Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 17 de 17
Filter
Add more filters











Publication year range
1.
Braz. j. biol ; 84: e260065, 2024. tab, graf
Article in English | VETINDEX | ID: biblio-1384082

ABSTRACT

Achatina fulica is a terrestrial mollusk known as the giant African snail that is related to environmental, economic, urban, and public health problems. As control measures for this mollusk, cooking salt (NaCl) and calcium oxide (CaO) are used, and baits are composed of metaldehyde. However, these measures have environmental toxicity and impact the soil. In this way, natural products have been tested on this mollusk to discover and develop a substance to combat this urban and agricultural pest. This article aims to evaluate studies involving natural products to control the population of Achatina fulica. Articles and works published in books were included in the present work. A total of 1,103 works were found during the search. Of these, 14 works met the objective of these review and were included in this article. The tests do not possess methodological standardization, do not have a maximum concentration to be considered active, or a maximum exposure time. A lack of standardization in the methodology of tests on A. fulica was observed. The performance of tests on other life stages of the mollusk, as well as tests that analyze other parameters, are essential. Only one article analyzed presented phytochemical analysis. No ecotoxicity tests were reported either. Some extracts showed promising results, highlighting the aqueous extract of Capsicum frutescens. More studies investigating the molluscicidal activity of natural products on A. fulica are needed. It is very relevant that the new studies present a phytochemical analysis of the tested extracts, as well as ecotoxicity studies.


Achatina fulica é um molusco terrestre conhecido como caramujo gigante africano que está relacionado a problemas ambientais, econômicos, urbanos e de saúde pública. Como medidas de controle para esse molusco, são utilizados sal de cozinha (NaCl) e óxido de cálcio (CaO), e as iscas são compostas de metaldeído. No entanto, essas medidas têm toxicidade ambiental e impactam o solo. Desta forma, produtos naturais foram testados neste molusco para descobrir e desenvolver uma substância para combater esta praga urbana e agrícola. Este artigo tem como objetivo avaliar estudos envolvendo produtos naturais para controle da população de Achatina fulica. Artigos e trabalhos publicados em livros foram incluídos no presente trabalho. Um total de 1.103 trabalhos foram encontrados durante a pesquisa. Destes, 14 trabalhos atendiam ao objetivo desta revisão e foram incluídos neste artigo. Os testes não possuem padronização metodológica, não possuem concentração máxima para serem considerados ativos ou tempo máximo de exposição. Observou-se uma falta de padronização na metodologia de testes em A. fulica. A realização de testes em outras fases da vida do molusco, bem como testes que analisem outros parâmetros, são essenciais. Apenas um artigo analisado apresentou análise fitoquímica. Também não foram relatados testes de ecotoxicidade. Alguns extratos apresentaram resultados promissores, com destaque para o extrato aquoso de Capsicum frutescens. Mais estudos investigando a atividade molusquicida de produtos naturais sobre A. fulica são necessários. É muito relevante que os novos estudos apresentem uma análise fitoquímica dos extratos testados, bem como estudos de ecotoxicidade.


Subject(s)
Animals , Snails , Biological Products/administration & dosage , Pest Control , Agriculture , Public Health
2.
Braz J Biol ; 83: e266526, 2023.
Article in English | MEDLINE | ID: mdl-37283371

ABSTRACT

Schistosomiasis is a neglected tropical disease caused by parasitic worms of several species of the genus Schistosoma. Transmission occurs by parasitic larvae that stay in freshwater snails of the genus Biomphalaria. Thus, the search for new products that are biodegradable has increased the interest in products of plant origin. The aim of this article is to review the isolated substances from natural products that showed molluscicidal activity against the species Biomphalaria glabrata in order to reevaluate the most promising prototypes and update the progress of research to obtain a new molluscicide. We perform searches using scientific databases, such as Scientific Electronic Library Online (SciELO), Google schoolar, PUBMED, Web of Science and Latin American and Caribbean Literature on Health Sciences (LILACS). From 2000 to 2022, using the keywords "isolated substances", "molluscicidal activity" and "Biomphalaria glabrata". In the present study, it was possible to observe 19 promising molluscicidal molecules with a lethal concentration below 20 µg/mL. Of these promising isolates, only 5 isolates had the CL90 calculated and within the value recommended by WHO: Benzoic acid, 2',4',6'-Trihydroxydihydrochalcone, Divaricatic acid, Piplartine and 2-hydroxy-1,4-naphthoquinone (Lapachol). We conclude that beyond a few results in the area, the researches don't follow the methodological pattern (exposure time and measure units, toxicity test), in this way, as they don't follow a pattern on the result's exposure (LC), not following, in sum, the recommended by WHO.


Subject(s)
Biological Products , Biomphalaria , Molluscacides , Animals , Biomphalaria/parasitology , Biological Products/pharmacology , Snails , Molluscacides/toxicity
3.
Braz J Biol ; 83: e268859, 2023.
Article in English | MEDLINE | ID: mdl-37132741

ABSTRACT

The use of medicinal plants as raw material for extracts production and pure substances isolation and subsequence development of new drugs represents a constantly growing area. However, some stages are indispensable before pharmacologically evaluating natural products such as medicines. Toxicity tests in mammalian cells are essential to initiate new drugs development or verify the substance's biocompatibility. Thus, we verified the toxicity of crude extracts and fractions with different polarities obtained from the leaves and stems of eight plant species. The toxic effect was evaluated on macrophages obtained from the bone marrow and peritoneal cavity of a Swiss webster mouse and J774 macrophages. G8 cell lineage. These macrophages were cultured in a 96-well plate, and the compounds were added at a concentration of 100 µg/mL for 24 hours. After this time, the supernatant was removed. The toxicity was evaluated for lactate dehydrogenase (LDH) release assay and the resazurin assay, which uses an indicator dye to measure oxidation-reduction reactions. The results showed a difference in the percentage of toxicity when comparing the same extract in different types of macrophages. This outcome indicates that these cells from different origins may exhibit different responses when exposed to the same natural compounds.


Subject(s)
Plant Extracts , Plants, Medicinal , Mice , Animals , Plant Extracts/toxicity , Macrophages , Plant Leaves , Mammals
4.
Braz. j. biol ; 83: e266526, 2023. tab, ilus
Article in English | VETINDEX | ID: biblio-1439655

ABSTRACT

Schistosomiasis is a neglected tropical disease caused by parasitic worms of several species of the genus Schistosoma. Transmission occurs by parasitic larvae that stay in freshwater snails of the genus Biomphalaria. Thus, the search for new products that are biodegradable has increased the interest in products of plant origin. The aim of this article is to review the isolated substances from natural products that showed molluscicidal activity against the species Biomphalaria glabrata in order to reevaluate the most promising prototypes and update the progress of research to obtain a new molluscicide. We perform searches using scientific databases, such as Scientific Electronic Library Online (SciELO), Google schoolar, PUBMED, Web of Science and Latin American and Caribbean Literature on Health Sciences (LILACS). From 2000 to 2022, using the keywords "isolated substances", "molluscicidal activity" and "Biomphalaria glabrata". In the present study, it was possible to observe 19 promising molluscicidal molecules with a lethal concentration below 20 µg/mL. Of these promising isolates, only 5 isolates had the CL90 calculated and within the value recommended by WHO: Benzoic acid, 2',4',6'-Trihydroxydihydrochalcone, Divaricatic acid, Piplartine and 2-hydroxy-1,4-naphthoquinone (Lapachol). We conclude that beyond a few results in the area, the researches don't follow the methodological pattern (exposure time and measure units, toxicity test), in this way, as they don't follow a pattern on the result's exposure (LC), not following, in sum, the recommended by WHO.


A esquistossomose é uma doença tropical negligenciada causada por vermes parasitas de várias espécies do gênero Schistosoma. A transmissão ocorre por larvas parasitas que ficam em caramujos de água doce do gênero Biomphalaria. Assim, a busca por novos produtos biodegradáveis ​​tem aumentado o interesse por produtos de origem vegetal. O objetivo deste artigo é revisar as substâncias isoladas de produtos naturais que apresentaram atividade moluscicida contra a espécie Biomphalaria glabrata a fim de reavaliar os protótipos mais promissores e atualizar o progresso das pesquisas para a obtenção de um novo moluscicida. Realizamos buscas em bases de dados científicas, como Scientific Electronic Library Online (SciELO), Google acadêmico, PUBMED, Web of Science e Literatura Latina-Americana e do Caribe em Ciências da saúde (LILACS). De 2000 a 2022, utilizando as palavras-chave "substâncias isoladas", "atividade moluscicida" e "Biomphalaria glabrata". No presente estudo, foi possível observar 19 moléculas moluscicidas promissoras com concentração letal abaixo de 20 µg/mL. Destes isolados promissores, apenas 5 isolados tiveram o CL90 calculado e dentro do valor recomendado pela OMS: ácido benzóico, 2',4',6'-triidroxidihidrocalcona, ácido divaricático, piplartina e 2-hidroxi-1,4-naftoquinona (Lapachol). Concluímos que além de poucos resultados na área, as pesquisas não seguem o padrão metodológico (tempo de exposição e unidades de medida, teste de toxicidade), assim como não seguem um padrão na exposição do resultado (CL), não seguindo, em suma, o recomendado pela OMS.


Subject(s)
Animals , Schistosoma , Schistosomiasis , Biomphalaria , Mollusca
5.
Braz. j. biol ; 83: e268859, 2023. tab
Article in English | VETINDEX | ID: biblio-1429987

ABSTRACT

The use of medicinal plants as raw material for extracts production and pure substances isolation and subsequence development of new drugs represents a constantly growing area. However, some stages are indispensable before pharmacologically evaluating natural products such as medicines. Toxicity tests in mammalian cells are essential to initiate new drugs development or verify the substance's biocompatibility. Thus, we verified the toxicity of crude extracts and fractions with different polarities obtained from the leaves and stems of eight plant species. The toxic effect was evaluated on macrophages obtained from the bone marrow and peritoneal cavity of a Swiss webster mouse and J774 macrophages. G8 cell lineage. These macrophages were cultured in a 96-well plate, and the compounds were added at a concentration of 100 µg/mL for 24 hours. After this time, the supernatant was removed. The toxicity was evaluated for lactate dehydrogenase (LDH) release assay and the resazurin assay, which uses an indicator dye to measure oxidation-reduction reactions. The results showed a difference in the percentage of toxicity when comparing the same extract in different types of macrophages. This outcome indicates that these cells from different origins may exhibit different responses when exposed to the same natural compounds.


A utilização de plantas medicinais como matéria-prima para a produção de extratos e isolamento de substâncias puras para o desenvolvimento de novos fármacos representa uma área em constante crescimento. No entanto, existem processos a serem realizados antes de avaliar farmacologicamente produtos naturais como medicamentos. Os testes de toxicidade em células de mamíferos são fundamentais para iniciar o desenvolvimento de novas drogas ou verificar a biocompatibilidade de substâncias. Assim, verificamos a toxicidade de extratos brutos e frações com diferentes polaridades obtidos de folhas e caule de oito espécies de planta. Para comparar o efeito tóxico, os testes foram realizados em macrófagos obtidos da medula óssea e cavidade do peritônio de camundongo Swiss webster, bem como no macrófago da linhagem celular J774.G8. Esses macrófagos foram cultivados em placa de 96 poços e os compostos adicionados na concentração de 100 µg/mL por 24 horas. Após esse período o sobrenadante foi removido. A toxicidade foi avaliada pelos ensaios de detecção da enzima lactato-desidrogenase (LDH) e pelo ensaio de resazurina, que usa um corante indicador para medir as reações de oxidação-redução. Os resultados mostraram uma diferença na porcentagem de toxicidade quando comparamos o mesmo extrato em diferentes tipos de macrófagos. Este resultado indica que essas células de várias origens podem exibir respostas distintas quando expostas aos mesmos compostos naturais.


Subject(s)
Animals , Mice , Plants, Medicinal/toxicity , Plant Extracts , Macrophages
6.
Braz J Biol ; 84: e260065, 2022.
Article in English | MEDLINE | ID: mdl-35766654

ABSTRACT

Achatina fulica is a terrestrial mollusk known as the giant African snail that is related to environmental, economic, urban, and public health problems. As control measures for this mollusk, cooking salt (NaCl) and calcium oxide (CaO) are used, and baits are composed of metaldehyde. However, these measures have environmental toxicity and impact the soil. In this way, natural products have been tested on this mollusk to discover and develop a substance to combat this urban and agricultural pest. This article aims to evaluate studies involving natural products to control the population of Achatina fulica. Articles and works published in books were included in the present work. A total of 1,103 works were found during the search. Of these, 14 works met the objective of these review and were included in this article. The tests do not possess methodological standardization, do not have a maximum concentration to be considered active, or a maximum exposure time. A lack of standardization in the methodology of tests on A. fulica was observed. The performance of tests on other life stages of the mollusk, as well as tests that analyze other parameters, are essential. Only one article analyzed presented phytochemical analysis. No ecotoxicity tests were reported either. Some extracts showed promising results, highlighting the aqueous extract of Capsicum frutescens. More studies investigating the molluscicidal activity of natural products on A. fulica are needed. It is very relevant that the new studies present a phytochemical analysis of the tested extracts, as well as ecotoxicity studies.


Subject(s)
Biological Products , Animals , Biological Products/pharmacology , Birds , Snails
7.
Biomed Pharmacother ; 142: 112006, 2021 Oct.
Article in English | MEDLINE | ID: mdl-34392085

ABSTRACT

P2X7 receptor promotes inflammatory response and neuropathic pain. New drugs capable of impairing inflammation and pain-reducing adverse effects extracted from plant extracts have been studied. Physalis angulate L. possesses traditional uses and exhibits antiparasitic, anti-inflammatory, antimicrobial, antinociceptive, antimalarial, antileishmanial, immunosuppressive, antiasthmatic. diuretic, and antitumor activities. The most representative phytochemical constituents identified with medicinal importance are the physalins and withanolides. However, the mechanism of anti-inflammatory action is scarce. Although some physalins and withanolides subtypes have anti-inflammatory activity, only four physalins subtypes (B, D, F, and G) have further studies. Therefore, we evaluated the crude ethanolic extract enriched with physalins B, D, F, and G from P. angulata leaves, a pool containing the physalins B, D, F, G, and the physalins individually, as P2X7 receptor antagonists. For this purpose, we evaluated ATP-induced dye uptake, macroscopic currents, and interleukin 1-ß (IL-1ß) in vitro. The crude extract and pool dose-dependently inhibited P2X7 receptor function. Thus, physalin B, D, F, and G individually evaluated for 5'-triphosphate (ATP)-induced dye uptake assay, whole-cell patch-clamp, and cytokine release showed distinct antagonist levels. Physalin D displayed higher potency and efficacy than physalin B, F, and G for all these parameters. In vivo mice model as ATP-induced paw edema was potently inhibited for physalin D, in contrast to physalin B, F, and G. ATP and lipopolysaccharide (LPS)-induced pleurisy in mice were reversed for physalin D treatment. Molecular modeling and computational simulation predicted the intermolecular interactions between the P2X7 receptor and physalin derivatives. In silico results indicated physalin D and F as a potent allosteric P2X7 receptor antagonist. These data confirm physalin D as a promisor source for developing a new P2X7 receptor antagonist with anti-inflammatory action.


Subject(s)
Acute Lung Injury/drug therapy , Physalis/chemistry , Plant Extracts/pharmacology , Secosteroids/pharmacology , Acute Lung Injury/physiopathology , Animals , Anti-Inflammatory Agents/administration & dosage , Anti-Inflammatory Agents/isolation & purification , Anti-Inflammatory Agents/pharmacology , Computer Simulation , Disease Models, Animal , Dose-Response Relationship, Drug , HEK293 Cells , Humans , Male , Mice , Models, Molecular , Plant Extracts/administration & dosage , Plant Leaves , Purinergic P2X Receptor Antagonists/administration & dosage , Purinergic P2X Receptor Antagonists/isolation & purification , Purinergic P2X Receptor Antagonists/pharmacology , Receptors, Purinergic P2X7/drug effects , Secosteroids/isolation & purification
8.
Bioorg Med Chem ; 27(8): 1449-1455, 2019 04 15.
Article in English | MEDLINE | ID: mdl-30528164

ABSTRACT

Extracellular adenosine 5'-triphosphate (ATP) triggers the P2X7 receptor (P2X7R) ionic channel to stimulate the release of the interleukin-IL-1ß cytokine into macrophages. The current study explored the reaction of six structurally diverse triazole derivatives on P2X7-mediated dye uptake into murine peritoneal macrophages. P2X7R activity determined by ATP-evoked fluorescent dye uptake. Triazole derivatives toxicity measured using dextran rhodamine exclusion based colorimetric assay. A740004 and BBG, both P2X7R antagonist, inhibited ATP-induced dye uptake. In contrast, the derivatives 5a, 5b, 5e, and 5f did not diminish P2X7R activity in concentrations until 100 µM. 5c and 5d analogs caused a potent inhibitory activity on P2X7-induced dye uptake. Dextran Rhodamine exclusion measurements after 24 h of continuous treatment with triazole derivatives indicated a moderated toxicity for all molecules. In conclusion, this study showed that a series of new hybrid 1,2,3-triazolic naphthoquinones reduces P2X7R-induced dye uptake into murine macrophages. In silico analysis indicates a good pharmacokinetic profile and molecular docking results of these analogs indicate the potential to bind into an allosteric site located into the P2X7R pore and juxtaposed with the ATP binding pocket. In this manner, the compounds 5c and 5d may be used as a scaffold for new P2X7R inhibitors with reduced toxicity, and good anti-inflammatory activity.


Subject(s)
Naphthoquinones/chemistry , Purinergic P2X Receptor Antagonists/chemistry , Receptors, Purinergic P2X7/metabolism , Triazoles/chemistry , Allosteric Site , Animals , Binding Sites , Caco-2 Cells , Cell Line , Coloring Agents/metabolism , Humans , Macrophages/cytology , Macrophages/metabolism , Mice , Microsomes, Liver/metabolism , Molecular Docking Simulation , Permeability/drug effects , Protein Structure, Tertiary , Purinergic P2X Receptor Antagonists/metabolism , Purinergic P2X Receptor Antagonists/pharmacology , Receptors, Purinergic P2X7/chemistry , Triazoles/metabolism , Triazoles/pharmacology
9.
J Bioenerg Biomembr ; 48(1): 1-12, 2016 Feb.
Article in English | MEDLINE | ID: mdl-26728159

ABSTRACT

Ion channels allow for rapid ion diffusion through the plasma membrane. In some conditions, ion channels induce changes in the critical plasma membrane permeability that permit 900-Da solutes to enter cells. This process is known as the pore phenomenon. Some transient receptor potential (TRP) channel subtypes have been highlighted such as the P2X7 receptor, plasma membrane VDAC-1 channel, and pannexin hemichannels. The TRP ion channels are considered multimodal transducers that respond to several kinds of stimuli. In addition, many TRP channel subtypes are involved in physiological and pathophysiological processes such as inflammation, pain, and cancer. The TRPA1, TRPM8, and TRPV1-4 subtypes have been shown to promote large-molecular-weight solute uptake, including impermeable fluorescent dyes, QX-314 hydrophilic lidocaine derivative, gabapentin, and antineoplastic drugs. This review discusses the current knowledge of TRP-associated pores and encourages scientists to study their features and explore them as novel therapeutic tools.


Subject(s)
Cell Membrane Permeability , Ligand-Gated Ion Channels/metabolism , Membrane Potentials , Voltage-Dependent Anion Channels/metabolism , Animals , Humans , Inflammation/drug therapy , Inflammation/metabolism , Ion Transport , Neoplasm Proteins/metabolism , Neoplasms/drug therapy , Neoplasms/metabolism , Pain/drug therapy , Pain/metabolism
10.
Naunyn Schmiedebergs Arch Pharmacol ; 386(9): 775-87, 2013 Sep.
Article in English | MEDLINE | ID: mdl-23657251

ABSTRACT

The P2X7 receptor (P2X7R), an ATP-gated cation channel, is expressed predominantly in leukocytes. Activation of P2X7R has been implicated in the formation of a cytolytic pore (i.e., a large conductance channel) that allows the passage of molecules up to 900 Da in macrophages. At least two hypotheses have been presented to explain the conversion of a nonselective cation channel to a cytolytic pore. One hypothesis suggests that the pore is a separate molecular structure activated by P2X7R, and the second asserts that this is an intrinsic property of P2X7R (pore dilation). Based on connexin knockout and hemichannel antagonist studies, some groups have concluded that connexins and pannexins, the hemichannel-forming proteins in vertebrates, are fundamental components of the large conductance channel associated with P2X7R. Dye uptake and electrophysiology experiments were used to evaluate the efficacy and specificity of some hemichannel antagonists under conditions known to open the large conductance channel associated with P2X7R. Hemichannel antagonists and interference RNA (RNAi) targeting pannexin-1 did not affect P2X7R macroscopic currents [ATP, 1,570±189 pA; ATP+100 µM carbenoxolone (CBX), 1,498±100 pA; ATP+1 mM probenecid (Prob), 1,522±9 pA] or dye uptake in a FACS assay (ATP, 63±5%; ATP+100 µM CBX, 51.51±8.4%; ATP+1 mM Prob, 57.7±4.3%) in mouse macrophages. These findings strongly suggest that the high-permeability pore evident after prolonged P2X7R activation does not occur through connexin or pannexin hemichannels in murine macrophages. Another membrane protein may be involved in P2X7R pore formation.


Subject(s)
Connexins/physiology , Macrophages, Peritoneal/physiology , Nerve Tissue Proteins/physiology , Receptors, Purinergic P2X7/physiology , Adenosine Triphosphate/pharmacology , Animals , Cell Line , Cells, Cultured , Male , Mice , Purinergic P2X Receptor Antagonists/pharmacology , Rats , Rats, Wistar
11.
Naunyn Schmiedebergs Arch Pharmacol ; 382(1): 73-87, 2010 Jul.
Article in English | MEDLINE | ID: mdl-20508916

ABSTRACT

The P2X(7) receptor (P2X7R) is a ligand-gated ATP receptor that acts as a low- and large-conductance channel (pore) and is known to be coupled to several downstream effectors. Recently, we demonstrated that the formation of a large-conductance channel associated with the P2X(7) receptor is induced by increasing the intracellular Ca(2+) concentration (Faria et al., Am J Physiol Cell Physiol 297:C28-C42, 2005). Here, we investigated the intracellular signaling pathways associated with P2X(7) large-conductance channel formation using the patch clamp technique in conjunction with fluorescent imaging and flow cytometry assays in 2BH4 cells and peritoneal macrophages. Different antagonists were applied to investigate the following pathways: Ca(2+)-calmodulin, phospholipase A, phospholipase D, phospholipase C, protein kinase C (PKC), mitogen-activated protein kinase (MAPK), MAPK/extracellular signal-regulated kinase, phosphoinositide 3-kinase (PI3K), and cytoskeletal proteins. Macroscopic ionic currents induced by 1 mM ATP were reduced by 85% in the presence of PKC antagonists. The addition of antagonists for MAPK, PI3K, and the cytoskeleton (actin, intermediary filament, and microtubule) blocked 92%, 83%, and 95% of the ionic currents induced by 1 mM ATP, respectively. Our results show that PKC, MAPK, PI3K, and cytoskeletal components are involved in P2X(7) receptor large-channel formation in 2BH4 cells and peritoneal macrophages.


Subject(s)
Adenosine Triphosphate/metabolism , Ion Channels/metabolism , Receptors, Purinergic P2/metabolism , Adenosine Triphosphate/administration & dosage , Animals , Cells, Cultured , Flow Cytometry , Macrophages, Peritoneal/metabolism , Mice , Mice, Inbred C57BL , Mitogen-Activated Protein Kinases/metabolism , Patch-Clamp Techniques , Phosphatidylinositol 3-Kinases/metabolism , Protein Kinase C/metabolism , Receptors, Purinergic P2X7 , Signal Transduction
12.
Am J Physiol Cell Physiol ; 297(1): C28-42, 2009 Jul.
Article in English | MEDLINE | ID: mdl-19321740

ABSTRACT

Recent studies on the P2X(7) receptor in 2BH4 cells and peritoneal macrophages have demonstrated that the raise in intracellular Ca(2+) concentration induces a pore opening similar to P2X(7) receptor pore. Herein, we have investigated whether the pore activated by the elevation of intracellular Ca(2+) concentration is associated to P2X(7) receptor. Using patch clamp in cell attached, whole cell configuration, and dye uptake, we measured the pore opening in cell types that express the P2X(7) receptor (2BH4 cells and peritoneal macrophages) and in cells that do not express this receptor (HEK-293 and IT45-RI cells). In 2BH4 cells, the stimulation with ionomycin (5-10 microM) increased intracellular free Ca(2+) concentration and induced pore formation with conductance of 421 +/- 14 pS, half-time (t(1/2)) for ethidium bromide uptake of 118 +/- 17 s, and t(1/2) for Lucifer yellow of 122 +/- 11 s. P2X(7) receptor antagonists did not block these effects. Stimulation of HEK-293 and IT45-RI cells resulted in pore formation with properties similar to those found for 2BH4 cells. Connexin hemichannel inhibitors (carbenoxolone and heptanol) also did not inhibit the pore-induced effect following the increase in intracellular Ca(2+) concentration. However, 5-(N,N-hexamethylene)-amiloride, a P2X(7) receptor pore blocker, inhibited the induced pore. Moreover, intracellular signaling modulators, such as calmodulin, phospholipase C, mitogen-activated protein kinase, and cytoskeleton components were important for the pore formation. Additionally, we confirmed the results obtained for electrophysiology by using the flow cytometry, and we discarded the possibility of cellular death induced by raising intracellular Ca(2+) at the doses used by using lactate dehydrogenase release assay. In conclusion, increased concentration in intracellular Ca(+2) induces a novel membrane pore pharmacologically different from the P2X(7) associated pore and hemigap-junction pore.


Subject(s)
Calcium Signaling/drug effects , Cell Membrane/drug effects , Ion Channel Gating/drug effects , Membrane Transport Modulators/pharmacology , Membrane Transport Proteins/drug effects , Adenosine Triphosphate/metabolism , Animals , Calmodulin/antagonists & inhibitors , Calmodulin/metabolism , Cell Line , Cell Membrane/metabolism , Cell Survival , Connexins/drug effects , Connexins/metabolism , Cyclic AMP-Dependent Protein Kinases/metabolism , Cytoskeleton/drug effects , Cytoskeleton/metabolism , Dose-Response Relationship, Drug , Enzyme Activators/pharmacology , Enzyme Inhibitors/pharmacology , Flow Cytometry , Fluorescent Dyes/metabolism , Humans , Ionomycin/pharmacology , Ionophores/pharmacology , Kinetics , Macrophages/drug effects , Macrophages/metabolism , Membrane Potentials , Membrane Transport Proteins/metabolism , Mice , Mitogen-Activated Protein Kinases/antagonists & inhibitors , Mitogen-Activated Protein Kinases/metabolism , Patch-Clamp Techniques , Protein Kinase C/antagonists & inhibitors , Protein Kinase C/metabolism , Rats , Receptors, Purinergic P2/drug effects , Receptors, Purinergic P2/metabolism , Receptors, Purinergic P2X7 , Tubulin Modulators/pharmacology , Type C Phospholipases/antagonists & inhibitors , Type C Phospholipases/metabolism
13.
Am J Physiol Cell Physiol ; 288(2): C260-71, 2005 Feb.
Article in English | MEDLINE | ID: mdl-15469955

ABSTRACT

Stimulation of the P2X7 receptor by ATP induces cell membrane depolarization, increase in intracellular Ca2+ concentration, and, in most cases, permeabilization of the cell membrane to molecules up to 900 Da. After the activation of P2X7, at least two phenomena occur: the opening of low-conductance (8 pS) cationic channels and pore formation. At least two conflicting hypotheses have been postulated to reconcile these findings: 1) the P2X7 pore is formed as a result of gradual permeability increase (dilation) of cationic channels, and 2) the P2X7 pore represents a distinct channel, possibly activated by a second messenger and not directly by extracellular nucleotides. In this study, we investigated whether second messengers are necessary to open the pore associated with the P2X7 receptor in cells that expressed the pore activity by using the patch-clamp technique in whole cell and cell-attached configurations in conjunction with fluorescent imaging. In peritoneal macrophages and 2BH4 cells, we detected permeabilization and single-channel currents in the cell-attached configuration when ATP was applied outside the membrane patch in a condition in which oxidized ATP and Lucifer yellow were maintained within the pipette. Our data support Ca2+ as a second messenger associated with pore formation because the permeabilization depended on the presence of intracellular Ca2+ and was blocked by BAPTA-AM. In addition, MAPK inhibitors (SB-203580 and PD-98059) blocked the permeabilization and single-channel currents in these cells. Together our data indicate that the P2X7 pore depends on second messengers such as Ca2+ and MAP kinases.


Subject(s)
Calcium/metabolism , Cell Membrane/physiology , Receptors, Purinergic P2/metabolism , Second Messenger Systems/physiology , Adenosine Triphosphate/metabolism , Animals , Cell Line , Enzyme Inhibitors/pharmacology , Fluorescent Dyes , Membrane Potentials/drug effects , Membrane Potentials/physiology , Mice , Mitogen-Activated Protein Kinases/metabolism , Patch-Clamp Techniques , Receptors, Purinergic P2/drug effects , Receptors, Purinergic P2X7 , Second Messenger Systems/drug effects
14.
Arq. bras. med. vet. zootec ; 55(6): 677-684, dez. 2003. ilus
Article in Portuguese | VETINDEX | ID: vti-299

ABSTRACT

Foram utilizados sete cães adultos, três machos e quatro fêmeas, sem raça definida, com pesos entre 10 e 22kg, para avaliação do processo cicatricial do músculo diafragma, na presença do implante de pericárdio bovino conservado em solução supersaturada de açúcar a 300 por cento. Foi criado um defeito na porção muscular do hemidiafragma esquerdo de dimensões 8,0 x 5,0cm. Após a toracotomia no oitavo espaço intercostal esquerdo, o implante heterógeno foi fixado com fio poliamida nº 3-0 por meio de sutura simples contínua. Decorrido o período pré-estabelecido de pós-operatório, os animais foram submetidos a exames radiográficos simples e contrastado e a estudos macroscópico e histológico. Na avaliação radiográfica, foi verificada presença das silhuetas diafragmática e cardíaca, sem evidências de vísceras abdominais no interior do tórax. Macroscopicamente, notou-se a formação de tecido conjuntivo fibroso semi-transparente que ocluia o defeito diafragmático. O segmento de pericárdio bovino conservado em solução supersaturada de açúcar a 300 por cento, em temperatura ambiente, é substituído por uma fina camada de tecido conjuntivo fibroso e promove a restauração do defeito no músculo diafragma de cão(AU)


Seven adult mongrel dogs, three males and four females, weighting between 10 and 22kg were used to evaluate the diaphragmatic muscle healing process. A defect of 8.0×5.5cm was created at the muscular portion of the left hemidiaphragm, through a thoracotomy at the eighth left intercostal space. A segment of bovine pericardium, preserved in 300% sugar solution, was implanted in the diaphragmatic defect. The heterologous implant was sutured with 3.0 polyamide using simple continuous suture. After the observation period, radiologic analysis and macroscopic and histopathologic evaluations were performed. Upon radiographic examination, there was no evidence of interruption of diaphragmatic outline or increased radiopacity at the implantation site. Histologically, fine connective tissue occluded the diaphragmatic defect. Bovine pericardium preserved in 300% supersaturated sugar solution at room temperature is replaced by a fine layer of connective fibrous tissue and promote repair of large diaphragmatic defects in dogs.(AU)


Subject(s)
Animals , Male , Female , Adult , Dogs , Diaphragm , Pericardium , General Surgery
15.
Arq. bras. med. vet. zootec ; Arq. bras. med. vet. zootec. (Online);55(6): 677-684, dez. 2003. ilus
Article in Portuguese | LILACS | ID: lil-359838

ABSTRACT

Foram utilizados sete cães adultos, três machos e quatro fêmeas, sem raça definida, com pesos entre 10 e 22kg, para avaliação do processo cicatricial do músculo diafragma, na presença do implante de pericárdio bovino conservado em solução supersaturada de açúcar a 300 por cento. Foi criado um defeito na porção muscular do hemidiafragma esquerdo de dimensões 8,0 x 5,0cm. Após a toracotomia no oitavo espaço intercostal esquerdo, o implante heterógeno foi fixado com fio poliamida nº 3-0 por meio de sutura simples contínua. Decorrido o período pré-estabelecido de pós-operatório, os animais foram submetidos a exames radiográficos simples e contrastado e a estudos macroscópico e histológico. Na avaliação radiográfica, foi verificada presença das silhuetas diafragmática e cardíaca, sem evidências de vísceras abdominais no interior do tórax. Macroscopicamente, notou-se a formação de tecido conjuntivo fibroso semi-transparente que ocluia o defeito diafragmático. O segmento de pericárdio bovino conservado em solução supersaturada de açúcar a 300 por cento, em temperatura ambiente, é substituído por uma fina camada de tecido conjuntivo fibroso e promove a restauração do defeito no músculo diafragma de cão


Subject(s)
Animals , Male , Female , Adult , Diaphragm , Dogs , General Surgery , Pericardium
16.
Arq. bras. med. vet. zootec ; 53(1): 21-26, fev. 2001. ilus
Article in Portuguese | VETINDEX | ID: vti-7400

ABSTRACT

0 uso de enxerto muscular homólogo conservado em solução supersaturada de açúcar a 300 por cento foi pesquisado no músculo diafragma de cães. Foram utilizados 12 cães adultos, quatro machos e oito fêmeas, sem raça definida, com peso entre 9 e l8kg, para confecção de um defeito diafragmático na porção muscular, com dimensões de 4,0 x 4,5cm, seguido da implantação de um segmento de músculo diafragma homólogo. Seis cães foram observados por um período de 30 dias de pós-operatório e seis por 60 dias, quando foram reoperados para observação macroscópica e coleta de amostra para avaliação histológica. Nos animais do grupo de 30 dias de pós-operatório verificou-se substituição parcial e nos de 60 dias, substituição total da porção muscular do diafragma por tecido de granulação, o que permitiu o restabelecimento completo do diafragma por meio de firme inserção. 0 segmento de músculo diafragma homólogo conservado em solução supersaturada de açúcar a 300 por cento, em temperatura ambiente, pode ser utilizado para reparação de defeitos diafragmáticos, uma vez que é substituido por tecido conjuntivo fibroso, sem apresentar sinais clínicos nem histológico de rejeição (AU)


The viability of tissular healing of a muscular homologous ortothopic diaphragmatic segment preserved in hipersaturated sugar solution at 300% was studied as an implant in the canine diaphragmatic muscle. Twelve adult mongrel dogs were used, four males, and eight females weighing 9 to 18kg. A diaphragmatic defect, measuring 4.0 ´ 4.5 cm, was provoked in the muscular portion of the diaphragm for the implantation of the homologous diaphragmatic muscle segment. Six animals were observed for 30 days after the surgery and the other six for 60 days. After this period, they were reoperated, for macroscopic observation and collection of samples for histologic evaluation. A partial replacement of the implant was observed in the 30-day observation group whereas in the 60-day group a total substitution of the diaphragmatic muscular portion by granulation tissue rich in collagen fibers had occurred, allowing the reconstruction of the diaphragm. The homologous diaphragmatic muscle segment preserved in 300%, satured sugar solution, at room temperature, was substituted by fibrous connective tissue. The implant did not present clinical and histological signs of rejection and therefore it can be used for the repair of diaphragmatic defects(AU)


Subject(s)
Animals , Male , Female , Adult , Dogs , Prostheses and Implants , Surgery, Veterinary/methods , Dogs/surgery
17.
Arq. bras. med. vet. zootec ; Arq. bras. med. vet. zootec. (Online);53(1): 21-6, fev. 2001. ilus
Article in Portuguese | LILACS | ID: lil-290492

ABSTRACT

0 uso de enxerto muscular homólogo conservado em soluçäo supersaturada de açúcar a 300 por cento foi pesquisado no músculo diafragma de cäes. Foram utilizados 12 cäes adultos, quatro machos e oito fêmeas, sem raça definida, com peso entre 9 e l8kg, para confecçäo de um defeito diafragmático na porçäo muscular, com dimensöes de 4,0 x 4,5cm, seguido da implantaçäo de um segmento de músculo diafragma homólogo. Seis cäes foram observados por um período de 30 dias de pós-operatório e seis por 60 dias, quando foram reoperados para observaçäo macroscópica e coleta de amostra para avaliaçäo histológica. Nos animais do grupo de 30 dias de pós-operatório verificou-se substituiçäo parcial e nos de 60 dias, substituiçäo total da porçäo muscular do diafragma por tecido de granulaçäo, o que permitiu o restabelecimento completo do diafragma por meio de firme inserçäo. 0 segmento de músculo diafragma homólogo conservado em soluçäo supersaturada de açúcar a 300 por cento, em temperatura ambiente, pode ser utilizado para reparaçäo de defeitos diafragmáticos, uma vez que é substituido por tecido conjuntivo fibroso, sem apresentar sinais clínicos nem histológico de rejeiçäo


Subject(s)
Animals , Dogs , Adult , Female , Male , General Surgery , Prostheses and Implants
SELECTION OF CITATIONS
SEARCH DETAIL