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Coppey L, Davidson E, Shevalye H, Torres ME, Yorek MA. Effect of dietary oils on peripheral neuropathy-related endpoints in dietary obese rats. Diabetes Metab Syndr Obes 2018; 11:117-127. [PMID: 29674850 PMCID: PMC5898889 DOI: 10.2147/dmso.s159071] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
PURPOSE This study aimed to determine the effect of dietary oils (olive, safflower, evening primrose, flaxseed, or menhaden) enriched in different mono unsaturated fatty acids or polyunsaturated fatty acids on peripheral neuropathies in diet-induced obese Sprague-Dawley rats. MATERIALS AND METHODS Rats at 12 weeks of age were fed a high-fat diet (45% kcal) for 16 weeks. Afterward, the rats were fed diets with 50% of the kilocalories of fat derived from lard replaced by the different dietary oils. In addition, a control group fed a standard diet (4% kcal fat) and a high fat fed group (45% kcal) were maintained. The treatment period was 32 weeks. The endpoints evaluated included motor and sensory nerve conduction velocity, thermal sensitivity, innervation of sensory nerves in the cornea and skin, and vascular relaxation by epineurial arterioles. RESULTS Menhaden oil provided the greatest benefit for improving peripheral nerve damage caused by dietary obesity. Similar results were obtained when we examined acetylcholine-mediated vascular relaxation of epineurial arterioles of the sciatic nerve. Enriching the diets with fatty acids derived from the other oils provided minimal to partial improvements. CONCLUSION These studies suggest that omega-3 polyunsaturated fatty acids derived from fish oil could be an effective treatment for neural and vascular complications associated with obesity.
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Affiliation(s)
- Lawrence Coppey
- Department of Internal Medicine, University of Iowa, Iowa City, IA, USA
| | - Eric Davidson
- Department of Internal Medicine, University of Iowa, Iowa City, IA, USA
| | - Hanna Shevalye
- Department of Internal Medicine, University of Iowa, Iowa City, IA, USA
| | - Michael E Torres
- Department of Internal Medicine, University of Iowa, Iowa City, IA, USA
| | - Mark A Yorek
- Department of Internal Medicine, University of Iowa, Iowa City, IA, USA
- Department of Veterans Affairs Iowa City Health Care System, Iowa City, IA, USA
- Department of Veterans Affairs, Veterans Affairs Center for the Prevention and Treatment of Visual Loss, Iowa City, IA, USA
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA, USA
- Correspondence: Mark A Yorek, Building 41, Room 127, 601 Highway 6 West, Veteran Affairs Medical Center, Iowa City, IA 52246, USA, Tel +1 319 338 0581, ext 7696, Fax +1 319 339 7162, Email
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El-Lithy GM, El-Bakly WM, Matboli M, Abd-Alkhalek HA, Masoud SI, Hamza M. Prophylactic L-arginine and ibuprofen delay the development of tactile allodynia and suppress spinal miR-155 in a rat model of diabetic neuropathy. Transl Res 2016; 177:85-97.e1. [PMID: 27392937 DOI: 10.1016/j.trsl.2016.06.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/27/2016] [Revised: 06/11/2016] [Accepted: 06/14/2016] [Indexed: 02/08/2023]
Abstract
Diabetic neuropathy (DN) is a common complication of diabetes mellitus that is hardly reversible at the late stages. Since treatment of neuropathic pain is predominantly symptomatic, a prophylactic measure would be useful. Both ibuprofen and L-arginine exert antiallodynic effects on chronic constriction injury (CCI)-induced cold allodynia. Furthermore, ibuprofen is effective in CCI-induced mechanical allodynia. The aim of the study was to assess the antiallodynic effect of prophylactic ibuprofen and L-arginine in streptozotocin-induced DN in rats and to further investigate the role of spinal miR-155 and nitric oxide (NO) in this effect. Tactile allodynia was assessed weekly by von Frey filaments. Oral daily administration of ibuprofen, L-arginine and their combination, for 4 weeks starting 1 week after streptozotocin injection (ie, before the development of tactile allodynia), resulted in a significant decrease of tactile allodynia compared with the control diabetic group. This was evident in the fifth week of the experiment. The 3 treatments prevented the decrease in muscle fiber diameter and epidermal thickness, seen in the control diabetic group. Furthermore, ibuprofen, L-arginine and their combination prevented the increase in the spinal NO level and miRNA-155, seen in the control diabetic group. In conclusion, both ibuprofen and L-arginine delayed the development of behavioral and histologic changes of DN, with concomitant suppression of spinal miR-155 and NO level. L-arginine being tolerable may be useful prophylactically in diabetic patients.
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Affiliation(s)
- Ghada M El-Lithy
- Department of Pharmacology, Faculty of Medicine, Ain Shams University, Cairo, Egypt
| | - Wesam M El-Bakly
- Department of Pharmacology, Faculty of Medicine, Ain Shams University, Cairo, Egypt
| | - Marwa Matboli
- Department of Biochemistry, Faculty of Medicine, Ain Shams University, Cairo, Egypt
| | - Hadwa A Abd-Alkhalek
- Department of Histology and Cell Biology, Faculty of Medicine, Ain Shams University, Cairo, Egypt
| | - Somaia I Masoud
- Department of Pharmacology, Faculty of Medicine, Ain Shams University, Cairo, Egypt
| | - May Hamza
- Department of Pharmacology, Faculty of Medicine, Ain Shams University, Cairo, Egypt.
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Singh R, Devi S, Gollen R. Role of free radical in atherosclerosis, diabetes and dyslipidaemia: larger-than-life. Diabetes Metab Res Rev 2015; 31:113-26. [PMID: 24845883 DOI: 10.1002/dmrr.2558] [Citation(s) in RCA: 97] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/25/2013] [Revised: 04/17/2014] [Accepted: 04/29/2014] [Indexed: 02/02/2023]
Abstract
During the past few decades, there have been numerous studies related to free radical chemistry. Free radicals including reactive oxygen species (ROS) and reactive nitrogen species are generated by the human body by various endogenous systems, exposure to different physiochemical conditions, or pathological states, and have been implicated in the pathogenesis of many diseases. These free radicals are also the common by-products of many oxidative biochemical reactions in cells. When free radicals overwhelm the body's ability to regulate them, a condition known as oxidative stress ensues. They adversely alter lipids, proteins, and DNA, which trigger a number of human diseases. In a number of pathophysiological conditions, the delicate equilibrium between free radical production and antioxidant capability is distorted, leading to oxidative stress and increased tissue injury. ROS which are mainly produced by vascular cells are implicated as possible underlying pathogenic mechanisms in a progression of cardiovascular diseases including ischemic heart disease, atherosclerosis, cardiac arrhythmia, hypertension, and diabetes. This review summarizes the key roles played by free radicals in the pathogenesis of atherosclerosis, diabetes, and dyslipidaemia. Although not comprehensive, this review also provides a brief perspective on some of the current research being conducted in this area for a better understanding of the role free radicals play in the pathogenesis of atherosclerosis, diabetes, and dyslipidaemia.
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Affiliation(s)
- Randhir Singh
- MM College of Pharmacy, Maharishi Markandeshwar University, Mullana, Ambala, India
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Olver TD, Grisé KN, McDonald MW, Dey A, Allen MD, Rice CL, Lacefield JC, Melling CJ, Noble EG, Shoemaker JK. The relationship between blood pressure and sciatic nerve blood flow velocity in rats with insulin-treated experimental diabetes. Diab Vasc Dis Res 2014; 11:281-289. [PMID: 24853907 DOI: 10.1177/1479164114533357] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Peripheral nerve blood flow (NBF) does not autoregulate but, instead, responds passively to changes in mean arterial pressure (MAP). How this relationship is impacted by insulin-treated experimental diabetes (ITED) is unknown. We tested the hypothesis that ITED will reduce NBF across a range of MAP in Sprague Dawley rats. Following 10 weeks of control or ITED conditions, conscious MAP (tail-cuff) was measured, and under anaesthesia, the MAP (carotid artery catheter, pressure transducer) and NBF (Doppler ultrasound, 40 MHz) responses to sodium nitroprusside (60 µg/kg) and phenylephrine (12 µg/kg) infusion were recorded (regression equations for MAP vs NBF were created for each rodent). Thereafter, motor nerve conduction velocity (MNCV) and nerve vascularization (haematoxylin and eosin stain) were determined. Conscious MAP was higher and MNCV was lower in the ITED group (p < 0.01). In response to drug infusions, the ΔMAP and ΔNBF were similar between groups (p ≥ 0.18). Estimated conscious NBF (based on substituting conscious MAP values into each individual regression equation) was greater in the ITED group (p < 0.01). Sciatic nerve vascularization was similar between groups (p ≥ 0.50). In contrast to the hypothesis, NBF was not reduced across a range of MAP. In spite of increased estimated conscious NBF values, MNCV was reduced in rats with ITED.
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Affiliation(s)
- T Dylan Olver
- Neurovascular Research Laboratory, School of Kinesiology, Western University, London, ON, Canada
| | - Kenneth N Grisé
- Exercise Biochemistry Laboratory, School of Kinesiology, Western University, London, ON, Canada
| | - Matthew W McDonald
- Exercise Biochemistry Laboratory, School of Kinesiology, Western University, London, ON, Canada
| | - Adwitia Dey
- Exercise Biochemistry Laboratory, School of Kinesiology, Western University, London, ON, Canada
| | - Matti D Allen
- Neuromuscular Research Laboratory, School of Kinesiology, Western University, London, ON, Canada
| | - Charles L Rice
- Neuromuscular Research Laboratory, School of Kinesiology, Western University, London, ON, Canada
| | - James C Lacefield
- Department of Electrical and Computer Engineering, Western University, London, ON, Canada Department of Medical Biophysics, Western University, London, ON, Canada Robarts Research Institute, Western University, London, ON, Canada
| | - Cw James Melling
- Exercise Biochemistry Laboratory, School of Kinesiology, Western University, London, ON, Canada
| | - Earl G Noble
- Exercise Biochemistry Laboratory, School of Kinesiology, Western University, London, ON, Canada
| | - J Kevin Shoemaker
- Neurovascular Research Laboratory, School of Kinesiology, Western University, London, ON, Canada Department of Physiology and Pharmacology, Western University, London, ON, Canada
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Olver TD, McDonald MW, Grisé KN, Dey A, Allen MD, Medeiros PJ, Lacefield JC, Jackson DN, Rice CL, Melling CWJ, Noble EG, Shoemaker JK. Exercise training enhances insulin-stimulated nerve arterial vasodilation in rats with insulin-treated experimental diabetes. Am J Physiol Regul Integr Comp Physiol 2014; 306:R941-50. [DOI: 10.1152/ajpregu.00508.2013] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Insulin stimulates nerve arterial vasodilation through a nitric oxide (NO) synthase (NOS) mechanism. Experimental diabetes reduces vasa nervorum NO reactivity. Studies investigating hyperglycemia and nerve arterial vasodilation typically omit insulin treatment and use sedentary rats resulting in severe hyperglycemia. We tested the hypotheses that 1) insulin-treated experimental diabetes and inactivity (DS rats) will attenuate insulin-mediated nerve arterial vasodilation, and 2) deficits in vasodilation in DS rats will be overcome by concurrent exercise training (DX rats; 75–85% V̇o2 max, 1 h/day, 5 days/wk, for 10 wk). The baseline index of vascular conductance values (VCi = nerve blood flow velocity/mean arterial blood pressure) were similar ( P ≥ 0.68), but peak VCi and the area under the curve (AUCi) for the VCi during a euglycemic hyperinsulinemic clamp (EHC; 10 mU·kg−1·min−1) were lower in DS rats versus control sedentary (CS) rats and DX rats ( P ≤ 0.01). Motor nerve conduction velocity (MNCV) was lower in DS rats versus CS rats and DX rats ( P ≤ 0.01). When compared with DS rats, DX rats expressed greater nerve endothelial NOS (eNOS) protein content ( P = 0.04). In a separate analysis, we examined the impact of diabetes in exercise-trained rats alone. When compared with exercise-trained control rats (CX), DX rats had a lower AUCi during the EHC, lower MNCV values, and lower sciatic nerve eNOS protein content ( P ≤ 0.03). Therefore, vasa nervorum and motor nerve function are impaired in DS rats. Such deficits in rats with diabetes can be overcome by concurrent exercise training. However, in exercise-trained rats (CX and DX groups), moderate hyperglycemia lowers vasa nervorum and nerve function.
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Affiliation(s)
- T. Dylan Olver
- Neurovascular Research Laboratory, School of Kinesiology, The University of Western Ontario, London, Ontario, Canada
| | - Matthew W. McDonald
- Exercise Biochemistry Laboratory, School of Kinesiology, The University of Western Ontario, London, Ontario, Canada
| | - Kenneth N. Grisé
- Exercise Biochemistry Laboratory, School of Kinesiology, The University of Western Ontario, London, Ontario, Canada
| | - Adwitia Dey
- Exercise Biochemistry Laboratory, School of Kinesiology, The University of Western Ontario, London, Ontario, Canada
| | - Matti D. Allen
- Neuromusclar Research Laboratory, School of Kinesiology, The University of Western Ontario, London, Ontario, Canada
| | - Philip J. Medeiros
- A. C. Burton Laboratory for Vascular Research, Department of Medical Biophysics, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, Ontario, Canada
| | - James C. Lacefield
- Department of Electrical and Computer Engineering, Department of Medical Biophysics and Robarts Research Institute, The University of Western Ontario, London, Ontario, Canada
| | - Dwayne N. Jackson
- A. C. Burton Laboratory for Vascular Research, Department of Medical Biophysics, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, Ontario, Canada
| | - Charles L. Rice
- Neuromusclar Research Laboratory, School of Kinesiology, The University of Western Ontario, London, Ontario, Canada
- Department of Anatomy and Cell Biology, The University of Western Ontario, London, Ontario, Canada; and
| | - C. W. James Melling
- Exercise Biochemistry Laboratory, School of Kinesiology, The University of Western Ontario, London, Ontario, Canada
| | - Earl G. Noble
- Exercise Biochemistry Laboratory, School of Kinesiology, The University of Western Ontario, London, Ontario, Canada
| | - J. Kevin Shoemaker
- Neurovascular Research Laboratory, School of Kinesiology, The University of Western Ontario, London, Ontario, Canada
- Department of Physiology and Pharmacology, The University of Western Ontario, London, Ontario, Canada
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Higashimori H, Whetzel TP, Carlsen RC. Inhibition of inducible nitric oxide synthase reduces an acute peripheral motor neuropathy produced by dermal burn injury in mice. J Peripher Nerv Syst 2009; 13:289-98. [PMID: 19192069 DOI: 10.1111/j.1529-8027.2008.00195.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
The systemic inflammatory response produced by a full-thickness dermal burn injury is associated with a peripheral motor neuropathy. We previously reported that a 20% body surface area (BSA) full-thickness dermal burn in C57BL6 mice produced structural and functional deficits in motor axons at a distance from the burn site. The etiology of the neuropathy, however, is not well characterized. Burn injury leads to an increase in production of a number of proinflammatory mediators, including nitric oxide (NO). We tested the hypothesis that dermal burn-induced motor neuropathy is mediated by increased production of NO. NO synthase (NOS) activity was inhibited following a 20% BSA full-thickness burn by injection of non-specific NOS inhibitor, nitro-L-arginine methyl ester or inducible NOS (iNOS) inhibitors, L-N6-(1-iminoethyl) lysine, and aminoguanidine. NOS inhibitors also prevented the reduction in ventral roots mean axon caliber and the decrease in a motor nerve conduction velocity (MCV) following burn. iNOS knockout mice prevented MCV decrease in the first 3 days post-burn, but iNOS knockout MCV was significantly reduced at 7-14 days post-burn. These results suggest that an increase in NO production generated by systemic inflammatory response pathways after burn injury contributes to the development of structural and functional deficits in peripheral motor axons.
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Affiliation(s)
- Haruki Higashimori
- Department of Neurobiology and Center for Glial Biology in Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
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8
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Bohlen HG. Microvascular Consequences of Obesity and Diabetes. Microcirculation 2008. [DOI: 10.1016/b978-0-12-374530-9.00021-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Shotton HR, Clarke S, Lincoln J. The effectiveness of treatments of diabetic autonomic neuropathy is not the same in autonomic nerves supplying different organs. Diabetes 2003; 52:157-64. [PMID: 12502507 DOI: 10.2337/diabetes.52.1.157] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The aim of the study was to investigate antioxidant (alpha-lipoic acid [LA]) and gamma-linolenic acid treatments in the prevention of changes in autonomic nerves induced in streptozotocin-diabetic rats. Autonomic nerves supplying the heart, penis, and gut were examined using immunohistochemical and biochemical techniques. LA and gamma-linolenic acid (present in evening primrose oil [EPO]) were administered as dietary supplements ( approximately 80 and 200 mg. kg(-1). day(-1), respectively). LA treatment prevented the diabetes-induced decrease of norepinephrine (NA) in the heart and of type I nitric oxide synthase (NOS-I) expression in erectile tissue of the penis but failed to prevent diabetes-induced changes in NA-, vasoactive intestinal polypeptide-, or calcitonin gene-related peptide-containing nerves supplying the ileum. LA partially prevented and EPO totally prevented the increase in NOS-I activity induced by diabetes in the ileum. EPO treatment failed to prevent any other diabetes-induced changes in the heart, penis, or ileum. These results demonstrate that, whereas LA treatment is more effective than EPO in preventing diabetes-induced changes in autonomic nerves, the effectiveness of LA treatment varies with the target organ studied. Diabetes-induced changes in nerves supplying the ileum are more resistant to treatment than those of the heart and penis.
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Affiliation(s)
- Hannah R Shotton
- Department of Anatomy and Developmental Biology, Autonomic Neuroscience Institute, Royal Free and University College Medical School, London, U.K
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Yorek MA, Coppey LJ, Gellett JS, Davidson EP, Bing X, Lund DD, Dillon JS. Effect of treatment of diabetic rats with dehydroepiandrosterone on vascular and neural function. Am J Physiol Endocrinol Metab 2002; 283:E1067-75. [PMID: 12376336 DOI: 10.1152/ajpendo.00173.2002] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Nutritional supplementation with dehydroepiandrosterone (DHEA) may be a candidate for treating diabetes-induced vascular and neural dysfunction. DHEA is a naturally occurring adrenal androgen that has antioxidant properties and is reportedly reduced in diabetes. Using a prevention protocol, we found that dietary supplementation of streptozotocin-induced diabetic rats with 0.1, 0.25, or 0.5% DHEA caused a concentration-dependent prevention in the development of motor nerve conduction velocity and endoneurial blood flow impairment, which are decreased in diabetes. At 0.25%, DHEA significantly prevented the diabetes-induced increase in serum thiobarbituric acid-reactive substances and sciatic nerve conjugated diene levels. This treatment also reduced the production of superoxide by epineurial arterioles of the sciatic nerve. DHEA treatment (0.25%) significantly improved vascular relaxation mediated by acetylcholine in epineurial vessels of diabetic rats. Sciatic nerve Na+-K+-ATPase activity and myoinositol content was also improved by DHEA treatment, whereas sorbitol and fructose content remained elevated. These studies suggest that DHEA, by preventing oxidative stress and perhaps improving sciatic nerve Na+-K+-ATPase activity, may improve vascular and neural dysfunction in diabetes.
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Affiliation(s)
- Mark A Yorek
- Veterans Affairs Medical Center, Diabetes Endocrinology Research Center, and Department of Internal Medicine, University of Iowa, Iowa City, Iowa 52246, USA.
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11
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Terata K, Coppey LJ, Davidson EP, Dunlap JA, Gutterman DD, Yorek MA. Acetylcholine-induced arteriolar dilation is reduced in streptozotocin-induced diabetic rats with motor nerve dysfunction. Br J Pharmacol 1999; 128:837-43. [PMID: 10516670 PMCID: PMC1571695 DOI: 10.1038/sj.bjp.0702856] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
1. Diabetes mellitus produces marked abnormalities in motor nerve conduction, but the mechanism is not clear. In the present study we hypothesized that in the streptozotocin (STZ)-induced diabetic rat impaired vasodilator function is associated with reduced endoneural blood flow (EBF) which may contribute to nerve dysfunction. 2. We examined whether diabetes-induced reductions in sciatic nerve conduction velocity and EBF were associated with impaired endothelium-dependent dilation in adjacent arterioles. We measured motor nerve conduction velocity (MNCV) in the sciatic nerve using a non-invasive procedure, and sciatic nerve nutritive blood flow using microelectrode polarography and hydrogen clearance. In vitro videomicroscopy was used to quantify arteriolar diameter responses to dilator agonists in arterioles overlying the sciatic nerve. 3. MNCV and EBF in 4-week-STZ-induced diabetic rats were decreased by 22% and 49% respectively. Arterioles were constricted with U46619 and dilation to acetylcholine (ACh), aprikalim, or sodium nitroprusside (SNP) examined. All agonists elicited dose-dependent dilation in control and diabetic rats, although ACh-induced dilation was significantly reduced in diabetic rats. Treating vessels from normal or diabetic rats with indomethacin (INDO) alone did not significantly affect ACh-induced relaxation. However, ACh-induced vasodilation was significantly reduced by treatment with KCl or Nomega-nitro-L-arginine (LNNA) alone. Combining LNNA and KCl further reduced ACh-induced dilation in these vessels. 4. Diabetes causes vasodilator dysfunction in a microvascular bed that provides circulation to the sciatic nerve. These studies imply that ACh-induced dilation in these vessels is mediated by multiple mechanisms that may include the endothelial-dependent production of nitric oxide and endothelial-derived hyperpolarizing factor. This impaired vascular response is associated with neural dysfunction.
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Affiliation(s)
- K Terata
- Veterans Affairs Medical Center, Diabetes Endocrinology Research Center and Department of Internal Medicine, University of Iowa, Iowa City, Indiana, IA, 52246, U.S.A
| | - L J Coppey
- Veterans Affairs Medical Center, Diabetes Endocrinology Research Center and Department of Internal Medicine, University of Iowa, Iowa City, Indiana, IA, 52246, U.S.A
| | - E P Davidson
- Veterans Affairs Medical Center, Diabetes Endocrinology Research Center and Department of Internal Medicine, University of Iowa, Iowa City, Indiana, IA, 52246, U.S.A
| | - J A Dunlap
- Veterans Affairs Medical Center, Diabetes Endocrinology Research Center and Department of Internal Medicine, University of Iowa, Iowa City, Indiana, IA, 52246, U.S.A
| | - D D Gutterman
- Veterans Affairs Medical Center, Diabetes Endocrinology Research Center and Department of Internal Medicine, University of Iowa, Iowa City, Indiana, IA, 52246, U.S.A
| | - M A Yorek
- Veterans Affairs Medical Center, Diabetes Endocrinology Research Center and Department of Internal Medicine, University of Iowa, Iowa City, Indiana, IA, 52246, U.S.A
- Author for correspondence:
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Sadri P, Lautt WW. Blockade of hepatic nitric oxide synthase causes insulin resistance. THE AMERICAN JOURNAL OF PHYSIOLOGY 1999; 277:G101-8. [PMID: 10409156 DOI: 10.1152/ajpgi.1999.277.1.g101] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The hypothesis was tested that insulin sensitivity, previously shown to depend on a functional hepatic parasympathetic reflex, was mediated by hepatic production of nitric oxide (NO). Insulin sensitivity was measured using the rapid insulin sensitivity test. N-nitro-L-arginine methyl ester (L-NAME, 2.5 and 5.0 mg/kg iv) and N-monomethyl-L-arginine (L-NMMA, 0.73 mg/kg), nitric oxide synthase (NOS) antagonists, caused insulin resistance in rats. Intraportal administration of L-NAME at a dose of 1.0 mg/kg significantly reduced the response to insulin (54.9 +/- 5.2%); however, administration of the same dose of L-NAME intravenously did not cause a significant decrease in insulin response. Intraportal, but not intravenous, administration of 3-morpholinosydnonimine (SIN-1, 5. 0 mg/kg), a NO donor, partially reversed the insulin resistance caused by L-NMMA. Intraportal administration of SIN-1 (10.0 mg/kg) completely restored insulin sensitivity after L-NMMA or surgical denervation of the liver. Insulin resistance produced by denervation was not further increased by NOS blockade. These results suggest that blockade of NOS causes peripheral insulin resistance secondary to blockade of the hepatic parasympathetic reflex release of hepatic insulin-sensitizing substance in response to insulin.
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Affiliation(s)
- P Sadri
- Department of Pharmacology and Therapeutics, Faculty of Medicine, University of Manitoba, Winnipeg, Manitoba, Canada R3E 0W3
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Pieper GM. Review of alterations in endothelial nitric oxide production in diabetes: protective role of arginine on endothelial dysfunction. Hypertension 1998; 31:1047-60. [PMID: 9576113 DOI: 10.1161/01.hyp.31.5.1047] [Citation(s) in RCA: 267] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- G M Pieper
- Department of Transplant Surgery, Medical College of Wisconsin, Froedtert Memorial Hospital, Milwaukee 53226, USA.
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14
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Tong YC, Wang CJ, Cheng JT. The role of nitric oxide in the control of plasma glucose concentration in spontaneously hypertensive rats. Neurosci Lett 1997; 233:93-6. [PMID: 9350840 DOI: 10.1016/s0304-3940(97)00636-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Glucose homeostasis was studied in the spontaneously hypertensive rat (SHR). The fasting plasma glucose levels were similar in the SHR and normotensive Wistar-Kyoto (WKY) rat (102.7+/-2.4 vs. 107.4+/-4.2 mg/dl, P > 0.01). One hour after glucose challenge, the plasma glucose level was slightly but insignificantly increased in both SHR and WKY rat (117+/-2.5 vs. 114.3+/-3.2 mg/dl, P > 0.01). After N(G)nitro-L-arginine methyl ester (L-NAME) 20 mg/kg per day was administered intraperitoneally (i.p.) for 4 days, the plasma glucose level was significantly increased in the rats (SHR 167.3+/-4.9; WKY rat 136.0+/-4.8 mg/dl); the increase was significantly more pronounced in the SHR. The fasting insulin levels were similar in the SHR and WKY rats (2.3+/-0.4 vs. 2.0+/-0.3 ng/ml, P > 0.01). One hour after glucose challenge, the insulin level was significantly increased in the WKY rat (4.8+/-0.7 ng/ml) but not in the SHR (2.2+/-0.4 ng/ml). With L-NAME treatment, plasma insulin increase was noted in the WKY rat but not SHR (4.6+/-0.6 vs. 2.6+/-0.4 ng/ml, n = 8, P < 0.01). One hour after insulin 1 IU/kg was injected intramuscularly (i.m.), the plasma glucose level was significantly decreased in both the SHR (from 115.0+/-6.5 to 48.6+/-3.6 mg/dl, n = 8) and WKY rat (from 108.3+/-3.8 to 52.6+/-4.2 mg/dl, n = 8). No significant difference was noted between the decrease of the two groups (P > 0.01). The present findings suggested that NO plays a role in the glucose homeostasis of rats. NO-synthase blockade resulted in an increase of plasma glucose level. The SHR maintains normal glucose level and tolerance in spite of a defective insulin release response. This is probably due the compensatory effect of a more prominent NO-dependent glucose homeostatic function.
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Affiliation(s)
- Y C Tong
- Department of Urology, National Cheng Kung University Medical College, Tainan, Taiwan
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15
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Vo PA, Tomlinson DR. Effects of adrenergic stimulation on sciatic nerve blood flow in diabetic and control rats. Eur J Pharmacol 1997. [DOI: 10.1016/s0014-2999(97)89176-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Fang C, Jiang Z, Tomlinson DR. Expression of constitutive cyclo-oxygenase (COX-1) in rats with streptozotocin-induced diabetes; effects of treatment with evening primrose oil or an aldose reductase inhibitor on COX-1 mRNA levels. Prostaglandins Leukot Essent Fatty Acids 1997; 56:157-63. [PMID: 9051726 DOI: 10.1016/s0952-3278(97)90513-5] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Altered prostanoid metabolism participates in the pathogenesis of diabetic complications. The rate-limiting enzyme in the control of prostanoid metabolism is constitutive cyclo-oxygenase (COX-1). This study examined the possibility that altered prostanoid metabolism derives from altered COX-1 expression in those tissues from diabetic rats, with characteristic changes in prostanoid production and related haemodynamics. This account also describes a procedure for estimation of minute amounts of COX-1 mRNA by reverse transcription and competitive polymerase chain reaction (RT-cPCR) amplification. In streptozotocin-diabetic rats (STZ-D, 55 mg/kg body weight), compared with age-matched controls, the level of COX-1 mRNA (in attomoles/micrograms tRNA +/- 1SD) was significantly decreased in sciatic nerve (0.50 +/- 0.26 versus 0.89 +/- 0.32 in controls; P < 0.05) and thoracic aorta (3.99 +/- 1.67 versus 8.80 +/- 2.37 in controls; P < 0.05). There were no differences in COX-1 mRNA in diabetic and control rat kidney and retina, though there was a trend towards increased expression with diabetes in the latter. Evening primrose oil (EPO) treatment increased COX-1 mRNA in nerve and retina to levels in diabetic rats that were higher than those of non-diabetic controls (1.21 +/- 0.28 for nerve and 0.065 +/- 0.017 for retina, where control retinae gave 0.031 +/- 0.020-see above for nerve). Treatment of diabetic rats with an aldose reductase inhibitor was without effect on COX-1 mRNA levels in the tissues examined. This study demonstrates that the changes in COX-1 mRNA levels in diabetic rats are organ specific and suggests that altered prostanoid metabolism can, in part, be explained by altered COX-1 expression. Apart from providing arachidonate as substrate for COX, EPO stimulates COX-1 expression in some tissues.
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Affiliation(s)
- C Fang
- Department of Pharmacology, St. Bartholomew's, London, UK
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Dewhurst M, Omawari N, Tomlinson DR. Aminoguanidine--effects on endoneurial vasoactive nitric oxide and on motor nerve conduction velocity in control and streptozotocin-diabetic rats. Br J Pharmacol 1997; 120:593-8. [PMID: 9051296 PMCID: PMC1564506 DOI: 10.1038/sj.bjp.0700946] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
1. The effects of aminoguanidine (AG) treatment on reductions in motor nerve conduction velocity (MNCV) and sciatic nerve blood flow, indexed by laser Doppler flux (LDF), were investigated in rats with experimental diabetes (streptozotocin-induced; 8-10 weeks duration). The contribution of endoneurial vasoactive nitric oxide to the LDF of these animals was also investigated by the direct micro-injection of NG-nitro-L-arginine methyl ester (L-NAME; 1 nmol in 1 microliter), followed by L-arginine (100 nmol in 1 microliter), into the sciatic nerve endoneurium. 2. The MNCV (m s-1, mean +/- 1 s.d.) of diabetic rats (38.2 +/- 1.5) was lower (P < 0.01) than that of age-matched controls (47.2 +/- 4.2). AG treatment (50 mg kg-1 day-1, i.p.) attenuated the diabetes-induced deficits in MNCV (43.4 +/- 5.9; P < 0.01), but had no effect in controls (48.8 +/- 3.8) or, if administered via drinking water (1 gl-1), diabetics (37.4 +/- 4.1). 3. L-NAME markedly reduced the resting LDF (arbitrary units; mean +/- s.e.mean) of controls (209 +/- 13 to 120 +/- 18; P < 0.005), an effect reversed by subsequent L-arginine (to 206 +/- 27). In diabetic rats the LDF reduction following L-NAME was much smaller (111 +/- 11 to 84 +/- 6; P < 0.05), but the change with L-arginine was significantly increased (to 145 +/- 12; P < 0.001). 4. AG treatment increased the resting LDF of control (265 +/- 34) and diabetic rats (133 +/- 14 for daily injection and 119 +/- 13 for drinking water). The responses to L-NAME and L-arginine were not changed markedly by AG treatment. However, L-arginine appeared to be less effective. 5. In conclusion, these data suggest that AG treatment may affect nitric oxide production in the vasa nervorum of peripheral nerves. However, the effects of AG-treatment are not consistent with the prevention of a diabetes-associated reduction in endoneurial nitric oxide production. The mechanisms by which AG attenuates nerve conduction slowing in streptozotocin-diabetic rats therefore remain unclear.
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Affiliation(s)
- M Dewhurst
- Department of Pharmacology, St. Bartholomew's, London
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Communications. Br J Pharmacol 1996. [DOI: 10.1111/j.1476-5381.1996.tb17246.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
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