Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 18 de 18
Filtrar
Mais filtros

Base de dados
Tipo de documento
Intervalo de ano de publicação
1.
Bioconjug Chem ; 34(7): 1234-1243, 2023 07 19.
Artigo em Inglês | MEDLINE | ID: mdl-37418494

RESUMO

Membrane interaction constitutes to be an essential parameter in the mode of action of entities such as proteins, as well as cell-penetrating and antimicrobial peptides, resulting in noninvasive or lytic activities depending on the membrane compositions and interactions. Recently, a nanobody able to interact with the top priority, multidrug-resistant bacterial pathogen Acinetobacter baumannii was discovered, although binding took place with fixed cells only. To potentially overcome this limitation, linear peptides corresponding to the complementarity-determining regions (CDR) were synthesized and fluorescently labeled. Microscopy data indicated clear membrane interactions of the CDR3 sequence with living A. baumannii cells, indicating both the importance of the CDR3 as part of the parent nanobody paratope and the improved binding ability and thus avoiding the need for permeabilization of the cells. In addition, cyclization of the peptide with an additionally introduced rigidifying 1,2,3-triazole bridge retains its binding ability while proteolytically protecting the peptide. Overall, this study resulted in the discovery of novel peptides binding a multidrug-resistant pathogen.


Assuntos
Acinetobacter baumannii , Peptídeos , Peptídeos/farmacologia , Peptídeos/química , Microscopia , Bactérias , Antibacterianos , Testes de Sensibilidade Microbiana
2.
Org Biomol Chem ; 16(8): 1242-1246, 2018 02 21.
Artigo em Inglês | MEDLINE | ID: mdl-29379930

RESUMO

A 3-step methodology for the synthesis of 1,5-benzothiazepin-4(5H)-one dipeptidomimetics has been elaborated via an Ugi-4CR followed by a S-trityl deprotection and an intramolecular Cu(i)-catalyzed Ullmann condensation with moderate to good yields. In silico and NMR conformational studies showed that the lowest energy conformers stabilize γ- and ß-turn structures.

3.
Org Biomol Chem ; 14(20): 4669-77, 2016 May 18.
Artigo em Inglês | MEDLINE | ID: mdl-27117259

RESUMO

Herein we describe a catalyst-free, one-pot procedure employing an Ugi-4CR between propargyl glycine, functionalised 2-azidoanilines, different isocyanides and aldehydes, followed by a thermal azide-alkyne Huisgen cycloaddition to generate a 14-member set of amino-benzotriazolodiazocine-bearing dipeptides with multiple points of diversification and high atom economy. These structures were derivatized by means of Suzuki-Miyaura cross-coupling reactions at two positions with good to excellent yields, leading to conformationally constrained tricyclic structures. In silico and NMR conformational analysis studies demonstrated that turn conformations are adopted by these structures.

4.
Org Biomol Chem ; 13(36): 9398-404, 2015 Sep 28.
Artigo em Inglês | MEDLINE | ID: mdl-26246017

RESUMO

The Glaser-Hay diyne coupling proved to be an efficient cyclisation approach towards diyne containing peptidic macrocycles. A variety of tetrapeptide-based macrocyclic 1,3-diynes were obtained from O-propargylated serine or tyrosine residues using Cu(OAc)2·H2O and NiCl2 under an O2-atmosphere. The effect of the linear 1,3-diyne on peptide conformations was studied by NMR and compared with a macrocycle bearing a saturated linker.


Assuntos
Di-Inos/química , Compostos Macrocíclicos/síntese química , Peptídeos/síntese química , Ciclização , Compostos Macrocíclicos/química , Conformação Molecular , Oxirredução , Peptídeos/química
5.
Org Biomol Chem ; 12(36): 6986-9, 2014 Sep 28.
Artigo em Inglês | MEDLINE | ID: mdl-25116189

RESUMO

Herein we describe a catalyst-free procedure employing an Ugi-4CR between a ß-azido-α-amino acid, propargylamine, an isocyanide and an aldehyde, followed by a thermal azide-alkyne Huisgen cycloaddition to generate a 16-member library of amino-triazoloazepinone-bearing di- and tripeptides with up to four points of diversification and high atom economy.


Assuntos
Azepinas/química , Oligopeptídeos/síntese química , Biblioteca de Peptídeos , Peptidomiméticos/síntese química , Triazóis/química , Reação de Cicloadição , Dipeptídeos/síntese química , Dipeptídeos/química , Conformação Molecular , Oligopeptídeos/química , Peptidomiméticos/química
6.
Neuropharmacology ; 38(9): 1317-24, 1999 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-10471085

RESUMO

Behavioural studies have suggested that endogenous opioids mediate the antinociceptive action of neuropeptide FF (FLFQPQRF-NH2) at the spinal level in the rat. This hypothesis was directly assessed by investigating the effects of a NPFF analogue, 1DMe ([D-Tyr1,(NMe)Phe3]NPFF), on the spinal outflow of met-enkephalin-like material (MELM) in halothane-anaesthetised rats. Intrathecal infusion (0.1 ml/min) of 1DMe (0.1 microM-0.1 mM, for 45 min) produced a concentration-dependent increase in spinal MELM outflow which persisted for at least 90 min at the highest concentration tested. Intrathecal coadministration of the micro-opioid receptor antagonist CTOP (1 microM) did not significantly affect the spinal MELM overflow due to 0.1 mM 1DMe. In contrast, both naltrindole and nor-binaltorphimine, at concentrations (10 microM) that allow the selective blockade of alpha- and kappa-opioid receptors, respectively, significantly reduced the stimulatory effect of 1DMe on spinal MELM outflow. These data provide the first direct demonstration that met-enkephalin (among other opioid peptides) can mediate the antinociceptive action of NPFF at the spinal level in rats. In addition, they suggest that reciprocal excitatory interactions between opioids and opioid-modulatory factors (such as NPFF) participate in the physiological control of nociception.


Assuntos
Encefalina Metionina/metabolismo , Oligopeptídeos/farmacologia , Medula Espinal/efeitos dos fármacos , Analgésicos/metabolismo , Anestesia , Animais , Halotano , Masculino , Antagonistas de Entorpecentes , Oligopeptídeos/química , Ratos , Ratos Sprague-Dawley , Receptores Opioides/metabolismo , Medula Espinal/metabolismo
7.
Neuropharmacology ; 40(4): 578-89, 2001 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-11249967

RESUMO

Although previous studies have established that cizolirtine (5-([(N,N-dimethylaminoethoxy)phenyl]methyl)-1-methyl-1H-pyrazol citrate) is a potent analgesic in rodents, its mechanism(s) of action remain(s) unclear. In vitro and in vivo approaches were used to assess whether cizolirtine could affect the spinal release of two pain-related neuropeptides, substance P (SP) and calcitonin gene-related peptide (CGRP), in rats. Cizolirtine significantly reduced the K(+)-evoked overflow of both the SP-like material (SPLM; -25% at 0.1 microM--0.1 mM) and CGRPLM (-20% at 0.1--1.0 microM) from slices of the dorsal half of the lumbar enlargement of the spinal cord. Intrathecal perfusion in halothane-anaesthetized rats showed that local application of cizolirtine markedly diminished the spinal outflow of SPLM (up to -50% at 0.1 mM) but only marginally that of CGRPLM. Systemic administration of cizolirtine at an analgesic dose (80 mg/kg i.p.) also reduced spinal SPLM outflow (-50%) but not that of CGRPLM. Under both in vitro and in vivo conditions, idazoxan (10 microM) antagonized the effects of cizolirtine on SPLM and CGRPLM release, suggesting their mediation through alpha(2) adrenoceptors.


Assuntos
Analgésicos/farmacologia , Peptídeo Relacionado com Gene de Calcitonina/efeitos dos fármacos , Pirazóis/farmacologia , Medula Espinal/efeitos dos fármacos , Substância P/efeitos dos fármacos , Ácido Acético/administração & dosagem , Anestesia , Anestésicos Inalatórios/farmacologia , Animais , Aspirina/farmacologia , Peptídeo Relacionado com Gene de Calcitonina/metabolismo , Relação Dose-Resposta a Droga , Halotano/farmacologia , Técnicas In Vitro , Injeções Intraperitoneais , Injeções Espinhais , Masculino , Dor/induzido quimicamente , Dor/prevenção & controle , Potássio/farmacologia , Ratos , Ratos Sprague-Dawley , Medula Espinal/metabolismo , Substância P/metabolismo
8.
Neuropeptides ; 37(4): 211-9, 2003 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-12906839

RESUMO

Although chronic inflammatory pain is known to be associated with hypersensitivity to mu opioid receptor agonists, no evidence for changes in the expression and/or characteristics of central mu opioid receptors has yet been reported in relevant models of this type of pain. In the present study, both immunohistochemical and autoradiographic approaches were used to address this question in polyarthritic rats, on the 4th week after intradermal injection of complete Freund's adjuvant, when inflammatory pain was at its maximum. Immunohistochemical labeling with specific anti-mu opioid receptor antibodies and autoradiographic labeling with [3H]DAMGO showed an upregulation of mu opioid receptors in the dorsal root ganglia but no changes in the density of these receptors in the dorsal horn at the level of L4-L6 segments in polyarthritic compared to age-paired control rats. On the other hand, autoradiographic quantification of the concentration-dependent increase in [35S]GTP-gamma-S binding by the mu-opioid receptor agonist DAMGO did not show any significant differences within the lumbar dorsal horn between polyarthritic and control rats. These data indicate that chronic inflammatory pain caused by polyarthritis was associated with an increased expression of mu-opioid receptors in dorsal root ganglion sensory neurones that did not result in an increased spinal density of these receptors, in spite of their well established axonal transport in the central portion of primary afferent fibres to the dorsal horn. In contrast, axonal transport of mu-opioid receptors in the peripheral portion of these fibres probably accounts for the increased receptor density in inflamed tissues already reported in the literature.


Assuntos
Artrite Experimental/metabolismo , Proteínas de Ligação ao GTP/metabolismo , Gânglios Espinais/metabolismo , Receptores Opioides mu/metabolismo , Medula Espinal/metabolismo , Analgésicos Opioides/metabolismo , Analgésicos Opioides/farmacologia , Animais , Autorradiografia , Doença Crônica , Ala(2)-MePhe(4)-Gly(5)-Encefalina/metabolismo , Ala(2)-MePhe(4)-Gly(5)-Encefalina/farmacologia , Guanosina 5'-O-(3-Tiotrifosfato)/metabolismo , Guanosina 5'-O-(3-Tiotrifosfato)/farmacologia , Vértebras Lombares , Masculino , Dor/metabolismo , Ratos , Ratos Sprague-Dawley , Radioisótopos de Enxofre , Trítio
9.
Brain Res ; 796(1-2): 198-208, 1998 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-9689470

RESUMO

As a model of chronic inflammatory pain, Freund's adjuvant-induced polyarthritis has been shown to be associated with marked alterations in the activity of opioid- and calcitonin gene-related peptide (CGRP)-containing neurons in the dorsal horn of the spinal cord in rats. Possible changes in the interactions between these two peptidergic systems in chronic inflammatory pain were investigated by comparing the effects of various opioid receptor ligands on the spinal outflow of CGRP-like material (CGRPLM) in polyarthritic and age-paired control rats. Intrathecal perfusion of an artificial cerebrospinal fluid in halothane-anaesthetized animals allowed the collection of CGRPLM released from the spinal cord and the application of opioid receptor ligands. The blockade of kappa-opioid receptors similarly increased CGRPLM release in both groups of rats as expected of a kappa-mediated tonic inhibitory control of CGRP-containing fibres in control, as well as in polyarthritic rats. In contrast, the higher increase in CGRPLM outflow due to the preferential blockade of mu opioid receptors by naloxone in polyarthritic rats as compared to non-suffering animals supports the idea of a reinforced mu opioid receptor-mediated tonic inhibitory control of CGRP-containing fibres in rats suffering from chronic pain. Even more strikingly, the differences observed in the effects of delta-opioid receptor ligands on CGRPLM outflow suggest that delta receptors are functionally shifted from a participation in a phasic excitatory control in non-suffering rats to a tonic inhibitory control in polyarthritic rats. These data indicate that agonists acting at the three types of opioid receptors all exert a tonic inhibitory influence on CGRP-containing nociceptive primary afferent fibres within the spinal cord of polyarthritic rats. Such a convergence probably explains why morphine and other opioids are especially potent to reduce pain in subjects suffering from chronic inflammatory diseases.


Assuntos
Artrite Experimental/metabolismo , Artrite/metabolismo , Peptídeo Relacionado com Gene de Calcitonina/metabolismo , Entorpecentes/farmacologia , Medula Espinal/metabolismo , Animais , Ligantes , Masculino , Ratos , Ratos Sprague-Dawley , Receptores Opioides delta/metabolismo , Receptores Opioides kappa/metabolismo , Receptores Opioides mu/metabolismo , Valores de Referência , Medula Espinal/efeitos dos fármacos
10.
Brain Res ; 749(1): 18-28, 1997 Feb 21.
Artigo em Inglês | MEDLINE | ID: mdl-9070623

RESUMO

Complex and contradictory data have been reported regarding the changes in spinal opioidergic systems associated with chronic inflammatory pain in the rat. In an attempt to solve these discrepancies, the in vivo release of met-enkephalin and dynorphin and the expression of the corresponding propeptide genes were investigated at the spinal level in arthritic rats and paired controls. A dramatic increase in the concentration of prodynorphin mRNA (+300-550%) and a less pronounced elevation of that of dynorphin-like material (+40-50%) were found in the dorsal part of cervical and lumbar segments of the spinal cord in rats rendered arthritic by an intradermal injection of Freund's adjuvant four weeks prior to these measurements. In addition, the spinal release of dynorphin-like material (assessed through an intrathecal perfusion procedure in halothane-anaesthetized animals) was approximately twice as high in arthritic rats as in controls. In spite of significant elevations in the levels of both met-enkephalin (+30-70%) and proenkephalin A mRNA (+40-50%) in the dorsal part of cervical and lumbar segments, the spinal release of met-enkephalin-like material was decreased (-50%) in arthritic rats as compared to paired controls. Proenkephalin A mRNA (but not prodynorphin mRNA) could be measured in dorsal root ganglia, and its levels were dramatically reduced in ganglia at the lumbar segments in arthritic rats. Such parallel reductions in the spinal release of met-enkephalin-like material and the levels of proenkephalin A mRNA in dorsal root ganglia of arthritic rats support the idea that the activity of primary afferent enkephalinergic fibres decreases markedly during chronic inflammatory pain.


Assuntos
Artrite Experimental/patologia , Dinorfinas/fisiologia , Encefalinas/fisiologia , Gânglios Espinais/patologia , Neurônios/fisiologia , Medula Espinal/patologia , Animais , Artrite Experimental/metabolismo , Northern Blotting , DNA Complementar/metabolismo , Dinorfinas/metabolismo , Encefalinas/biossíntese , Encefalinas/metabolismo , Gânglios Espinais/metabolismo , Hibridização In Situ , Masculino , Neurônios/metabolismo , Precursores de Proteínas/biossíntese , RNA Mensageiro/biossíntese , Radioimunoensaio , Ratos , Ratos Sprague-Dawley , Medula Espinal/metabolismo
11.
Contrast Media Mol Imaging ; 8(2): 157-64, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23281288

RESUMO

Vascular damage plays a critical role after stroke, leading notably to edema, hemorrhages and stroke recurrence. Tools to characterize the vascular lesion are thus a real medical need. In this context, the specific nanoparticular contrast agent P03011, an USPIO (ultrasmall superparamagnetic iron oxide) conjugated to a peptide that targets VCAM-1 (vascular cell adhesion molecule-1), was developed to detect this major component of the vascular inflammatory response. This study aimed to make the proof of concept of the capacity of this targeted USPIO to detect VCAM-1 with MRI after cerebral ischemia in mouse. The time course of VCAM-1 expression was first examined by immunohistochemistry in our model of cerebral ischemia-reperfusion. Secondly, P03011 or nontargeted USPIO P03007 were injected 5 h after ischemia (100 µmol iron kg⁻¹; i.v.) and in vivo and ex vivo MRI were performed 24 h after ischemia onset. Double labeling immunofluorescence was then performed on brain slices in order to detect both USPIO and VCAM-1. VCAM-1 expression was significantly up-regulated 24 h after ischemia in our model. In animals receiving P03011, both in vivo and ex vivo MRI performed 24 h after ischemia onset showed hypointense foci which could correspond to iron particles. Histological analysis showed a co-localization of the targeted USPIO and VCAM-1. This study demonstrates that VCAM-1 detection is possible with the USPIO P03011 in a model of cerebral ischemia. This kind of contrast agent could be an interesting clinical tool to characterize ischemic lesions in terms of vascular damage.


Assuntos
Isquemia Encefálica/metabolismo , Encéfalo/metabolismo , Dextranos/farmacocinética , Imageamento por Ressonância Magnética/métodos , Nanopartículas de Magnetita , Imagem Molecular/métodos , Molécula 1 de Adesão de Célula Vascular/metabolismo , Animais , Biomarcadores/metabolismo , Isquemia Encefálica/patologia , Meios de Contraste/farmacocinética , Masculino , Camundongos , Distribuição Tecidual
12.
Atherosclerosis ; 228(2): 339-45, 2013 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-23582588

RESUMO

PURPOSE: The aim of this study was to compare the ability of (18)F-FDG PET and iron contrast-enhanced MRI with a novel USPIO (P904) to assess change in plaque inflammation induced by atorvastatin and dietary change in a rabbit model of atherosclerosis using a combined PET/MR scanner. MATERIALS AND METHODS: Atherosclerotic rabbits underwent USPIO-enhanced MRI and (18)F-FDG PET in PET/MR hybrid system at baseline and were then randomly divided into a progression group (high cholesterol diet) and a regression group (chow diet and atorvastatin). Each group was scanned again 6 months after baseline imaging. R2* (i.e. 1/T2*) values were calculated pre/post P904 injection. (18)F-FDG PET data were analyzed by averaging the mean Standard Uptake Value (SUVmean) over the abdominal aorta. The in vivo imaging was then correlated with matched histological sections stained for macrophages. RESULTS: (18)F-FDG PET showed strong FDG uptake in the abdominal aorta and P904 injection revealed an increase in R2* values in the aortic wall at baseline. At 6 months, SUVmean values measured in the regression group showed a significant decrease from baseline (p = 0.015). In comparison, progression group values remained constant (p = 0.681). R2* values showed a similar decreasing trend in the regression group suggesting less USPIO uptake in the aortic wall. Correlations between SUVmean or Change in R2* value and macrophages density (RAM-11 staining) were good (R(2) = 0.778 and 0.707 respectively). CONCLUSION: This experimental study confirms the possibility to combine two functional imaging modalities to assess changes in the inflammation of atherosclerotic plaques. (18)F-FDG-PET seems to be more sensitive than USPIO P904 to detect early changes in plaque inflammation.


Assuntos
Aorta Abdominal , Doenças da Aorta/diagnóstico , Aterosclerose/diagnóstico , Meios de Contraste , Dextranos , Fluordesoxiglucose F18 , Inflamação/diagnóstico , Imageamento por Ressonância Magnética , Nanopartículas de Magnetita , Placa Aterosclerótica , Tomografia por Emissão de Pósitrons , Compostos Radiofarmacêuticos , Animais , Aorta Abdominal/diagnóstico por imagem , Aorta Abdominal/efeitos dos fármacos , Aorta Abdominal/patologia , Doenças da Aorta/diagnóstico por imagem , Doenças da Aorta/tratamento farmacológico , Doenças da Aorta/patologia , Aterosclerose/diagnóstico por imagem , Aterosclerose/tratamento farmacológico , Aterosclerose/patologia , Atorvastatina , Modelos Animais de Doenças , Progressão da Doença , Ácidos Heptanoicos/farmacologia , Inibidores de Hidroximetilglutaril-CoA Redutases/farmacologia , Inflamação/diagnóstico por imagem , Inflamação/tratamento farmacológico , Inflamação/patologia , Valor Preditivo dos Testes , Pirróis/farmacologia , Coelhos , Radiografia , Fatores de Tempo
13.
J Pept Sci ; 13(3): 164-70, 2007 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-17266049

RESUMO

High affinity peptide ligands for the bradykinin (BK) B(2) subtype receptor have been shown to adopt a beta-turn conformation of the C-terminal tetrapeptide (H-Arg(1)-Pro(2)-Pro(3)-Gly(4)-Phe(5)-Ser(6)-Pro(7)-Phe(8)-Arg(9)-OH). We investigated the replacement of the Pro(7)-Phe(8) dipeptide moiety in BK or the D-Tic(7)-Oic(8) subunit in HOE140 (H-D-Arg(0)-Arg(1)-Pro(2)-Hyp(3)-Gly(4)-Thi(5)-Ser(6)-D-Tic(7)-Oic(8)-Arg(9)-OH) by 4-amino-1,2,4,5-tetrahydro-2-benzazepin-3-one templates (Aba). Binding studies to the human B(2) receptor showed a correlation between the affinities of the BK analogs and the propensity of the templates to adopt a beta-turn conformation. The L-spiro-Aba-Gly containing HOE140 analog BK10 has the best affinity, which correlates with the known turn-inducing property of this template. All the compounds did not modify basal inositolphosphate (IP) output in B(2)-expressing CHO cells up to 10 microM concentration. The antagonist properties were confirmed by the guinea pig ileum smooth muscle contractility assay. The new amino-benzazepinone (Aba) substituted BK analogs were found to be surmountable antagonists.


Assuntos
Benzazepinas/química , Bradicinina/análogos & derivados , Músculo Liso/fisiologia , Receptor B2 da Bradicinina/metabolismo , Sequência de Aminoácidos , Animais , Benzazepinas/síntese química , Benzazepinas/farmacologia , Bradicinina/síntese química , Bradicinina/metabolismo , Bradicinina/farmacologia , Células CHO , Cricetinae , Cricetulus , Cobaias , Humanos , Contração Muscular/efeitos dos fármacos , Músculo Liso/efeitos dos fármacos , Conformação Proteica
14.
Br J Cancer ; 95(10): 1326-33, 2006 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-17088915

RESUMO

To retrospectively evaluate the incidence of tumour cell contamination of peripheral blood stem cell (PBSC) collections and to correlate these data with the clinical outcome after high-dose chemotherapy (HDCT) with stem cell rescue in patients with a high-risk Ewing tumour. Peripheral blood stem cell collections obtained from 171 patients were analysed. Tumour contamination was assessed by reverse transcriptase-polymerase chain reaction (RT-PCR). The files of 88 patients who underwent HDCT followed by PBSC reinfusion were reviewed in detail, and their outcome compared to the PBSC RT-PCR results. Seven of 88 PBSC collections (8%) contained tumour cells as detected by RT-PCR. Peripheral blood stem cells were collected after a median of five cycles of chemotherapy. No clinical factor predictive of tumour cell contamination of PBSC harvest could be identified. Event-free survival (EFS) and overall survival (OS) of the whole study population were 45.3 % and 51.8 % at 3 years from the date of the graft, respectively. Forty-five patients relapsed with a median time of 15 months after graft, only four of whom had tumour cell contamination of the PBSC harvest. Tumour cell contamination of PBSC collection is rare and does not seem to be associated with a significantly poorer EFS or OS in this high-risk population.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Mobilização de Células-Tronco Hematopoéticas/métodos , Transplante de Células-Tronco Hematopoéticas/métodos , Proteínas de Fusão Oncogênica/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa/normas , Sarcoma de Ewing/patologia , Fatores de Transcrição/genética , Adolescente , Adulto , Antígenos CD34/análise , Neoplasias da Medula Óssea/genética , Neoplasias da Medula Óssea/secundário , Criança , Pré-Escolar , Intervalo Livre de Doença , Feminino , Fator Estimulador de Colônias de Granulócitos/uso terapêutico , Humanos , Lactente , Leucaférese , Masculino , Proteínas de Fusão Oncogênica/metabolismo , Proteína Proto-Oncogênica c-fli-1 , RNA Mensageiro/análise , Proteína EWS de Ligação a RNA , Estudos Retrospectivos , Reação em Cadeia da Polimerase Via Transcriptase Reversa/métodos , Sarcoma de Ewing/genética , Sensibilidade e Especificidade , Taxa de Sobrevida , Fatores de Transcrição/metabolismo , Resultado do Tratamento
15.
J Pept Res ; 66(5): 222-30, 2005 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-16218989

RESUMO

The synthesis of conformationally restricted dipeptidic moieties 4-amino-1,2,4,5-tetrahydro-2-benzazepin-3-one (Aba)-Gly ([(4S)-amino-3-oxo-1,2,4,5-tetrahydro-1H-2-benzazepin-2-yl]-acetic acid) and 8-hydroxy-4-amino-1,2,4,5-tetrahydro-2-benzazepin-3-one (Hba)-D-Ala ([(4S)-amino-8-hydroxy-3-oxo-1,2,4,5-tetrahydro-benzo[c]azepin-2-yl]-propionic acid) was based on a synthetic strategy that uses an oxazolidinone as an N-acyliminium precursor. Introducing these Aba scaffolds into the N-terminal tetrapeptide of dermorphin (H-Tyr-D-Ala-Phe-Gly-Tyr-Pro-Ser-NH2)-induced remarkable shifts in affinity and selectivity towards the opioid mu- and delta-receptors. This paper provides the synthesis and biological in vitro and in vivo evaluation of constricted analogues of the N-terminal tetrapeptide H-Tyr-D-Ala-Phe-Gly-NH2, which is the minimal subunit of dermorphin needed for dermorphin-like opiate activity.


Assuntos
Peptídeos Opioides/síntese química , Animais , Relação Dose-Resposta a Droga , Masculino , Estrutura Molecular , Oligopeptídeos/síntese química , Peptídeos Opioides/química , Conformação Proteica , Ratos , Ratos Sprague-Dawley , Receptores Opioides/química , Receptores Opioides/metabolismo , Relação Estrutura-Atividade , Fatores de Tempo
16.
Synapse ; 37(4): 262-72, 2000 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-10891863

RESUMO

Previous studies showed that spinal opioidergic neurotransmission is markedly altered in the polyarthritic rat, a model of chronic inflammatory pain. Present investigations aimed at assessing possible changes in opioid-mediated control of the spinal outflow of met-enkephalin (ME) and dynorphin (DYN) in these animals. Intrathecal (i.t.) perfusion under halothane anesthesia showed that polyarthritis was associated with both a 40% decrease in the spinal outflow of ME-like material (MELM) and a 90% increase in that of DYNLM. Local treatment with the mu-opioid agonist DAGO (10 microM i.t.) inhibited equally (-30%) the MELM outflow in polyarthritic and control rats, whereas the delta agonist DTLET (10 microM i.t.) also reduced the peptide outflow in controls (-27%) but enhanced it in polyarthritic animals (+56%). On the other hand, both DAGO (10 microM i.t.) and DTLET (10 microM i.t.) decreased (-40 and -49%) DYNLM outflow in polyarthritic rats, but were inactive in controls. Finally, neither MELM outflow nor that of DYNLM were affected by the kappa-agonist U50488H (10 microM i.t.) in both groups of rats. In all cases, the changes due to active agonists could be prevented by specific antagonists which were inactive on their own except the kappa antagonist nor-binaltorphimine (10 microM i.t.) that decreased (-38%) DYNLM outflow in polyarthritic rats. These data indicate that functional changes in spinal opioid receptors may promote enkephalinergic neurotransmission and reduce dynorphinergic neurotransmission in polyarthritic rats, thereby contributing to the analgesic efficacy of opioids in inflammatory pain.


Assuntos
Analgésicos Opioides/farmacologia , Artrite/metabolismo , Dinorfinas/metabolismo , Ala(2)-MePhe(4)-Gly(5)-Encefalina/farmacologia , Encefalina Metionina/metabolismo , Medula Espinal/metabolismo , (trans)-Isômero de 3,4-dicloro-N-metil-N-(2-(1-pirrolidinil)-ciclo-hexil)-benzenoacetamida/farmacologia , Analgésicos não Narcóticos/farmacologia , Anestesia , Animais , Artrite/tratamento farmacológico , Dinorfinas/análise , Encefalina Metionina/análise , Radioisótopos do Iodo , Ligantes , Masculino , Naloxona/farmacologia , Naltrexona/análogos & derivados , Naltrexona/farmacologia , Antagonistas de Entorpecentes/farmacologia , Oligopeptídeos/farmacologia , Radioimunoensaio , Ratos , Ratos Sprague-Dawley , Receptores Opioides delta/agonistas , Receptores Opioides kappa/agonistas , Receptores Opioides mu/agonistas , Medula Espinal/efeitos dos fármacos
17.
Eur J Neurosci ; 12(12): 4496-504, 2000 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-11122360

RESUMO

Cholinergic and PACAPergic systems within the oral pontine reticular nucleus (PnO) play a critical role in REM sleep generation in rats. In this present work, we have investigated whether REM sleep enhancement induced by carbachol (a cholinergic agonist) or PACAP, depends on an interaction between muscarinic and PACAP receptors. This hypothesis was tested by recording sleep-wake cycles in freely moving rats injected into the PnO with PACAP in combination with the muscarinic receptor antagonist atropine, or with carbachol in combination with the PACAP receptor antagonist PACAP6-27. When administered alone, PACAP (3 pmol) or carbachol (110 pmol) induced an enhancement of REM sleep during 8 h (+61%, n = 8; +70%, n = 5), which was totally prevented by infusion of atropine (290 pmol) for PACAP, or of PACAP6-27 (3 pmol) for carbachol. Quantitative autoradiographic studies indicated that (i) PACAP (10-9-10-7 M) induced in the PnO an increase (+35%) of the specific binding of the muscarinic antagonist [3H]quinuclidinyl benzylate, which could be completely prevented by PACAP6-27 (IC50 = 8 x 10-8 M) and (ii) both carbachol and PACAP enhanced [35S]GTP-gamma-S binding in a concentration-dependent manner in the PnO. The maximal increase due to carbachol was significantly higher in the presence (+126%) than in the absence (+102%) of PACAP (0.1 microM). These data showed that interactions between muscarinic and PACAP receptors do exist within the PnO and play a role in the local mechanisms of REM sleep control in the rat.


Assuntos
Neuropeptídeos/farmacologia , Neurotransmissores/farmacologia , Fragmentos de Peptídeos/farmacologia , Ponte/fisiologia , Receptores Muscarínicos/fisiologia , Receptores do Hormônio Hipofisário/fisiologia , Sono REM/fisiologia , Animais , Carbacol/administração & dosagem , Carbacol/farmacologia , Córtex Cerebral/efeitos dos fármacos , Córtex Cerebral/fisiologia , Masculino , Microinjeções , Neuropeptídeos/administração & dosagem , Neurotransmissores/administração & dosagem , Fragmentos de Peptídeos/administração & dosagem , Polipeptídeo Hipofisário Ativador de Adenilato Ciclase , Tratos Piramidais/efeitos dos fármacos , Tratos Piramidais/fisiologia , Ratos , Ratos Sprague-Dawley , Receptores Muscarínicos/efeitos dos fármacos , Receptores de Polipeptídeo Hipofisário Ativador de Adenilato Ciclase , Receptores do Hormônio Hipofisário/efeitos dos fármacos , Fases do Sono/efeitos dos fármacos , Fases do Sono/fisiologia , Sono REM/efeitos dos fármacos , Vigília/efeitos dos fármacos , Vigília/fisiologia
18.
J Biol Chem ; 276(16): 13217-25, 2001 Apr 20.
Artigo em Inglês | MEDLINE | ID: mdl-11278962

RESUMO

CCR5 is a G-protein-coupled receptor activated by the chemokines RANTES (regulated on activation normal T cell expressed and secreted), macrophage inflammatory protein 1alpha and 1beta, and monocyte chemotactic protein 2 and is the main co-receptor for the macrophage-tropic human immunodeficiency virus strains. We have identified a sequence motif (TXP) in the second transmembrane helix of chemokine receptors and investigated its role by theoretical and experimental approaches. Molecular dynamics simulations of model alpha-helices in a nonpolar environment were used to show that a TXP motif strongly bends these helices, due to the coordinated action of the proline, which kinks the helix, and of the threonine, which further accentuates this structural deformation. Site-directed mutagenesis of the corresponding Pro and Thr residues in CCR5 allowed us to probe the consequences of these structural findings in the context of the whole receptor. The P84A mutation leads to a decreased binding affinity for chemokines and nearly abolishes the functional response of the receptor. In contrast, mutation of Thr-82(2.56) into Val, Ala, Cys, or Ser does not affect chemokine binding. However, the functional response was found to depend strongly on the nature of the substituted side chain. The rank order of impairment of receptor activation is P84A > T82V > T82A > T82C > T82S. This ranking of impairment parallels the bending of the alpha-helix observed in the molecular simulation study.


Assuntos
Quimiocinas/farmacologia , Receptores CCR5/química , Receptores CCR5/fisiologia , Sequência de Aminoácidos , Substituição de Aminoácidos , Animais , Sítios de Ligação , Células CHO , Bovinos , Quimiocina CCL4 , Quimiocina CCL5/farmacocinética , Quimiocina CCL5/farmacologia , Quimiocina CCL8 , Cricetinae , Proteínas de Ligação ao GTP/metabolismo , Humanos , Proteínas Inflamatórias de Macrófagos/farmacologia , Camundongos , Modelos Moleculares , Dados de Sequência Molecular , Proteínas Quimioatraentes de Monócitos/farmacologia , Mutagênese Sítio-Dirigida , Estrutura Secundária de Proteína , Receptores CCR5/efeitos dos fármacos , Receptores de Quimiocinas/química , Receptores de HIV/química , Receptores de HIV/efeitos dos fármacos , Receptores de HIV/fisiologia , Proteínas Recombinantes/química , Proteínas Recombinantes/efeitos dos fármacos , Proteínas Recombinantes/metabolismo , Rodopsina/química , Alinhamento de Sequência , Homologia de Sequência de Aminoácidos , Transfecção
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA