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Abstract
Painful neuropathy, like the other complications of diabetes, is a growing healthcare concern. Unfortunately, current treatments are of variable efficacy and do not target underlying pathogenic mechanisms, in part because these mechanisms are not well defined. Rat and mouse models of type 1 diabetes are frequently used to study diabetic neuropathy, with rats in particular being consistently reported to show allodynia and hyperalgesia. Models of type 2 diabetes are being used with increasing frequency, but the current literature on the progression of indices of neuropathic pain is variable and relatively few therapeutics have yet been developed in these models. While evidence for spontaneous pain in rodent models is sparse, measures of evoked mechanical, thermal and chemical pain can provide insight into the pathogenesis of the condition. The stocking and glove distribution of pain tantalizingly suggests that the generator site of neuropathic pain is found within the peripheral nervous system. However, emerging evidence demonstrates that amplification in the spinal cord, via spinal disinhibition and neuroinflammation, and also in the brain, via enhanced thalamic activity or decreased cortical inhibition, likely contribute to the pathogenesis of painful diabetic neuropathy. Several potential therapeutic strategies have emerged from preclinical studies, including prophylactic treatments that intervene against underlying mechanisms of disease, treatments that prevent gains of nociceptive function, treatments that suppress enhancements of nociceptive function, and treatments that impede normal nociceptive mechanisms. Ongoing challenges include unraveling the complexity of underlying pathogenic mechanisms, addressing the potential disconnect between the perceived location of pain and the actual pain generator and amplifier sites, and finding ways to identify which mechanisms operate in specific patients to allow rational and individualized choice of targeted therapies.
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Affiliation(s)
- Corinne A Lee-Kubli
- Graduate School of Biomedical Sciences, Sanford-Burnham Institute for Molecular Medicine, La Jolla, CA, USA; Department of Pathology, University of California San Diego, La Jolla, CA, USA
| | - Nigel A Calcutt
- Department of Pathology, University of California San Diego, La Jolla, CA, USA.
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Moriarty O, Lang Y, Idrees Z, McGuire BE, Finn DP. Impaired cued and spatial learning performance and altered cannabinoid CB₁ receptor functionality in the substantia nigra in a rat model of diabetic neuropathy. Behav Brain Res 2016; 303:61-70. [PMID: 26774979 DOI: 10.1016/j.bbr.2016.01.027] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2015] [Revised: 01/06/2016] [Accepted: 01/10/2016] [Indexed: 12/25/2022]
Abstract
Diabetes, and associated diabetic neuropathic pain, impact negatively on cognitive function. However, the underlying mechanisms remain poorly understood. This study investigated neuropathic pain-related behaviour and cognitive function in the rat streptozotocin (STZ) model of diabetes, and assessed cannabinoid1 (CB1) receptor functionality in discrete brain regions. Male Lister-Hooded rats received STZ (60 mg/kgs.c.) or vehicle. Sensory responses were assessed in von Frey and Hargreaves tests. Cognitive, motor and sensorimotor functions were assessed using novel object recognition and Morris water maze tasks. CB1 receptor functionality was assessed by [(35)S]GTPγS (guanosine 5'-O-[gamma-thio]triphosphate) autoradiography. STZ treatment was associated with mechanical allodynia and thermal hypoalgesia. Novel object recognition was unaltered in diabetic rats. STZ treatment was associated with impaired performance in the Morris water maze acquisition phase, but there were no differences in memory retrieval in the probe trial. Stimulus-response learning in the water maze cued trial was also disrupted in STZ-treated rats, possibly indicating sensorimotor deficits. CB1 receptor agonist-stimulated [(35)S]GTPγS binding was attenuated in the substantia nigra of STZ-treated rats but unaltered in the hippocampus. In conclusion, STZ treatment as a model of diabetic neuropathy was associated with specific functional deficits in the Morris water maze, effects which may be related to altered CB1 receptor functionality in the substantia nigra.
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Affiliation(s)
- Orla Moriarty
- Pharmacology and Therapeutics, School of Medicine, Ireland; NCBES Neuroscience Centre, Ireland; Centre for Pain Research, Ireland
| | - Yvonne Lang
- Pharmacology and Therapeutics, School of Medicine, Ireland; NCBES Neuroscience Centre, Ireland; Centre for Pain Research, Ireland
| | - Zubair Idrees
- Department of Opthalmology, Galway University Hospital, Ireland
| | - Brian E McGuire
- School of Psychology, Ireland; NCBES Neuroscience Centre, Ireland; Centre for Pain Research, Ireland; Galway Diabetes Research Centre, National University of Ireland, Galway, Ireland
| | - David P Finn
- Pharmacology and Therapeutics, School of Medicine, Ireland; NCBES Neuroscience Centre, Ireland; Centre for Pain Research, Ireland; Galway Diabetes Research Centre, National University of Ireland, Galway, Ireland.
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Dobretsov M, Backonja MM, Romanovsky D, Stimers JR. Animal Models of Diabetic Neuropathic Pain. ANIMAL MODELS OF PAIN 2011. [DOI: 10.1007/978-1-60761-880-5_9] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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Baluchnejadmojarad T, Roghani M, Khastehkhodaie Z. Chronic treatment of silymarin improves hyperalgesia and motor nerve conduction velocity in diabetic neuropathic rat. Phytother Res 2010; 24:1120-5. [PMID: 19960427 DOI: 10.1002/ptr.3078] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The effect of chronic silymarin (SM) treatment on hyperalgesia, sciatic motor nerve conduction velocity (MNCV) and oxidative stress in streptozotocin (STZ)-diabetic neuropathic rat was evaluated. Rats were divided into control, diabetic, SM-treated control and diabetic, and sodium salisylate (SS)-treated control and diabetic. SM was administered daily at a dose of 100 mg/kg for two months. Finally, hyperalgesia and sciatic MNCV and oxidative stress markers were assessed. Diabetic rats showed a significant deficit in MNCV and markedly exhibited chemical and thermal hyperalgesia, indicating development of diabetic neuropathy. Antioxidant enzyme superoxide dismutase (SOD) level significantly reduced and malondialdehyde (MDA) level significantly increased in diabetic rats compared to control rats; SM treatment significantly ameliorated the alteration in MNCV, hyperalgesia, MDA level and antioxidant enzyme SOD in diabetic rats. These results clearly suggest the potential effect of SM in prevention and treatment of diabetic neuropathy.
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Taherianfard M, Akbarpour M, Jelodar G. Pain sensitivity in diabetic rats during estrous. COMPARATIVE CLINICAL PATHOLOGY 2010. [DOI: 10.1007/s00580-009-0830-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Moreira-Rodrigues M, Quelhas-Santos J, Serrão P, Fernandes-Cerqueira C, Sampaio-Maia B, Pestana M. Glycaemic control with insulin prevents the reduced renal dopamine D1 receptor expression and function in streptozotocin-induced diabetes. Nephrol Dial Transplant 2010; 25:2945-53. [PMID: 20339101 DOI: 10.1093/ndt/gfq150] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
BACKGROUND It was demonstrated in streptozotocin (STZ)-induced diabetic rats that the D(1) receptor agonist failed to promote sodium excretion as a result of reduced renal D(1) receptor expression and decreased receptor G protein coupling. The present study examined the influence of glycaemic control with insulin on the renal D(1) receptor dysfunction in STZ-induced type 1 diabetes. METHODS Renal function, blood pressure, the natriuretic response to 5% volume expansion (VE) and the effects of the D(1) receptor agonist fenoldopam on natriuresis and on Na(+)/K(+)-ATPase activity in renal tubules were evaluated in uninephrectomized and sham-operated Wistar rats treated with STZ and compared with controls and STZ-treated rats made euglycaemic with insulin. D(1) receptor immunohistochemistry and protein abundance by western blot were also determined in all groups. RESULTS Treatment of sham and uninephrectomized rats with STZ caused a 4-fold increase in glucose plasma levels compared to controls and euglycaemic diabetic rats. A blunted natriuretic response to VE was observed in both sham and uninephrectomized hyperglycaemic diabetic rats, and this was accompanied by failure of fenoldopam to increase natriuresis and to inhibit renal Na(+)/K(+)-ATPase activity. In contrast, in both sham and uninephrectomized euglycaemic diabetic rats, the natriuretic response to VE, the fenoldopam-induced natriuresis and the accompanied inhibition of Na(+)/K(+)-ATPase activity were similar to those of the corresponding controls. D(1) receptor immunodetection and protein abundance were reduced in hyperglycaemic diabetic rats, but not in euglycaemic diabetic animals. CONCLUSIONS We conclude that the renal expression and natriuretic response to D(1) receptor activation is compromised in both sham and uninephrectomized rats with STZ-induced diabetes. These abnormalities were prevented by lowering glucose blood levels with insulin, thus providing evidence for the involvement of hyperglycaemia in the disturbances that underlie the compromised dopamine-sensitive natriuresis and increase of blood pressure in type 1 diabetes.
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Affiliation(s)
- Mónica Moreira-Rodrigues
- Nephrology Research and Development Unit, Faculty of Medicine & Hospital S. João EPE, Porto, Portugal
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Tamae A, Nakatsuka T, Koga K, Kato G, Furue H, Katafuchi T, Yoshimura M. Direct inhibition of substantia gelatinosa neurones in the rat spinal cord by activation of dopamine D2-like receptors. J Physiol 2005; 568:243-53. [PMID: 15975975 PMCID: PMC1474768 DOI: 10.1113/jphysiol.2005.091843] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Dopaminergic innervation of the spinal cord is largely derived from the brain. To understand the cellular mechanisms of antinociception mediated by descending dopaminergic pathways, we examined the actions of dopamine (DA) on nociceptive transmission by using behavioural studies and whole-cell patch-clamp recordings from substantia gelatinosa (SG) neurones in the spinal cord. Intrathecal administration of DA increased the mechanical nociceptive threshold and this effect was mimicked by a D2-like receptor agonist, quinpirole, but not by a D1-like receptor agonist, SKF 38393. In current-clamp mode of patch-clamp recordings, bath application of DA hyperpolarized the membrane potential of SG neurones and suppressed action potentials evoked by electrical stimulation of a dorsal root. In voltage-clamp mode, DA induced an outward current that was resistant to TTX, was blocked by the addition of Cs+ or GDP-beta-S in the pipette solution, and was inhibited in the presence of Ba+. The DA-induced current reversed its polarity at a potential close to the equilibrium potential of the K+ channel calculated from the Nernst equation. The DA-induced outward current was mimicked by quinpirole, but not by SKF 38393. The DA-induced outward current was suppressed by a D2-like receptor antagonist, sulpiride, but not by a D1-like receptor antagonist, SCH 23390. In contrast, DA did not cause any significant change in amplitude and frequency of miniature excitatory postsynaptic currents (mEPSCs). These results indicate that DA mainly acts on postsynaptic SG neurones to induce an outward current via G-protein-mediated activation of K+ channels through D2-like receptors. This may be a possible mechanism for antinociception by the descending dopaminergic pathway.
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Affiliation(s)
- Akihiro Tamae
- Department of Physiology, Faculty of Medicine, Saga University, Saga 849-8501, Japan
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Baluchnejadmojarad T, Roghani M, Roghani-Dehkordi F. Antinociceptive effect of Teucrium polium leaf extract in the diabetic rat formalin test. JOURNAL OF ETHNOPHARMACOLOGY 2005; 97:207-210. [PMID: 15707753 DOI: 10.1016/j.jep.2004.10.030] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2003] [Revised: 09/28/2004] [Accepted: 10/11/2004] [Indexed: 05/24/2023]
Abstract
This study was designed to evaluate the analgesic effect of Teucrium polium leaf extract in the diabetic rat formalin test. For this purpose, streptozotocin (STZ)-diabetic rats received intraperitoneal injection of this extract (100 and 200 mg/kg per day) for a period of 2 weeks. It was found out that Teucrium polium-treated diabetic rats exhibited a lower nociceptive score as compared to untreated diabetics. The results may suggest therapeutic potential of Teucrium polium extract for the treatment of diabetic hyperalgesia.
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Fontella FU, Nunes ML, Crema LM, Balk RS, Dalmaz C, Netto CA. Taste modulation of nociception differently affects chronically stressed rats. Physiol Behav 2004; 80:557-61. [PMID: 14741241 DOI: 10.1016/j.physbeh.2003.10.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Stress responses cover a wide range of physiological changes, including alterations in the perception of and response to pain. Animals submitted to repeated stress present altered nociception and this effect is part of this process of adaptation; in addition pleasant and unpleasant experiences with tastes and odors have been shown to affect distinct behavioral aspects, such as pain perception. The aim of the present study is to verify the responses of repeatedly stressed rats (1 h of daily immobilization during 40 days) to pleasant and unpleasant tastes on nociception, when compared to control animals. An increase in the tail-flick latency (TFL) was observed 5 min after exposure to a sweet taste in the control group, whereas no effect was observed in chronically stressed animals. When submitted to an unpleasant taste (5% acetic acid), the chronically stressed group presented an increase in TFL, whereas no effect was observed in the control group. In conclusion, chronically stressed animals present different nociceptive responses to sweet and acid tastes; although control animals suitably respond to a sweet stimulus, stressed animals seem to be more apt to react to the unpleasant stimulus.
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Affiliation(s)
- Fernanda Urruth Fontella
- Departamento de Fisiologia, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul (UFRGS), Rua Domingos Crescêncio 215/101, CEP 90650-090, Porto Alegre, RS, Brazil.
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Marwaha A, Banday AA, Lokhandwala MF. Reduced renal dopamine D1 receptor function in streptozotocin-induced diabetic rats. Am J Physiol Renal Physiol 2003; 286:F451-7. [PMID: 14612382 DOI: 10.1152/ajprenal.00227.2003] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Dopamine, via activation of renal D(1) receptors, inhibits the activities of Na-K-ATPase and Na/H exchanger and subsequently increases sodium excretion. Decreased renal dopamine production and sodium excretion are associated with type I diabetes. However, it is not known whether the response to D(1) receptor activation is altered in type I diabetes. The present study was designed to examine the effect of streptozotocin-induced type I diabetes on renal D(1) receptor expression and function. Streptozotocin treatment of Sprague-Dawley rats caused a fourfold increase in plasma levels of glucose along with a significant decrease in insulin levels compared with control rats. Intravenous administration of SKF-38393, a D(1) receptor agonist, caused a threefold increase in sodium excretion in control rats. However, SKF-38393 failed to produce natriuresis in diabetic rats. SKF-38393 caused a concentration-dependent inhibition of Na-K-ATPase activity in renal proximal tubules of control rats. However, the ability of SKF-38393 to inhibit Na-K-ATPase activity was markedly diminished in diabetic rats. D(1) receptor numbers and protein abundance as determined by [(3)H]SCH-23390 ligand binding and Western blot analysis were markedly reduced in diabetic rats compared with control rats. Moreover, SKF-38393 failed to stimulate GTP gamma S binding in proximal tubular membranes from diabetic rats compared with control rats. We conclude that the natriuretic response to D(1) receptor activation is reduced in type I diabetes as a result of a decrease in D(1) receptor expression and defective receptor G protein coupling. These abnormalities may contribute to the sodium retention associated with type I diabetes.
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MESH Headings
- 2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine/pharmacology
- Animals
- Diabetes Mellitus, Experimental/diagnosis
- Diabetes Mellitus, Experimental/etiology
- Diabetes Mellitus, Experimental/metabolism
- Dopamine Agonists/pharmacology
- Guanosine 5'-O-(3-Thiotriphosphate)/metabolism
- Kidney Tubules, Proximal/chemistry
- Kidney Tubules, Proximal/drug effects
- Kidney Tubules, Proximal/metabolism
- Male
- Rats
- Rats, Sprague-Dawley
- Receptors, Dopamine D1/agonists
- Receptors, Dopamine D1/analysis
- Receptors, Dopamine D1/metabolism
- Sodium-Potassium-Exchanging ATPase/metabolism
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Affiliation(s)
- Aditi Marwaha
- Heart and Kidney Institute, College of Pharmacy, University of Houston, Houston, TX 77204-5041, USA
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