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Id: lil-741540
Autor: Britto, Fernanda Carneiro Corujeira de; Rosier, Vitor Veloso; Luz, Tovar Vicente; Verde, Raquel Crisóstomo Lima; Lima, Clara Mônica Figueiredo de; Lessa, Marcus Miranda.
Título: Nasolacrimal Duct Mucocele: Case Report and Literature Review
Fonte: Int. arch. otorhinolaryngol. (Impr.);19(1):96-98, Jan-Mar/2015. graf.
Idioma: en.
Resumo: Introduction Mucoceles are benign expansive cystic formations, composed of a mucus-secreting epithelium (respiratory or pseudostratified epithelium). Nasolacrimal mucocele occurs in a small proportion of children with nasolacrimal duct obstruction and is characterized by a cystic mass in the medial canthus with dilation of the nasolacrimal duct; although dacryocystoceles are rare in adults, they have been reported in patients with trachoma. Objective Discuss clinical aspects, diagnosis, and therapeutic management of mucocele of nasolacrimal duct based on literature review. Resumed Report The authors report a case of bilateral congenital nasolacrimal duct cysts in a 30-year-old man, identified as a tumor in the topography of both lacrimal sacs since birth without associated symptoms. The patient underwent successive surgical treatments, leading to recurrence of the tumor at the right side and recurrent local infections. Conclusion Endoscopic dacryocystorhinostomy has been increasingly used with good results and success rates similar to the external access. .
Descritores: Predisposição Genética para Doença/genética
Mutação/genética
Doenças do Sistema Nervoso/genética
ATPase Trocadora de Sódio-Potássio/genética
-Bases de Dados Bibliográficas/estatística & dados numéricos
Hemiplegia/genética
Modelos Moleculares
Doenças do Sistema Nervoso/diagnóstico
Doença de Parkinson/genética
ATPase Trocadora de Sódio-Potássio/metabolismo
Limites: Animais
Humanos
Tipo de Publ: Research Support, Non-U.S. Gov't
Revisão
Responsável: BR1.1 - BIREME


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Quevedo, Joäo
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Id: lil-710202
Autor: Rezin, Gislaine T.; Scaini, Giselli; Gonçalves, Cinara L.; Ferreira, Gabriela K.; Cardoso, Mariane R.; Ferreira, Andréa G.K.; Cunha, Maira J.; Schmitz, Felipe; Varela, Roger B.; Quevedo, João; Wyse, Angela T.S.; Streck, Emilio L..
Título: Evaluation of Na+, K+-ATPase activity in the brain of young rats after acute administration of fenproporex
Fonte: Rev. bras. psiquiatr;36(2):138-142, 13/05/2014. graf.
Idioma: en.
Resumo: Objectives: Fenproporex is an amphetamine-based anorectic which is rapidly converted into amphetamine in vivo. Na+, K+-ATPase is a membrane-bound enzyme necessary to maintain neuronal excitability. Considering that the effects of fenproporex on brain metabolism are poorly known and that Na+, K+-ATPase is essential for normal brain function, this study sought to evaluate the effect of this drug on Na+, K+-ATPase activity in the hippocampus, hypothalamus, prefrontal cortex, and striatum of young rats. Methods: Young male Wistar rats received a single injection of fenproporex (6.25, 12.5, or 25 mg/kg intraperitoneally) or polysorbate 80 (control group). Two hours after the last injection, the rats were killed by decapitation and the brain was removed for evaluation of Na+, K+-ATPase activity. Results: Fenproporex decreased Na+, K+-ATPase activity in the striatum of young rats at doses of 6.25, 12.5, and 25 mg/kg and increased enzyme activity in the hypothalamus at the same doses. Na+, K+-ATPase activity was not affected in the hippocampus or prefrontal cortex. Conclusion: Fenproporex administration decreased Na+, K+-ATPase activity in the striatum even in low doses. However, in the hypothalamus, Na+, K+-ATPase activity was increased. Changes in this enzyme might be the result of the effects of fenproporex on neuronal excitability. .
Descritores: Anfetaminas/administração & dosagem
Encéfalo/efeitos dos fármacos
Encéfalo/enzimologia
ATPase Trocadora de Sódio-Potássio/metabolismo
-Injeções Intraperitoneais
Ratos Wistar
Fatores de Tempo
Limites: Animais
Masculino
Tipo de Publ: Estudo de Avaliação
Research Support, Non-U.S. Gov't
Responsável: BR1.1 - BIREME


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Id: lil-689862
Autor: Sterzelecki, FC.; Rodrigues, E.; Fanta, E.; Ribeiro, CAO..
Título: The effect of salinity on osmoregulation and development of the juvenile fat snook, Centropomus parallelus (POEY) / O efeito da salinidade sobre a osmoregulacao e o desenvolvimento do juvenil de robalo-peva, Centropomus parallelus (POEY)
Fonte: Braz. j. biol;73(3):609-615, ago. 2013. tab, graf.
Idioma: en.
Resumo: Eurihaline fish support waters with different salt concentration. However, numerous studies have shown that salinity can affect fish development. Thus, the effect of salinity change from 20 to 5 and 35 on survival, weight, length, gill chloride cell ultrastructure and gill Na+, K+ ATPase activity was evaluated in Centropomus parallelus following short-term (6, 24 and 96 hours) and long-term exposure (30 and 60 days). Salinity did not affect C. parallelus survival, final weight and length. The quantity of chloride cells increased visibly at salinities of 5 and 35, with the cells exhibiting the typical features of uptake and secretory cells, respectively. Na+, K+ ATPase activity in the gill of the C. parallelus was significantly greater at a salinity of 5 than at a salinity of 20 or 35 after 96 hours, but not after 30 or 60 days. These results indicate that salinity change from high to low salt water induces gill chloride cell and Na+, K+ ATPase activity adaptations after short-term exposure. However, after long-term exposure at salinity 5, gill Na+, K+ ATPase activity is no more necessary at high levels. The increase in salinity to 35 does not induce significant change in gills. Juveniles of C. parallelus may thus be capable of acclimating to salinities of 5 to 35 for 60 days without significant effects on development.

Peixes eurihalinos suportam águas com diferentes concentrações de sal. Contudo, muitos estudos têm mostrado que a salinidade pode afetar o desenvolvimento do peixe. Portanto, o efeito da mudança de salinidade de 20 para 5 e 35 na taxa de sobrevivência, peso, comprimento, morfologia das células de cloreto branquiais e atividade da Na+, K+ ATPase foram avaliadas no Centropomus parallelus após curto (6, 24 e 96 horas) e longo tempo de exposição (30 e 60 dias). A salinidade não afetou a sobrevivência, o peso e comprimento final do robalo-peva. A quantidade de células de cloreto aumentou visivelmente nas salinidades 5 e 35, exibindo morfologias típicas de células que absorvem e secretam sal, respectivamente. A atividade da Na+, K+ ATPase nas brânquias do C. parallelus foi significativamente maior na salinidade 5 do que nas salinidades 20 ou 35 após 96 horas, mas não após 30 e 60 dias. Esses resultados indicam que a mudança de alta para baixa salinidade provoca adaptações nas células de cloreto e na atividade da Na+, K+ ATPase branquial em curto prazo. Contudo, após longa exposição na salinidade 5, a alta atividade da Na+, K+ ATPase branquial não é mais necessária. O aumento de salinidade para 35 não induz mudanças significativas nas brânquias. Portanto, juvenis de C. parallelus possuem a capacidade de aclimatação nas salinidades de 5 a 35 semefeitos significativos no desenvolvimento após 60 dias.
Descritores: Brânquias/crescimento & desenvolvimento
Osmorregulação/efeitos dos fármacos
Perciformes/crescimento & desenvolvimento
Salinidade
Tolerância ao Sal
ATPase Trocadora de Sódio-Potássio/efeitos dos fármacos
-Brânquias/efeitos dos fármacos
Brânquias/ultraestrutura
Microscopia Eletrônica de Transmissão
Perciformes/metabolismo
Fatores de Tempo
Limites: Animais
Responsável: BR1.1 - BIREME


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Id: lil-606539
Autor: Cui, Xin; Sun, Zheng-Rong; Ren, Gao-Wei; Wang, Gui-Li; Qi, Ying; Ma, Yan-Ping; Ruan, Qiang.
Título: Interaction between human cytomegalovirus UL136 protein and ATP1B1 protein
Fonte: Braz. j. med. biol. res = Rev. bras. pesqui. méd. biol;44(12):1251-1255, Dec. 2011. ilus.
Idioma: en.
Resumo: Interplay between the host and human cytomegalovirus (HCMV) has a pivotal role in the outcome of infection. A region (referred to as UL/b’) present in the Toledo strain of HCMV and low passage clinical isolates contains 19 additional genes, which are absent in the highly passaged laboratory strain AD169. Products of the UL/b’ genes may determine the manifestations of HCMV infection in vivo. However, little is known about the host factors, which interact with UL/b’ proteins. This study was conducted to investigate the function of the HCMV UL136 protein. By yeast two-hybrid screening, the β1 subunit of the host Na+/K+-ATPase (ATP1B1) was identified to be a candidate protein, which interacts with the HCMV UL136 protein. The interaction was further evaluated both in vitro by pull-down assay and in vivo by immunofluorescent co-localization. The results showed that the UL136 protein can interact with ATP1B1 in vitro. Co-localization of UL136-EGFP and ATP1B1-DsRed in cell membranes suggests that ATP1B1 was a partner of the UL136 protein. It can be proposed that the HCMV UL136 protein may have important roles in processes such as cell-to-cell spread, and in maintaining cell osmotic pressure and intracellular ion homeostasis during HCMV infection.
Descritores: Citomegalovirus/química
Mapeamento de Interação de Proteínas
ATPase Trocadora de Sódio-Potássio/metabolismo
Técnicas do Sistema de Duplo-Híbrido
Proteínas do Envelope Viral/metabolismo
-Análise de Sequência de Proteína
Limites: Humanos
Tipo de Publ: Research Support, Non-U.S. Gov't
Responsável: BR1.1 - BIREME


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Vassallo, D. V
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Id: lil-599668
Autor: Padilha, A. S; Salaices, M; Vassallo, D. V; Batista, P. R; Siman, F. D. M.
Título: Hypertensive effects of the iv administration of picomoles of ouabain
Fonte: Braz. j. med. biol. res = Rev. bras. pesqui. méd. biol;44(9):933-938, Sept. 2011. ilus.
Idioma: en.
Conferência: Apresentado em: XV Simpósio Brasileiro de Fisiologia Cardiovascular, São Paulo, February 2-5, 2011.
Resumo: Ouabain, an endogenous digitalis compound, has been detected in nanomolar concentrations in the plasma of several mammals and is associated with the development of hypertension. In addition, plasma ouabain is increased in several hypertension models, and the acute or chronic administration of ouabain increases blood pressure in rodents. These results suggest a possible association between ouabain and the genesis or development and maintenance of arterial hypertension. One explanation for this association is that ouabain binds to the α-subunit of the Na+ pump, inhibiting its activity. Inhibition of this pump increases intracellular Na+, which reduces the activity of the sarcolemmal Na+/Ca2+ exchanger and thereby reduces Ca2+ extrusion. Consequently, intracellular Ca2+ increases and is taken up by the sarcoplasmic reticulum, which, upon activation, releases more calcium and increases the vascular smooth muscle tone. In fact, acute treatment with ouabain enhances the vascular reactivity to vasopressor agents, increases the release of norepinephrine from the perivascular adrenergic nerve endings and promotes increases in the activity of endothelial angiotensin-converting enzyme and the local synthesis of angiotensin II in the tail vascular bed. Additionally, the hypertension induced by ouabain has been associated with central mechanisms that increase sympathetic tone, subsequent to the activation of the cerebral renin-angiotensin system. Thus, the association with peripheral mechanisms and central mechanisms, mainly involving the renin-angiotensin system, may contribute to the acute effects of ouabain-induced elevation of arterial blood pressure.
Descritores: Pressão Sanguínea/efeitos dos fármacos
Cardiotônicos/farmacologia
Hipertensão/induzido quimicamente
Ouabaína/farmacologia
-Angiotensina II/biossíntese
Cálcio/metabolismo
Cardiotônicos/administração & dosagem
Cardiotônicos/metabolismo
Sistema Nervoso Central/efeitos dos fármacos
Hipertensão/metabolismo
Injeções Intravenosas
Norepinefrina
Ouabaína/administração & dosagem
Ouabaína/metabolismo
Peptidil Dipeptidase A/metabolismo
Sistema Renina-Angiotensina/efeitos dos fármacos
ATPase Trocadora de Sódio-Potássio/efeitos dos fármacos
ATPase Trocadora de Sódio-Potássio/fisiologia
Limites: Animais
Humanos
Ratos
Tipo de Publ: Research Support, Non-U.S. Gov't
Revisão
Responsável: BR1.1 - BIREME


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Id: lil-564797
Autor: Romero, Freddy.
Título: Solubilization and partial characterization of ouabain-insensitive Na+-ATPase from basolateral plasma membranes of the instestinal epithelial cells
Fonte: Invest. clín;50(3):303-314, sept. 2009. tab, graf.
Idioma: en.
Resumo: It has been proposed that intestinal sodium transport is mediated by two different active mechanisms: the ouabain-sensitive Na+/K+-ATPase and ouabain-insensitive Na+-ATPase. In order to determine the optimum conditions to solubilize the membrane-bound Na+-ATPase of enterocyte, basolateral plasma membranes were solubilized using different amounts of octyl glucoside (O.G), Tween 20, octaethylene glycol monododecyl ether (C12E8), and polyoxyethylene 9-lauryl ether (C12E9). Solubilized fractions were assayed for protein concentration and ATPase activity and characterized by electrophoresis analysis. Optimal solubilization of Na+-ATPase was obtained after mixing of 1 mg of basolateral plasma membrane with 1.5 mg of C12E9. Under these conditions, C12E9 solubilized over 60% membrane protein and Na+- and Na+/K+- ATPases activities were recovered over 80% in the soluble fraction without inactivation. In addition, when 25 % glycerol and 2 mM ATP were added, the solubilized Na+-ATPase was stable after 3 days at 4°C. The C12E9-solubilized Na+-ATPase presented the following kinetic characteristics: 1) is only stimulated by the Na+ salt, 2) K0.5 for Na+= 4.62 ± 0.06 mM, 3) is similarly stimulated by the Na+ salt of different anions, 4) optimal pH= 7.0, 5) inhibited by furosemide (IC50= 0.52 ± 0.10 nm). These kinetic properties of the solubilized Na+-ATPase were similar to those described to the native membrane-bound enzyme. This work reports for the first time, solubilization and characterization of a fully active and stable Na+-ATPase from basolateral plasma membranes of enterocyte using C12E9.

Ha sido propuesto que el transporte intestinal del sodio es mediado por dos mecanismos: la ATPasa de Na+/K+, inhibida por ouabaina y la ATPasa de Na+ la cual es insensible a la ouabaina y es inhibida por la furosemida. Con la finalidad de determinar las condiciones óptimas para solubilizar la ATPasa de Na+ del enterocito, membranas plasmáticas laterobasales fueron solubilizadas utilizando diferentes detergentes, octyl glucoside, Tween 20, C12E8 y C12E9. La solubilización de la ATPasa de Na+ y de la ATPasa de Na+/K+ fue óptima después de mezclar 1 mg de membranas con 1,5 mg de C12E9. El C12E9 solubilizó más del 60% de las proteinas de membranas y las ATPasas de Na+ y Na+/K+ fueron recuperadas en un 80% en la fracción soluble. Adicionalmente, cuando glicerol al 25 % y ATP 2 mM fueron utilizados, la ATPasa de Na+ fue estable despues de 3 dias. La ATPasa de Na+ soluble demostró las siguientes características cinéticas: 1) es específicamente estimulada por sales de Na+; 2) K0.5 para Na+= 4.62 ± 0.1 mM; 3) es estimulada por todas las sales de Na+, 4) pH óptimo= 7.0; 5) es inhibida por furosemida (IC50= 0,52 ± 0,10 nm). Las características cinéticas de la enzima solubilizada fueron similares a las descritas para la forma de la enzima unida a la membrana. Este trabajo demuestra la solubilización y caracterización de la ATPasa Na+ a partir de membranas laterobasales del enterocito usando C12E9.
Descritores: Células Epiteliais
Intestino Delgado
ATPase Trocadora de Sódio-Potássio
-Fenômenos Fisiológicos do Sistema Digestório
Limites: Humanos
Tipo de Publ: Revisão
Responsável: VE1.1 - Biblioteca Humberto Garcia Arocha


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Id: lil-555239
Autor: Souza, Geane Felix de; Saldanha, Gláucio Barros; Freitas, Rivelilson Mendes de.
Título: Lipoic acid increases glutathione peroxidase, Na+, K+-ATPase and acetylcholinesterase activities in rat hippocampus after pilocarpine-induced seizures? / O ácido lipóico aumenta as atividades da glutationa peroxidase, da Na+, K+-ATPase e da acetilcolinesterase no hipocampo de ratos após convulsões induzidas por pilocarpina?
Fonte: Arq. neuropsiquiatr;68(4):586-591, Aug. 2010. graf, tab.
Idioma: en.
Resumo: In the present study we investigated the effects of lipoic acid (LA) on acetylcholinesterase (AChE), glutathione peroxidase (GPx) and Na+, K+-ATPase activities in rat hippocampus during seizures. Wistar rats were treated with 0.9 percent saline (i.p., control group), lipoic acid (20 mg/kg, i.p., LA group), pilocarpine (400 mg/kg, i.p., P400 group), and the association of pilocarpine (400 mg/kg, i.p.) plus LA (20 mg/kg, i.p.), 30 min before of administration of P400 (LA plus P400 group). After the treatments all groups were observed for 1 h. In P400 group, there was a significant increase in GPx activity as well as a decrease in AChE and Na+, K+-ATPase activities after seizures. In turn, LA plus P400 abolished the appearance of seizures and reversed the decreased in AChE and Na+, K+-ATPase activities produced by seizures, when compared to the P400 seizing group. The results from the present study demonstrate that preadministration of LA abolished seizure episodes induced by pilocarpine in rat, probably by increasing AChE and Na+, K+-ATPase activities in rat hippocampus.

No presente estudo nós investigamos os efeitos do ácido lipóico (AL) sobre as atividades da acetilcolinesterase (AChE), da glutationa peroxidase (GPx) e da Na+, K+-ATPase no hipocampo de ratos durante crises convulsivas. Ratos Wistar foram tratados com solução salina a 0,9 por cento (i.p., grupo controle), ácido lipóico (20 mg/kg, i.p., grupo AL), pilocarpina (400 mg/kg, i.p., grupo P400), e a associação de AL (20 mg/kg, i.p.) com a pilocarpina (400 mg/kg, i.p.), 30 min antes da administração de pilocarpina (grupo AL + P400). Após os tratamentos todos os grupos foram observados durante 1 h. No grupo P400, houve um aumento significativo na atividade da GPx, assim como uma diminuição das atividades da AChE e Na+, K+-ATPase. Por sua vez, o pré-tratamento com AL aboliu o aparecimento de convulsões e reverteu a diminuição das atividades da AChE e da Na+, K+-ATPase causadas pelas convulsões, quando comparada com o grupo P400 sozinho. Os resultados do estudo demonstram que o pré-tratamento com AL aboliu os episódios de convulsão induzido pela pilocarpina em ratos, provavelmente por meio do aumento das atividades das enzimas AChE e Na+, K+-ATPase no hipocampo de ratos.
Descritores: Acetilcolinesterase/metabolismo
Antioxidantes/farmacologia
Glutationa Peroxidase/metabolismo
Hipocampo/enzimologia
Convulsões/enzimologia
ATPase Trocadora de Sódio-Potássio/metabolismo
Ácido Tióctico/farmacologia
-Hipocampo/efeitos dos fármacos
Pilocarpina
Ratos Wistar
Convulsões/induzido quimicamente
Limites: Animais
Masculino
Ratos
Tipo de Publ: Research Support, Non-U.S. Gov't
Responsável: BR1.1 - BIREME


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Stefanon, I
Vassallo, D. V
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Id: lil-554957
Autor: Siman, F. D. M; Stefanon, I; Vassallo, D. V; Padilha, A. S.
Título: A low concentration of ouabain (0.18 µg/kg) enhances hypertension in spontaneously hypertensive rats by inhibiting the Na+ pump and activating the renin-angiotensin system
Fonte: Braz. j. med. biol. res = Rev. bras. pesqui. méd. biol;43(8):767-776, Aug. 2010. tab, ilus.
Idioma: en.
Resumo: We investigated the effects of low ouabain concentrations on systolic (SAP) and diastolic (DAP) arterial pressures and on pressor reactivity in 3-month-old male spontaneously hypertensive rats (SHR). Arterial blood pressure (BP) and pressor reactivity to phenylephrine (PHE) were investigated before and after 0.18 ìg/kg ouabain administration (N = 6). The influence of hexamethonium (N = 6), canrenone (N = 6), enalapril (N = 6), and losartan (N = 6) on ouabain actions was evaluated. Ouabain increased BP (SAP: 137 ± 5.1 to 150 ± 4.7; DAP: 93.7 ± 7.7 to 116 ± 3.5 mmHg; P<0.05) but did not change PHE pressor reactivity. Hexamethonium reduced basal BP in control but not in ouabain-treated rats. However, hexamethonium + ouabain increased DAP sensitivity to PHE. Canrenone did not affect basal BP but blocked ouabain effects on SAP. However, after canrenone + ouabain administration, DAP pressor reactivity to PHE still increased. Enalapril and losartan reduced BP and abolished SAP and DAP responses to ouabain. Enalapril + ouabain reduced DAP reactivity to PHE, while losartan + ouabain reduced SAP and DAP reactivity to PHE. In conclusion, a small dose of ouabain administered to SHR increased BP without altering PHE pressor reactivity. Although the renin-angiotensin system (RAS), Na+ pump and autonomic reflexes are involved in the effects of ouabain on PHE reactivity, central mechanisms might blunt the actions of ouabain on PHE pressor reactivity. The effect of ouabain on SAP seems to depend on the inhibition of both Na+ pump and RAS, whereas the effect on DAP seems to depend only on RAS.
Descritores: Inibidores Enzimáticos/farmacologia
Hipertensão/induzido quimicamente
Ouabaína/farmacologia
Sistema Renina-Angiotensina/efeitos dos fármacos
ATPase Trocadora de Sódio-Potássio/antagonistas & inibidores
-Anti-Hipertensivos/farmacologia
Hipertensão/prevenção & controle
Fenilefrina/farmacologia
Ratos Endogâmicos SHR
Sistema Renina-Angiotensina/fisiologia
Limites: Animais
Masculino
Ratos
Tipo de Publ: Research Support, Non-U.S. Gov't
Responsável: BR1.1 - BIREME


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Id: lil-537155
Autor: Rocafull, Miguel Ángel; Del Castillo, Jesús R.
Título: La segunda bomba de sodio: de la proteína al gen / The second sodium pump: from protein to gene
Fonte: Acta cient. venez;56(4):168-175, 2005. graf.
Idioma: es.
Resumo: En la membrana laterobasal del epitelio del intestino delgado y del túbulo renal proximal han sido descrito dos mecanismos diferentes de transporte activo primario de Na+: (1) uno dependiente de K+, sensible a la ouabaina e insensible a la furosemida, correspondiente a la bomba de Na+/K+; y (2) otro independiente de K+, insensible a la ouabaina pero inhibida por furosemida, el cual es referido como la segunda bomba de sodio. De igual modo, dos actividades ATPásicas, dependientes de Mg2+, estimuladas por Na+ e inhibidas por vanadato, han sido descritas en esta membrana: (1) una dependiente de K+, sensible a la ouabaina e insensible a la furosemida, correspondiente a la ATPasa de Na+/K+; y (2) otra independiente de K+, insensible a la iuabaina pero inhibida por furosemida, la cual ha sido denominada como la ATPasa de Na+. Dadas las similitudes bioquímicas, se considera que la bomba de Na+/K+ y la segunda bomba de sodio están asociadas con las ATPasas de Na+/K+ y de Na+, respectivamente, como una entidad bioquímica única. No obstante, no había sido posible la separación óptima de ambas enzimas. Recientemente, se logró solubilizar ambas ATPasas utilizando un detergente no-iónico (C12E9), preservando sus actividades, y purificar la ATPasa de Na+ por selección negativa a través de una cromatografía de afinidad con Concanavalina-A-sefarosa. La ATPasa de Na+ esta constituida por dos subunidades: una subunidad alfa de 98 KDa y una subunidad beta de 50 KDa. La subunidad alfa fue parcialmente secuenciada por espectrometría de masa en serie, identificándose tres péptidos que están presentes en la subunidad alfa1 de la ATPasa de Na+/K+. La formación de intermediarios fosforilados durante el ciclo de reacción de la ATPasa de Na+, así como su dependencia de Mg2+ y sensibilidad a vanadato, identifican a esta enzima como integrante de las ATPasas tipo P.

Basolateral plasma membranes of small intestine and proximal renal tubule present two active Na+-transportmechanisms: (1) The Na+/K+-pump, which depends on K+, is inhibited by ouabain but insensitive to furosemide and (2) The Second sodium pump, which is K+-independent, insensitive to ouabain but inhibited by furosemide. Thse two transport mechanisms have been associated with two different Mg2+-dependent Na+-ATPases, inhibited by vanadate: (1) The K+-dependent Na+/K+-ATPase, sensitive to ouabain and insensitive to furosemide, and (2) The K+ independent, Na+-ATPase, which is inhibitable by furosemide and insensitiveto ouabain. There exist multiple biochemical and functional evidences indicating that these two ATPases are different but only recently it has been possible to identify the Na+-ATPase as a unique biochemical entity. Both ATPases can be solubilized in an active form using C12E9 as detergent and separated by exclusion chromatography in sepharose 6-B and affinity chromatography in concanavalinA-sepharose. The Na+-ATPase is constituted by two sub-units: an alpha subunit of 98 KDa and a beta subunit of 50 KDa. The alpha subunit was partially sequenced by Tandem Mass Spectrometry, evidenced three peptides that are also present in the alpha1 subunit of the Na+/K+-ATPase. Na+-ATPase is Mg2+-dependent, inhibited by vanadate and forms phosphorylated intermediate during its reaction cycle ATP, indicating that it si a P-type ATPase. These facts induced us to design degenerated primers against the most preserves motifs present in these ATPases and to intent the cloning of the Na+-ATPase. Thus, we identified a cDNA for a new P-type ATPase probably related with this enzyme.
Descritores: ATPase Trocadora de Sódio-Potássio/análise
Adenosina Trifosfatases/análise
Adenosina Trifosfatases/química
Furosemida/análise
Furosemida/química
Proteínas/análise
-Bioquímica
Fisiologia
Tipo de Publ: Estudo Comparativo
Responsável: VE1.1 - Biblioteca Humberto Garcia Arocha


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Id: lil-529110
Autor: Giachini, F. R. C; Carneiro, F. S; Lima, V. V; Carneiro, Z. N; Brands, M. W; Webb, R. C; Tostes, R. C.
Título: A key role for Na+/K+-ATPase in the endothelium-dependent oscillatory activity of mouse small mesenteric arteries
Fonte: Braz. j. med. biol. res = Rev. bras. pesqui. méd. biol;42(11):1058-1067, Nov. 2009. ilus.
Idioma: en.
Projeto: National Institutes of Health; . FAPESP.
Resumo: Oscillatory contractile activity is an inherent property of blood vessels. Various cellular mechanisms have been proposed to contribute to oscillatory activity. Mouse small mesenteric arteries display a unique low frequency contractile oscillatory activity (1 cycle every 10-12 min) upon phenylephrine stimulation. Our objective was to identify mechanisms involved in this peculiar oscillatory activity. First-order mesenteric arteries were mounted in tissue baths for isometric force measurement. The oscillatory activity was observed only in vessels with endothelium, but it was not blocked by L-NAME (100 µM) or indomethacin (10 µM), ruling out the participation of nitric oxide and prostacyclin, respectively, in this phenomenon. Oscillatory activity was not observed in vessels contracted with K+ (90 mM) or after stimulation with phenylephrine plus 10 mM K+. Ouabain (1 to 10 µM, an Na+/K+-ATPase inhibitor), but not K+ channel antagonists [tetraethylammonium (100 µM, a nonselective K+ channel blocker), Tram-34 (10 µM, blocker of intermediate conductance K+ channels) or UCL-1684 (0.1 µM, a small conductance K+ channel blocker)], inhibited the oscillatory activity. The contractile activity was also abolished when experiments were performed at 20°C or in K+-free medium. Taken together, these results demonstrate that Na+/K+-ATPase is a potential source of these oscillations. The presence of α-1 and α-2 Na+/K+-ATPase isoforms was confirmed in murine mesenteric arteries by Western blot. Chronic infusion of mice with ouabain did not abolish oscillatory contraction, but up-regulated vascular Na+/K+-ATPase expression and increased blood pressure. Together, these observations suggest that the Na+/K+ pump plays a major role in the oscillatory activity of murine small mesenteric arteries.
Descritores: Endotélio Vascular/enzimologia
Hipertensão/fisiopatologia
Artérias Mesentéricas/enzimologia
ATPase Trocadora de Sódio-Potássio/fisiologia
Resistência Vascular/fisiologia
-Endotélio Vascular/fisiologia
Inibidores Enzimáticos/farmacologia
Hipertensão/induzido quimicamente
Artérias Mesentéricas/fisiologia
MICE, INBRED CABDOMENABDOMINAL INJURIESBL
Ouabaína/farmacologia
Limites: Animais
Masculino
Camundongos
Tipo de Publ: Research Support, N.I.H., Extramural
Research Support, Non-U.S. Gov't
Responsável: BR1.1 - BIREME



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