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4.
Transplant Proc ; 48(9): 3095-3098, 2016 Nov.
Article En | MEDLINE | ID: mdl-27932155

BACKGROUND: Allograft renal vein thrombosis is a rare complication of kidney transplantation. Most cases occur in the first 2 weeks after transplantation, but there are cases described many years after the transplant surgery. Allograft loss is the usual outcome. METHODS: We present a case of a renal transplant recipient with allograft renal vein thrombosis associated with deep venous thrombosis of a lower limb, 9 years after transplantation. He was successfully treated with anticoagulation alone, with recovery of allograft function. RESULTS: The patient was given unfractioned heparin and elastic compression stockings. Five days later, the patient recovered diuresis and hemodialysis treatment was discontinued. Doppler ultrasound was done and revealed partial re-permeabilization of allograft renal vein, with maximal velocity of 15 cm/s. After 30 months of follow-up, the patient was maintained on oral anticoagulation with warfarin, and no thromboembolic or hemorrhagic events were documented. The patient's serum creatinine was stable, between 1.6 and 1.8 mg/dL. CONCLUSIONS: Our patient demonstrated that anticoagulation alone and dialytic support might be able to promote total recovery of allograft function after renal vein thrombosis.


Anticoagulants/therapeutic use , Kidney Transplantation/adverse effects , Venous Thrombosis/drug therapy , Allografts , Heparin/therapeutic use , Humans , Male , Middle Aged , Postoperative Complications/drug therapy , Postoperative Complications/etiology , Renal Dialysis , Renal Veins , Stockings, Compression , Transplantation, Homologous , Venous Thrombosis/etiology , Warfarin/therapeutic use
5.
Int J Impot Res ; 28(4): 133-8, 2016 Jul.
Article En | MEDLINE | ID: mdl-27169491

Diabetes Mellitus type 1 is a metabolic disease that predisposes to erectile dysfunction, partly owing to structural and molecular changes in the corpus cavernosum (CC) vessels. The aim of this study was to determine the effects of early treatment with the antioxidant epigallocatechin gallate (EGCG) in cavernous diabetes-induced vascular modifications. Diabetes was induced in two groups of young Wistar rats; one group was treated with EGCG for 10 weeks. A reduction in smooth muscle content was observed in the CC of diabetic rats, which was significantly attenuated with EGCG consumption. No differences were observed among groups, neither in the expression of VEGF assayed by western blotting nor in the immunofluorescent labeling of vascular endothelial growth factor (VEGF) and its receptors (VEGFR1 and VEGFR2). VEGFR2 was restricted to the endothelium, whereas VEGF and VEGFR1 co-localized in the smooth muscle layer. With regard to the Angiopoietin/Tie-2 system, no quantitative differences in Angiopoietin 1 were observed among the experimental groups. Ang1 localization was restricted to the smooth muscle layer, and receptor Tie2 and Angiopoietin 2 were both expressed in the endothelium. In brief, our results suggest that EGCG consumption prevented diabetes-induced loss of cavernous smooth muscle but does not affect vascular growth factor expression in young rats.


Catechin/analogs & derivatives , Diabetes Mellitus, Experimental/complications , Diabetes Mellitus, Type 1/complications , Diabetic Angiopathies/drug therapy , Penis/drug effects , Animals , Catechin/therapeutic use , Diabetes Mellitus, Experimental/metabolism , Diabetes Mellitus, Experimental/pathology , Diabetes Mellitus, Type 1/metabolism , Diabetes Mellitus, Type 1/pathology , Diabetic Angiopathies/metabolism , Diabetic Angiopathies/pathology , Male , Muscle, Smooth/drug effects , Muscle, Smooth/metabolism , Muscle, Smooth/pathology , Penis/metabolism , Penis/pathology , Rats , Rats, Wistar , Vascular Endothelial Growth Factor A/metabolism , Vascular Endothelial Growth Factor Receptor-1/metabolism , Vascular Endothelial Growth Factor Receptor-2/metabolism
6.
Neuropharmacology ; 107: 49-57, 2016 08.
Article En | MEDLINE | ID: mdl-26965218

The involvement of transient receptor vanilloid type-1 (TRPV1) channels in pain modulation by the brain remains understudied. The rostroventromedial medulla (RVM) plays a key role in conveying to the spinal cord pain modulatory influences triggered in higher brain centres, with co-existence of inhibitory (antinociceptive) and facilitatory (pronociceptive) effects. In spite of some reports of TRPV1 expression in the RVM, it remains unknown if endovanilloid signalling plays a direct role in local pain modulation. Here we used a model of diabetic neuropathy, the streptozotocin (STZ)-diabetic rat, to study the role of endovanilloid signalling in RVM-mediated pain modulation during chronic pain. Four weeks after diabetes induction, the levels of TRPV1 mRNA and fatty acid amide hydrolase (FAAH), a crucial enzyme for endovanilloid catabolism, in the RVM of STZ-diabetic rats were higher than control. The RVM of STZ-diabetic rats presented decreased levels of several TRPV1 endogenous ligands, namely anandamide (AEA), palmitoylethanolamide (PEA) and oleoylethanolamide (OEA). Administration of capsaicin (a TRPV1 agonist) into the RVM decreased nociceptive behavioural responses in the inflammatory phase of the formalin test (phase 2). These findings suggest that diabetic neuropathy induces plastic changes of RVM endovanilloid signalling, indicating that TRPV1 may be a putative target for pain modulation in this chronic pain condition.


Amidohydrolases/metabolism , Diabetes Mellitus, Experimental/metabolism , Diabetic Neuropathies/metabolism , Medulla Oblongata/metabolism , Nociceptive Pain/metabolism , TRPV Cation Channels/metabolism , Amides , Analgesics, Non-Narcotic/pharmacology , Animals , Arachidonic Acids/metabolism , Capsaicin/pharmacology , Chronic Pain/drug therapy , Chronic Pain/metabolism , Diabetic Neuropathies/drug therapy , Endocannabinoids/metabolism , Ethanolamines/metabolism , Formaldehyde , Male , Nociceptive Pain/drug therapy , Oleic Acids/metabolism , Palmitic Acids/metabolism , Polyunsaturated Alkamides/metabolism , RNA, Messenger/metabolism , Rats, Wistar , TRPV Cation Channels/agonists
8.
ACS Chem. Neurosci ; 7(8): p. 1130-1140, 2016.
Article | SES-SP, SESSP-IBPROD, SES-SP | ID: but-ib14534

Kyotorphin (KTP) is an endogenous peptide with analgesic properties when administered into the central nervous system (CNS). Its amidated form (L-Tyr-L-Arg-NH2; KTP-NH2) has improved analgesic efficacy after systemic administration, suggesting blood-brain barrier (BBB) crossing. KTP-NH2 also has anti-inflammatory action impacting on microcirculation. In this work, selected derivatives of KTP-NH2 were synthesized to improve lipophilicity and resistance to enzymatic degradation while introducing only minor changes in the chemical structure: N-terminal methylation and/or use of D amino acid residues. Intravital microscopy data show that KTP-NH2 having a D-Tyr residue, KTP-NH2-DL, efficiently decreases the number of leukocyte rolling in a murine model of inflammation induced by bacterial lipopolysaccharide (LPS): down to 46% after 30 min with 96 mu M KTP-NH2-DL. The same molecule has lower ability to permeate membranes (relative permeability of 0.38) and no significant activity in a behavioral test which evaluates thermal nociception (hot-plate test). On the contrary, methylated isomers at 96 mu M increase leukocyte rolling up to nearly 5-fold after 30 min, suggesting a proinflammatory activity. They have maximal ability to permeate membranes (relative permeability of 0.8) and induce long-lasting antinociception


Anesthesiology , Pharmacology , Allergy and Immunology
10.
Neuroscience ; 304: 228-39, 2015 Sep 24.
Article En | MEDLINE | ID: mdl-26210577

Spinal 5-HT3 receptor (5-HT3R) has been implicated in chronic pain development. The extent to which 5-HT3R contributes to spinal sensitization and diabetic neuropathic pain (DNP) remains elusive and the mechanisms subserving the effects of 5-HT3R activation on spinal pain processing during chronic pain are still unclear. In this study, we evaluated the contribution of spinal 5-HT3R to pain facilitation and spinal sensitization during DNP, exploiting the role of GABAAR-mediated neurotransmission and glial activation in the effects elicited by intrathecal administration of a 5-HT3R antagonist. Mechanical nociception was evaluated by paw pressure test in streptozotocin (STZ)-diabetic and control rats after intrathecal (i.t.) administration of a 5-HT3R antagonist (Y25130). The spinal activation of extracellular signal-regulated kinases (ERKs) pathway and the expression of 5-HT3R, glial fibrillary acidic protein (GFAP; marker of astroglia activation) and ionized calcium binding adaptor molecule 1 (IBA-1; marker of microglia activation) were evaluated at the peak maximum effect of Y25130. The involvement of GABAAR-mediated neurotransmission in the behavioral pain effect of Y25130, was assessed in STZ-diabetic animals receiving i.t. administrations of muscimol (GABAAR agonist). Intrathecal administration of Y25130 reverted mechanical hyperalgesia and decreased the activation of ERKs in STZ-diabetic rats, while no effects were observed in control animals. The spinal activation of GABAAR by i.t. administration of muscimol abolished Y25130-driven antinociception. The expression of IBA-1, GFAP and 5-HT3R was unaltered by treatment. These findings point to a GABA-mediated pronociceptive role of spinal 5-HT3R during DNP.

11.
Acta Anaesthesiol Scand ; 59(7): 822-9, 2015 Aug.
Article En | MEDLINE | ID: mdl-25950123

BACKGROUND: General anesthetics (GA) are well known for the ability to induce a state of reversible loss of consciousness and unresponsiveness to painful stimuli. However, evidence from animal models and clinical studies show that GA exposure may induce behavioral changes beyond acute effects. Most research and concerns are focused on changes in cognition and memory. METHODS: We will look at effects of GA on behavior that is mediated by the dopaminergic system. RESULTS: Pharmacological resemblance of GA with drugs of abuse, and the complexity and importance of dopaminergic systems in both reward seeking and addictive illnesses make us believe that it deserves an overview about what is already known and what matters to us as healthcare workers and specifically as anesthesiologists. CONCLUSION: A review of available evidence strongly suggests that there may be a link between the effects of GA on the brain and substance abuse, partly explained by their influence on the dopaminergic system.


Anesthetics, General/pharmacology , Behavior, Addictive/physiopathology , Brain/drug effects , Dopamine Agents/pharmacology , Dopamine/pharmacology , Substance-Related Disorders/physiopathology , Animals , Brain/physiopathology , Humans
12.
Clin Genet ; 88(5): 462-7, 2015 Nov.
Article En | MEDLINE | ID: mdl-25307721

Alport syndrome (AS) is caused by pathogenic mutations in the genes encoding α3, α4 or α5 chains of collagen IV (COL4A3/COL4A4/COL4A5), resulting in hematuria, chronic renal failure (CRF), sensorineural hearing loss (SNHL) and ocular abnormalities. Mutations in the X-linked COL4A5 gene have been identified in 85% of the families (XLAS). In this study, 22 of 60 probands (37%) of unrelated Portuguese families, with clinical diagnosis of AS and no evidence of autosomal inheritance, had pathogenic COL4A5 mutations detected by Sanger sequencing and/or multiplex-ligation probe amplification, of which 12 (57%) are novel. Males had more severe and earlier renal and extrarenal complications, but microscopic hematuria was a constant finding irrespective of gender. Nonsense and splice site mutations, as well as small and large deletions, were associated with younger age of onset of SNHL in males, and with higher risk of CRF and SNHL in females. Pathogenic COL4A3 or COL4A4 mutations were subsequently identified in more than half of the families without a pathogenic mutation in COL4A5. The lower than expected prevalence of XLAS in Portuguese families warrants the use of next-generation sequencing for simultaneous COL4A3/COL4A4/COL4A5 analysis, as first-tier approach to the genetic diagnosis of collagen type IV-related nephropathies.


Collagen Type IV/genetics , Mutation , Nephritis, Hereditary/diagnosis , Nephritis, Hereditary/genetics , Adolescent , Adult , Aged , Child , Child, Preschool , DNA Mutational Analysis , Exome , Female , Genetic Association Studies , Humans , Infant , Male , Middle Aged , Nephritis, Hereditary/metabolism , Portugal , Young Adult
13.
Brain Res Bull ; 110: 68-75, 2015 Jan.
Article En | MEDLINE | ID: mdl-25522867

Spinal cord neurons located in laminae I-III respond to nociceptive stimuli and participate in the transmission of painful information to the brain. In the present study we evaluated if nociceptive laminae I-III neurons are affected by oxidative stress damage in a model of diabetic neuropathic pain (DNP), the streptozotocin-induced diabetic rat (STZ rat). Additionally, we evaluated the effects of a preventive antioxidant treatment with epigallocatechin-gallate (EGCG) in nociceptive neuronal activation and behavioural signs of DNP. Three days after diabetes induction, a treatment protocol of STZ rats with an aqueous solution of EGCG in the drinking water was initiated. Ten weeks after the onset of treatment, the spinal cords were immunoreacted against validated markers of oxidative stress damage (8-hydroxy-2'-deoxyguanosine; 8-OHdG) and of nociceptive neuronal activation (Fos). Mechanical hypersensitivity was assessed before and after EGCG treatment. Untreated STZ rats presented increased levels of 8-OHdG immunoreaction, higher numbers of Fos-immunoreacted neurons and high levels of co-localization of 8-OHdG and Fos in laminae I-III. Treatment with EGCG normalized the increase of the above mentioned parameters and ameliorated mechanical hypersensitivity. The present study shows that nociceptive neurons in spinal cord laminae I-III exhibit oxidative stress damage during diabetic neuropathy, which probably affects ascending pain transmission during DNP. The neurobiological mechanisms and translational perspectives of the beneficial effects of a preventive and sustained EGCG treatment in DNP need to be evaluated in the future.


Antioxidants/pharmacology , Catechin/analogs & derivatives , Diabetic Neuropathies/drug therapy , Nociceptors/drug effects , Oxidative Stress/drug effects , Spinal Cord/drug effects , 8-Hydroxy-2'-Deoxyguanosine , Animals , Catechin/pharmacology , Deoxyguanosine/analogs & derivatives , Deoxyguanosine/metabolism , Diabetes Mellitus, Experimental/drug therapy , Diabetes Mellitus, Experimental/physiopathology , Diabetic Neuropathies/physiopathology , Hyperalgesia/drug therapy , Hyperalgesia/physiopathology , Immunohistochemistry , Male , Neuralgia/drug therapy , Neuralgia/physiopathology , Neuroprotective Agents , Nociceptors/physiology , Oxidative Stress/physiology , Proto-Oncogene Proteins c-fos/metabolism , Rats, Wistar , Spinal Cord/physiopathology , Touch
14.
Transpl Infect Dis ; 16(6): 1007-11, 2014 Dec.
Article En | MEDLINE | ID: mdl-25296529

Campylobacter species are the leading cause of acute bacterial diarrhea in industrialized countries. However, bacteremia is detected in <1% of patients with Campylobacter enteritis and is most likely to occur in patients who are immunocompromised or of older age. To our knowledge, only 2 cases of Campylobacter jejuni bacteremia have been reported in renal transplant recipients (RTRs). We present a case of an RTR with C. jejuni bacteremia presenting as self-limiting diarrhea followed by fever and cellulitis. The patient was successfully treated with a 2-week course of imipenem and developed no other complications. We review all cases of Campylobacter bacteremia in RTRs, and discuss clinical presentation and treatment of this potentially fatal disease.


Bacteremia/microbiology , Campylobacter Infections/etiology , Kidney Transplantation/adverse effects , Anti-Bacterial Agents/therapeutic use , Humans , Imipenem/therapeutic use , Male , Middle Aged
15.
Transplant Proc ; 46(6): 1718-22, 2014.
Article En | MEDLINE | ID: mdl-25131020

INTRODUCTION: Renal transplantation (RT) in patients infected with human immunodeficiency virus (HIV) has significantly improved under the advent of combined antiretroviral therapy (cART). The authors describe their experience in RT in patients with HIV from September 2010 to June 2013. CASES REPORT: Four patients underwent transplantation (3 with HIV-1 and 1 with HIV-2), three patients were male, and one was black. None were coinfected with hepatitis B virus (HBV) or hepatitis C virus (HCV). Etiology of kidney disease was HIV-associated nephropathy (2 patients), immunoglobulin (Ig)A nephropathy, and unknown. Average age at RT was 51 (range, 41-63) years. No patient was of high immunologic risk. Immunosuppression consisted of basiliximab for induction and prednisolone, tacrolimus (TAC), and mycophenolate mofetil for maintenance. TAC levels varied considerably in the early days (8.5-46 ng/mL), requiring major adjustments in TAC dose. Only the HIV-2 patient had delayed graft function. The follow-up of patients with HIV-1 was 37, 19, and 16 months, and 3 months for the HIV-2 patient. CD4+ T cells decreased in the early days after transplantation with subsequent improvement, along with persistent virological suppression. In the HIV-1 group there were no major infectious, cardiovascular, or neoplastic complications. Nevertheless, the HIV-2 patient died 3 months after RT due to H1N1 pneumonia complicated by pulmonary aspergillosis. Average estimated (CKD- EPI) glomerular filtration rate (eGFR) at 6 months was 85.6 mL/min/1.73 m(2). CONCLUSION: Besides the difficulty in adjusting calcineurin inhibitors levels due to its interaction with antiretroviral therapy, namely with protease inhibitors, no patient had acute rejection. Furthermore, all patients presented an excellent control of viro-immunologic parameters. At the last follow-up neither cardiovascular events nor neoplastic complications were observed. Our results highlight the favorable outcome of RT in HIV-1-infected patients. The HIV-2 patient died due to severe infection, and the clinical management and potential benefit of RT in HIV-2-infected patients needs further study.


HIV Infections/complications , Kidney Transplantation , Adult , Anti-Retroviral Agents/therapeutic use , CD4 Lymphocyte Count , Delayed Graft Function , Female , Glomerular Filtration Rate , HIV Infections/drug therapy , HIV-1 , HIV-2 , Humans , Immunosuppressive Agents/therapeutic use , Influenza A Virus, H1N1 Subtype , Male , Middle Aged , Pneumonia, Viral/virology
16.
Transplant Proc ; 46(6): 1789-93, 2014.
Article En | MEDLINE | ID: mdl-25131038

This study evaluated the relationship between intraoperative hemodynamic instability (IOHI) and the development of calcineurin inhibitor (CNI) toxicity in the early postoperative period after liver transplantation (LT). Eighty-two patients were enrolled during a 1-year period and a 3-month follow-up. IOHI, requiring continuous infusion of vasopressors, was observed in 31 patients (38%, group 1; control group 2, n = 51). Acute kidney injury (AKI) developed in 28 patients (52% in group 1 vs 24% in group 2, P = .02), and CNI-related neurotoxicity (CNI-NT) in 26 (48% in group 1 vs 22% in group 2, P = .03). Group 1 patients received mainly deceased donor grafts (87% vs 57% in group 2, P < .001). An independent association between IOHI and CNI-NT (P = .029) and AKI (P = .016) was observed. The receiver-operator characteristic curve revealed an area under the curve of 0.63 for IHI (sensitivity 56%; specificity 75%) and 0.65 for AKI (sensitivity 56%; specificity 70.2%). In conclusion, patients undergoing LT with IOHI may be more prone to developing CNI-NT and AKI in the early postoperative period.


Calcineurin Inhibitors/adverse effects , Hypotension , Intraoperative Complications , Liver Transplantation , Postoperative Complications/chemically induced , Acute Kidney Injury/chemically induced , Adult , Female , Follow-Up Studies , Hemodynamics , Humans , Hypertension/chemically induced , Hypotension/drug therapy , Hypotension/etiology , Intraoperative Complications/drug therapy , Intraoperative Complications/etiology , Male , Middle Aged , Neurotoxicity Syndromes/etiology , Prospective Studies , ROC Curve , Treatment Outcome , Vasoconstrictor Agents/therapeutic use
17.
Transplant Proc ; 46(6): 1812-8, 2014.
Article En | MEDLINE | ID: mdl-25131044

In this prospective study, we comparatively evaluated the accuracy of several biomarkers of acute kidney injury (AKI) on predicting its occurrence after liver transplantation (LT). The parameters evaluated were urinary tubular enzymes (γ-glutamyl transpeptidase [γGT], alkaline phosphatase, and urinary lactate dehydrogenase) and urinary neutrophil gelatinase-associated lipocalin. These parameters were evaluated both as isolated variables and divided by urinary creatinine. Samples were collected by the end of surgery (determination 1) and at 12 to 24 hours after surgery (determination 2). The study endpoint was the development of AKI. The study was performed over a 1-year period, and 61 of 77 patients were enrolled (main exclusion criteria were perioperative death, previous known renal failure, and insufficient data for analysis). Of these 61 patients, AKI was observed in 19 (group 1). The main relevant parameter to predict AKI was the absolute value of urinary γGT at determination 1 (area under the curve, 0.74; specificity, 72.5%; sensitivity, 70.3%; cutoff, 36 U/mL). Urinary neutrophil gelatinase-associated lipocalin was not as accurate; the best predicted value for this parameter was absolute value at D1 with an area under the curve of 0.5 (specificity, 84.2%; sensitivity, 35.7%; cutoff value, 44.6 ng/mL). We concluded that the absolute value of urinary γGT evaluated at the end of LT was the most accurate parameter to predict AKI in our cohort. Urinary enzyme levels must be taken into account in future analysis of this issue.


Acute Kidney Injury/diagnosis , Lipocalins/urine , Liver Transplantation , Postoperative Complications/diagnosis , gamma-Glutamyltransferase/urine , Acute Kidney Injury/enzymology , Acute Kidney Injury/etiology , Acute Kidney Injury/urine , Adult , Biomarkers/urine , Clinical Enzyme Tests , Creatinine/urine , Female , Humans , L-Lactate Dehydrogenase/urine , Logistic Models , Male , Middle Aged , Postoperative Complications/enzymology , Postoperative Complications/urine , Predictive Value of Tests , Prospective Studies , Sensitivity and Specificity
18.
Neuropharmacology ; 85: 151-7, 2014 Oct.
Article En | MEDLINE | ID: mdl-24887171

The TRPV1 (vanilloid 1) channel is best known for its role in sensory transmission in the nociceptive neurons of the peripheral nervous system. Although first studied in the dorsal root ganglia as the receptor for capsaicin, TRPV1 has been recently recognized to have a broader distribution in the central nervous system, where it is likely to constitute an atypical neurotransmission system involved in several functions through modulation of both neuronal and glial activities. The endovanilloid-activated brain TRPV1 channels seem to be involved in somatosensory, motor and visceral functions. Recent studies suggested that TRPV1 channels also account for more complex functions, as addiction, anxiety, mood and cognition/learning. However, more studies are needed before the relevance of TRPV1 in brain activity can be clearly stated. This review highlights the increasing importance of TRPV1 as a regulator of brain function and discusses possible bases for the future development of new therapeutic approaches that by targeting brain TRPV1 receptors might be used for the treatment of several neurological disorders.


Brain/physiology , Brain/physiopathology , TRPV Cation Channels/metabolism , Animals , Humans , Neuroglia/physiology , Neuronal Plasticity/physiology , Neurons/physiology , Pain Perception/physiology
19.
Ann Phys Rehabil Med ; 56(7-8): 576-94, 2013 Oct.
Article En | MEDLINE | ID: mdl-24140440

BACKGROUND: Physical exercise is widely prescribed in rehabilitation programmes for low back pain (LBP). The LBP patient often asks whether this physical activity should be maintained and, in some cases, whether he/she should resume or take up a sport. PURPOSE: To answer these two questions by performing a review of literature on the efficacy and safety of post-rehabilitation physical activities and sport in LBP. METHOD: A systematic search of computerized databases from 1990 to 2011 was performed using grade 1 to 4 studies articles in English or French. RESULTS: Of the 2583 initially identified articles, 121 articles were analysed. Globally, physical activities like swimming, walking and cycling, practiced at moderate-intensity help to maintain fitness and control pain. Inconsistent results were found for avoiding recommendations according to the nature of PA. Sport activities, except ballgames, can be easily resume or take up as tennis, horse riding, martial arts, gymnastics, golf and running which can be performed at a lower intensity or lower competitive level. DISCUSSION AND CONCLUSION: Moderate but regular physical activity helps to improve fitness and does not increase the risk of acute pain in chronic LBP patients. The resumption of a sport may require a number of adaptations; dialogue between the therapist and the sports trainer is therefore recommended.


Chronic Pain/rehabilitation , Low Back Pain/rehabilitation , Sports , Humans , Motor Activity
20.
Brain Res Bull ; 96: 39-44, 2013 Jul.
Article En | MEDLINE | ID: mdl-23644033

Neuropathic pain is one of the most frequent complications of diabetes. The increased neuronal activity of primary afferents and spinal cord neurons in streptozotocin (STZ)-diabetic rats increases the recruitment of the nociceptive ascending pathways, which may affect the activity of pain control circuits in the brain. This study aimed to characterize the electrophysiological responses of neurons of the rostroventromedial medulla (RVM), a key brainstem area involved in descending modulation of nociceptive neurotransmission at the spinal cord, in STZ-diabetic rats. Spontaneous and noxious-evoked activity of ON-like cells (pain facilitatory cells) and OFF-like cells (pain inhibitory cells) in the RVM were analyzed by single cell extracellular electrophysiological recordings in STZ-diabetic rats with behavioral signs of diabetic neuropathic pain 4 weeks after diabetes induction and in age-matched non-diabetic controls (CTRL). The electrophysiological analysis revealed an increase in the spontaneous activity of RVM pronociceptive ON-like cells in STZ-diabetic rats when compared to CTRL. On the contrary, the number of active antinociceptive OFF-like cells was significantly lower in the STZ-diabetic rats and their spontaneous activity was decreased when compared with CTRL. Overall, the changes in the activity of RVM pain modulatory cells in STZ-diabetic rats point to enhancement of descending pain facilitation. Based on similar results obtained at the RVM in traumatic neuropathic pain models, the changes in the electrophysiological responses of RVM in STZ-diabetic rats may account for exacerbated pain-like behaviors in diabetic neuropathy.


Diabetes Mellitus, Experimental/diagnostic imaging , Diabetic Neuropathies/metabolism , Neuralgia/metabolism , Animals , Diabetes Mellitus, Experimental/complications , Diabetic Neuropathies/etiology , Disease Models, Animal , Male , Neuralgia/etiology , Neuralgia/physiopathology , Neurons/metabolism , Pain Measurement/methods , Rats , Rats, Wistar , Streptozocin , Synaptic Transmission/physiology , Ultrasonography
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