RESUMO
Sodium deoxycholate (NaDOC) inhibits the intestinal Ca2+ absorption and ursodeoxycholic acid (UDCA) stimulates it. The aim of this study was to determine whether NaDOC and UDCA produce differential effects on the redox state of duodenal mitochondria altering the Krebs cycle and the electron transport chain (ETC) functioning, which could lead to perturbations in the mitochondrial dynamics and biogenesis. Rat intestinal mitochondria were isolated from untreated and treated animals with either NaDOC, UDCA, or both. Krebs cycle enzymes, ETC components, ATP synthase, and mitochondrial dynamics and biogenesis markers were determined. NaDOC decreased isocitrate dehydrogenase (ICDH) and malate dehydrogenase activities affecting the ETC and ATP synthesis. NaDOC also induced oxidative stress and increased the superoxide dismutase activity and impaired the mitochondrial biogenesis and functionality. UDCA increased the activities of ICDH and complex II of ETC. The combination of both bile acids conserved the functional activities of Krebs cycle enzymes, ETC components, oxidative phosphorylation, and mitochondrial biogenesis. In conclusion, the inhibitory effect of NaDOC on intestinal Ca2+ absorption is mediated by mitochondrial dysfunction, which is avoided by UDCA. The stimulatory effect of UDCA alone is associated with amelioration of mitochondrial functioning. This knowledge could improve treatment of diseases that affect the intestinal Ca2+ absorption.
Assuntos
Colagogos e Coleréticos/farmacologia , Ácido Desoxicólico/farmacologia , Duodeno/efeitos dos fármacos , Mitocôndrias/metabolismo , Ácido Ursodesoxicólico/farmacologia , Animais , Cálcio/farmacocinética , Colagogos e Coleréticos/farmacocinética , Ciclo do Ácido Cítrico/efeitos dos fármacos , Ácido Desoxicólico/farmacocinética , Transporte de Elétrons , Absorção Intestinal/efeitos dos fármacos , Masculino , ATPases Mitocondriais Próton-Translocadoras/metabolismo , Biogênese de Organelas , Fosforilação Oxidativa/efeitos dos fármacos , Estresse Oxidativo , Ratos , Ratos Wistar , Superóxido Dismutase/metabolismo , Ácido Ursodesoxicólico/farmacocinéticaRESUMO
AIM: Myocardial ischaemia/reperfusion (I/R) produces structural and functional alterations depending on the duration of ischaemia. Brief ischaemia followed by reperfusion causes reversible contractile dysfunction (stunned heart) but long-lasting ischaemia followed by reperfusion can result in irreversible injury with cell death. Events during I/R can alter endoplasmic reticulum (ER) function leading to the accumulation of unfolded/misfolded proteins. The resulting ER stress induces activation of several signal transduction pathways, known as unfolded protein response (UPR). Experimental evidence shows that UPR contributes to cell death in irreversible I/R injury; however, there is still uncertainty for its occurrence in the stunned myocardium. This study investigated the ER stress response and its functional impact on the post-ischaemic cardiac performance of the stunned heart. METHODS: Perfused rat hearts were subjected to 20 minutes of ischaemia followed by 30 minutes of reperfusion. UPR markers were evaluated by qRT-PCR and western blot. Post-ischaemic mechanical recovery was measured in absence and presence of two chemical chaperones: tauroursodeoxycholic acid (TUDCA) and 4-phenylbutyric acid (4-PBA). RESULTS: Analysis of mRNA and protein levels of various ER stress effectors demonstrated that different UPR signalling cascades, involving both pro-survival and pro-apoptotic pathways, are activated. Inhibition of the UPR with chemical chaperones improved the post-ischaemic recovery of cardiac mechanical function without affecting the I/R-induced increase in oxidative stress. CONCLUSION: Our results suggest that prevention of ER stress by chemical chaperones could be a therapeutic tool to limit deterioration of the contractile function in clinical settings in which the phenomenon of myocardial stunning is present.
Assuntos
Estresse do Retículo Endoplasmático/efeitos dos fármacos , Traumatismo por Reperfusão Miocárdica/fisiopatologia , Miocárdio Atordoado/tratamento farmacológico , Miocárdio/metabolismo , Fenilbutiratos/farmacologia , Ácido Tauroquenodesoxicólico/farmacologia , Animais , Antineoplásicos/farmacologia , Apoptose/efeitos dos fármacos , Colagogos e Coleréticos/farmacologia , Modelos Animais de Doenças , Proteínas de Choque Térmico/metabolismo , Masculino , Miocárdio Atordoado/etiologia , Miocárdio Atordoado/patologia , Miocárdio/patologia , Ratos , Ratos Wistar , Transdução de Sinais , Resposta a Proteínas não DobradasRESUMO
Lipopolysaccharide (LPS) from Gram (-) bacteria induces inflammatory cholestasis by impairing the expression/localization of transporters involved in bile formation (e.g., Bsep, Mrp2). Therapeutic options for this disease are lacking. Ursodeoxycholic acid (UDCA) is the first choice therapy in cholestasis, but its anticholestatic efficacy in this hepatopathy remains to be evaluated. To asses it, male Wistar rats received UDCA for 5â¯days (25â¯mg/Kg/day, i.p.) with or without LPS, administered at 8â¯a.m. of the last 2â¯days (4â¯mg/Kg/day, i.p.), plus half of this dose at 8â¯p.m. of the last day. Then, plasma alkaline phosphatase (ALP), bile flow, basal and taurocholate-stimulated bile acid output, total glutathione output, and total/plasma membrane liver protein expression of Bsep and Mrp2 by confocal microscopy were assessed. mRNA levels of both transporters were assessed by Real-Time PCR. Plasma pro-inflammatory cytokines (IL-6 and TNF-α) were measured by ELISA. Our results showed that UDCA attenuated LPS-induced ALP plasma release and the impairment in the excretion of the Bsep substrate, taurocholate. This was associated with an improved Bsep expression at both mRNA and protein levels, and by an improved localization of Bsep in plasma membrane. UDCA failed to reduce the increase in plasma pro-inflammatory cytokines induced by LPS and Mrp2 expression/function. In conclusion, UDCA protects the hepatocyte against the damaging effect of bile acids accumulated by the LPS-induced secretory failure. This involved an enhanced synthesis of Bsep and an improved membrane stability of the newly synthesized transporters.
Assuntos
Colagogos e Coleréticos/uso terapêutico , Colestase/induzido quimicamente , Colestase/tratamento farmacológico , Lipopolissacarídeos/farmacologia , Ácido Ursodesoxicólico/uso terapêutico , Membro 11 da Subfamília B de Transportadores de Cassetes de Ligação de ATP/metabolismo , Transportadores de Cassetes de Ligação de ATP/metabolismo , Fosfatase Alcalina/sangue , Animais , Ácidos e Sais Biliares/metabolismo , Colagogos e Coleréticos/administração & dosagem , Colagogos e Coleréticos/farmacologia , Modelos Animais de Doenças , Hepatócitos/efeitos dos fármacos , Hepatócitos/metabolismo , Fígado/metabolismo , Masculino , Ratos , Ratos Wistar , Resultado do Tratamento , Ácido Ursodesoxicólico/administração & dosagem , Ácido Ursodesoxicólico/farmacologiaAssuntos
Antiasmáticos , Anticoagulantes , Antieméticos , Diarreia , Aprovação de Drogas , Monofosfato de Adenosina/análogos & derivados , Monofosfato de Adenosina/uso terapêutico , Aminopiridinas/análise , Aminopiridinas/farmacologia , Aminopiridinas/uso terapêutico , Antiasmáticos/análise , Antiasmáticos/farmacologia , Antiasmáticos/uso terapêutico , Anticorpos Monoclonais Humanizados/análise , Anticorpos Monoclonais Humanizados/farmacologia , Anticorpos Monoclonais Humanizados/uso terapêutico , Anticoagulantes/análise , Anticoagulantes/farmacologia , Anticoagulantes/uso terapêutico , Antieméticos/análise , Antieméticos/farmacologia , Antieméticos/uso terapêutico , Benzodioxóis/análise , Benzodioxóis/farmacologia , Benzodioxóis/uso terapêutico , Colagogos e Coleréticos/análise , Colagogos e Coleréticos/farmacologia , Colagogos e Coleréticos/uso terapêutico , Regulador de Condutância Transmembrana em Fibrose Cística/análise , Regulador de Condutância Transmembrana em Fibrose Cística/farmacologia , Regulador de Condutância Transmembrana em Fibrose Cística/uso terapêutico , Ácido Desoxicólico/análise , Ácido Desoxicólico/farmacologia , Ácido Desoxicólico/uso terapêutico , Diarreia/tratamento farmacológico , Imidazóis/análise , Imidazóis/farmacologia , Imidazóis/uso terapêutico , Síndrome do Intestino Irritável/fisiopatologia , Compostos de EspiroRESUMO
We have reported previously that centrally applied ET (endothelin)-1 and ET-3 induce either choleresis or cholestasis depending on the dose. In the present study, we sought to establish the role of these endothelins in the short-term peripheral regulation of bile secretion in the rat. Intravenously infused endothelins induced significant choleresis in a dose-dependent fashion, ET-1 being more potent than ET-3. Endothelins (with the exception of a higher dose of ET-1) did not affect BP (blood pressure), portal venous pressure or portal blood flow. ET-1 and ET-3 augmented the biliary excretion of bile salts, glutathione and electrolytes, suggesting enhanced bile acid-dependent and -independent bile flows. ET-induced choleresis was mediated by ET(B) receptors coupled to NO and inhibited by truncal vagotomy, atropine administration and capsaicin perivagal application, supporting the participation of vagovagal reflexes. RT (reverse transcription)-PCR and Western blot analysis revealed ETA and ET(B) receptor expression in the vagus nerve. Endothelins, through ET(B) receptors, augmented the hepatocyte plasma membrane expression of Ntcp (Naâº/taurocholate co-transporting polypeptide; Slc10a1), Bsep (bile-salt export pump; Abcb11), Mrp2 (multidrug resistance protein-2; Abcc2) and Aqp8 (aquaporin 8). Endothelins also increased the mRNAs of these transporters. ET-1 and ET-3 induced choleresis mediated by ET(B) receptors coupled to NO release and vagovagal reflexes without involving haemodynamic changes. Endothelin-induced choleresis seems to be caused by increased plasma membrane translocation and transcriptional expression of key bile transporters. These findings indicate that endothelins are able to elicit haemodynamic-independent biological effects in the liver and suggest that these peptides may play a beneficial role in pathophysiological situations where bile secretion is impaired.
Assuntos
Colestase/induzido quimicamente , Endotelina-1/farmacologia , Endotelina-3/farmacologia , Óxido Nítrico/fisiologia , Receptor de Endotelina B/fisiologia , Nervo Vago/efeitos dos fármacos , Animais , Bile/metabolismo , Pressão Sanguínea/efeitos dos fármacos , Colagogos e Coleréticos/farmacologia , Colestase/metabolismo , Hemodinâmica/efeitos dos fármacos , Óxido Nítrico/metabolismo , Ratos , Ratos Sprague-Dawley , Receptor de Endotelina B/metabolismo , Reflexo/efeitos dos fármacos , Fluxo Sanguíneo Regional/efeitos dos fármacos , Vagotomia , Nervo Vago/metabolismo , Nervo Vago/fisiologiaRESUMO
UDCA (ursodeoxycholic acid) is the therapeutic agent most widely used for the treatment of cholestatic hepatopathies. Its use has expanded to other kinds of hepatic diseases, and even to extrahepatic ones. Such versatility is the result of its multiple mechanisms of action. UDCA stabilizes plasma membranes against cytolysis by tensioactive bile acids accumulated in cholestasis. UDCA also halts apoptosis by preventing the formation of mitochondrial pores, membrane recruitment of death receptors and endoplasmic-reticulum stress. In addition, UDCA induces changes in the expression of metabolizing enzymes and transporters that reduce bile acid cytotoxicity and improve renal excretion. Its capability to positively modulate ductular bile flow helps to preserve the integrity of bile ducts. UDCA also prevents the endocytic internalization of canalicular transporters, a common feature in cholestasis. Finally, UDCA has immunomodulatory properties that limit the exacerbated immunological response occurring in autoimmune cholestatic diseases by counteracting the overexpression of MHC antigens and perhaps by limiting the production of cytokines by immunocompetent cells. Owing to this multi-functionality, it is difficult to envisage a substitute for UDCA that combines as many hepatoprotective effects with such efficacy. We predict a long-lasting use of UDCA as the therapeutic agent of choice in cholestasis.
Assuntos
Colagogos e Coleréticos/farmacologia , Colestase/tratamento farmacológico , Ácido Ursodesoxicólico/farmacologia , Animais , Apoptose/efeitos dos fármacos , Ácidos e Sais Biliares/fisiologia , Canalículos Biliares/efeitos dos fármacos , Colagogos e Coleréticos/uso terapêutico , Colestase/patologia , Colestase/fisiopatologia , Humanos , Fatores Imunológicos/farmacologia , Fatores Imunológicos/uso terapêutico , Mitocôndrias Hepáticas/efeitos dos fármacos , Mitocôndrias Hepáticas/metabolismo , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Ácido Ursodesoxicólico/uso terapêuticoRESUMO
Pancreatitis is a disease with high morbidity and mortality. In vitro experiments on pancreatic acini showed that supramaximal but not submaximal cholecystokinin (CCK) stimulation induces effects in the acinar cell that can be correlated with acinar morphological changes observed in the in vivo experimental model of cerulein-induced pancreatitis. The GTPase Rac1 was previously reported to be involved in CCK-evoked amylase release from pancreatic acinar cells. Here, we demonstrate that pretreatment with the Rac1 inhibitor NSC23766 (100 microM, 2 h) effectively blocked Rac1 translocation and activation in CCK-stimulated pancreatic acini, without affecting activation of its closely related GTPase, RhoA. This specific Rac1 inhibition decreased supramaximal (10 nM) CCK-stimulated acinar amylase release (27.% reduction), which seems to be connected to the reduction observed in serum amylase (46.6% reduction) and lipase levels (46.1% reduction) from cerulein-treated mice receiving NSC23766 (100 nmol h(-1)). The lack of Rac1 activation also reduced formation of reactive oxygen species (ROS; 20.8% reduction) and lactate dehydrogenase release (LDH; 24.3% reduction), but did not alter calcium signaling or trypsinogen activation in 10 nM CCK-stimulated acini. In the in vivo model, the cerulein-treated mice receiving NSC23766 also presented a decrease in both pancreatic and lung histopathological scores (reduction in oedema, 32.4 and 66.4%; haemorrhage, 48.3 and 60.2%; and leukocyte infiltrate, 53.5 and 43.6%, respectively; reduction in pancreatic necrosis, 65.6%) and inflammatory parameters [reduction in myeloperoxidase, 52.2 and 38.9%; nuclear factor kappaB (p65), 61.3 and 48.6%; and nuclear factor kappaB (p50), 46.9 and 44.9%, respectively], together with lower serum levels for inflammatory (TNF-alpha, 40.4% reduction) and cellular damage metabolites (LDH, 52.7% reduction). Collectively, these results suggest that pharmacological Rac1 inhibition ameliorates the severity of pancreatitis and pancreatitis-associated lung injury through the reduction of pancreatic acinar damage induced by pathological digestive enzyme secretion and overproduction of ROS.
Assuntos
Pneumopatias/metabolismo , Pneumopatias/patologia , Neuropeptídeos/antagonistas & inibidores , Pancreatite/metabolismo , Pancreatite/patologia , Índice de Gravidade de Doença , Proteínas rac de Ligação ao GTP/antagonistas & inibidores , Aminoquinolinas/farmacologia , Amilases/metabolismo , Animais , Cálcio/metabolismo , Membrana Celular/metabolismo , Ceruletídeo/efeitos adversos , Ceruletídeo/farmacologia , Colagogos e Coleréticos/efeitos adversos , Colagogos e Coleréticos/farmacologia , Colecistocinina/efeitos adversos , Colecistocinina/análogos & derivados , Colecistocinina/farmacologia , Citosol/metabolismo , Modelos Animais de Doenças , Relação Dose-Resposta a Droga , Pneumopatias/induzido quimicamente , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Neuropeptídeos/efeitos dos fármacos , Pancreatite/induzido quimicamente , Pirimidinas/farmacologia , Espécies Reativas de Oxigênio/metabolismo , Proteínas rac de Ligação ao GTP/efeitos dos fármacos , Proteínas rac1 de Ligação ao GTPRESUMO
The aqueous extract of the aerial parts of Lippia integrifolia has been assayed for its choleretic and antispasmodic effects. Doses of 250, 500 and 750 mg/kg administered orally in rats significantly increased the bile flow and the bile acid output. The extract also showed a significant reduction of the contractions induced by acetylcholine, CaCl2 and KCl on isolated rat jejunum. The total caffeoyl quinic acids derivatives content, expressed as chlorogenic acid was 0.10 percent w/v by spectrophotometric determination.
O extrato aquoso das partes aéreas de Lippia integrifolia foi ensaiado quanto aos seus efeitos colerético e antiespasmódico. Doses de 250, 500 e 750 mg/kg administradas oralmente em ratos aumentaram significativamente o fluxo biliar e a saída de ácidos biliares. O extrato também exibiu uma significativa redução das contrações induzidas por acetilcolina, CaCl2 e KCl em jejuno isolado de rato. O conteúdo total de derivados dos ácidos cafeoilquínicos, expressado como ácido clorogênico foi de 0.10 por cento w/v através de determinação espectrofotométrica.
Assuntos
Animais , Ratos , Colagogos e Coleréticos/farmacologia , Lippia , Parassimpatolíticos , VerbenaceaeRESUMO
The role of Endothelin-1 (ET-1) in the central nervous system is not fully understood yet although several studies strongly support its neuromodulatory role. A high density of endothelin receptors is present in the dorsal vagal complex that is the major site for the regulation of the digestive function. Therefore in the present study we sought to establish the role of ET-1 in the central regulation of bile secretion in the rat. Intracerebroventricular ET-1 injection exhibited opposite behaviors on spontaneous bile secretion according to the dose administered. Lower doses of ET-1 (1 fM) increased bile flow and bicarbonate excretion whereas higher doses (1 nM) decreased bile flow and bile acid output. Both the choleretic and the cholestatic effects of ET-1 were abolished in animals pretreated with icv BQ-610 (selective ETA antagonist) but not with BQ-788 (selective ETB antagonist). In addition, truncal vagotomy but not adrenergic blockade abolished ET-1 effects on bile secretion. Brain nitric oxide was not involved in ET-1 response since L-NAME pretreatment failed to affect ET-1 actions on the liver. Portal venous pressure was increased by centrally administered ET-1 being the magnitude of the increase similar with low and high doses of the peptide. These results show that centrally applied ET-1 modified different bile flow fractions independent of hemodynamic changes. Lower doses of ET-1 increased bile acid independent flow whereas higher doses decreased bile acid dependent flow. Vagal pathways through the activation of apparently distinct ETA receptors mediated the cholestatic as well as the choleretic effects induced by ET-1. Present findings show that ET-1 participates in the central regulation of bile secretion in the rat and give further insights into the complexity of brain-liver interaction.
Assuntos
Sistema Nervoso Central/efeitos dos fármacos , Colagogos e Coleréticos/farmacologia , Endotelina-1/farmacologia , Receptor de Endotelina A/metabolismo , Nervo Vago/metabolismo , Animais , Anti-Hipertensivos/metabolismo , Bicarbonatos/metabolismo , Bile/metabolismo , Pressão Sanguínea/fisiologia , Relação Dose-Resposta a Droga , Antagonistas do Receptor de Endotelina A , Endotelina-1/metabolismo , Glutationa/metabolismo , Óxido Nítrico/metabolismo , Oligopeptídeos/metabolismo , Piperidinas/metabolismo , Potássio/metabolismo , Ratos , Ratos Sprague-Dawley , Sódio/metabolismoRESUMO
Ligaria cuneifolia (R. et P.) Tiegh. (Loranthaceae) (Argentine mistletoe) is usually used in local folk medicine. This work focuses on the hemorrheologic parameters in the treatment with an aqueous extract of Ligaria cuneifolia (Lc) by two different administration routes: intraperitoneal (i.p.) and intravenous (i.v.). Adult male Wistar rats were injected by via i.p. or by via i.v. with: saline solution; 2.5 mg/100 g body weight of Lc and 5.5 mg/100 g body weight of Lc. The relative viscosity of blood (eta r)(45/Hct) was measured showing that Lc-treatment by via i.p. produced an increase of about 69% while Lc by via i.v. enhanced the parameter about 47%. All of Lc-treated animals showed a significant increase in the rigidity index (RI). The mean corpuscular hemoglobin concentration (MCHC) exhibited an increase of about 15% in all the treated groups. Lc-treatment by via i.p. produced a diminution of plasma cholesterol level associated with RI augmentation which induced an increase of (eta r)(45/Hct). By via i.v. Lc produces both RI and (eta r)(45/Hct) augmentation by increasing MCHC but without modifying plasma cholesterol level, indicating a direct Lc-action on the internal viscosity of the erythrocyte.