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Hallman I, Tapio H, Raekallio M, Karikoski N. Effect of constant rate infusion of detomidine with and without vatinoxan on blood glucose and insulin concentrations in horses. Vet Anaesth Analg 2024; 51:144-151. [PMID: 38103967 DOI: 10.1016/j.vaa.2023.11.005] [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] [Received: 06/28/2023] [Revised: 11/15/2023] [Accepted: 11/15/2023] [Indexed: 12/19/2023]
Abstract
OBJECTIVE To assess the effects of an α2-adrenoceptor agonist (detomidine) constant rate infusion (CRI) with and without an α2-adrenoceptor antagonist (vatinoxan) CRI on blood insulin and glucose concentrations, heart rate, intestinal borborygmi, and sedation during and after infusion in horses. STUDY DESIGN Randomized, blinded, crossover, experimental study. ANIMALS A total of nine healthy, adult Finnhorse mares. METHODS Horses were treated with an intravenous (IV) detomidine loading dose (0.01 mg kg-1), followed by CRI (0.015 mg kg-1 hour-1), and the same doses of detomidine combined with an IV vatinoxan loading dose (0.15 mg kg-1), followed by CRI (detomidine and vatinoxan; 0.05 mg kg-1 hour-1) with an 18 day washout period. Infusion time was 60 minutes and horses were monitored for 240 minutes after the infusion. Heart rate, borborygmi score and sedation were assessed, and blood glucose, insulin and triglyceride concentrations were measured. Data were analyzed using repeated measures ancova and Wilcoxon signed-rank tests. Values of p < 0.05 were considered statistically significant. RESULTS Insulin concentration decreased during (median nadir 1.7, range 0.0-2.9 μIU mL-1 at 60 minutes, p < 0.0001) and increased after detomidine CRI (median 36.6, range 11.7-78.4 μIU mL-1 at 180 minutes, p = 0.0001) significantly compared with detomidine and vatinoxan CRI. A significant elevation of blood glucose (peak 11.5 ± 1.6 mmol L-1 at 60 minutes, p < 0.0001) was detected during detomidine CRI. Vatinoxan alleviated the insulin changes and abolished the significant increase in blood glucose. Vatinoxan alleviated the decrease in heart rate (p = 0.0001) during detomidine infusion. No significant differences were detected in sedation scores between treatments. CONCLUSIONS AND CLINICAL RELEVANCE Vatinoxan attenuated the negative adverse effects of detomidine CRI and thus is potentially beneficial when used in combination with an α2-adrenoceptor agonist CRI in horses.
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Affiliation(s)
- Isa Hallman
- Department of Equine and Small Animal Medicine, Faculty of Veterinary Medicine, University of Helsinki, Helsinki, Finland.
| | - Heidi Tapio
- Department of Equine and Small Animal Medicine, Faculty of Veterinary Medicine, University of Helsinki, Helsinki, Finland
| | - Marja Raekallio
- Department of Equine and Small Animal Medicine, Faculty of Veterinary Medicine, University of Helsinki, Helsinki, Finland
| | - Ninja Karikoski
- Department of Equine and Small Animal Medicine, Faculty of Veterinary Medicine, University of Helsinki, Helsinki, Finland
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2
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Hu W, Yan G, Ding Q, Cai J, Zhang Z, Zhao Z, Lei H, Zhu YZ. Update of Indoles: Promising molecules for ameliorating metabolic diseases. Biomed Pharmacother 2022; 150:112957. [PMID: 35462330 DOI: 10.1016/j.biopha.2022.112957] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Revised: 03/30/2022] [Accepted: 04/11/2022] [Indexed: 11/15/2022] Open
Abstract
Obesity and metabolic disorders have gradually become public health-threatening problems. The metabolic disorder is a cluster of complex metabolic abnormalities which are featured by dysfunction in glucose and lipid metabolism, and results from the increasing prevalence of visceral obesity. With the core driving factor of insulin resistance, metabolic disorder mainly includes type 2 diabetes mellitus (T2DM), micro and macro-vascular diseases, non-alcoholic fatty liver disease (NAFLD), dyslipidemia, and the dysfunction of gut microbiota. Strategies and therapeutic attention are demanded to decrease the high risk of metabolic diseases, from lifestyle changes to drug treatment, especially herbal medicines. Indole is a parent substance of numerous bioactive compounds, and itself can be produced by tryptophan catabolism to stimulate glucagon-like peptide-1 (GLP-1) secretion and inhibit the development of obesity. In addition, in heterocycles drug discovery, the indole scaffold is primarily found in natural compounds with versatile biological activity and plays a prominent role in drug molecules synthesis. In recent decades, plenty of natural or synthesized indole deriviatives have been investigated and elucidated to exert effects on regulating glucose hemeostasis and lipd metabolism. The aim of this review is to trace and emphasize the compounds containing indole scaffold that possess immense potency on preventing metabolic disorders, particularly T2DM, obesity and NAFLD, along with the underlying molecular mechanisms, therefore facilitate a better comprehension of their druggability and application in metabolic diseases.
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Affiliation(s)
- Wei Hu
- State Key Laboratory of Quality Research in Chinese Medicine, Faculty of Chinese Medicine and School of Pharmacy, Macau University of Science and Technology, Macau, China
| | - Guanyu Yan
- Department of Allergy and Clinical Immunology, National Center for Respiratory Medicine, The First Affiliated Hospital of Guangzhou Medical University, National Clinical Research Center for Respiratory Disease, State Key Laboratory of Respiratory Disease, Guangzhou Institute of Respiratory Health, Guangzhou, China
| | - Qian Ding
- State Key Laboratory of Quality Research in Chinese Medicine, Faculty of Chinese Medicine and School of Pharmacy, Macau University of Science and Technology, Macau, China
| | - Jianghong Cai
- State Key Laboratory of Quality Research in Chinese Medicine, Faculty of Chinese Medicine and School of Pharmacy, Macau University of Science and Technology, Macau, China
| | - Zhongyi Zhang
- State Key Laboratory of Quality Research in Chinese Medicine, Faculty of Chinese Medicine and School of Pharmacy, Macau University of Science and Technology, Macau, China
| | - Ziming Zhao
- State Key Laboratory of Quality Research in Chinese Medicine, Faculty of Chinese Medicine and School of Pharmacy, Macau University of Science and Technology, Macau, China
| | - Heping Lei
- Guangdong Provincial Key Laboratory of Coronary Heart Disease Prevention, Guangdong Cardiovascular Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China.
| | - Yi Zhun Zhu
- State Key Laboratory of Quality Research in Chinese Medicine, Faculty of Chinese Medicine and School of Pharmacy, Macau University of Science and Technology, Macau, China; Shanghai Key Laboratory of Bioactive Small Molecules, School of Pharmacy, Fudan University, Shanghai, China.
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3
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Borck PC, Leite NDC, Valcanaia AC, Rickli S, Alípio JCDL, Machado M, Vellosa JC, Mathias PCDF, Boschero AC, Grassiolli S. Swimming training reduces glucose‐amplifying pathway and cholinergic responses in islets from lean‐ and MSG‐obese rats. Clin Exp Pharmacol Physiol 2019; 47:286-293. [DOI: 10.1111/1440-1681.13197] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Revised: 10/11/2019] [Accepted: 10/15/2019] [Indexed: 12/26/2022]
Affiliation(s)
- Patricia C. Borck
- Department of Structural and Functional Biology Institute of Biology University of Campinas/UNICAMP Campinas Brazil
| | - Nayara de C. Leite
- Department of Structural and Functional Biology Institute of Biology University of Campinas/UNICAMP Campinas Brazil
| | - Ana C. Valcanaia
- Biologica Science and Health Center University of West Parana (UNIOESTE) Cascavel Brazil
| | - Sarah Rickli
- Department of Structural and Functional Biology Institute of Biology University of Campinas/UNICAMP Campinas Brazil
| | | | - Michael Machado
- Department of Nursing University of Ponta Grossa/UEPG Ponta Grossa Brazil
| | - Jose C. Vellosa
- Department of Pharmaceutical Sciences University of Ponta Grossa/UEPG Ponta Grossa Brazil
| | - Paulo C. de F. Mathias
- Department of Biotechnology, Genetics and Cell Biology University of Maringá/UEM Maringa Brazil
| | - Antonio C. Boschero
- Department of Structural and Functional Biology Institute of Biology University of Campinas/UNICAMP Campinas Brazil
- Biologica Science and Health Center University of West Parana (UNIOESTE) Cascavel Brazil
| | - Sabrina Grassiolli
- Biologica Science and Health Center University of West Parana (UNIOESTE) Cascavel Brazil
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4
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Prates KV, de Oliveira JC, Malta A, Matiusso CCI, Miranda RA, Ribeiro TA, Francisco FA, Franco CCS, Moreira VM, Alves VS, Torrezan R, Mathias PCF, Barella LF. Sympathetic innervation is essential for metabolic homeostasis and pancreatic beta cell function in adult rats. Mol Cell Endocrinol 2018; 462:119-126. [PMID: 28962894 DOI: 10.1016/j.mce.2017.09.031] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Revised: 09/24/2017] [Accepted: 09/26/2017] [Indexed: 11/16/2022]
Abstract
Obesity is associated with an imbalance in the activity of the autonomic nervous system (ANS), specifically in the organs involved in energy metabolism. The pancreatic islets are richly innervated by the ANS, which tunes the insulin release due to changes in energy demand. Therefore, changes in the sympathetic input that reach the pancreas can lead to metabolic dysfunctions. To evaluate the role of the sympathetic ends that innervate the pancreas, 60-day-old male Wistar rats were subjected to sympathectomy (SYM) or were sham-operated (SO). At 120 day-old SYM rats exhibited an increase in body weight, fat pads and metabolic dysfunctions. Decreases in the HOMA-IR and reductions in insulin release were observed both in vivo and in vitro. Furthermore, the SYM rats exhibited altered pancreatic islet function in both muscarinic and adrenergic assays and exhibited high protein expression of the alpha-2 adrenergic receptor (α2AR). Because α2AR has been linked to type 2 diabetes, these findings demonstrate the clinical implications of this study.
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Affiliation(s)
- Kelly V Prates
- Laboratory of Secretion Cell Biology, Department of Biotechnology, Genetics and Cell Biology, State University of Maringá, Maringá, Paraná, Brazil.
| | - Júlio C de Oliveira
- Institute of Health Sciences, Federal University of Mato Grosso, Sinop, MT, Brazil
| | - Ananda Malta
- Laboratory of Secretion Cell Biology, Department of Biotechnology, Genetics and Cell Biology, State University of Maringá, Maringá, Paraná, Brazil
| | - Camila C I Matiusso
- Laboratory of Secretion Cell Biology, Department of Biotechnology, Genetics and Cell Biology, State University of Maringá, Maringá, Paraná, Brazil
| | - Rosiane A Miranda
- Carlos Chagas Filho Biophysics Institute, Federal University of Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Tatiane A Ribeiro
- Laboratory of Secretion Cell Biology, Department of Biotechnology, Genetics and Cell Biology, State University of Maringá, Maringá, Paraná, Brazil
| | - Flávio A Francisco
- Laboratory of Secretion Cell Biology, Department of Biotechnology, Genetics and Cell Biology, State University of Maringá, Maringá, Paraná, Brazil
| | - Claudinéia C S Franco
- Laboratory of Secretion Cell Biology, Department of Biotechnology, Genetics and Cell Biology, State University of Maringá, Maringá, Paraná, Brazil
| | - Veridiana M Moreira
- Laboratory of Secretion Cell Biology, Department of Biotechnology, Genetics and Cell Biology, State University of Maringá, Maringá, Paraná, Brazil
| | - Vander S Alves
- Laboratory of Secretion Cell Biology, Department of Biotechnology, Genetics and Cell Biology, State University of Maringá, Maringá, Paraná, Brazil
| | - Rosana Torrezan
- Laboratory of Secretion Cell Biology, Department of Biotechnology, Genetics and Cell Biology, State University of Maringá, Maringá, Paraná, Brazil
| | - Paulo C F Mathias
- Laboratory of Secretion Cell Biology, Department of Biotechnology, Genetics and Cell Biology, State University of Maringá, Maringá, Paraná, Brazil
| | - Luiz F Barella
- Laboratory of Secretion Cell Biology, Department of Biotechnology, Genetics and Cell Biology, State University of Maringá, Maringá, Paraná, Brazil
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5
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Central Circadian Clock Regulates Energy Metabolism. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 1090:79-103. [PMID: 30390286 DOI: 10.1007/978-981-13-1286-1_5] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Our body not only responds to environmental changes but also anticipates them. The light and dark cycle with the period of about 24 h is a recurring environmental change that determines the diurnal variation in food availability and safety from predators in nature. As a result, the circadian clock is evolved in most animals to align locomotor behaviors and energy metabolism with the light cue. The central circadian clock in mammals is located at the suprachiasmatic nucleus (SCN) of the hypothalamus in the brain. We here review the molecular and anatomic architecture of the central circadian clock in mammals, describe the experimental and observational evidence that suggests a critical role of the central circadian clock in shaping systemic energy metabolism, and discuss the involvement of endocrine factors, neuropeptides, and the autonomic nervous system in the metabolic functions of the central circadian clock.
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Ruohonen ST, Ranta-Panula V, Bastman S, Chrusciel P, Scheinin M, Streng T. Potentiation of Glibenclamide Hypoglycaemia in Mice by MK-467, a Peripherally Acting Alpha2-Adrenoceptor Antagonist. Basic Clin Pharmacol Toxicol 2015; 117:392-8. [PMID: 26132275 DOI: 10.1111/bcpt.12440] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2015] [Accepted: 06/25/2015] [Indexed: 12/17/2022]
Abstract
Pharmacological antagonism and genetic depletion of pancreatic α2A-adrenoceptors increase insulin secretion in mice and enhance the insulinotropic action of glibenclamide, a representative of the sulphonylurea class of insulin secretagogues used in the therapy of type 2 diabetes. Antagonism of α2-adrenoceptors in the central nervous system (CNS) causes tachycardia and hypertension, making generalized α2-adrenoceptor blockade unfavourable for clinical use despite its potential to decrease blood glucose levels. The purpose of this study was to test the acute effects of the peripherally acting α2-adrenoceptor antagonist MK-467 alone and in combination with glibenclamide in non-diabetic C57BL/6N mice. Cardiovascular safety was assessed in freely moving mice with radiotelemetry. Dose-dependent decreases in blood glucose and increases in plasma insulin concentrations were seen with the combination of MK-467 and glibenclamide; the combinations were much more potent than glibenclamide or MK-467 alone. Furthermore, MK-467 had no effect on mean arterial pressure or heart rate in freely moving mice and did not prevent the centrally mediated hypotensive effect of the α2-adrenoceptor agonist medetomidine. Thus, peripheral blockade of α2-adrenoceptors does not evoke the same cardiovascular adverse effects as antagonism of CNS α2-adrenoceptors. The current results indicate that the combined use of small doses of a peripherally acting α2-adrenoceptor antagonist with a sulphonylurea drug could provide a novel option for the treatment of type 2 diabetes, especially in patients with increased tonic α2-adrenoceptor-mediated inhibition of insulin secretion.
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Affiliation(s)
- Suvi T Ruohonen
- Department of Pharmacology, Drug Development and Therapeutics, University of Turku, Turku, Finland.,Turku Center for Disease Modeling, University of Turku, Turku, Finland
| | - Ville Ranta-Panula
- Department of Pharmacology, Drug Development and Therapeutics, University of Turku, Turku, Finland
| | - Sanna Bastman
- Department of Pharmacology, Drug Development and Therapeutics, University of Turku, Turku, Finland
| | - Paulina Chrusciel
- Department of Pharmacology, Drug Development and Therapeutics, University of Turku, Turku, Finland.,Turku Center for Disease Modeling, University of Turku, Turku, Finland
| | - Mika Scheinin
- Department of Pharmacology, Drug Development and Therapeutics, University of Turku, Turku, Finland.,Unit of Clinical Pharmacology, Turku University Hospital, Turku, Finland
| | - Tomi Streng
- Department of Pharmacology, Drug Development and Therapeutics, University of Turku, Turku, Finland.,Turku Center for Disease Modeling, University of Turku, Turku, Finland.,Department of Biology, Laboratory of Animal Physiology, University of Turku, Turku, Finland
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7
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Mesarwi OA, Sharma EV, Jun JC, Polotsky VY. Metabolic dysfunction in obstructive sleep apnea: A critical examination of underlying mechanisms. Sleep Biol Rhythms 2014; 13:2-17. [PMID: 26412981 DOI: 10.1111/sbr.12078] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
It has recently become clear that obstructive sleep apnea (OSA) is an independent risk factor for the development of metabolic syndrome, a disorder of defective energy storage and use. Several mechanisms have been proposed to explain this finding, drawing upon the characteristics that define OSA. In particular, intermittent hypoxia, sleep fragmentation, elevated sympathetic tone, and oxidative stress - all consequences of OSA - have been implicated in the progression of poor metabolic outcomes in OSA. In this review we examine the evidence to support each of these disease manifestations of OSA as a unique risk for metabolic dysfunction. Tissue hypoxia and sleep fragmentation are each directly connected to insulin resistance and hypertension, and each of these also may increase sympathetic tone, resulting in defective glucose homeostasis, excessive lipolysis, and elevated blood pressure. Oxidative stress further worsens insulin resistance and in turn, metabolic dysfunction also increases oxidative stress. However, despite many studies linking each of these individual components of OSA to the development of metabolic syndrome, there are very few reports that actually provide a coherent narrative about the mechanism underlying metabolic dysfunction in OSA.
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Affiliation(s)
- Omar A Mesarwi
- Johns Hopkins University School of Medicine, Baltimore, Maryland
| | | | - Jonathan C Jun
- Johns Hopkins University School of Medicine, Baltimore, Maryland
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8
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Shin MK, Han W, Bevans-Fonti S, Jun JC, Punjabi NM, Polotsky VY. The effect of adrenal medullectomy on metabolic responses to chronic intermittent hypoxia. Respir Physiol Neurobiol 2014; 203:60-7. [PMID: 25179887 DOI: 10.1016/j.resp.2014.08.018] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2014] [Revised: 08/22/2014] [Accepted: 08/24/2014] [Indexed: 01/14/2023]
Abstract
Obstructive sleep apnea causes intermittent hypoxia (IH) and is associated with insulin resistance and type 2 diabetes. IH increases plasma catecholamine levels, which may increase insulin resistance and suppress insulin secretion. The objective of this study was to determine if adrenal medullectomy (MED) prevents metabolic dysfunction in IH. MED or sham surgery was performed in 60 male C57BL/6J mice, which were then exposed to IH or control conditions (intermittent air) for 6 weeks. IH increased plasma epinephrine and norepinephrine levels, increased fasting blood glucose and lowered basal and glucose-stimulated insulin secretion. MED decreased baseline epinephrine and prevented the IH induced increase in epinephrine, whereas the norepinephrine response remained intact. MED improved glucose tolerance in mice exposed to IH, attenuated the impairment in basal and glucose-stimulated insulin secretion, but did not prevent IH-induced fasting hyperglycemia or insulin resistance. We conclude that the epinephrine release from the adrenal medulla during IH suppresses insulin secretion causing hyperglycemia.
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Affiliation(s)
- Mi-Kyung Shin
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins University School of Medicine, United States
| | - Woobum Han
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins University School of Medicine, United States
| | - Shannon Bevans-Fonti
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins University School of Medicine, United States
| | - Jonathan C Jun
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins University School of Medicine, United States
| | - Naresh M Punjabi
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins University School of Medicine, United States
| | - Vsevolod Y Polotsky
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins University School of Medicine, United States.
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9
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Blood glucose, acid–base and electrolyte changes during loading doses of alpha2-adrenergic agonists followed by constant rate infusions in horses. Vet J 2013; 198:684-9. [DOI: 10.1016/j.tvjl.2013.09.063] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2013] [Revised: 08/20/2013] [Accepted: 09/29/2013] [Indexed: 11/21/2022]
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10
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Boyda HN, Procyshyn RM, Pang CCY, Barr AM. Peripheral adrenoceptors: the impetus behind glucose dysregulation and insulin resistance. J Neuroendocrinol 2013; 25:217-28. [PMID: 23140239 DOI: 10.1111/jne.12002] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/04/2012] [Revised: 10/10/2012] [Accepted: 11/04/2012] [Indexed: 12/20/2022]
Abstract
It is now accepted that several pharmacological drug treatments trigger clinical manifestations of glucose dysregulation, such as hyperglycaemia, glucose intolerance and insulin resistance, in part through poorly understood mechanisms. Persistent sympathoadrenal activation is linked to glucose dysregulation and insulin resistance, both of which significantly increase the risk of emergent endocrinological disorders, including metabolic syndrome and type 2 diabetes mellitus. Through the use of targeted mutagenesis and pharmacological methods, preclinical and clinical research has confirmed physiological glucoregulatory roles for several peripheral α- and β-adrenoceptor subtypes. Adrenoceptor isoforms in the pancreas (α(2A) and β(2) ), skeletal muscle (α(1A) and β(2) ), liver (α(1A & B) and β(2) ) and adipose tissue (α(1A) and β(1 & 3) ) are convincing aetiological targets that account for both immediate and long-lasting alterations in blood glucose homeostasis. Because significant overlap exists between the therapeutic applications of numerous classes of drugs and their associated adverse side-effects, a better understanding of peripheral adrenoceptor-mediated glucose metabolism is thus warranted. Therefore, at the same time as providing a brief review of glucose homeostasis in the periphery, the present review addresses both functional and pathophysiological roles of the mammalian α(1) , α(2) , and β-adrenoceptor isoforms in whole-body glucose turnover. We highlight evidence relating to the clinical use of common adrenergic drugs and their impacts on glucose metabolism.
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Affiliation(s)
- H N Boyda
- Department of Anesthesiology, Pharmacology & Therapeutics, University of British Columbia, Vancouver, Canada.
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11
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Lehner Z, Stadlbauer K, Adorjan I, Rustenbeck I, Belz M, Fenzl A, de Cillia VAM, Gruber D, Bauer L, Frobel K, Brunmair B, Luger A, Fürnsinn C. Mechanisms of antihyperglycaemic action of efaroxan in mice: time for reappraisal of α2A-adrenergic antagonism in the treatment of type 2 diabetes? Diabetologia 2012; 55:3071-82. [PMID: 22898767 DOI: 10.1007/s00125-012-2679-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/07/2012] [Accepted: 07/20/2012] [Indexed: 10/28/2022]
Abstract
AIMS/HYPOTHESIS Inspired by recent speculation about the potential utility of α(2A)-antagonism in the treatment of type 2 diabetes, the study examined the contribution of α(2)-antagonism vs other mechanisms to the antihyperglycaemic activity of the imidazoline (±)-efaroxan. METHODS Effects of the racemate and its pure enantiomers on isolated pancreatic islets and beta cells in vitro, as well as on hyperglycaemia in vivo, were investigated in a comparative manner in mice. RESULTS In isolated perifused islets, the two enantiomers of efaroxan were equally potent in counteracting inhibition of insulin release by the ATP-dependent K(+) (K(ATP)) channel-opener diazoxide but (+)-efaroxan, the presumptive carrier of α(2)-antagonistic activity, was by far superior in counteracting inhibition of insulin release by the α(2)-agonist UK14,304. In vivo, (+)-efaroxan improved oral glucose tolerance at 100-fold lower doses than (-)-efaroxan and, in parallel with observations made in vitro, was more effective in counteracting UK14,304-induced than diazoxide-induced hyperglycaemia. The antihyperglycaemic activity of much higher doses of (-)-efaroxan was associated with an opposing pattern (i.e. with stronger counteraction of diazoxide-induced than UK14,304-induced hyperglycaemia), which implicates a different mechanism of action. CONCLUSIONS/INTERPRETATION The antihyperglycaemic potency of (±)-efaroxan in mice is almost entirely due to α(2)-antagonism, but high doses can also lower blood glucose via another mechanism. Our findings call for reappraisal of the possible clinical utility of α(2A)-antagonistic compounds in recently identified subpopulations of patients in which a congenitally higher level of α(2A)-adrenergic activation contributes to the development and pathophysiology of type 2 diabetes.
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Affiliation(s)
- Z Lehner
- Division of Endocrinology and Metabolism, Department of Medicine III, Medical University of Vienna, Währinger Gürtel 18-20, A-1090 Vienna, Austria
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