NIlberto Nascimento | Universidade Estadual do Ceara (original) (raw)

Papers by NIlberto Nascimento

PubMed, 2019

The association between hypertension and obesity has been shown to be an important cause of kidne... more The association between hypertension and obesity has been shown to be an important cause of kidney disease. We aimed to investigate the impact of a high-fat diet (HFD) administered in spontaneously hypertensive rats (SHR) after weaning in renal morphology and functional parameters. Male post-weaned SHR were divided into two groups: standard control diet (CD) (3% lipids; n = 8) or HFD (30% lipids; n = 8) during 8 weeks. The group HFD showed an increase in serum triglycerides (HFD: 96 ± 7 vs. CD: 33 ± 2 mg/dL) and glucose intolerance (HFD: 185 ± 7 vs. CD: 149 ± 4 mg/dL/min). Moreover, the HFD also showed an increase in almost 90% of the periepididymal and retroperitoneal adiposity. There was no difference in arterial blood pressure between groups. Renal morphofunctional parameters were decreased in HFD group for glomerular tuft area and diameter (4733 ± 65 µm2 and 82 ± 1 µm, respectively) when compared with CD group (5289 ± 171 µm2 and 88 ± 2 µm, respectively). HFD also showed a decrease of 50% of the renal function, which was associated with higher renal extracellular matrix and lipid deposition. Therefore, our data suggest that HFD since early period of life may contribute to renal damage in adults with hypertension, and this impairment can be associated with increased renal lipid accumulation.

Brazilian Journal of Biology, Aug 1, 2013

Uroguanylin (UGN) is an endogenous peptide that acts on membrane-bound guanylate cyclase receptor... more Uroguanylin (UGN) is an endogenous peptide that acts on membrane-bound guanylate cyclase receptors of intestinal and renal cells increasing cGMP production and regulating electrolyte and water epithelial transport. Recent research works demonstrate the expression of this peptide and its receptor in the central nervous system. The current work was undertaken in order to evaluate modifications of electroencephalographic spectra (EEG) in anesthetized Wistar rats, submitted to intracisternal infusion of uroguanylin (0.0125 nmoles/min or 0.04 nmoles/min). The current observations demonstrate that 0.0125 nmoles/min and 0.04 nmoles/min intracisternal infusion of UGN significantly enhances amplitude and frequency of sharp waves and evoked spikes (p = 0.03). No statistical significance was observed on absolute alpha and theta spectra amplitude. The present data suggest that UGN acts on bioelectrogenesis of cortical cells by inducing hypersynchronic firing of neurons. This effect is blocked by nedocromil, suggesting that UGN acts by increasing the activity of chloride channels.

International braz j urol, 2012

The aim of this study was to evaluate the relaxation in vitro of cavernous smooth muscle induced ... more The aim of this study was to evaluate the relaxation in vitro of cavernous smooth muscle induced by a new NO donor of the complex nitrosil-ruthenium, named trans-[Ru(NH3) 4 (caffeine)(NO)]C 13 (Rut-Caf) and sodium nitroprusside (SNP). Materials and Methods: The tissues, immersed in isolated bath systems, were pre-contracted with phenilephrine (PE) (1 µM) and then concentration-response curves (10-12-10-4 M) were obtained. To clarify the mechanism of action involved, it was added to the baths ODQ (10 µM, 30 µM), oxyhemoglobin (10 µM), L-cysteine (100 µM), hydroxicobalamine (100 µM), glibenclamide, iberotoxin and apamine. Tissue samples were frozen in liquid nitrogen to measure the amount of cGMP and cAMP produced. Results: The substances provoked significant relaxation of the cavernous smooth muscle. Both Rut-Caf and SNP determined dose-dependent relaxation with similar potency (pEC 50) and maximum effect (E max). The substances showed activity through activation of the soluble guanylyl cyclase (sGC), because the relaxations were inhibited by ODQ. Oxyhemoglobin significantly diminished the relaxation effect of the substances. L-cysteine failed to modify the relaxations caused by the agents. Hydroxicobalamine significantly diminished the relaxation effect of Rut-Caf. Glibenclamide significantly increased the efficacy of Rut-Caf (pEC 50 4.09 x 7.09). There were no alterations of potency or maximum effect of the substances with the addition of the other ion channel blockers. Rut-Caf induced production of significant amounts of cGMP and cAMP during the relaxation process. Conclusions: In conclusion, Rut-Caf causes relaxation of smooth muscle of corpus cavernosum by means of activation of sGC with intracellular production of cGMP and cAMP; and also by release of NO in the intracellular environment. Rut-Caf releases the NO free radical and it does not act directly on the potassium ion channels. INTROdUCTION Human corpus cavernosum contains vascular smooth muscle, kept under tonic contraction induced by adrenergic excitation to maintain penile flaccidity (1). Nitric oxide (NO), the endothelium-derived relaxation factor discovered by Palmer and Moncada, is the main inhibitory neu

Toxicon, 2006

Renal changes determined by Lys49 myotoxin I (BmTx I), isolated from Bothrops moojeni are well kn... more Renal changes determined by Lys49 myotoxin I (BmTx I), isolated from Bothrops moojeni are well known. The scope of the present study was to investigate the possible mechanisms involved in the production of these effects by using indomethacin (10 mg/mL), a non-selective inhibitor of cyclooxygenase, and tezosentan (10 mg/mL), an endothelin antagonist. By means of the method of mesenteric vascular bed, it has been observed that B. moojeni myotoxin (5 mg/mL) affects neither basal perfusion pressure nor phenylephrine-preconstricted vessels. This fact suggests that the increase in renal perfusion pressure and in renal vascular resistance did not occur by a direct effect on renal vasculature. Isolated kidneys from Wistar rats, weighing 240-280 g, were perfused with Krebs-Henseleit solution. The infusion of BmTx-I increased perfusion pressure, renal vascular resistance, urinary flow and glomerular filtration rate. Sodium, potassium and chloride tubular transport was reduced after addition of BmTx-I. Indomethacin blocked the effects induced by BmTx-I on perfusion pressure and renal vascular resistance, however, it did not revert the effect on urinary flow and sodium, potassium and chloride tubular transport. The alterations of glomerular filtration rate were inhibited only at 90 min of perfusion. The partial blockade exerted by indomethacin treatment showed that prostaglandins could have been important mediators of BmTx-I renal effects, but the participation of other substances cannot be excluded. The blockage of all renal alterations observed after tezosentan treatment support the hypothesis that endothelin is the major substance involved in the renal pathophysiologic alterations promoted by the Lys49 PLA 2 myotoxin I, isolated from B. moojeni. In conclusion, the rather intense renal effects promoted by B. moojeni myotoxin-I were probably caused by the release of renal endothelin, interfering with the renal parameters studied.

Toxicon, 2011

Natural intoxication of livestock by ingestion of Ipomoea asarifolia leaves has been reported to ... more Natural intoxication of livestock by ingestion of Ipomoea asarifolia leaves has been reported to occur widely in Brazil. Previous studies carried out by our research group provided strong evidence that a lectin could be involved with the toxic properties of I. asarifolia. To reinforce this hypothesis, a lectin-enriched fraction (LEF) was isolated from I. asarifolia leaves and its toxic effects were assessed. Leaves of I. asarifolia were excised from plants growing widely in the field, mechanically wounded and maintained in a chamber at 25 AE 3 C for 72 h in the dark, under near 100% relative humidity. The leaf proteins were extracted, ammonium sulfate precipitated, chromatographed on DEAE-cellulose and Phenyl-Sepharose to produce LEF that under SDS-PAGE showed a molecular mass of 44.0 kDa and after N-terminal amino acid analysis a primary sequence composed of AGYTPVLDIGAEVLAAGEPY. The in vivo toxicity of LEF assessed by intraorbital injection in mice showed induced severe uncoordinated movements without death. LEF reduced the muscular contraction in a dose depend way and at 29.8 mg/mL (CE 50) it produces 50% inhibition of contraction, suggesting that LEF blunts autonomic neurotransmission. Isolated rat kidneys were perfused with LEF and no effects on the perfusion pressure or renal vascular resistance were observed, but urinary flow and glomerular filtration rate increased. Moreover, the percentage of tubular transport of Na þ , K þ and Cl À decreased. Histological examination of the kidneys perfused with LEF exhibited little alterations. These toxic effects observed above were concomitant with the increase of LEF hemagglutination activity, which strongly suggest that one of the toxic principles of I. asarifolia is a lectin present in its leaves.

Proceedings of the National Academy of Sciences, 2005

Endothelial dysfunction (ED) is an early feature of cardiovascular risk and diabetes. Hyperglycem... more Endothelial dysfunction (ED) is an early feature of cardiovascular risk and diabetes. Hyperglycemia and hyperlipidemia are causative factors. Excessive endothelial mitochondrial superoxide (ROS) production with hyperglycemia and hyperlipidemia is a key mechanism. Inositol components of an insulin inositol glycan mediator, d -chiro-inositol (DCI) and 3- O -methyl DCI (pinitol), decrease hyperglycemia and hyperlipidemia. We tested whether these, myoinositol and dibutyryl DCI (db-DCI), would prevent or reverse ED in diabetic rats and rabbits. Oral inositols reduced hyperglycemia and hypertriglyceridemia with different potencies and prevented ED in rat aortic rings and mesenteric beds. Inositols added in vitro to five diabetic tissues reversed ED. Relaxation by Ach, NO, and electrical field stimulation was potentiated by inositols in vitro in rabbit penile corpus cavernosa. Inositols in vitro restored impaired contraction by the eNOS inhibitor l -NAME and increased NO effectiveness. DCI...

Journal of Applied Microbiology, 2008

International Journal of Impotence Research, 2004

$Research paper thumbnail of In vitro and in vivo leishmanicidal activity of Dysoxylum binectariferum and its fractions against Leishmania donovani$

Phytomedicine, 2007

In vitro and in vivo leishmanicidal activity of a ruthenium nitrosyl complex against Leishmania (... more In vitro and in vivo leishmanicidal activity of a ruthenium nitrosyl complex against Leishmania (Viannia) braziliensis Nilberto Robson Falcão do Nascimento a, *; Francisco Léo Nascimento de Aguiar a ; Cláudia

Journal of Photochemistry and Photobiology B: Biology, 2016

Background and Objective-Over the last decade we have seen an increased interest in the use of Lo... more Background and Objective-Over the last decade we have seen an increased interest in the use of Low-Level Laser Therapy (LLLT) in diseases that involve increased oxidative stress. It is well established that hyperglycemia in diabetes elicits a rise in reactive oxygen species (ROS) production but the effect of LLLT remains unclear. This study aimed to investigate whether LLLT was able to improve oxidative/nitrosative stress parameters in the wound healing process in diabetic mice. Study Design/Materials and Methods-Twenty male mice were divided into four groups: non-irradiated control (NIC), irradiated control (IC), non-irradiated and diabetic (NID), irradiated and diabetic (ID). Diabetes was induced by administration of streptozotocin. Wounds were created 120 days after the induction of diabetes in groups IC and ID and these groups were irradiated daily for 5 days (superpulsed 904 nm laser, average power 40 mW, 60 sec). All animals were sacrificed 1 day after the last irradiation and histology, collagen amount, catalase activity, nitrite and thiobarbituric acid reactive substances (TBARS) were measured.

Journal of Applied Toxicology, 2011

Brazilian Journal of Medical and Biological Research

The transport of myo-inositol is the main mechanism for the maintenance of its high intracellular... more The transport of myo-inositol is the main mechanism for the maintenance of its high intracellular levels. We aimed to measure the mRNA and protein levels of myo-inositol cotransporters in the sciatic nerve (SN) and dorsal root ganglia (DRG) during experimental diabetes. Streptozotocin-induced (STZ; 4, 8, and 12 weeks; 65 mg/kg; ip) diabetic rats (DB) and age-matched euglycemic (E) rats were used for the analysis of mRNA and protein levels of sodium myo-inositol cotransporters 1, 2 (SMIT1, SMIT2) or H + /myo-inositol cotransporter (HMIT). There was a significant reduction in the mRNA levels for SMIT1 in the SN and DRG (by 36.9 and 31.0%) in the 4-week DB (DB4) group compared to the E group. SMIT2 was not expressed in SN. The mRNA level for SMIT2 was up-regulated only in the DRG in the DB4 group. On the other hand, the protein level of SMIT1 decreased by 42.5, 41.3, and 44.8% in the SN after 4, 8, and 12 weeks of diabetes, respectively. In addition, there was a decrease of 64.3 and 58.0% of HMIT in membrane and cytosolic fractions, respectively, in the SN of the DB4 group. In the DRG, there was an increase of 230 and 86.3% for SMIT1 and HMIT, respectively, in the DB12 group. The levels of the main inositol transporters, SMIT1 and HMIT, were greatly reduced in the SN but not in the DRG. SMIT-1 was selectively reduced in the sciatic nerve during experimental STZ-induced diabetes.

The FASEB Journal, 2015

Rabbit kidneys were perfused with a high K+ and Mg++ solution as previously described with additi... more Rabbit kidneys were perfused with a high K+ and Mg++ solution as previously described with addition of substrates and hypothermia. Briefly the animals were anesthetized with urethane and sodium pentobarbital and the left kidney perfused at 37oC with a previously dialyzed solution (4g% albumin) in an artificial heart-lung machine. Several functional parameters were evaluated such as perfusate and urine flow, GFR, %TNa, %TK, perfusion pressure and vascular resistance. The experiments lasted 2 hours. Two identical groups were perfused in normothermia (98,6oF) or hypothermia (73,4oF). The concentration of subtrates in the perfusion solution were 2mM of glutation and 1mM of glutamine. To measure kidney function creatinine was added to the perfusate and Na,K, and osmolarities were measured every ten minutes.Urinary flow in normothermic group is 16,7% higher than in hypothermic group. The same trend was observed with GFR that was, in normothermia, 39,5% higher than in hypothermia. The frac...

O presente estudo objetivou investigar os efeitos do veneno da serpente Crotalus durissus cascave... more O presente estudo objetivou investigar os efeitos do veneno da serpente Crotalus durissus cascavella na pressão arterial sanguínea em ratos. O veneno foi inoculado através de uma cânula introduzida na veia jugular , em doses crescentes (100 μg/Kg; 300 μg/Kg); salina foi injetada nos animais controles. A concentração de nitrito foi determinada pela reação de Griess, após os experimentos de pressão arterial. As pressões sistólicas e diastólicas, bem como a Pressão Arterial Média (PAM), diminuíram de forma dose-dependente após a inoculação do veneno. Foi observado um aumento sanguíneo na produção de nitrito e o envolvimento do Óxido Nítrico no efeito hipotensor do veneno. Para analisar a significância das diferenças entre os grupos foi utilizado a Análise de Variação entre grupos (ANOV A) seguida do teste de S tudent-Neuman-keul. Foi considerado significante um p< 0,05. Este projeto foi aprovado pelo Comitê de Ética para Uso de Animais da Universidade Estadual do Ceará, processo no ...

Cardiotonic steroids (CE) are known as sodium-pump inhibitors. The natriuretic property of these ... more Cardiotonic steroids (CE) are known as sodium-pump inhibitors. The natriuretic property of these compounds is related to the inhibition of the α1 isoform of Na+/K+ATPase (NKA) in renal tubules. NHE...