sciences, Smętna 12, 31-343 Kraków, Poland; (P.C.); (J.K.); (K.R.-Z.); (K.C.); (M.K.)
| | - Katarzyna Rafa-Zabłocka
- Department of Brain Biochemistry, Maj Institute of Pharmacology, Polish Academy of Sciences, Smętna 12, 31-343 Kraków, Poland; (P.C.); (J.K.); (K.R.-Z.); (K.C.); (M.K.)
| | - Katarzyna Chorązka
- Department of Brain Biochemistry, Maj Institute of Pharmacology, Polish Academy of Sciences, Smętna 12, 31-343 Kraków, Poland; (P.C.); (J.K.); (K.R.-Z.); (K.C.); (M.K.)
| | - Marta Kowalska
- Department of Brain Biochemistry, Maj Institute of Pharmacology, Polish Academy of Sciences, Smętna 12, 31-343 Kraków, Poland; (P.C.); (J.K.); (K.R.-Z.); (K.C.); (M.K.)
| | - Grzegorz Satała
- Department of Medicinal Chemistry, Maj Institute of Pharmacology, Polish Academy of Sciences, Smętna 12, 31-343 Kraków, Poland;
| | - Irena Nalepa
- Department of Brain Biochemistry, Maj Institute of Pharmacology, Polish Academy of Sciences, Smętna 12, 31-343 Kraków, Poland; (P.C.); (J.K.); (K.R.-Z.); (K.C.); (M.K.)
- Correspondence: ; Tel.: +48-12-6623225
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Lipid Emulsion Enhances Vasoconstriction Induced by Dexmedetomidine in the Isolated Endothelium-Intact Aorta. Int J Mol Sci 2021; 22:ijms22073309. [PMID: 33804982 PMCID: PMC8038020 DOI: 10.3390/ijms22073309] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Revised: 03/16/2021] [Accepted: 03/20/2021] [Indexed: 11/16/2022] Open
Abstract
This study aimed to examine the effect of lipid emulsion (LE) on the vasoconstriction induced by dexmedetomidine (DMT) in the isolated rat aorta and elucidate the associated cellular mechanism. The effect of LE, NW-nitro-L-arginine methyl ester (L-NAME), and methyl-β-cyclodextrin (MβCD) on the DMT-induced contraction was examined. We investigated the effect of LE on the DMT-induced cyclic guanosine monophosphate (cGMP) formation and DMT concentration. The effect of DMT, LE, 4-Amino-3-(4-chlorophenyl)-1-(t-butyl)-1H-pyrazolo[3,4-d]pyrimidine,4-Amino-5-(4-chlorophenyl)-7-(t-butyl)pyrazolo[3,4-d]pyrimidine (PP2), and rauwolscine on the phosphorylation of endothelial nitric oxide synthase (eNOS), caveolin-1, and Src kinase was examined in the human umbilical vein endothelial cells. L-NAME, MβCD, and LE (1%, standardized mean difference (SMD): 2.517) increased the DMT-induced contraction in the endothelium-intact rat aorta. LE (1%) decreased the DMT (10−6 M) concentration (SMD: −6.795) and DMT-induced cGMP formation (SMD: −2.132). LE (1%) reversed the DMT-induced eNOS (Ser1177 and Thr496) phosphorylation. PP2 inhibited caveolin-1 and eNOS phosphorylation induced by DMT. DMT increased the Src kinase phosphorylation. Thus, LE (1%) enhanced the DMT-induced contraction by inhibition of NO synthesis, which may be caused by the decreased DMT concentration. DMT-induced NO synthesis may be caused by the increased eNOS (Ser1177) phosphorylation and decreased eNOS (Thr495) phosphorylation potentially mediated by Src kinase-induced caveolin-1 phosphorylation.
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Idazoxan and Efaroxan Potentiate the Endurance Performances and the Antioxidant Activity of Ephedrine in Rats. ACTA ACUST UNITED AC 2021; 57:medicina57030194. [PMID: 33668888 PMCID: PMC7996498 DOI: 10.3390/medicina57030194] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Revised: 02/15/2021] [Accepted: 02/17/2021] [Indexed: 12/19/2022]
Abstract
Background and objectives: The connections between the imidazoline system and multiple other neurotransmitter systems in the brain (adrenergic, dopaminergic, serotoninergic, glutamatergic, opioid) indicate the complexity of the mechanisms underlying motor activity and behavior. The aim of the present research was to investigate the effects of the combination of ephedrine (EPD) and imidazoline antagonists idazoxan (IDZ) and efaroxan (EFR) on the endurance performance in the treadmill test in rats. Materials and Methods: We used Wistar rats distributed as follows: Group 1 (Control) receiving distilled water 0.3 mL/100 g body weight; Group 2 (EPD) receiving 20 mg/kg ephedrine; Group 3 (EPD + IDZ) receiving 20 mg/kg ephedrine + 3 mg/kg idazoxan; Group 4 (EPD + EFR) receiving 20 mg/kg ephedrine + 1 mg/kg efaroxan. An additional group (C) of animals receiving 0.3 mL/100 g body weight distilled water (but not subjected to effort) was used. Endurance capacity was evaluated using a treadmill running PanLAB assay. The evaluation of the substances’ influence on oxidative stress was performed by spectrophotometric determination of superoxide dismutase (SOD) and glutathione peroxidase (GPX) activity. Results: Treatment with EPD-IDZ and EPD-EFR were correlated with a longer distance traveled on the belt and with a decrease in the necessary electric shocks to motivate the animal to continue running in the forced locomotion test. Additionally, an increase in the activity of antioxidant enzymes was found. Conclusions: Idazoxan and efaroxan potentiated the physical effort-related effects of ephedrine with regard to endurance capacity and antioxidant activity in rats.
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Pillay Y, Nagiah S, Phulukdaree A, Krishnan A, Chuturgoon AA. Patulin suppresses α 1-adrenergic receptor expression in HEK293 cells. Sci Rep 2020; 10:20115. [PMID: 33208818 PMCID: PMC7674415 DOI: 10.1038/s41598-020-77157-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Accepted: 11/03/2020] [Indexed: 12/16/2022] Open
Abstract
Patulin (PAT) is a common mycotoxin contaminant of apple products linked to impaired metabolic and kidney function. Adenosine monophosphate activated protein kinase (AMPK), abundantly expressed in the kidney, intercedes metabolic changes and renal injury. The alpha-1-adrenergic receptors (α1-AR) facilitate Epinephrine (Epi)-mediated AMPK activation, linking metabolism and kidney function. Preliminary molecular docking experiments examined potential interactions and AMPK-gamma subunit 3 (PRKAG3). The effect of PAT exposure (0.2-2.5 µM; 24 h) on the AMPK pathway and α1-AR was then investigated in HEK293 human kidney cells. AMPK agonist Epi determined direct effects on the α1-AR, metformin was used as an activator for AMPK, while buthionine sulphoximine (BSO) and N-acetyl cysteine (NAC) assessed GSH inhibition and supplementation respectively. ADRA1A and ADRA1D expression was determined by qPCR. α1-AR, ERK1/2/MAPK and PI3K/Akt protein expression was assessed using western blotting. PAT (1 µM) decreased α1-AR protein and mRNA and altered downstream signalling. This was consistent in cells stimulated with Epi and metformin. BSO potentiated the observed effect on α1-AR while NAC ameliorated these effects. Molecular docking studies performed on Human ADRA1A and PRKAG3 indicated direct interactions with PAT. This study is the first to show PAT modulates the AMPK pathway and α1-AR, supporting a mechanism of kidney injury.
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Affiliation(s)
- Yashodani Pillay
- Discipline of Medical Biochemistry, University of KwaZulu-Natal, Durban, South Africa
| | - Savania Nagiah
- Discipline of Medical Biochemistry, University of KwaZulu-Natal, Durban, South Africa.,Department of Physiology, Nelson Mandela Metropolitan University, Port Elizabeth, South Africa
| | - Alisa Phulukdaree
- Discipline of Medical Biochemistry, University of KwaZulu-Natal, Durban, South Africa.,Department of Physiology, University of Pretoria, Pretoria, South Africa
| | - Anand Krishnan
- Discipline of Medical Biochemistry, University of KwaZulu-Natal, Durban, South Africa.,Department of Chemical Pathology, University of Free State, Bloemfontein, South Africa
| | - Anil A Chuturgoon
- Discipline of Medical Biochemistry, University of KwaZulu-Natal, Durban, South Africa. .,Discipline of Medical Biochemistry and Chemical Pathology, Faculty of Health Sciences, Howard College, University of KwaZulu-Natal, George Campbell Building, Durban, 4041, South Africa.
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