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Dudele A, Rasmussen PM, Østergaard L. Sural Nerve Perfusion in Mice. Front Neurosci 2020; 14:579373. [PMID: 33362454 PMCID: PMC7758475 DOI: 10.3389/fnins.2020.579373] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Accepted: 11/09/2020] [Indexed: 11/13/2022] Open
Abstract
Peripheral nerve function is metabolically demanding and nerve energy failure has been implicated in the onset and development of diabetic peripheral neuropathy and neuropathic pain conditions. Distal peripheral nerve oxygen supply relies on the distribution of red blood cells (RBCs) in just a few, nearby capillary-sized vessels and is therefore technically challenging to characterize. We developed an approach to characterize distal sural nerve hemodynamics in anesthetized, adult male mice using in vivo two-photon laser scanning microscopy. Our results show that RBC velocities in mouse sural nerve vessels are higher than those previously measured in mouse brain, and are sensitive to hindlimb temperatures. Nerve blood flow, measured as RBC flux, however, was similar to that of mouse brain and unaffected by local temperature. Power spectral density analysis of fluctuations in RBC velocities over short time intervals suggest that the technique is sufficiently sensitive and robust to detect subtle flow oscillations over time scales from 0.1 to tens of seconds. We conclude that in vivo two-photon laser scanning microscopy provides a suitable approach to study peripheral nerve hemodynamics in mice, and that local temperature control is important during such measurements.
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Affiliation(s)
- Anete Dudele
- Center of Functionally Integrative Neuroscience (CFIN), Department of Clinical Medicine, Aarhus University, Aarhus, Denmark.,The International Diabetic Neuropathy Consortium, Aarhus University Hospital, Aarhus, Denmark
| | - Peter Mondrup Rasmussen
- Center of Functionally Integrative Neuroscience (CFIN), Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Leif Østergaard
- Center of Functionally Integrative Neuroscience (CFIN), Department of Clinical Medicine, Aarhus University, Aarhus, Denmark.,The International Diabetic Neuropathy Consortium, Aarhus University Hospital, Aarhus, Denmark.,Department of Neuroradiology, Aarhus University Hospital, Aarhus, Denmark
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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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Kumar S, Arun KHS, Kaul CL, Sharma SS. Effects of adenosine and adenosine A2Areceptor agonist on motor nerve conduction velocity and nerve blood flow in experimental diabetic neuropathy. Neurol Res 2013; 27:60-6. [PMID: 15829161 DOI: 10.1179/016164105x18278] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
This study examined the effects of chronic administration of adenosine and CGS 21680 hydrochloride (adenosine A(2A) receptor agonist) on motor nerve conduction velocity (MNCV), nerve blood flow (NBF) and histology of sciatic nerve in animal model of diabetic neuropathy. Adenosinergic agents were administered for 2 weeks after 6 weeks of streptozotocin-induced (50 mg/kg i.p.) diabetes in male Sprague-Dawley rats. Significant reduction in sciatic MNCV and NBF were observed after 8 weeks in diabetic animals in comparison with control (non diabetic) rats. Adenosine (10 mg/kg, i.p.) significantly improved sciatic MNCV and NBF in diabetic rats. The protective effect of adenosine on MNCV and NBF was completely reversed by theophylline (50 mg/kg, i.p.), a non-selective adenosine receptor antagonist, suggesting that the adenosine effect was mediated via adenosinergic receptors. CGS 21680 (0.1 mg/kg, i.p.) significantly improved NBF; however, MNCV was not significantly improved in diabetic rats. At a dose of 1 mg/kg, neither MNCV nor NBF was improved by CGS 21680 in diabetic rats. ZM 241385 (adenosine A(2A) receptor antagonist) prevented the effect of CGS 21680 (0.1 mg/kg, i.p.). Histological changes observed in sciatic nerve were partially improved by the adenosinergic agents in diabetic rats. Results of the present study, suggest the potential of adenosinergic agents in the therapy of diabetic neuropathy.
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Affiliation(s)
- Sokindra Kumar
- Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research (NIPER), Sec-67, SAS Nagar, Punjab-160062, India
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Anderson LC, Garrett JR. Neural regulation of submandibular gland blood flow in the streptozotocin-diabetic rat: evidence for impaired endothelium-dependent vasodilatation. Arch Oral Biol 2004; 49:183-91. [PMID: 14725809 DOI: 10.1016/j.archoralbio.2003.09.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Functional changes in vascular tone and reactivity arise early in diabetes, and endothelial dysfunction plays a central role in the development of these microvascular abnormalities. Blood flow in the rat submandibular gland is mainly under neural regulation, which is mediated in part via endothelium-dependent mechanisms. Given the role of the endothelium in regulating blood flow and the deleterious effects of diabetes on endothelial cell function, we hypothesised that diabetes would significantly impair neural regulation of submandibular gland vascular perfusion. Three weeks after the induction of streptozotocin diabetes continuous 2 Hz sympathetic stimulation resulted in a similar degree of vasoconstriction (as measured by a decrease in perfusion) in both diabetic (-31+/-17%) and control rats (-22+/-7%). However, the magnitude and the duration of the after-dilatation were significantly less in diabetic animals. The same number of impulses delivered at 20 Hz in bursts (1s in every 10s) also resulted in vasoconstriction with each burst, but unlike the effects of burst stimulation in control rats the initial vasoconstriction was not converted to a net vasodilatation between bursts. Parasympathetic stimulation (2, 5 and 10 Hz) caused a marked vasodilatation in both control and diabetic rats, but the initial responses were delayed in diabetic animals, the maintained phases were smaller in magnitude (P<0.02) and it took longer to return to resting levels. In conclusion, submandibular gland vascular responses are altered in streptozotocin-induced diabetic rats. Vasoconstrictor responses evoked by sympathetic impulses were unaffected, but vasodilatory responses, particularly those associated with endothelium-dependent mechanisms, were significantly reduced.
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Affiliation(s)
- Leigh C Anderson
- Department of Anatomy, University of the Pacific, San Francisco, CA 94115, USA.
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Zochodne DW. Nerve and ganglion blood flow in diabetes: an appraisal. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2003; 50:161-202. [PMID: 12198810 DOI: 10.1016/s0074-7742(02)50077-5] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Vasa nervorum, the vascular supply to peripheral nerve trunks, and their associated cell bodies in ganglia have unique anatomical and physiological characteristics. Several different experimental approaches toward understanding the changes in vase nervorum following injury and disease have been used. Quantative techniques most widely employed have been microelectrode hydrogen clearance palarography and [14C]iodoantipyrine autoradiographic distribution, whereas estimates of red blood cell flux using a fiber-optic laser Doppler probe offer real time data at different sites along the nerve trunk. There are important caveats about the use of these techniques, their advantages, and their limitations. Reports of nerve blood flow require careful documentation of physiological variables, including mean arterial pressure and nerve temperature during the recordings. Several ischemic models of the peripheral nerve trunk have addressed the ischemic threshold below which axonal degeneration ensues (< 5ml/100 g/min). Following injury, rises in local blood flow reflect acitons of vasoactive peptides, nitric oxide, and the development of angiogenesis. In experimental diabetes, a large number of studies have documented reductions in nerve blood flow and tandem corrections of nerve blood flow and conduction slowing. A significant proportions, however, of the work can be criticized on the basis of methodology and interpretation. Similarly, not all work has confirmed that reductions of nerve blood flow are an invariable feature of experimental or human diabetic polyneuropathy. Therefore, while there is disagreement as to whether early declines in nerve blood flow "account" for diabetic polyneuropathy, there is unquestioned eveidence of early microangiopathy. Abnormalities of vase nervorum and micorvessels supplying ganglia at the very least develop parallel to and together with changes in neurons, Schwann cells, and axons.
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Affiliation(s)
- Douglas W Zochodne
- Department of Clinical Neurosciences, University of Calgary, Calgary, Alberta, Canada T2N 4N1
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Eichberg J. Protein kinase C changes in diabetes: is the concept relevant to neuropathy? INTERNATIONAL REVIEW OF NEUROBIOLOGY 2003; 50:61-82. [PMID: 12198821 DOI: 10.1016/s0074-7742(02)50073-8] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Protein kinase C (PKC) comprises a superfamily of isoenzymes, many of which are activated by 1,2-diacylglycerol (DAG) in the presence of phosphatidylserine. In order to be capable of DAG activation, PKC must first undergo a series of phosphorylation at three conserved sites. PKC isoforms phosphorylate a wide variety of intracellular target proteins and have multiple functions in signal transduction-mediated cellular regulation. An elevation in DAG levels and an increase in composite PKC activity and/or certain isoforms occurs in several nonneural tissues from diabetic animals, including the vasculature. The ability of isoform-specific PKC inhibitors to antagonize diabetes-induced abnormalities has implicated altered PKC beta activity in the onset of several diabetic complications, In contrast to many other tissues, DAG levels fall in diabetic nerve and a consistent pattern of change in PKC activity has not been observed. Treatments that alter PKC activity affect nerve Na+, K+-ATPase activity, but the mechanism involved is not well understood, Inhibition of PKC beta in diabetic rats appears to correct reduced nerve blood flow and decreased nerve conduction velocity. These and other findings indicate that changes in the neurovasculature exert adverse effects during the pathogenesis of diabetic neuropathy. Still unresolved is a clear-cut role for PKC in the development of abnormalities in neural cell metabolism. Further progress will depend on a more complete understanding of the functions of individual PKC isoforms in nerve. Future investigation could focus profitably on biochemical processes in nerve cells that modulate PKC activity and that are altered in diabetes, such as vascular endothelial growth factor levels and production of reactive oxygen species arising from oxidative stress.
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Affiliation(s)
- Joseph Eichberg
- Department of Biology and Biochemistry, University of Houston, Houston, Texas 77204, USA
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Obrosova IG, Van Huysen C, Fathallah L, Cao X, Stevens MJ, Greene DA. Evaluation of α 1‐adrenoceptor antagonist on diabetes‐induced changes in peripheral nerve function, metabolism, and antioxidative defense. FASEB J 2000. [DOI: 10.1096/fj.99-0803com] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Irina G. Obrosova
- Division of Endocrinology and MetabolismDepartment of Internal MedicineUniversity of Michigan Medical CenterAnn ArborMichigan48109‐0354USA
| | - Carol Van Huysen
- Division of Endocrinology and MetabolismDepartment of Internal MedicineUniversity of Michigan Medical CenterAnn ArborMichigan48109‐0354USA
| | - Lamia Fathallah
- Division of Endocrinology and MetabolismDepartment of Internal MedicineUniversity of Michigan Medical CenterAnn ArborMichigan48109‐0354USA
| | - Xianghui Cao
- Division of Endocrinology and MetabolismDepartment of Internal MedicineUniversity of Michigan Medical CenterAnn ArborMichigan48109‐0354USA
| | - Martin J. Stevens
- Division of Endocrinology and MetabolismDepartment of Internal MedicineUniversity of Michigan Medical CenterAnn ArborMichigan48109‐0354USA
| | - Douglas A. Greene
- Division of Endocrinology and MetabolismDepartment of Internal MedicineUniversity of Michigan Medical CenterAnn ArborMichigan48109‐0354USA
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