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1.
NPJ Sci Food ; 8(1): 5, 2024 Jan 13.
Artigo em Inglês | MEDLINE | ID: mdl-38216591

RESUMO

Progress in science, technology, innovation, and digital capabilities call for reassessing food science, technology, and engineering (FST&E) education and research programs. This survey targeted global professionals and students across food disciplines and nutrition. Its main objectives included assessing the status of FST&E higher education, identifying challenges and opportunities, and furnishing recommendations. Seven topics affecting the future of the FST&E curricula were evaluated by the panel as 'High' to 'Very high', namely: 'Critical thinking', followed by 'Problem-solving projects', 'Teamwork/collaboration', 'Innovation/Open innovation' and 'Multidisciplinary'. The importance of academic partnership/collaboration with the Food Industry and Nutrition Sciences was demonstrated. Significant positive roles of the food industry in collaboration and partnerships were found. Other essential food industry attributes were related to internships, education, strategy, and vision. Collaboration between FST&E and nutrition sciences indicated the high standing of this direction. The need to integrate or converge nutrition sciences and FST&E is emphasized, especially with the growing consumer awareness of health and wellness. The study provides insights into new education and learning opportunities and new topics for future curricula.

2.
J Ind Microbiol Biotechnol ; 38(9): 1535-43, 2011 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-21298318

RESUMO

Ethylene oxide is currently a dominant agent in medical device sterilization. This work intends to study the main effects and interactions of temperature, ethylene oxide concentration, and relative humidity on commercial spore strips of Bacillus subtilis, var. niger (ATCC 9372) inactivation, the most common microorganism used in controlling the efficacy of the process. Experiments were carried out using a full factorial experimental design at two levels (2(3) factorial design). Limit target exposure conditions for ethylene oxide concentration, temperature, and relative humidity were 250-1,000 mg EO/l, 40-60°C, and 50-90%, respectively. Adopting a different approach from the first-order kinetics, a Gompertz model was successfully applied in data fitting of the inactivation curves. Bacillus subtilis kinetic behavior presented a sigmoidal inactivation with an initial shoulder (λ), followed by a maximum inactivation rate (k(max)), these being model parameters. It was concluded that temperature and ethylene oxide concentration were the most significant factors and consequently, additional experiments were carried out aiming at describing the parameters' dependence on these process factors. Mathematical relations describing such dependences were successfully developed and included in the Gompertz kinetic model. The predictive ability of this integrated model was assessed, and its adequacy in predicting B. subtilis inactivation was proven.


Assuntos
Bacillus subtilis/efeitos dos fármacos , Desinfetantes/farmacologia , Óxido de Etileno/farmacologia , Modelos Biológicos , Umidade , Cinética , Viabilidade Microbiana , Esporos Bacterianos/efeitos dos fármacos , Esterilização , Temperatura
4.
Microbes Infect ; 9(8): 1020-5, 2007 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-17544802

RESUMO

Murine Schistosoma mansoni infection is related to an increased contraction of portal vein in response to 5-hydroxytryptamine (5-HT). The present study addressed a putative alteration of ion channels and enzymes involved in vascular contraction. In control group, either inhibition of K+ channels sensitive to ATP (K(ATP)) or Ca2+ (BK(Ca)) increased 5-HT-induced contraction, but the same did not occur in infected mice. On the other hand, inhibition of p38 MAP kinase markedly decreased the vascular contraction to 5-HT in the infected mice with minor effects in the control group. Accordingly, we observed a higher density of phospho-p38 MAP kinase, that refers to the fully active state of the enzyme, in portal veins from infected mice as compared to control animals. These results suggest that the reduced function of K(ATP) and BK(Ca) channels along with an increased contribution of p38 MAP kinase contribute to the increased contraction of portal veins to 5-HT observed in murine schistosomiasis.


Assuntos
Veia Porta/fisiopatologia , Canais de Potássio/metabolismo , Schistosoma mansoni/patogenicidade , Esquistossomose mansoni/fisiopatologia , Vasoconstrição , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo , Animais , Animais Recém-Nascidos , Feminino , Interações Hospedeiro-Parasita , Humanos , Masculino , Camundongos , Schistosoma mansoni/crescimento & desenvolvimento , Esquistossomose mansoni/parasitologia , Serotonina/farmacologia
5.
Br J Pharmacol ; 151(2): 195-205, 2007 May.
Artigo em Inglês | MEDLINE | ID: mdl-17375079

RESUMO

BACKGROUND AND PURPOSE: We have previously shown that melatonin inhibits bradykinin-induced NO production by endothelial cells in vitro. The purpose of this investigation was to extend this observation to an in vivo condition and to explore the mechanism of action of melatonin. EXPERIMENTAL APPROACH: RT-PCR assays were performed with rat cultured endothelial cells. The putative effect of melatonin upon arteriolar tone was investigated by intravital microscopy while NO production by endothelial cells in vitro was assayed by fluorimetry, and intracellular Ca(2+) measurements were assayed by confocal microscopy. KEY RESULTS: No expression of the mRNA for the melatonin synthesizing enzymes, arylalkylamine N-acetyltransferase and hydroxyindole-O-methyltransferase, or for the melatonin MT(2) receptor was detected in microvascular endothelial cells. Melatonin fully inhibited L-NAME-sensitive bradykinin-induced vasodilation and also inhibited NO production induced by histamine, carbachol and 2-methylthio ATP, but did not inhibit NO production induced by ATP or alpha, beta-methylene ATP. None of its inhibitory effects was prevented by the melatonin receptor antagonist, luzindole. In nominally Ca(2+)-free solution, melatonin reduced intracellular Ca(2+) mobilization induced by bradykinin (40%) and 2-methylthio ATP (62%) but not Ca(2+) mobilization induced by ATP. CONCLUSIONS AND IMPLICATIONS: We have confirmed that melatonin inhibited NO production both in vivo and in vitro. In addition, the melatonin effect was selective for some G protein-coupled receptors and most probably reflects an inhibition of Ca(2+) mobilization from intracellular stores.


Assuntos
Células Endoteliais/efeitos dos fármacos , Melatonina/farmacologia , Artérias Mesentéricas/efeitos dos fármacos , Óxido Nítrico/biossíntese , Acetilserotonina O-Metiltransferasa/genética , Trifosfato de Adenosina/farmacologia , Animais , Arilalquilamina N-Acetiltransferase/genética , Velocidade do Fluxo Sanguíneo/efeitos dos fármacos , Cálcio/metabolismo , Carbacol/farmacologia , Células Cultivadas , Células Endoteliais/citologia , Células Endoteliais/metabolismo , Fluorometria , Expressão Gênica/efeitos dos fármacos , Histamina/farmacologia , Masculino , Artérias Mesentéricas/fisiologia , Microscopia Confocal , Microscopia de Vídeo , NG-Nitroarginina Metil Éster/farmacologia , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Ratos , Ratos Wistar , Receptor MT2 de Melatonina/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Vasodilatação/efeitos dos fármacos
6.
Vascul Pharmacol ; 46(2): 122-8, 2007 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-17049461

RESUMO

Schistosomiasis, an intravascular parasitic disease caused by Schistosoma mansoni, is related to alterations of murine vascular reactivity in the mesenteric bed, characterized by an impairment of the l-arginine/NO pathway and an increased potency of 5-hydroxytryptamine. The current study was performed to test the hypothesis that a similar alteration of reactivity also occurs in the aorta and to identify the mechanism behind such an increase. We found that aorta from mice infected with male S. mansoni exhibited an enhanced contraction in response to noradrenaline and 100 mM KCl. The inhibition of nitric oxide synthase increased aortic maximal contraction in response to noradrenaline in both groups, but the effect was less pronounced in infected mice than in control mice. Endothelium-dependent relaxation induced by acetylcholine was also smaller in infected mice compared to control mice, while endothelial-independent relaxation induced by sodium nitroprusside and forskolin was similar in both groups. The inhibition of voltage-dependent L-type Ca(2+) channels reduced the maximal contraction in response to noradrenaline more effectively in infected than in control mice. Conversely the inhibition of K(ATP) channels had a smaller effect in the infected group. As a conclusion, our data indicate that schistosomiasis also alters murine vascular reactivity outside the mesenteric bed, due to a partial impairment of NO signaling, a reduced contribution of K(ATP) channels and an increased Ca(2+) influx through L-type Ca(2+) channels.


Assuntos
Aorta Torácica/fisiopatologia , Norepinefrina/farmacologia , Esquistossomose mansoni/fisiopatologia , Vasoconstritores/farmacologia , Vasodilatação/efeitos dos fármacos , Trifosfato de Adenosina/metabolismo , Animais , Aorta Torácica/efeitos dos fármacos , Aorta Torácica/metabolismo , Aorta Torácica/parasitologia , Canais de Cálcio Tipo L/metabolismo , Sinalização do Cálcio , Modelos Animais de Doenças , Relação Dose-Resposta a Droga , Endotélio Vascular/efeitos dos fármacos , Endotélio Vascular/fisiopatologia , Masculino , Camundongos , Óxido Nítrico/metabolismo , Canais de Potássio/metabolismo , Cloreto de Potássio/farmacologia , Esquistossomose mansoni/metabolismo , Esquistossomose mansoni/parasitologia , Vasodilatadores/farmacologia
7.
Braz J Med Biol Res ; 49(12): e5542, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27901175

RESUMO

This study aimed to estimate the absorption, distribution, metabolism and excretion (ADME) properties and safety of LDT5, a lead compound for oral treatment of benign prostatic hyperplasia that has previously been characterized as a multi-target antagonist of α1A-, α1D-adrenoceptors and 5-HT1A receptors. The preclinical characterization of this compound comprised the evaluation of its in vitro properties, including plasma, microsomal and hepatocytes stability, cytochrome P450 metabolism and inhibition, plasma protein binding, and permeability using MDCK-MDR1 cells. De-risking and preliminary safety pharmacology assays were performed through screening of 44 off-target receptors and in vivo tests in mice (rota-rod and single dose toxicity). LDT5 is stable in rat and human plasma, human liver microsomes and hepatocytes, but unstable in rat liver microsomes and hepatocytes (half-life of 11 min). LDT5 is highly permeable across the MDCK-MDR1 monolayer (Papp ∼32×10-6 cm/s), indicating good intestinal absorption and putative brain penetration. LDT5 is not extensively protein-bound and is a substrate of human CYP2D6 and CYP2C19 but not of CYP3A4 (half-life >60 min), and did not significantly influence the activities of any of the human cytochrome P450 isoforms screened. LDT5 was considered safe albeit new studies are necessary to rule out putative central adverse effects through D2, 5-HT1A and 5-HT2B receptors, after chronic use. This work highlights the drug-likeness properties of LDT5 and supports its further preclinical development.


Assuntos
Avaliação Pré-Clínica de Medicamentos , Piperazinas/farmacologia , Hiperplasia Prostática/tratamento farmacológico , Animais , Estabilidade de Medicamentos , Feminino , Humanos , Masculino , Camundongos , Permeabilidade , Piperazinas/química , Piperazinas/metabolismo , Ratos , Fatores de Tempo
8.
Br J Pharmacol ; 135(1): 293-8, 2002 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-11786506

RESUMO

. The effects of LASSBio 294, a new 3,4-methylenedioxybenzoyl-2-thienylhydrazone, on vascular tonus were investigated in isolated rat aortic rings. 2. LASSBio 294 induced a concentration-dependent relaxation of intact rat aortic rings with an inhibitory concentration (IC(50)) of 74 microM (95% confidence limits: 59 - 92). The mechanical removal of the endothelium abolished this effect. 3. In aortic rings with intact endothelium the effect of 100 microM LASSBio 294 was not altered by the pharmacological inhibition of NOS and cyclo-oxygenase pathways with 500 microM L-NAME and 10 microM indomethacin, respectively. 4. LASSBio 294 (100 microM) was able to relax aortic rings pre-contracted with high extracellular K(+) (KCl 100 mM). 5. The relaxant effect of LASSBio 294 was fully reversed (and prevented) by the addition of 1 microM ODQ (1H-(1,2,4)oxadiazolo[4,3-a]quinoxaline-1-one), a selective inhibitor of soluble guanylate cyclase. 6. LASSBio 294 (100 microM) had no direct effect on PDE3 and PDE4 activities, however, it increased by 150% cyclic GMP content in aortic rings pre-treated with 100 microM L-NAME and 10 microM indomethacin, as did 1 microM zaprinast, a selective PDE5 inhibitor. 7. In conclusion, LASSBio 294 induced relaxation of isolated rat aorta probably by directly increasing cyclic GMP content, possibly as a consequence of PDE5 inhibition.


Assuntos
Aorta Torácica/efeitos dos fármacos , GMP Cíclico/metabolismo , Hidrazonas/farmacologia , Tiofenos/farmacologia , Vasoconstrição/efeitos dos fármacos , Vasodilatadores/farmacologia , 3',5'-GMP Cíclico Fosfodiesterases/metabolismo , Animais , Aorta Torácica/metabolismo , Aorta Torácica/fisiologia , Nucleotídeo Cíclico Fosfodiesterase do Tipo 5 , Guanilato Ciclase/antagonistas & inibidores , Guanilato Ciclase/metabolismo , Hidrazonas/química , Técnicas In Vitro , Indometacina/farmacologia , Masculino , Estrutura Molecular , NG-Nitroarginina Metil Éster/farmacologia , Óxido Nítrico Sintase/efeitos dos fármacos , Óxido Nítrico Sintase/metabolismo , Oxidiazóis/farmacologia , Prostaglandina-Endoperóxido Sintases/efeitos dos fármacos , Prostaglandina-Endoperóxido Sintases/metabolismo , Quinoxalinas/farmacologia , Ratos , Ratos Wistar , Tiofenos/química
9.
Neuroscience ; 231: 315-27, 2013 Feb 12.
Artigo em Inglês | MEDLINE | ID: mdl-23219939

RESUMO

Angiotensins (Angs) modulate blood pressure, hydro-electrolyte composition, and antinociception. Although Ang (5-8) has generally been considered to be inactive, we show here that Ang (5-8) was the smallest Ang to elicit dose-dependent responses and receptor-mediated antinociception in the rat ventrolateral periaqueductal gray matter (vlPAG). Ang (5-8) antinociception seems to be selective, because it did not alter blood pressure or act on vascular or intestinal smooth muscle cells. The non-selective Ang-receptor (Ang-R) antagonist saralasin blocked Ang (5-8) antinociception, but selective antagonists of Ang-R types I, II, IV, and Mas did not, suggesting that Ang (5-8) may act via an unknown receptor. Endopeptidase EP 24.11 and amastatin-sensitive aminopeptidase from the vlPAG catalyzed the synthesis (from Ang II or Ang III) and inactivation of Ang (5-8), respectively. Selective inhibitors of neuronal-nitric oxide (NO) synthase, soluble guanylyl cyclase (sGC) and a non-selective opioid receptor (opioid-R) inhibitor blocked Ang (5-8)-induced antinociception. In conclusion, Ang (5-8) is a new member of the Ang family that selectively and strongly modulates antinociception via NO-sGC and endogenous opioid in the vlPAG.


Assuntos
Angiotensina I/farmacologia , Guanilato Ciclase/metabolismo , Óxido Nítrico/metabolismo , Nociceptividade/efeitos dos fármacos , Peptídeos Opioides/metabolismo , Fragmentos de Peptídeos/farmacologia , Substância Cinzenta Periaquedutal/efeitos dos fármacos , Receptores Citoplasmáticos e Nucleares/metabolismo , Transdução de Sinais/efeitos dos fármacos , Antagonistas de Receptores de Angiotensina/farmacologia , Animais , Aorta/efeitos dos fármacos , Relação Dose-Resposta a Droga , Frequência Cardíaca/fisiologia , Masculino , Contração Muscular/efeitos dos fármacos , Músculo Liso/efeitos dos fármacos , Peptídeos Opioides/antagonistas & inibidores , Ratos , Ratos Wistar , Saralasina/farmacologia , Guanilil Ciclase Solúvel , Teprotida/farmacologia
10.
Braz. j. med. biol. res ; 49(12): e5542, 2016. tab, graf
Artigo em Inglês | LILACS | ID: biblio-828179

RESUMO

This study aimed to estimate the absorption, distribution, metabolism and excretion (ADME) properties and safety of LDT5, a lead compound for oral treatment of benign prostatic hyperplasia that has previously been characterized as a multi-target antagonist of α1A-, α1D-adrenoceptors and 5-HT1A receptors. The preclinical characterization of this compound comprised the evaluation of its in vitro properties, including plasma, microsomal and hepatocytes stability, cytochrome P450 metabolism and inhibition, plasma protein binding, and permeability using MDCK-MDR1 cells. De-risking and preliminary safety pharmacology assays were performed through screening of 44 off-target receptors and in vivo tests in mice (rota-rod and single dose toxicity). LDT5 is stable in rat and human plasma, human liver microsomes and hepatocytes, but unstable in rat liver microsomes and hepatocytes (half-life of 11 min). LDT5 is highly permeable across the MDCK-MDR1 monolayer (Papp ∼32×10-6 cm/s), indicating good intestinal absorption and putative brain penetration. LDT5 is not extensively protein-bound and is a substrate of human CYP2D6 and CYP2C19 but not of CYP3A4 (half-life >60 min), and did not significantly influence the activities of any of the human cytochrome P450 isoforms screened. LDT5 was considered safe albeit new studies are necessary to rule out putative central adverse effects through D2, 5-HT1A and 5-HT2B receptors, after chronic use. This work highlights the drug-likeness properties of LDT5 and supports its further preclinical development.


Assuntos
Humanos , Animais , Masculino , Feminino , Camundongos , Ratos , Avaliação Pré-Clínica de Medicamentos , Piperazinas/farmacologia , Hiperplasia Prostática/tratamento farmacológico , Estabilidade de Medicamentos , Permeabilidade , Piperazinas/química , Piperazinas/metabolismo , Fatores de Tempo
11.
Braz J Med Biol Res ; 43(5): 500-5, 2010 May.
Artigo em Inglês | MEDLINE | ID: mdl-20414585

RESUMO

The regulatory function of alpha(1B)-adrenoceptors in mammalian heart homeostasis is controversial. The objective of the present study was to characterize the expression/activity of key proteins implicated in cardiac calcium handling (Na(+)/K(+)-ATPase and Ca(2+)-ATPases) and growth (ERK1/2, JNK1/2 and p38) in mice with cardiac-selective overexpression of constitutively active mutant alpha1B-adrenoceptor (CAMalpha(1B)-AR), which present a mild cardiac hypertrophy phenotype. Immunoblot assays showed that myocardial plasma membrane Ca(2+)-ATPase (PMCA) expression was increased by 30% in CAMalpha(1B)-AR mice (N = 6, P < 0.05), although there was no change in sarco/endoplasmic reticulum Ca(2+)-ATPase (SERCA2) expression. Moreover, total Ca(2+)-ATPase activity was not modified, but a significant increase in the activity of the thapsigargin-resistant (PMCA) to thapsigargin-sensitive (SERCA) ratio was detected. Neither Na(+)/K(+)-ATPase activity nor the expression of alpha(1) and alpha(2) subunit isoforms was changed in CAMalpha(1B)-AR mouse hearts. Moreover, immunoblot assays did not provide evidence for an enhanced activation of the three mitogen-activated protein kinases studied in this stage of hypertrophy. Therefore, these findings indicate that chronic cardiac alpha(1B)-AR activation in vivo led to mild hypertrophy devoid of significant signs of adaptive modifications concerning primary intracellular calcium control and growth-related proteins, suggesting a minor pathophysiological role of this adrenergic receptor in mouse heart at this stage of development.


Assuntos
Adenosina Trifosfatases/metabolismo , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Miocárdio/enzimologia , Receptores Adrenérgicos alfa 1/metabolismo , Animais , Sinalização do Cálcio/fisiologia , Masculino , Camundongos , Camundongos Transgênicos , Regulação para Cima
12.
Parasitology ; 133(Pt 1): 67-74, 2006 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-16566851

RESUMO

We tested the hypothesis that voltage-operated Ca2+ channels mediate an extracellular Ca2+ influx in muscle fibres from the human parasite Schistosoma mansoni and, along with Ca2+ mobilization from the sarcoplasmic reticulum, contribute to muscle contraction. Indeed, whole-cell voltage clamp revealed voltage-gated inward currents carried by divalent ions with a peak current elicited by steps to +20 mV (from a holding potential of -70 mV). Depolarization of the fibres by elevated extracellular K+ elicited contractions that were completely dependent on extracellular Ca2+ and inhibited by nicardipine (half inhibition at 4.1 microM). However these contractions were not very sensitive to other classical blockers of voltage-gated Ca2+ channels, indicating that the schistosome muscle channels have an atypical pharmacology when compared to their mammalian counterparts. Futhermore, the contraction induced by 5 mM caffeine was inhibited after depletion of the sarcoplasmic reticulum either with thapsigargin (10 microM) or ryanodine (10 microM). These data suggest that voltage-operated Ca2+ channels do contribute to S. mansoni contraction as does the mobilization of stored Ca2+, despite the small volume of sarcoplasmic reticulum in schistosome smooth muscles.


Assuntos
Canais de Cálcio/fisiologia , Cálcio/metabolismo , Schistosoma mansoni/fisiologia , Animais , Cafeína/farmacologia , Bloqueadores dos Canais de Cálcio , Canais de Cálcio/metabolismo , Eletrofisiologia , Potenciais da Membrana , Contração Muscular/efeitos dos fármacos , Músculos/efeitos dos fármacos , Músculos/fisiologia , Técnicas de Patch-Clamp , Rianodina/farmacologia , Schistosoma mansoni/metabolismo , Tapsigargina/farmacologia
13.
Braz. j. med. biol. res ; 43(5): 500-505, May 2010. tab, ilus
Artigo em Inglês | LILACS | ID: lil-546327

RESUMO

The regulatory function of á1B-adrenoceptors in mammalian heart homeostasis is controversial. The objective of the present study was to characterize the expression/activity of key proteins implicated in cardiac calcium handling (Na+/K+-ATPase and Ca2+-ATPases) and growth (ERK1/2, JNK1/2 and p38) in mice with cardiac-selective overexpression of constitutively active mutant á1B-adrenoceptor (CAMá1B-AR), which present a mild cardiac hypertrophy phenotype. Immunoblot assays showed that myocardial plasma membrane Ca2+-ATPase (PMCA) expression was increased by 30 percent in CAMá1B-AR mice (N = 6, P < 0.05), although there was no change in sarco/endoplasmic reticulum Ca2+-ATPase (SERCA2) expression. Moreover, total Ca2+-ATPase activity was not modified, but a significant increase in the activity of the thapsigargin-resistant (PMCA) to thapsigargin-sensitive (SERCA) ratio was detected. Neither Na+/K+-ATPase activity nor the expression of á1 and á2 subunit isoforms was changed in CAMá1B-AR mouse hearts. Moreover, immunoblot assays did not provide evidence for an enhanced activation of the three mitogen-activated protein kinases studied in this stage of hypertrophy. Therefore, these findings indicate that chronic cardiac á1B-AR activation in vivo led to mild hypertrophy devoid of significant signs of adaptive modifications concerning primary intracellular calcium control and growth-related proteins, suggesting a minor pathophysiological role of this adrenergic receptor in mouse heart at this stage of development.


Assuntos
Animais , Masculino , Camundongos , Adenosina Trifosfatases/metabolismo , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Miocárdio/enzimologia , Receptores Adrenérgicos alfa 1/metabolismo , Sinalização do Cálcio/fisiologia , Camundongos Transgênicos , Regulação para Cima
14.
Parasitol Res ; 89(1): 16-22, 2003 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-12474038

RESUMO

We previously reported that portal veins from mice infected with male Schistosoma mansoni exhibited an increased reactivity to 5-hydroxytryptamine (5-HT). Here, we extended our observations to mice infected by both male and female worms and we further investigated another constrictor agent and the mechanism(s) responsible for the enhanced maximal contraction ( E(max)). Bisexual infection increased the E(max) of 5-HT (from 0.66+/-0.06 mN.s to 1.56+/-0.38 mN.s), in a similar way to the unisexual (male) infection. Infection with male worms increased portal vein reactivity to acetylcholine, as revealed by a higher E(max) (1.03+/-0.2 mN.s) in relation to non-infected control animals ( E(max)= 0.54+/-0.08 mN.s). Sarcoplasmic/endoplasmic reticulum Ca(2+)-ATPase (SERCA) inhibition with 100 nM thapsigargin reduced the E(max) of 5-HT by 35% in both tissues, discharging a deficiency of SERCA pump in infected animals. In contrast, the number of voltage-dependent Ca(2+) channels (L-type) was higher in portal veins from infected than non-infected control mice. Inhibition of Ca(2+)-activated chloride channels (Cl(Ca)) with 10 micro M niflumic acid reduced the E(max) of 5-HT in portal veins more from infected than non-infected animals (remaining tension = 60.9+/-2.2% and 70.4+/-2.3%, respectively). Histopathological analysis revealed an increased content of collagen and elastin in portal veins from male S. mansoni-infected mice, compatible with an increased intraluminal pressure. In conclusion, male S. mansoni altered portal vein physiology, increasing the E(max) of two vasoconstrictors, possibly by increasing membrane depolarisation through a more effective opening of Cl(Ca) channels, with calcium entering through L-type Ca(2+) channels.


Assuntos
Veia Porta/fisiopatologia , Schistosoma mansoni/patogenicidade , Esquistossomose mansoni/fisiopatologia , Vasoconstrição , Acetilcolina/farmacologia , Animais , Cálcio/metabolismo , Relação Dose-Resposta a Droga , Feminino , Histocitoquímica , Masculino , Camundongos , Veia Porta/citologia , Veia Porta/patologia , Retículo Sarcoplasmático/efeitos dos fármacos , Retículo Sarcoplasmático/metabolismo , Esquistossomose mansoni/metabolismo , Esquistossomose mansoni/parasitologia , Esquistossomose mansoni/patologia , Serotonina/farmacologia , Fatores Sexuais , Caramujos
15.
Mem. Inst. Oswaldo Cruz ; 93(supl.1): 153-5, Oct. 1998. tab, graf
Artigo em Inglês | LILACS | ID: lil-218656

RESUMO

In chronic severe infection with Schistosoma mansoni, portal hypertension and related vascular alterations usually develop as a consequence of granolomatous response to eggs. In order to investigate a putative direct effect of worms on the reactivity of their host portal vein, mice infected only with male worms were used in the present study. An higher reactivity to 5-hydroxytryptamine (5-HT) characterized by an increase in the maximal contraction and sensitivity was observed in portal vein from infected mice compared to healthy mice. Blockade of NO-synthase with l-NAME induced a small increase in 5-HT potency in portal vein from non-infected mice without changing the amplitude of the contractions, whereas it did not alter the reactivity of veins from infected mice. The present results show that unisexual infection of mice with male S. mansoni increased the reactivity of the portal vein to 5-HT which seems to be partially related to an alteration in the nitric oxide release by endothelium.


Assuntos
Animais , Endotélio/parasitologia , Camundongos/parasitologia , Veia Porta , Schistosoma mansoni , Serotonina , Esquistossomose mansoni
16.
Mem. Inst. Oswaldo Cruz ; 96(suppl): 85-88, Sept. 2001. ilus, tab
Artigo em Inglês | LILACS | ID: lil-295884

RESUMO

Calcium signalling is fundamental for muscular contractility of Schistosoma mansoni. We have previously described the presence of transport ATPases (Na+,K+-ATPase and (Ca2+-Mg2+)-ATPase) and calcium channels (ryanodine receptors - RyR) involved in control of calcium homeostasis in this worm. Here we briefly review the main technics (ATPase activity, binding with specific radioligands, fluxes of 45Ca2+ and whole worm contractions) and results obtained in order to compare the distribution patterns of these proteins: thapsigargin-sensitive (Ca2+-Mg2+)-ATPase activity and RyR co-purified in P1 and P4 fractions mainly, which is compatible with a sarcoplasmic reticulum localization, while basal ATPase (along with Na+,K+-ATPase) and thapsigargin-resistant (Ca2+-Mg2+)-ATPase have a distinct distribution, indicative of their plasma membrane localization. Finally we attempt to integrate these contributions with data from other groups in order to propose the first synoptic model for control of calcium homeostasis in S. mansoni


Assuntos
Animais , Cálcio/fisiologia , Homeostase/fisiologia , Schistosoma mansoni/metabolismo , ATPase de Ca(2+) e Mg(2+)/metabolismo , Sinalização do Cálcio , Cálcio/metabolismo , Músculo Liso/metabolismo , Canal de Liberação de Cálcio do Receptor de Rianodina/metabolismo , ATPase Trocadora de Sódio-Potássio/metabolismo
18.
Braz. j. med. biol. res ; 28(3): 363-7, Mar. 1995. tab, graf
Artigo em Inglês | LILACS | ID: lil-154705

RESUMO

The ratio of (Na++K+)-ATPase (EC 3.6.1.3.) isoforms with high and low affinity for cardiac glycosides was studied in heart preparations from neonatal, 3-month and 6-month old Wistar rats. Biphasic ouabain inhibition curves of (Na++K+)-ATPase activity indicated that the relative contribution of the high-affinity process decreased from 34 percent at 9 days to 23 percent at 3 months and to 10 percent at 6 months. Scatchard plots for [3H]ouabain binding were curvillinear and indicated that the relative contribution of the high-affinity sites (Kd = 0.1-0.25 µM) decreased by about one-half between 3 months (19-24 percent, N = 2) and 6 months (9-11 percent, N = 2)


Assuntos
Animais , Ratos , Isoenzimas/metabolismo , Ouabaína/farmacologia , ATPase Trocadora de Sódio-Potássio/metabolismo , Ventrículos do Coração , Fatores Etários , Sítios de Ligação , Ratos Wistar
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