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Sultan A, Jacobson M, Adeghate E, Oulhaj A, Shafiullah M, Qureshi A, Howarth FC. Effects of obesity and diabesity on heart rhythm in the Zucker rat. Clin Exp Pharmacol Physiol 2021; 48:735-747. [PMID: 33609055 DOI: 10.1111/1440-1681.13473] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Accepted: 01/19/2021] [Indexed: 12/24/2022]
Abstract
Obesity and type 2 diabetes mellitus are risk factors for hypertension, coronary heart disease, cardiac arrhythmias including atrial fibrillation, heart failure and sudden cardiac death. The effects of obesity and diabesity on heart rhythm were investigated in the Zucker diabetic fatty (ZDF) and Zucker fatty (ZF) compared to the Zucker lean (ZL) control rat. In vivo biotelemetry techniques were used to assess the electrocardiogram and other cardiac and metabolic parameters. ZDF rats were characterized by age-dependent elevations in fasting and non-fasting blood glucose, glucose intolerance and weight gain and ZF rats were characterized by smaller elevations in fasting and non-fasting blood glucose and greater weight gain compared to ZL rats. Heart rate (HR) was progressively reduced in ZDF, ZF and ZL rats. At 195 days (6.5 months) of age there were significant differences in HR between ZDF (265 ± 8 bpm, n = 10), ZF (336 ± 9 bpm, n = 10) and ZL (336 ± 10 bpm, n = 10) rats and significant differences in HRV between ZDF (22 ± 1 bpm, n = 10), ZF (27 ± 1 bpm, n = 10) and ZL (31 ± 1 bpm, n = 10) rats. Power spectral analysis revealed no significant (P > 0.05) differences in HRV at low frequencies, reduced HRV at high frequencies and increased sympathovagal balance in ZDF compared to ZF and ZL rats. HR was reduced by ageing and additionally reduced by diabesity in the absence of changes in physical activity and body temperature. Reductions in HRV associated with altered sympathovagal drive might partly underlie disturbed HR in the ZDF rat. Possible explanations for reduced HR and future mechanistic studies are discussed.
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Affiliation(s)
- Ahmed Sultan
- Department of Physiology, College of Medicine & Health Sciences, UAE University, Al Ain, UAE
| | | | - Ernest Adeghate
- Department of Anatomy, College of Medicine & Health Sciences, UAE University, Al Ain, UAE
| | - Abderrahim Oulhaj
- Institute of Public Health, College of Medicine & Health Sciences, UAE University, Al Ain, UAE
| | - Mohamed Shafiullah
- Department of Pharmacology, College of Medicine & Health Sciences, UAE University, Al Ain, UAE
| | - Anwar Qureshi
- Department of Physiology, College of Medicine & Health Sciences, UAE University, Al Ain, UAE
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Grisanti LA. Diabetes and Arrhythmias: Pathophysiology, Mechanisms and Therapeutic Outcomes. Front Physiol 2018; 9:1669. [PMID: 30534081 PMCID: PMC6275303 DOI: 10.3389/fphys.2018.01669] [Citation(s) in RCA: 71] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Accepted: 11/06/2018] [Indexed: 12/17/2022] Open
Abstract
The prevalence of diabetes is rapidly increasing and closely associated with cardiovascular morbidity and mortality. While the major cardiovascular complication associated with diabetes is coronary artery disease, it is becoming increasingly apparent that diabetes impacts the electrical conduction system in the heart, resulting in atrial fibrillation, and ventricular arrhythmias. The relationship between diabetes and arrhythmias is complex and multifactorial including autonomic dysfunction, atrial and ventricular remodeling and molecular alterations. This review will provide a comprehensive overview of the link between diabetes and arrhythmias with insight into the common molecular mechanisms, structural alterations and therapeutic outcomes.
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Affiliation(s)
- Laurel A Grisanti
- Department of Biomedical Sciences, College of Veterinary Medicine, University of Missouri, Columbia, MO, United States
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3
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Kawada T, Shimizu S, Hayama Y, Yamamoto H, Saku K, Shishido T, Sugimachi M. Derangement of open-loop static and dynamic characteristics of the carotid sinus baroreflex in streptozotocin-induced type 1 diabetic rats. Am J Physiol Regul Integr Comp Physiol 2018; 315:R553-R567. [DOI: 10.1152/ajpregu.00092.2018] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Although diabetes mellitus (DM) is a major risk factor for cardiovascular diseases, changes in open-loop static and dynamic characteristics of the arterial baroreflex in the early phase of DM remain to be clarified. We performed an open-loop systems analysis of the carotid sinus baroreflex in type 1 DM rats 4 to 5 wk after intraperitoneal streptozotocin injection ( n = 9) and we compared the results with control rats ( n = 9). The operating-point baroreflex gain was maintained in the DM rats compared with the control rats (2.07 ± 0.67 vs. 2.66 ± 0.22 mmHg/mmHg, P = 0.666). However, the range of arterial pressure (AP) control was narrower in the DM than in the control group (48.0 ± 5.0 vs. 77.1 ± 4.5 mmHg, P = 0.001), suggesting that the reserve for AP buffering is lost in DM. Although baroreflex dynamic characteristics were relatively preserved, coherences were lower in the DM than in the control group. The decreased coherence in the neural arc may be related to the narrowed quasi-linear range in the static relationship between carotid sinus pressure and sympathetic nerve activity in the DM group. Although the reason for the decreased coherences in the peripheral arc and the total reflex arc was inconclusive, the finding may indicate a loss of integrity of the baroreflex-mediated sympathetic AP control in the DM group. The derangement of the baroreflex dynamic characteristics is progressing occultly in this early stage of type 1 DM in a manner where dynamic gains are relatively preserved around the normal operating point.
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Affiliation(s)
- Toru Kawada
- Department of Cardiovascular Dynamics, National Cerebral and Cardiovascular Center, Osaka, Japan
| | - Shuji Shimizu
- Department of Cardiovascular Dynamics, National Cerebral and Cardiovascular Center, Osaka, Japan
| | - Yohsuke Hayama
- 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
| | - Keita Saku
- Department of Advanced Risk Stratification for Cardiovascular Diseases, Center for Disruptive Cardiovascular Medicine, Kyushu University, Fukuoka, Japan
| | - Toshiaki Shishido
- Department of Research Promotion, National Cerebral and Cardiovascular Center, Osaka, Japan
| | - Masaru Sugimachi
- Department of Cardiovascular Dynamics, National Cerebral and Cardiovascular Center, Osaka, Japan
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4
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Wan A, Rodrigues B. Endothelial cell-cardiomyocyte crosstalk in diabetic cardiomyopathy. Cardiovasc Res 2016; 111:172-83. [PMID: 27288009 DOI: 10.1093/cvr/cvw159] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/22/2016] [Accepted: 05/21/2016] [Indexed: 12/19/2022] Open
Abstract
The incidence of diabetes is increasing globally, with cardiovascular disease accounting for a substantial number of diabetes-related deaths. Although atherosclerotic vascular disease is a primary reason for this cardiovascular dysfunction, heart failure in patients with diabetes might also be an outcome of an intrinsic heart muscle malfunction, labelled diabetic cardiomyopathy. Changes in cardiomyocyte metabolism, which encompasses a shift to exclusive fatty acid utilization, are considered a leading stimulus for this cardiomyopathy. In addition to cardiomyocytes, endothelial cells (ECs) make up a significant proportion of the heart, with the majority of ATP generation in these cells provided by glucose. In this review, we will discuss the metabolic machinery that drives energy metabolism in the cardiomyocyte and EC, its breakdown following diabetes, and the research direction necessary to assist in devising novel therapeutic strategies to prevent or delay diabetic heart disease.
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Affiliation(s)
- Andrea Wan
- Faculty of Pharmaceutical Sciences, The University of British Columbia, 2405 Wesbrook Mall, Vancouver, BC, Canada V6T 1Z3
| | - Brian Rodrigues
- Faculty of Pharmaceutical Sciences, The University of British Columbia, 2405 Wesbrook Mall, Vancouver, BC, Canada V6T 1Z3
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Hattori Y, Hattori K, Suzuki T. Differential Modulation of Cardiac Sympathetic Neural Control and β-Adrenoceptor-G Protein Signaling Cascade in Rats With Type 1 and Type 2 Diabetes. Diabetes 2015. [PMID: 26207035 DOI: 10.2337/db15-0503] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Affiliation(s)
- Yuichi Hattori
- Department of Molecular and Medical Pharmacology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan
| | - Kohshi Hattori
- Anesthesiology and Pain Relief Center, The University of Tokyo Hospital, Tokyo, Japan
| | - Tokiko Suzuki
- Department of Molecular and Medical Pharmacology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan
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Thaung HPA, Baldi JC, Wang HY, Hughes G, Cook RF, Bussey CT, Sheard PW, Bahn A, Jones PP, Schwenke DO, Lamberts RR. Increased Efferent Cardiac Sympathetic Nerve Activity and Defective Intrinsic Heart Rate Regulation in Type 2 Diabetes. Diabetes 2015; 64:2944-56. [PMID: 25784543 DOI: 10.2337/db14-0955] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/20/2014] [Accepted: 03/09/2015] [Indexed: 11/13/2022]
Abstract
Elevated sympathetic nerve activity (SNA) coupled with dysregulated β-adrenoceptor (β-AR) signaling is postulated as a major driving force for cardiac dysfunction in patients with type 2 diabetes; however, cardiac SNA has never been assessed directly in diabetes. Our aim was to measure the sympathetic input to and the β-AR responsiveness of the heart in the type 2 diabetic heart. In vivo recording of SNA of the left efferent cardiac sympathetic branch of the stellate ganglion in Zucker diabetic fatty rats revealed an elevated resting cardiac SNA and doubled firing rate compared with nondiabetic rats. Ex vivo, in isolated denervated hearts, the intrinsic heart rate was markedly reduced. Contractile and relaxation responses to β-AR stimulation with dobutamine were compromised in externally paced diabetic hearts, but not in diabetic hearts allowed to regulate their own heart rate. Protein levels of left ventricular β1-AR and Gs (guanine nucleotide binding protein stimulatory) were reduced, whereas left ventricular and right atrial β2-AR and Gi (guanine nucleotide binding protein inhibitory regulatory) levels were increased. The elevated resting cardiac SNA in type 2 diabetes, combined with the reduced cardiac β-AR responsiveness, suggests that the maintenance of normal cardiovascular function requires elevated cardiac sympathetic input to compensate for changes in the intrinsic properties of the diabetic heart.
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Affiliation(s)
- H P Aye Thaung
- HeartOtago, Department of Physiology, Otago School of Medical Sciences, University of Otago, Dunedin, New Zealand
| | - J Chris Baldi
- Department of Medicine, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand
| | - Heng-Yu Wang
- HeartOtago, Department of Physiology, Otago School of Medical Sciences, University of Otago, Dunedin, New Zealand
| | - Gillian Hughes
- HeartOtago, Department of Physiology, Otago School of Medical Sciences, University of Otago, Dunedin, New Zealand
| | - Rosalind F Cook
- HeartOtago, Department of Physiology, Otago School of Medical Sciences, University of Otago, Dunedin, New Zealand
| | - Carol T Bussey
- HeartOtago, Department of Physiology, Otago School of Medical Sciences, University of Otago, Dunedin, New Zealand
| | - Phil W Sheard
- HeartOtago, Department of Physiology, Otago School of Medical Sciences, University of Otago, Dunedin, New Zealand
| | - Andrew Bahn
- HeartOtago, Department of Physiology, Otago School of Medical Sciences, University of Otago, Dunedin, New Zealand
| | - Peter P Jones
- HeartOtago, Department of Physiology, Otago School of Medical Sciences, University of Otago, Dunedin, New Zealand
| | - Daryl O Schwenke
- HeartOtago, Department of Physiology, Otago School of Medical Sciences, University of Otago, Dunedin, New Zealand
| | - Regis R Lamberts
- HeartOtago, Department of Physiology, Otago School of Medical Sciences, University of Otago, Dunedin, New Zealand
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Huang CJ, Franco RL, Evans RK, Mari DC, Acevedo EO. Stress-induced microvascular reactivity in normal-weight and obese individuals. Appl Physiol Nutr Metab 2013; 39:47-52. [PMID: 24383506 DOI: 10.1139/apnm-2013-0094] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Obesity has been shown to have profound effects on hemodynamics and neurological states in humans. Previous studies have demonstrated that obese individuals are highly susceptible to increases in tension, anxiety, and depression. However, the relationship between mental stressors and vascular fluidity in obese humans is not well understood. Thus, the purpose of this study was to investigate mental-stress-induced microvascular reactivity (excess blood flow (EBF)) in normal-weight and obese individuals. In addition, the relationships between potential vascular response modulators (heart rate (HR) and norepinephrine (NE)) and EBF were examined. Twenty-two male subjects were classified as obese (n = 12) or normal-weight (n = 10), and each subject completed a 20 min bout of acute mental stress. Our analyses demonstrate significant elevations in forearm blood flow (FBF) and EBF immediately after mental stress in both normal-weight and obese groups. HR was only correlated with EBF immediately poststress in the normal-weight group. Furthermore, stress-induced plasma NE was not associated with FBF or EBF in either group, although in the obese group, stress-induced plasma NE was associated with body mass index and percent body fat. These results suggest that microvascular reactivity after mental stress is not directly related to plasma NE in normal-weight or obese individuals. The novel results presented in this study provide a foundation for additional examination of the mechanisms involved in the effects of mental stress on microvascular reactivity.
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Affiliation(s)
- Chun-Jung Huang
- a Department of Exercise Science and Health Promotion, Florida Atlantic University, Boca Raton, FL 33431, USA
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8
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Limberg JK, Morgan BJ, Sebranek JJ, Proctor LT, Walker BJ, Eldridge MW, Schrage WG. Altered neurovascular control of the resting circulation in human metabolic syndrome. J Physiol 2012; 590:6109-19. [PMID: 23027821 DOI: 10.1113/jphysiol.2012.239780] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Young healthy adults exhibit an inverse linear relationship between muscle sympathetic nerve activity (MSNA) and α-adrenergic responsiveness. This balance may be reversed in metabolic syndrome (MetSyn) as animal models exhibit increased sympathetic activity and α-mediated vasoconstriction. We hypothesized humans with MetSyn would demonstrate increased α-adrenergic vasoconstriction and the inverse relationship between MSNA and adrenergic responsiveness would be lost. We measured MSNA (microneurography of the peroneal nerve) and forearm blood flow (FBF, Doppler ultrasound) in 16 healthy control subjects (31 ± 3 years) and 14 adults with MetSyn (35 ± 3 years; P > 0.05) during local administration of α-adrenergic agonists (phenylephrine (PE), α(1); clonidine (CL), α(2)). MSNA was greater in MetSyn subjects than in healthy controls (P < 0.05). A group difference in vasoconstriction to PE was not detected (P = 0.08). The level of α(1)-mediated vasoconstriction was inversely related to MSNA in control subjects (r = 0.5, P = 0.04); this balance between MSNA and α(1) responsiveness was lost in adults with MetSyn. MetSyn subjects exhibited greater vasoconstriction to CL infusion as compared with healthy controls (P < 0.01). A relationship between MSNA and α(2)-mediated vasoconstriction was not detected in either group. In summary, altered neurovascular control in human MetSyn is receptor specific. The observed uncoupling between MSNA and α(1)-adrenergic responsiveness and increased α(2) vasoconstriction may lead to reduced FBF, altered flow distribution, and/or severe hypertension with the progression toward diabetes and cardiovascular disease.
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Affiliation(s)
- Jacqueline K Limberg
- School of Education, Department of Kinesiology, University of Wisconsin-Madison, Madison, WI 53076, USA
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Alteration of the cardiac sympathetic innervation is modulated by duration of diabetes in female rats. EXPERIMENTAL DIABETES RESEARCH 2011; 2011:835932. [PMID: 21792353 PMCID: PMC3142701 DOI: 10.1155/2011/835932] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/20/2010] [Accepted: 05/13/2011] [Indexed: 12/02/2022]
Abstract
To evaluate the sympathetic innervation of the female diabetic heart, resting heart rate and sympathetic tone were assessed in vivo, and effect of tyramine on spontaneous beating rate, norepinephrine atrial concentrations, uptake, and release were determined in vitro in streptozotocin- (STZ-) treated rats and respective controls aged 3 months to 2 years. Resting bradycardia, decreased sympathetic tone, deceleration of spontaneous beating rate, and slightly declining carrier-mediated, but preserved exocytotic norepinephrine release from the atria were found in younger diabetic rats while the reactivity of the right atria to tyramine was not affected with age and disease duration. Diabetic two-year-old animals displayed symptoms of partial spontaneous recovery including normoglycemia, increased plasma insulin concentrations, fully recovered sympathetic tone, but putative change, in releasable norepinephrine tissue stores. Our data suggested that female diabetic heart exposed to long-lasting diabetic conditions seems to be more resistant to alteration in sympathetic innervation than the male one.
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Karasu Ç. Glycoxidative stress and cardiovascular complications in experimentally-induced diabetes: effects of antioxidant treatment. Open Cardiovasc Med J 2010; 4:240-56. [PMID: 21270942 PMCID: PMC3026340 DOI: 10.2174/1874192401004010240] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2010] [Revised: 09/24/2010] [Accepted: 10/04/2010] [Indexed: 02/07/2023] Open
Abstract
Diabetes mellitus (DM) is a common metabolic disease, representing a serious risk factor for the development of cardiovascular complications, such as coronary heart disease, peripheral arterial disease and hypertension. Oxidative stress (OS), a feature of DM, is defined as an increase in the steady-state levels of reactive oxygen species (ROS) and may occur as a result of increased free radical generation and/or decreased anti-oxidant defense mechanisms. Increasing evidence indicates that hyperglycemia is the initiating cause of the tissue damage in DM, either through repeated acute changes in cellular glucose metabolism, or through long-term accumulation of glycated biomolecules and advanced glycation end products (AGEs). AGEs are formed by the Maillard process, a non-enzymatic reaction between ketone group of the glucose molecule or aldehydes and the amino groups of proteins that contributes to the aging of proteins and to the pathological complications of DM. In the presence of uncontrolled hyperglycemia, the increased formation of AGEs and lipid peroxidation products exacerbate intracellular OS and results in a loss of molecular integrity, disruption in cellular signaling and homeostasis, followed by inflammation and tissue injury such as endothelium dysfunction, arterial stiffening and microvascular complications. In addition to increased AGE production, there is also evidence of multiple pathways elevating ROS generation in DM, including; enhanced glucose auto-oxidation, increased mitochondrial superoxide production, protein kinase C-dependent activation of NADPH oxidase, uncoupled endothelial nitric oxide synthase (eNOS) activity, increased substrate flux through the polyol pathway and stimulation of eicosanoid metabolism. It is, therefore, not surprising that the correction of these variables can result in amelioration of diabetic cardiovascular abnormalities. A linking element between these phenomena is cellular redox imbalance due to glycoxidative stress (GOS). Thus, recent interest has focused on strategies to prevent, reverse or retard GOS in order to modify the natural history of diabetic cardiovascular abnormalities. This review will discuss the links between GOS and diabetes-induced cardiovascular disorders and the effect of antioxidant therapy on altering the development of cardiovascular complications in diabetic animal models.
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Affiliation(s)
- Çimen Karasu
- The Leader of Antioxidants in Diabetes-Induced Complications (ADIC) Study Group. Cellular Stress Response & Signal Transduction Research Laboratory, Department of Medical Pharmacology, Faculty of Medicine, Gazi University, Ankara, Turkey
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Balakrishnan S, T PK, Paulose CS. Glutamate (mGluR-5) gene expression in brain regions of streptozotocin induced diabetic rats as a function of age: role in regulation of calcium release from the pancreatic islets in vitro. J Biomed Sci 2009; 16:99. [PMID: 19903331 PMCID: PMC2779807 DOI: 10.1186/1423-0127-16-99] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2009] [Accepted: 11/10/2009] [Indexed: 11/10/2022] Open
Abstract
Metabotrophic glutamate receptors (mGluRs) modulate cellular activities involved in the processes of differentiation and degeneration. In this study, we have analysed the expression pattern of group-I metabotropic glutamate receptor (mGlu-5) in cerebral cortex, corpus striatum, brainstem and hippocampus of streptozotocin induced and insulin treated diabetic rats (D+I) as a function of age. Also, the functional role of glutamate receptors in intra cellular calcium release from the pancreatic islets was studied in vitro. The gene expression studies showed that mGlu-5 mRNA in the cerebral cortex increased siginficantly in 7 weeks old diabetic rats whereas decreased expression was observed in brainstem, corpus striatum and hippocampus when compared to control. 90 weeks old diabetic rats showed decreased expression in cerebral cortex, corpus striatum and hippocampus whereas in brainstem the expression increased significantly compared to their respective controls. In 7 weeks old D+I group, mGlu-5 mRNA expression was significantly decreased in cerebral cortex and corpus striatum whereas the expression increased significantly in brainstem and hippocampus. 90 weeks old D+I group showed an increased expression in cerebral cortex, while it was decreased significantly in corpus striatum, brainstem and hippocampus compared to their respective controls. In vitro studies showed that glutamate at lower concentration (10(-7) M) stimulated calcium release from the pancreatic islets. Our results suggest that mGlu-5 receptors have differential expression in brain regions of diabetes and D+I groups as a function of age. This will have clinical significance in management of degeneration in brain function and memory enhancement through glutamate receptors. Also, the regulatory role of glutamate receptors in calcium release has immense therapeutic application in insulin secretion and function.
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Affiliation(s)
- Savitha Balakrishnan
- Molecular Neurobiology and Cell Biology Unit, Centre for Neuroscience, Department of Biotechnology, Cochin University of Science and Technology, Cochin-682 022, Kerala, India.
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Fuder H, Muscholl E. Heteroreceptor-mediated modulation of noradrenaline and acetylcholine release from peripheral nerves. Rev Physiol Biochem Pharmacol 2006; 126:265-412. [PMID: 7886380 DOI: 10.1007/bfb0049778] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- H Fuder
- IKP-AKP, Professo Lücker GmbH, Grünstadt, Germany
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Burgdorf C, Richardt G, Schütte F, Dendorfer A, Kurz T. Impairment of Presynaptic ??2-Adrenoceptor-Regulated Norepinephrine Overflow in Failing Hearts from Zucker Diabetic Fatty Rats. J Cardiovasc Pharmacol 2006; 47:256-62. [PMID: 16495764 DOI: 10.1097/01.fjc.0000202560.61667.3e] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The aim of this study was to assess whether cardiac norepinephrine overflow is affected in Type 2 diabetes mellitus. Homozygous (fa/fa) Zucker diabetic fatty (ZDF) rats were used as a model of Type 2 diabetes; heterozygous (fa/+) ZDF rats served as non-diabetic controls. Cardiac performance was determined in isolated working hearts; release of endogenous norepinephrine was induced by electrical field stimulation in Langendorff-perfused hearts. At a mean age of 30 weeks, left ventricular contraction, relaxation, and developed pressure were reduced by 20% to 35% in ZDF-fa/fa rats compared with ZDF-fa/+ rats. Stepwise increase of stimulation frequency gradually increased norepinephrine overflow in isolated hearts from both rat strains. Compared to ZDF-fa/+ rats, cardiac norepinephrine overflow was suppressed by 25% to 45% in ZDF-fa/fa rats. During presynaptic alpha2-adrenoceptor blockade with rauwolscine, increase of norepinephrine overflow was significantly higher in ZDF-fa/fa rats than in ZDF-fa/+ rats whereas alpha2-adrenoceptor activation with UK 14,304 suppressed norepinephrine overflow solely in ZDF-fa/+ rats. Myocardial tissue content of norepinephrine did not differ markedly between the two groups. In conclusion, cardiac norepinephrine overflow is inhibited in failing hearts from ZDF-fa/fa rats. This inhibition may result from a hyperactive status of presynaptic alpha2-adrenoceptors.
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MESH Headings
- Adrenergic alpha-Agonists/pharmacology
- Adrenergic alpha-Antagonists/pharmacology
- Animals
- Blood Glucose/analysis
- Body Weight/drug effects
- Brimonidine Tartrate
- Diabetes Mellitus, Type 2/complications
- Diabetes Mellitus, Type 2/metabolism
- Diabetes Mellitus, Type 2/physiopathology
- Electric Stimulation
- Heart Failure/metabolism
- Heart Failure/physiopathology
- Heterozygote
- Homozygote
- Male
- Norepinephrine/antagonists & inhibitors
- Organ Size/drug effects
- Perfusion
- Quinoxalines/pharmacology
- Rats
- Rats, Zucker
- Receptors, Adrenergic, alpha-2/drug effects
- Receptors, Adrenergic, alpha-2/metabolism
- Receptors, Presynaptic/drug effects
- Receptors, Presynaptic/metabolism
- Yohimbine/pharmacology
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Affiliation(s)
- Christof Burgdorf
- Medizinische Klinik II, Universitätsklinikum Schleswig-Holstein, Campus Lübeck, Lübeck, Germany.
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14
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Abstract
Diabetes is a risk factor for coronary atherosclerosis, myocardial infarction, and ischemic cardiomyopathy. Insulin resistance is associated with left ventricular (LV) hypertrophy and hypertensive cardiomyopathy. Even in the absence of coronary artery disease or hypertension, "diabetic cardiomyopathy" can develop because of myocardial autonomic dysfunction or impaired coronary flow reserve. The relationship between insulin resistance and cardiomyopathy is bidirectional. Systemic and myocardial glucose uptake is compromised in heart failure independent of etiology. These abnormalities are associated with cellular deficits of insulin signaling. Insulin resistance in heart failure can be detrimental, because transcriptional shifts in metabolic gene expression favor glucose over fat as a substrate for high-energy phosphate production. Although preexisting diabetes accelerates this process of "metabolic death," insulin resistance can also develop secondary to cardiomyopathy-associated overabundance of neurohormones and cytokines. Insulin resistance and fatty acid excess are potential therapeutic targets in heart failure, striving for efficient myocardial substrate utilization. Peroxisome proliferator activator receptor gamma (PPARgamma) agonists are antidiabetic agents with antilipemic and insulin-sensitizing activity. Experimental studies suggest salutary effects in limiting infarct size, attenuating myocardial reperfusion injury, inhibiting hypertrophic signaling and vascular antiinflammatory actions through cytokine inhibition. However, clinical applicability in diabetic patients experiencing heart failure has been hampered because of increased edema and even fewer reports of exacerbation associated with these compounds. Evidence to date argues for peripheral mechanisms of edema unrelated to central hemodynamics. Nevertheless, they are currently contraindicated in New York Heart Association (NYHA) III-IV patients, particularly in combination with insulin. Investigations are underway to decipher mechanisms, risks, and benefits of PPARgamma agonists, as well as the role of the structurally related PPARalpha receptor on cardiovascular metabolism and function.
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Affiliation(s)
- Lazaros A Nikolaidis
- Division of Cardiology, Department of Medicine, Drexel University College of Medicine, Allegheny General Hospital, Pittsburgh, Pennsylvania 15212, USA
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Burgdorf C, Richardt D, Kurz T, Adler S, Nötzold A, Kraatz EG, Sievers HH, Richardt G. Norepinephrine release is reduced in cardiac tissue of Type 2 diabetic patients. Diabetologia 2003; 46:520-3. [PMID: 12739025 DOI: 10.1007/s00125-003-1055-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/13/2002] [Revised: 10/11/2002] [Indexed: 10/20/2022]
Abstract
AIMS/HYPOTHESIS The aim of this study was to assess whether cardiac catecholamine release is affected in patients with Type 2 diabetes mellitus. METHODS A trial tissue was obtained from 19 diabetic (Type 2) and 43 non-diabetic patients undergoing coronary surgery. Endogenous norepinephrine release was examined under baseline conditions as well as during electrical field stimulation (effective voltage 5 V, stimulation frequency 4 Hz, pulse width 2 msec) by high performance liquid chromatography and electrochemical detection. Cardiac function and arterial blood pressure was assessed from coronary angiography. RESULTS In atrial tissue from diabetic patients, stimulation-induced norepinephrine release was reduced by 25% compared with non-diabetic patients, while baseline norepinephrine release did not differ between both groups. Preoperative plasma glucose and haemoglobin A(1C) concentrations were increased in patients with diabetes, however, no relation was found to catecholamine release. Diabetic and non-diabetic patients did not differ regarding left ventricular ejection fraction and arterial blood pressure. CONCLUSION/INTERPRETATION Cardiac norepinephrine release is suppressed in patients with Type 2 diabetes which could contribute to sympathetic neuropathy. The difference of norepinephrine release in diabetic and non-diabetic patients was independent of cardiac function and arterial blood pressure.
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Affiliation(s)
- C Burgdorf
- Medizinische Klinik II, Universitätsklinikum Lübeck, Ratzeburger Allee 160, 23538, Lübeck, Germany.
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16
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Houzen H, Hattori Y, Kanno M, Kikuchi S, Tashiro K, Motomura M, Nakao Y, Nakamura T. Functional evaluation of inhibition of autonomic transmitter release by autoantibody from Lambert-Eaton myasthenic syndrome. Ann Neurol 1998; 43:677-80. [PMID: 9585366 DOI: 10.1002/ana.410430520] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The effects of the anti-voltage-gated Ca2+ channel (VGCC) antibody obtained from patients with Lambert-Eaton myasthenic syndrome (LEMS) on autonomic neurotransmission were studied in in-vitro experiments. The releases of acetylcholine (ACh) and norepinephrine from the autonomic nerves were evaluated by changes in the contractile responses of guinea pig taenia caeci and left atria to electric field stimulation, respectively. Incubations for 6 hours with LEMS serum and IgG, both of which contain anti-VGCC antibody, markedly suppressed the parasympathetic response but did not affect the sympathetic response. Pharmacological experiments with specific blockers to the VGCC subtypes showed that the Q-type VGCC is closely linked to the genesis of the parasympathetic response. We suggest that the anti-VGCC antibody from the LEMS patients specifically reduces the ACh release from the parasympathetic nerve by binding to the Q-type VGCC.
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Affiliation(s)
- H Houzen
- Department of Pharmacology, Hokkaido University School of Medicine, Sapporo, Japan
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17
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Hicks KK, Seifen E, Stimers JR, Kennedy RH. Effects of streptozotocin-induced diabetes on heart rate, blood pressure and cardiac autonomic nervous control. JOURNAL OF THE AUTONOMIC NERVOUS SYSTEM 1998; 69:21-30. [PMID: 9672120 DOI: 10.1016/s0165-1838(98)00004-6] [Citation(s) in RCA: 88] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Diabetes-associated alterations in resting heart rate and blood pressure have been demonstrated in clinical studies and in animal models of insulin-dependent diabetes mellitus (IDDM). These alterations may result from changes in the heart, vasculature or autonomic nervous system control. Using the streptozotocin- (STZ-) treated rat model of IDDM, the current study was designed to: (1) monitor changes in heart rate and blood pressure continually during a 10-week period in conscious unrestrained animals; and (2) determine if observed alterations in heart rate were mediated by changes in sympathetic and/or parasympathetic nervous control. Biotelemetry techniques were used. Heart rate and blood pressure were recorded 24 h a day at 10 min intervals before and after induction of diabetes. Diabetes was induced by i.v. administration of 50 mg/kg STZ. Resting autonomic nervous system tone was estimated by chronotropic responses to full-blocking doses of nadolol (5 mg/kg i.p.) and atropine (10 mg/kg i.p.). STZ-induced diabetes was associated with time-dependent reductions in heart rate and its circadian variation. Diastolic blood pressure and mean arterial pressure did not differ significantly when compared between control and STZ-treated animals; however, pulse pressure was diminished in diabetic rats. Chronotropic responses to both nadolol and atropine were blunted significantly in diabetic animals suggesting that resting levels of both vagal and sympathetic nervous tone to the heart were diminished. Heart rate in the presence of both nadolol and atropine was also decreased in diabetic rats. All effects observed following administration of STZ were reversed, at least in part, by insulin treatment. These results suggest that IDDM is associated with time-dependent reductions in resting heart rate and autonomic nervous control of cardiac function.
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Affiliation(s)
- K K Hicks
- Department of Pharmacology and Toxicology, University of Arkansas for Medical Sciences, Little Rock 72205, USA
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18
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Lieu AT, Reid JJ. Changes in the responsiveness to endothelin-1 in isolated atria from diabetic rats. Eur J Pharmacol 1994; 261:33-42. [PMID: 8001651 DOI: 10.1016/0014-2999(94)90297-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
This study investigates the influence of diabetes on the cardiac responsiveness to endothelin-1. The effects of endothelin-1 on rate and force of contraction were examined in isolated right and left atria, respectively, obtained from either streptozotocin (65 mg/kg)-treated rats (diabetic) or vehicle (0.02 M citric acid)-treated rats (control). The positive chronotropic and inotropic effects of endothelin-1 did not change in atria from diabetic rats at 2 and 4 weeks, but were reduced at 8 and 12 weeks. The positive chronotropic response to noradrenaline, but not to sympathetic nerve stimulation, was also reduced in 12-week diabetic rats. Endothelin-1 caused a decrease in the positive chronotropic and inotropic responses to sympathetic nerve stimulation and to noradrenaline; these inhibitory effects of endothelin-1 were not altered in 2-, 4-, 8- or 12-week diabetic rats. The study demonstrates that atrial responses to endothelin-1 and to noradrenaline are reduced by streptozotocin-induced diabetes, but the alteration depends on the duration of diabetes.
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Affiliation(s)
- A T Lieu
- Department of Pharmacology, University of Melbourne, Parkville, Victoria, Australia
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