RESUMO
Estrogens reduce 0.3 M NaCl intake and palatability in a widely used model of essential hypertension, the spontaneously hypertensive rats (SHRs). Here we investigated whether the inhibitory effects of ß-estradiol (E2, 10 µg/kg b.w. subcutaneously for 8 days) on water deprived partially-rehydrated (WD-PR) ovariectomized (OVX) adult female SHRs (fSHRs, n = 4-10/group) are related to interferences on brain angiotensin II AT1 receptors (AT1r). After WD-PR, E2 reduced 0.3 M NaCl intake (1.3 ± 0.6, vs. vehicle: 3.5 ± 1.2 ml/30 min), the number of hedonic responses to intraoral NaCl infusion (57 ± 11, vs. vehicle: 176 ± 32/min), and the relative angiotensin AT1r (Agtr1a) mRNA expression in the hypothalamus. Losartan (AT1r antagonist, 100 µg) intracerebroventricularly in OVX fSHRs treated with vehicle subcutaneously abolished 0.3 M NaCl intake (0.1 ± 0.1 ml/30 min) and only transiently reduced hedonic responses to intraoral NaCl. Losartan combined with E2 decreased the number of hedonic and increased the number of aversive responses to intraoral NaCl and abolished 0.3 M NaCl intake. E2 also reduced the pressor and dipsogenic responses to intracerebroventricular angiotensin II. The results suggest that AT1r activation increases palatability and induces NaCl intake in WD-PR fSHRs. E2 reduced hypothalamic Agtr1a mRNA expression, which may account for the effects of E2 on NaCl intake and palatability and intracerebroventricular angiotensin II-induced pressor and dipsogenic responses in OVX fSHRs. Future studies considering natural fluctuations in estrogen secretion might help to determine the degree of such interference in brain neuronal activity.
Assuntos
Angiotensina II , Losartan , Angiotensina II/farmacologia , Animais , Estradiol/farmacologia , Feminino , Humanos , Losartan/farmacologia , RNA Mensageiro , Ratos , Ratos Endogâmicos SHR , Receptor Tipo 1 de Angiotensina/genética , Cloreto de SódioRESUMO
Spontaneously hypertensive rats (SHRs) ingest more NaCl than normotensive strains. Here we investigated NaCl intake and taste reactivity in adult male SHRs and normotensive Holtzman rats treated or not with AT1 receptor antagonist centrally in euhydrated condition and after fluid depletion. Taste reactivity was measured by the number of orofacial expressions to intra-oral infusions of 0.3 M NaCl. In euhydrated condition, intra-oral infusions of 0.3 M NaCl produced greater number of hedonic responses in SHRs than in normotensive rats, without differences in the number of aversive responses. Compared to euhydrated condition, the treatment with the diuretic furosemide + low dose of captopril (angiotensin converting enzyme blocker) increased the number of hedonic and reduced the number of aversive responses to intra-oral NaCl in normotensive rats, without changing the number of hedonic or aversive responses in SHRs. Losartan (AT1 receptor antagonist, 100 ng/1 µl) injected intracerebroventricularly in SHRs abolished 0.3 M NaCl intake induced by water deprivation + partial rehydration, whereas only transiently (first 30 min of the 60 min test) reduced hedonic responses, without changes in aversive responses to intra-oral NaCl. Losartan intracerebroventricularly also only transiently (first 30 min) reduced the number of hedonic responses to intra-oral NaCl in euhydrated SHRs. The results suggest that NaCl palatability is increased and independent from body fluid balance in SHRs. The results also suggest that central AT1 receptors are part of the mechanisms activated to increase NaCl intake and palatability in SHRs. A partial dissociation between NaCl intake and palatability in SHRs is also suggested.
Assuntos
Captopril , Sódio , Animais , Captopril/farmacologia , Furosemida/farmacologia , Losartan/farmacologia , Masculino , Ratos , Ratos Endogâmicos SHRRESUMO
Spontaneously hypertensive rats (SHRs) have increased daily or induced sodium intake compared to normotensive rats. In normotensive rats, angiotensin II (ANG II)-induced sodium intake is blocked by the inactivation of p42/44 mitogen-activated protein kinase, also known as extracellular signal-regulated protein kinase1/2 (ERK1/2). Here we investigated if inhibition of ERK1/2 pathway centrally would change sodium appetite and intracerebroventricular (icv) ANG II-induced pressor response in SHRs. SHRs (280-330 g, n = 07-14/group) with stainless steel cannulas implanted in the lateral ventricle (LV) were used. Water and 0.3 M NaCl intake was induced by the treatment with the diuretic furosemide + captopril (angiotensin converting enzyme blocker) subcutaneously or 24 h of water deprivation (WD) followed by 2 h of partial rehydration with only water (PR). The blockade of ERK1/2 activation with icv injections of U0126 (MEK1/2 inhibitor, 2 mM; 2 µl) reduced 0.3 M NaCl intake induced by furosemide + captopril (5.0 ± 1.0, vs. vehicle: 7.3 ± 0.7 mL/120 min) or WD-PR (4.6 ± 1.3, vs. vehicle: 10.3 ± 1.4 mL/120 min). PEP7 (selective inhibitor of AT1 receptor-mediated ERK1/2 activation, 2 nmol/2 µL) icv also reduced WD-PR-induced 0.3 M NaCl (2.8 ± 0.7, vs. vehicle: 6.8 ± 1.4 mL/120 min). WD-PR-induced water intake was also reduced by U0126 or PEP7. In addition, U0126 or PEP7 icv reduced the pressor response to icv ANG II. Therefore, the present results suggest that central AT1 receptor-mediated ERK1/2 activation is part of the mechanisms involved in sodium appetite and ANG II-induced pressor response in SHRs.
Assuntos
Bloqueadores do Receptor Tipo 1 de Angiotensina II/farmacologia , Angiotensina II/genética , Apetite/efeitos dos fármacos , Hipertensão/tratamento farmacológico , Receptor Tipo 1 de Angiotensina/genética , Animais , Apetite/genética , Butadienos/farmacologia , Captopril/farmacologia , Modelos Animais de Doenças , Furosemida/farmacologia , Humanos , Hipertensão/genética , Hipertensão/patologia , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Sistema de Sinalização das MAP Quinases/genética , Proteína Quinase 1 Ativada por Mitógeno/antagonistas & inibidores , Proteína Quinase 3 Ativada por Mitógeno/antagonistas & inibidores , Nitrilas/farmacologia , Ratos , Ratos Endogâmicos SHR , Sódio/metabolismoRESUMO
The renin-angiotensin system (RAS) controls hypertonic NaCl intake driven by sodium appetite. Here we investigated whether the antagonism of RAS interferes with hedonic and aversive orofacial motor responses, or palatability, to intraoral infusion of 0.3 M NaCl (hNaCl). Adult rats were depleted of sodium by combined sc injection of furosemide and 24 h removal of ambient sodium. In experiment 1, losartan (AT1 angiotensin II receptor antagonist, intracerebroventricular, 200 µg/µl), produced a three-fold increase in aversive orofacial motor responses to hNaCl. Losartan also suppressed hNaCl intake recorded immediately thereafter. In experiment 2, each animal had repeated recordings of hNaCl intake and orofacial responses to hNaCl distributed for 180 min. Paired recordings of intake and orofacial responses occurred within five successive blocks after the recordings of only orofacial responses when the animals were still sodium deplete (block zero). Captopril (angiotensin converting enzyme blocker, intraperitoneal, 30 mg/kg) inhibited by 75% the hedonic orofacial responses to hNaCl in blocks zero and 1. The hedonic responses to captopril remained the same throughout blocks, but became similar to vehicle from blocks 2 to 5. There was no difference in aversive responses to 0.3 M NaCl between captopril and vehicle. Captopril produced a 70-100% inhibition of hNaCl intake in blocks 1 to 5. The results suggest that angiotensin II acts in the brain increasing the palatability of hypertonic sodium during the consummatory phase of sodium appetite.
Assuntos
Sistema Renina-Angiotensina , Sódio , Animais , Apetite , Captopril/farmacologia , Losartan/farmacologia , Ratos , Cloreto de SódioRESUMO
Behavioral sensitization occurs during sodium appetite (expressed as sodium intake to compensate for depleted sodium) and need-free sodium intake (expressed as daily overnight sodium intake in excess of dietary sodium need). Previously, we found that a slow-onset sodium appetite protocol cross-sensitized need-free sucrose intake in sucrose-naïve adult rats. That is, a history of sodium depletion elevated later sucrose intake. The objective of the present work was, first, to investigate whether a protocol that evokes a rapid-onset (within 2 h) sodium appetite using furosemide along with a low dose captopril (Furo/Cap), also cross-sensitizes sucrose intake. Then, we investigated whether 1) sensitization of need-free 0.3 M NaCl intake interacts with need-free sucrose intake, and 2) MK-801, a glutamate NMDA receptor antagonist, inhibits cross-sensitization of sucrose intake. Groups received 3-4 Furo/Cap or vehicle treatments with 48/72-h intervals. We investigated sucrose intake in hydrated and fed conditions for 2 h/day for 5 days, starting 6-10 days after the last Furo/Cap treatment. Episodes of Furo/Cap sensitized need-free sodium intake, as expected. Similar to our prior work, the rapid-onset Furo/Cap protocol cross-sensitized sucrose intake in sucrose-naïve rats and had no persistent effect on blood biochemistry. MK-801 treatment along with Furo/Cap injections appeared to prevent cross-sensitization of sucrose consumption. Sucrose intake tests unexpectedly reduced sensitized need-free sodium intake. However, MK-801 treatment allowed a rebound in need-free sodium intake subsequent to the last sucrose intake test. The results suggest that plasticity in glutamatergic mechanisms mediate inverse and reciprocal interactions between the production of sodium appetite and sucrose intake.
Assuntos
Apetite , Sódio na Dieta , Animais , Diuréticos/farmacologia , Ratos , Ratos Sprague-Dawley , Sódio , AçúcaresRESUMO
OBJECTIVE: Studies have been conducted to determine the causal factors and clinical consequences of non-adherence to treatment in systemic lupus erythematosus (SLE). However, no interventions have been performed to increase drug adherence. Our objective was to assess the effectiveness of pharmaceutical care (PC) for drug treatment adherence in lupus nephritis (LN). METHODS: This was a randomized clinical trial (pragmatic trial) in patients with LN in Rio de Janeiro, Brazil, allocated in two groups: an intervention group (Dader Method for PC) and a control group (institution's usual care). Drug treatment adherence was measured by the combination of five questions normally used in clinical practice. RESULTS: A total of 131 patients were randomized, and 122 completed the study, with a mean follow-up of 12.7 months and use of six drugs per day and 10-12 doses per day. Low adherence was observed at baseline (intervention group: 30%; control group: 29%). PC showed 27% effectiveness (95% confidence interval (CI) -6% to 50%) in the intention to treat analysis and 31% (95% CI 0-52%) in per protocol analysis, considering all drugs. As for adherence to specific drugs for SLE, effectiveness of PC was 64% (95% CI 34-80%) with intention-to-treat analysis and 62% (95% CI 32-79%) in per protocol analysis. CONCLUSIONS: PC was effective for increasing drug treatment adherence in SLE. The detailed account provided by the Dader Method of the difficulties with patients' drug therapy proved invaluable to approach non-adherence.
Assuntos
Nefrite Lúpica/tratamento farmacológico , Adesão à Medicação/estatística & dados numéricos , Assistência Farmacêutica/organização & administração , Adulto , Brasil , Feminino , Seguimentos , Humanos , Análise de Intenção de Tratamento , Pessoa de Meia-Idade , Inquéritos e QuestionáriosRESUMO
Excessive salt intake has been associated with the development or worsening of chronic diseases such as hypertension and spontaneously hypertensive rats (SHR) have a typical increased sodium preference. Estrogens reduce sodium appetite, but we do not know whether such effect relates to alterations in sodium palatability. Here we evaluated the influence of ovarian hormones on orofacial motor responses, an index of palatability, to intra-oral infusion of 0.3â¯M NaCl (IONaCl). Adult female SHR and normotensive Holtzman rats (HTZ) were used. Sodium appetite was produced by water deprivation followed immediately by partial rehydration by drinking water to satiation (WD-PR protocol). Immediately at the end of WD-PR, animals received an IO-NaCl for videotape recording of orofacial motor responses. At the end of IO-NaCl, they had access to two bottles containing 0.3â¯M NaCl and water to ingest (sodium appetite test). Bilateral ovariectomy (OVX) enhanced 0.3â¯M NaCl intake during the sodium appetite test and increased the frequency of orofacial hedonic responses to IO-NaCl in both strains. It had no effect on aversive responses. Estradiol treatment in SHR-OVX decreased hedonic responses and increased aversive responses to IO-NaCl. It also reduced 0.3â¯M NaCl intake during the sodium appetite test, but had no effect on baseline mean arterial pressure and heart rate. The results suggest that ovarian hormones restrain WD-PR-induced sodium appetite by reducing the hedonic properties of sodium taste. The results also suggest that estrogens mediate such reduction, particularly in SHR.
Assuntos
Estradiol/farmacologia , Cloreto de Sódio/administração & dosagem , Privação de Água , Animais , Feminino , Ovariectomia , Distribuição Aleatória , Ratos Endogâmicos SHR , Ratos Sprague-Dawley , Paladar/fisiologiaRESUMO
The lateral parabrachial nucleus (LPBN) exerts an important inhibitory influence for the control of sodium and water intake. However, the importance of LPBN on renal responses and cardiovascular changes during extracellular dehydration are still unknown. Here we investigated the effects of bilateral injections of moxonidine (alpha2-adrenergic and imidazoline receptor agonist) on renal and cardiovascular changes in fluid-depleted rats. Male Wistar rats (n=4-8 per group) with bilateral stainless steel guide-cannulas implanted into the LPBN were treated with subcutaneous furosemide (10mg/kg)+captopril (5mg/kg) to induce fluid depletion. Forty-five min later vehicle or moxonidine (0.5nmol/0.2µl) were bilaterally injected into the LPBN. In fluid-depleted rats, moxonidine produced strong 0.3M NaCl and water intake without noticeable changes in cardiovascular parameters. Moxonidine did not change sodium excretion (488±135, vs. vehicle: 376±75µEq/1h) or urinary volume (2.5±0.7, vs. vehicle: 2.5±0.3ml/1h) in fluid-depleted rats without access to fluids for rehydration. However, moxonidine decreased natriuresis (462±127, vs. vehicle: 888±122µEq/1h) and diuresis (2.5±0.5, vs. vehicle: 4.5±0.5ml/1h) in fluid-depleted rats submitted to i.g. rehydration. These data suggest that alpha2-adrenergic mechanism of the LPBN facilitates sodium/water retention and body fluid volume expansion during extracellular dehydration.
Assuntos
Desidratação/fisiopatologia , Núcleos Parabraquiais/fisiologia , Sódio/fisiologia , Equilíbrio Hidroeletrolítico , Agonistas de Receptores Adrenérgicos alfa 2/farmacologia , Animais , Pressão Sanguínea/efeitos dos fármacos , Líquidos Corporais/fisiologia , Desidratação/urina , Diuréticos/farmacologia , Ingestão de Líquidos , Furosemida/farmacologia , Receptores de Imidazolinas/agonistas , Masculino , Natriurese , Ratos Wistar , Sódio/urina , UrinaRESUMO
The administration of cholinergic agonists like pilocarpine intraperitoneally (i.p.) or carbachol intracerebroventricularly (i.c.v.) induces water, but non significant hypertonic NaCl intake. These treatments also produce pressor responses, which may inhibit sodium intake. Noradrenaline (NOR) acting on α2-adrenoceptors in the lateral parabrachial nucleus (LPBN) deactivates inhibitory mechanisms increasing fluid depletion-induced sodium intake. In the present study, we investigated: (1) water and 1.8% NaCl intake in rats treated with pilocarpine i.p. or carbachol i.c.v. combined with NOR into the LPBN; (2) if inhibitory signals from cardiovascular receptors are blocked by NOR in the LPBN. Male Holtzman rats with stainless steel guide-cannulas implanted in the lateral ventricle and bilaterally in the LPBN were used. Bilateral injections of NOR (80nmol/0.2µl) into the LPBN decreased water intake (0.8±0.3, vs. saline (SAL): 2.9±0.3ml/180min) induced by pilocarpine (1mg/kg of body weight) i.p., without changing 1.8% NaCl intake (0.8±2.4, vs. SAL: 0.5±0.3ml/180min). Prazosin (1mg/kg of body weight) i.p. blocked pressor responses and increased water and 1.8% NaCl intake (6.3±1.7 and 14.7±3.5ml/180min, respectively) in rats treated with pilocarpine combined with NOR into the LPBN. Prazosin i.p. also increased 1.8% NaCl intake in rats treated with carbachol i.c.v combined with NOR into the LPBN. The results suggest that different signals inhibit sodium intake in rats treated with cholinergic agonists, among them those produced by increases of arterial pressure that are not efficiently deactivated by NOR acting in the LPBN.
Assuntos
Agonistas Colinérgicos/farmacologia , Ingestão de Líquidos/fisiologia , Norepinefrina/metabolismo , Núcleos Parabraquiais/metabolismo , Cloreto de Sódio na Dieta , Animais , Anti-Hipertensivos/farmacologia , Pressão Sanguínea/efeitos dos fármacos , Pressão Sanguínea/fisiologia , Carbacol/farmacologia , Cateteres de Demora , Ingestão de Líquidos/efeitos dos fármacos , Frequência Cardíaca/efeitos dos fármacos , Frequência Cardíaca/fisiologia , Masculino , Núcleos Parabraquiais/efeitos dos fármacos , Pilocarpina/farmacologia , Prazosina/farmacologia , Ratos Sprague-DawleyRESUMO
Central α2-adrenoceptors and the pontine lateral parabrachial nucleus (LPBN) are involved in the control of sodium and water intake. Bilateral injections of moxonidine (α2-adrenergic/imidazoline receptor agonist) or noradrenaline into the LPBN strongly increases 0.3 M NaCl intake induced by a combined treatment of furosemide plus captopril. Injection of moxonidine into the LPBN also increases hypertonic NaCl and water intake and reduces oxytocin secretion, urinary sodium, and water excreted by cell-dehydrated rats, causing a positive sodium and water balance, which suggests that moxonidine injected into the LPBN deactivates mechanisms that restrain body fluid volume expansion. Pretreatment with specific α2-adrenoceptor antagonists injected into the LPBN abolishes the behavioral and renal effects of moxonidine or noradrenaline injected into the same area, suggesting that these effects depend on activation of LPBN α2-adrenoceptors. In fluid-depleted rats, the palatability of sodium is reduced by ingestion of hypertonic NaCl, limiting intake. However, in rats treated with moxonidine injected into the LPBN, the NaCl palatability remains high, even after ingestion of significant amounts of 0.3 M NaCl. The changes in behavioral and renal responses produced by activation of α2-adrenoceptors in the LPBN are probably a consequence of reduction of oxytocin secretion and blockade of inhibitory signals that affect sodium palatability. In this review, a model is proposed to show how activation of α2-adrenoceptors in the LPBN may affect palatability and, consequently, ingestion of sodium as well as renal sodium excretion.
Assuntos
Agonistas de Receptores Adrenérgicos alfa 2/farmacologia , Líquidos Corporais/efeitos dos fármacos , Homeostase/efeitos dos fármacos , Núcleos Parabraquiais/efeitos dos fármacos , Agonistas de Receptores Adrenérgicos alfa 2/administração & dosagem , Animais , Líquidos Corporais/fisiologia , Captopril/administração & dosagem , Captopril/farmacologia , Ingestão de Líquidos/efeitos dos fármacos , Furosemida/administração & dosagem , Furosemida/farmacologia , Homeostase/fisiologia , Imidazóis/administração & dosagem , Imidazóis/farmacologia , Núcleos Parabraquiais/fisiologia , Ratos , Cloreto de Sódio na DietaRESUMO
Central α2-adrenoceptors and the pontine lateral parabrachial nucleus (LPBN) are involved in the control of sodium and water intake. Bilateral injections of moxonidine (α2-adrenergic/imidazoline receptor agonist) or noradrenaline into the LPBN strongly increases 0.3 M NaCl intake induced by a combined treatment of furosemide plus captopril. Injection of moxonidine into the LPBN also increases hypertonic NaCl and water intake and reduces oxytocin secretion, urinary sodium, and water excreted by cell-dehydrated rats, causing a positive sodium and water balance, which suggests that moxonidine injected into the LPBN deactivates mechanisms that restrain body fluid volume expansion. Pretreatment with specific α2-adrenoceptor antagonists injected into the LPBN abolishes the behavioral and renal effects of moxonidine or noradrenaline injected into the same area, suggesting that these effects depend on activation of LPBN α2-adrenoceptors. In fluid-depleted rats, the palatability of sodium is reduced by ingestion of hypertonic NaCl, limiting intake. However, in rats treated with moxonidine injected into the LPBN, the NaCl palatability remains high, even after ingestion of significant amounts of 0.3 M NaCl. The changes in behavioral and renal responses produced by activation of α2-adrenoceptors in the LPBN are probably a consequence of reduction of oxytocin secretion and blockade of inhibitory signals that affect sodium palatability. In this review, a model is proposed to show how activation of α2-adrenoceptors in the LPBN may affect palatability and, consequently, ingestion of sodium as well as renal sodium excretion.
Assuntos
Animais , Ratos , /farmacologia , Líquidos Corporais/efeitos dos fármacos , Homeostase/efeitos dos fármacos , Núcleos Parabraquiais/efeitos dos fármacos , /administração & dosagem , Líquidos Corporais/fisiologia , Captopril/administração & dosagem , Captopril/farmacologia , Ingestão de Líquidos/efeitos dos fármacos , Furosemida/administração & dosagem , Furosemida/farmacologia , Homeostase/fisiologia , Imidazóis/administração & dosagem , Imidazóis/farmacologia , Núcleos Parabraquiais/fisiologia , Cloreto de Sódio na DietaRESUMO
It is of current interest the identification of appropriate matrices for growing mesenchymal stem cells (MSC). These cells are able not only to regenerate themselves but also to differentiate into other type of functional cells, and so they have been extensively used in tissue engineering. In this work, we have evaluated the use of electric impedance spectroscopy (EIS) to follow the adhesion of MSC from Wharton's jelly of the human umbilical cord (hWJMSC) on sugarcane biopolymers (SCB). Impedance spectra of the systems were obtained in the frequency range of 10(2)-10(5) Hz. An EIS investigation showed that when deposited on a metallic electrode SCB films prevent the passage of electrons between the solution and the metallic interface. The impedance spectra of hWJMSCs adhered on SCB revealed that there is a significant increase in the magnitude of the impedance when compared to that of pure SCB. The corresponding resistance (real part of the impedance) was even higher for the SCB-hWJMSC system than for SCB without cells on their surface, in an indication of an increased blockage to the electron transfers. The resistance charge transfer is extracted by curve-fitting the impedance spectra to an equivalent circuit model. Also, a shift of the phase angle to higher frequencies was obtained for SCB-hWJMSC system as a result from hWJMSC adhesion. Our study demonstrates that EIS is an appropriate method to evaluate the adhesion of MSC. SCB can be considered as a promising biomaterial for tissue engineering.
Assuntos
Materiais Biocompatíveis/química , Biopolímeros/química , Células-Tronco Mesenquimais/citologia , Células-Tronco Mesenquimais/fisiologia , Saccharum/química , Cordão Umbilical/citologia , Adesão Celular , Células Cultivadas , Impedância Elétrica , Feminino , Humanos , Teste de Materiais , Microscopia de Força Atômica , Microscopia Eletrônica de Varredura , Gravidez , Engenharia Tecidual , Geleia de Wharton/citologiaRESUMO
The deactivation of the inhibitory mechanisms with injections of moxonidine (α2-adrenoceptor/imidazoline receptor agonist) into the lateral parabrachial nucleus (LPBN) increases hypertonic NaCl intake by intra- or extracellular dehydrated rats. In the present study, we investigated the changes in the urinary sodium and volume, sodium balance, and plasma vasopressin and oxytocin in rats treated with intragastric (i.g.) 2 M NaCl load (2 ml/rat) combined with injections of moxonidine into the LPBN. Male Holtzman rats (n=5-12/group) with stainless steel cannulas implanted bilaterally into LPBN were used. Bilateral injections of moxonidine (0.5 nmol/0.2 µl) into the LPBN decreased i.g. 2 M NaCl-induced diuresis (4.6±0.7 vs. vehicle: 7.4±0.6 ml/120 min) and natriuresis (1.65±0.29 vs. vehicle: 2.53±0.17 mEq/120 min), whereas the previous injection of the α2-adrenoceptor antagonist RX 821002 (10 nmol/0.2 µl) into the LPBN abolished the effects of moxonidine. Moxonidine injected into the LPBN reduced i.g. 2 M NaCl-induced increase in plasma oxytocin and vasopressin (14.6±2.8 and 2.2±0.3 vs. vehicle: 25.7±7 and 4.3±0.7 pg/ml, respectively). Moxonidine injected into the LPBN combined with i.g. 2 M NaCl also increased 0.3 M NaCl intake (7.5±1.7 vs. vehicle: 0.5±0.2 mEq/2 h) and produced positive sodium balance (2.3±1.4 vs. vehicle: -1.2±0.4 mEq/2 h) in rats that had access to water and NaCl. The present results show that LPBN α2-adrenoceptor activation reduces renal and hormonal responses to intracellular dehydration and increases sodium and water intake, which facilitates sodium retention and body fluid volume expansion.
Assuntos
Agonistas de Receptores Adrenérgicos alfa 2/farmacologia , Plexo Braquial , Desidratação/metabolismo , Hormônios/sangue , Imidazóis/farmacologia , Receptores de Imidazolinas/agonistas , Rim/efeitos dos fármacos , Agonistas de Receptores Adrenérgicos alfa 2/administração & dosagem , Antagonistas Adrenérgicos alfa/farmacologia , Animais , Arginina Vasopressina/sangue , Fator Natriurético Atrial/sangue , Volume Sanguíneo/efeitos dos fármacos , Desidratação/patologia , Diurese/efeitos dos fármacos , Idazoxano/análogos & derivados , Idazoxano/farmacologia , Imidazóis/administração & dosagem , Receptores de Imidazolinas/administração & dosagem , Rim/citologia , Masculino , Natriurese/efeitos dos fármacos , Concentração Osmolar , Ocitocina/sangue , Potássio/urina , Ratos , Ratos Sprague-Dawley , Renina/sangue , Sódio/sangue , Sódio/metabolismo , Cloreto de Sódio/farmacologia , Equilíbrio Hidroeletrolítico/efeitos dos fármacosRESUMO
A collaborative project was established between the Alli Causai Foundation in Ambato, Ecuador, and the University of Genoa, Italy, to introduce the microscopic observation drug susceptibility (MODS) assay for the rapid identification of Mycobacterium tuberculosis in Ecuador. A total of 507 samples were evaluated during a 10-month period, and DNA was extracted from each isolate and sent to Genoa for confirmatory molecular analysis. M. tuberculosis was identified in 45 samples by MODS, and drug resistance was observed in approximately 21% of the isolates, with four multidrug-resistant strains detected in two patients.
Assuntos
Antituberculosos/uso terapêutico , DNA Bacteriano/genética , Farmacorresistência Bacteriana Múltipla/genética , Mutação , Mycobacterium tuberculosis/isolamento & purificação , Tuberculose Resistente a Múltiplos Medicamentos/diagnóstico , Contagem de Colônia Microbiana/métodos , Equador/epidemiologia , Humanos , Incidência , Mycobacterium tuberculosis/genética , Reação em Cadeia da Polimerase , Prevalência , Estudos Retrospectivos , Tuberculose Resistente a Múltiplos Medicamentos/tratamento farmacológico , Tuberculose Resistente a Múltiplos Medicamentos/epidemiologiaRESUMO
The utilization of tannery sludge in agricultural areas can be an alternative for its disposal and recycling. Despite this procedure may cause the loss of nitrogen by ammonia volatilization, there is no information about this process in tropical soils. For two years a field experiment was carried out in Rolândia (Paraná State, Brazil), to evaluate the amount of NH(3) volatilization due to tannery sludge application on agricultural soil. The doses of total N applied varied from zero to 1200 kg ha(-1), maintained at the surface for 89 days, as usual in this region. The alkalinity of the tannery sludge used was equivalent to between 262 and 361 g CaCO(3) per kg. Michaelis-Menten equation was adequate to estimate NH(3)-N volatilization kinetics. The relation between total nitrogen applied as tannery sludge and the potentially volatilized NH(3)-N, calculated by the chemical-kinetics equation resulted in an average determination coefficient of 0.87 (P>0.01). In this period, the amount of volatilized NH(3) was more intense during the first 30 days; the time to reach half of the maximum NH(3) volatilization (K(m)) was 13 an 9 days for the first and second experiments, respectively. The total loss as ammonia in the whole period corresponded in average to 17.5% of the total N applied and to 35% of the NH(4)(+)-N present in the sludge. If tannery sludge is to be surface applied to supply N for crops, the amounts lost as NH(3) must be taken into consideration.
Assuntos
Amônia/análise , Resíduos Industriais/análise , Esgotos/química , Solo/análise , Curtume , Biodegradação Ambiental , Brasil , Concentração de Íons de Hidrogênio , Nitrogênio/análise , Esgotos/microbiologia , Microbiologia do Solo , VolatilizaçãoRESUMO
The lateral parabrachial nucleus (LPBN) and the central nucleus of the amygdala (CeA) are important areas for the control of sodium appetite. In the present study we investigated the effects of bilateral lesions of the CeA on the facilitation of water and 0.3 M NaCl intake produced by the blockade of serotonergic mechanisms or activation of alpha(2)-adrenoceptors with bilateral injections of methysergide or moxonidine, respectively, into the LPBN. Male Holtzman rats (n=5-8) with bilateral sham or electrolytic lesions of the CeA (2 mA; 10 s) and stainless steel cannulas implanted bilaterally in the LPBN were used. In sham rats treated with the diuretic furosemide (10 mg/kg b.w.) combined with the angiotensin converting enzyme inhibitor captopril (5 mg/kg b.w) subcutaneously, bilateral injections of moxonidine (0.5 nmol) or methysergide (4 microg) into the LPBN increased 0.3 M NaCl intake (29.8+/-5.1 and 19.5+/-3.7 ml/2 h, respectively, versus vehicle: 8.3+/-1.4 ml/2 h) and water intake (17.9+/-3.7 and 23.3+/-2.8 ml/2 h, respectively, versus vehicle: 11.5+/-1.6 ml/2 h). Lesions of the CeA (5-18 days) abolished the increase in 0.3 M NaCl and water intake produced by bilateral injections of moxonidine (10.3+/-2.8 and 6.8+/-2.3 ml/2 h, respectively) and reduced the increase produced by methysergide (13.6+/-2.5 and 14.5+/-3.2 ml/2 h, respectively) into the LPBN. The present results show that the increase in water and 0.3 M NaCl intake produced by serotonergic blockade and alpha(2)-adrenergic activation in the LPBN depends on the integrity of the CeA, suggesting that facilitatory mechanisms present in the CeA are essential for the increase of water and hypertonic NaCl intake produced by the blockade of the inhibitory mechanisms of the LPBN.
Assuntos
Tonsila do Cerebelo/fisiologia , Comportamento de Ingestão de Líquido/fisiologia , Ponte/fisiologia , Cloreto de Sódio na Dieta , Antagonistas Adrenérgicos/farmacologia , Tonsila do Cerebelo/efeitos dos fármacos , Inibidores da Enzima Conversora de Angiotensina/farmacologia , Animais , Peso Corporal , Captopril/farmacologia , Diuréticos/farmacologia , Comportamento de Ingestão de Líquido/efeitos dos fármacos , Furosemida/farmacologia , Imidazóis/farmacologia , Masculino , Metisergida/farmacologia , Ponte/efeitos dos fármacos , Ratos , Ratos Sprague-Dawley , Antagonistas da Serotonina/farmacologia , Fatores de Tempo , ÁguaRESUMO
AIMS: The aim of this work was to analyse the antimicrobial properties of a purified lectin from Eugenia uniflora L. seeds. METHODS AND RESULTS: The E. uniflora lectin (EuniSL) was isolated from the seed extract and purified by ion-exchange chromatography in DEAE-Sephadex with a purification factor of 11.68. The purified lectin showed a single band on denaturing electrophoresis, with a molecular mass of 67 kDa. EuniSL agglutinated rabbit and human erythrocytes with a higher specificity for rabbit erythrocytes. The haemagglutination was not inhibited by the tested carbohydrates but glycoproteins exerted a strong inhibitory action. The lectin proved to be thermo resistant with the highest stability at pH 6.5 and divalent ions did not affect its activity. EuniSL demonstrated a remarkable nonselective antibacterial activity. EuniSL strongly inhibited the growth of Staphylococcus aureus, Pseudomonas aeruginosa and Klebsiella sp. with a minimum inhibitory concentration (MIC) of 1.5 microg ml(-1), and moderately inhibited the growth of Bacillus subtilis, Streptococcus sp. and Escherichia coli with a MIC of 16.5 microg ml(-1). CONCLUSIONS: EuniSL was found to be effective against bacteria. SIGNIFICANCE AND IMPACT OF THE STUDY: The strong antibacterial activity of the studied lectin indicates a high potential for clinical microbiology and therapeutic applications.
Assuntos
Antibacterianos/farmacologia , Bactérias Gram-Negativas/efeitos dos fármacos , Bactérias Gram-Positivas/efeitos dos fármacos , Lectinas , Sementes/química , Syzygium/química , Hemaglutinação , Testes de Inibição da Hemaglutinação , Humanos , Lectinas/química , Lectinas/isolamento & purificação , Lectinas/metabolismo , Lectinas/farmacologia , Testes de Sensibilidade MicrobianaRESUMO
We report an electrical impedance spectroscopy (EIS) characterization of composite systems formed by emulsion polymerization of polypyrrole (PPY) in concentrated aqueous solutions of sodium dodecyl sulfate (SDS) containing dispersed magnetite particles. SDS-(Fe3O4)-(conducting polymer) microaggregates with different iron contents were prepared by varying in a reciprocal manner the relative amounts of the metal oxide and PPY. We have measured the zeta-potential and the average size of the corresponding dispersed particles and examined their relative composition through energy dispersive X-ray (EDX) microanalysis and Fourier transform infrared (FTIR) spectroscopy. Important aspects of the charge transport in these composite particles can be identified by mapping the real and imaginary parts of their complex impedance as a function of the frequency of the applied external electric field. For instance, for binary composites SDS-(Fe3O4) polarization effects are dominant at the low-frequency regime, with a well-defined dielectric relaxation easily identifiable. On the other hand, when the relative amount of PPY is progressively increased in the ternary SDS-(Fe3O4)-PPY composites, a transition between different charge transport mechanisms is observed at higher frequencies. The EIS results suggest that in these ternary aggregates the PPY chains envelop the metal oxide clusters and effectively shield them from the external field, and that only in binary samples that do not contain PPY is that the surfactant molecules can directly enclose the magnetite particles. These results are consistent with the fact that the average size of the aggregates in the ternary composites is in general larger than those of either SDS-PPY or SDS-magnetite binary particles.
RESUMO
The inhibition of sodium intake by increased plasma osmolarity may depend on inhibitory mechanisms present in the lateral parabrachial nucleus. Activation of alpha(2)-adrenergic receptors in the lateral parabrachial nucleus is suggested to deactivate inhibitory mechanisms present in this area increasing fluid depletion-induced 0.3 M NaCl intake. Considering the possibility that lateral parabrachial nucleus inhibitory mechanisms are activated and restrain sodium intake in animals with increased plasma osmolarity, in the present study we investigated the effects on water and 0.3 M NaCl intake produced by the activation of alpha(2)-adrenergic receptors in the lateral parabrachial nucleus in rats with increased plasma osmolarity. Male Holtzman rats with stainless steel cannulas implanted bilaterally into the lateral parabrachial nucleus were used. One hour after intragastric 2 M NaCl load (2 ml), bilateral injections of moxonidine (alpha(2)-adrenergic/imidazoline receptor agonist, 0.5 nmol/0.2 microl, n=10) into the lateral parabrachial nucleus induced a strong ingestion of 0.3 M NaCl intake (19.1+/-5.5 ml/2 h vs. vehicle: 1.8+/-0.6 ml/2 h), without changing water intake (15.8+/-3.0 ml/2 h vs. vehicle: 9.3+/-2.0 ml/2 h). However, moxonidine into the lateral parabrachial nucleus in satiated rats not treated with 2 M NaCl produced no change on 0.3 M NaCl intake. The pre-treatment with RX 821002 (alpha(2)-adrenergic receptor antagonist, 20 nmol/0.2 microl) into the lateral parabrachial nucleus almost abolished the effects of moxonidine on 0.3 M NaCl intake (4.7+/-3.4 ml/2 h). The present results suggest that alpha(2)-adrenergic receptor activation in the lateral parabrachial nucleus blocks inhibitory mechanisms, thereby allowing ingestion of hypertonic NaCl under conditions of extracellular hyperosmolarity. We suggest that during cell dehydration, circuits subserving sodium appetite are activated, but at the same time strongly inhibited through the lateral parabrachial nucleus.
Assuntos
Comportamento de Ingestão de Líquido/fisiologia , Bulbo/metabolismo , Receptores Adrenérgicos alfa 2/metabolismo , Cloreto de Sódio na Dieta/metabolismo , Antagonistas Adrenérgicos alfa/farmacologia , Animais , Anti-Hipertensivos/farmacologia , Comportamento Animal , Ingestão de Líquidos/efeitos dos fármacos , Ingestão de Líquidos/fisiologia , Comportamento de Ingestão de Líquido/efeitos dos fármacos , Interações Medicamentosas , Idazoxano/análogos & derivados , Idazoxano/farmacologia , Imidazóis/farmacologia , Masculino , Bulbo/efeitos dos fármacos , Inibição Neural/efeitos dos fármacos , Inibição Neural/fisiologia , Ratos , Fatores de TempoRESUMO
A atividade antibacteriana das flores da Acacia podalyriifolia A. Cunn. (Leguminosae) foi avaliada pelo método de difusão em disco. As bactérias testadas foram: Staphylococcus aureus (ATCC 6538), Staphylococcus epidermidis (ATCC 1228), Escherichia coli (ATCC 11229) e Pseudomonas aeruginosa (ATCC 27853). O meio de cultura utilizado foi ágar Müeller-Hinton. Foram utilizados discos de papel (6 mm de diâmetro) impregnados com 1000, 500, 250 e 125 mg dos extratos: Etanol Bruto, fração Acetato de Etila e fração Diclorometano obtidas a partir do extrato etanólico bruto. Os resultados indicam que as amostras avaliadas exercem ação contra as cepas gram positivo testadas, em graus variáveis sendo que a fração Acetato de Etila apresentou maior atividade. A triagem fitoquímica indicou a presença de fenóis e flavonoides nas flores de A. podalyriifolia.
The antibacterial activity of the flowers of Acacia podalyriifolia A. Cunn. (Leguminosae) was evaluated through the gel diffusion method. The bacteria tested were: Staphylococcus aureus (ATCC 6538), Staphylococcus epidermidis (ATCC 1228), Escherichia coli (ATCC 11229) and Pseudomonas aeruginosa (ATCC 27853). The culture media was agar Müeller-Hinton. Paper discs (6 mm in diameter) with 1000, 500, 250 e 125 mg of the tested extracts (crude ethanolic and its fractions; Ethyl Acetate and Dichloromethane) were used. The results indicated action against the gram-positive tested strains in different levels. The Ethyl Acetate extract showed a higher activity. Phenols and flavonoids were detected in the flowers of A. podalyriifolia through phytochemical screening.