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2.
Nat Prod Res ; 29(22): 2097-9, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25495879

RESUMO

This article deals with the comparison of the antioxidant activity of aqueous extracts of various parts of Carica papaya L. The evaluation of total phenolic content and total flavonoid content revealed high antioxidant potential of the seeds and fruits. The free radical-scavenging potential of the aqueous extracts indicated the seeds to have better DPPH-scavenging activity than fruits. The results were augmented by the FRAP activity as well. The phenolics present in the extracts were separated and identified as 5-hydroxy feruloyl quinic acid, acetyl p-coumaryl quinic acid, quercetin-3-O-rhamnoside, syringic acid hexoside, 5-hydroxy caffeic quinic acid, peonidin-3-O-glucoside, sinapic acid-O-hexoside, cyaniding-3-O-glucose and methyl feruloyl glycoside by LCMS-MS technique.


Assuntos
Antioxidantes/química , Carica/química , Fenóis/química , Extratos Vegetais/química , Antioxidantes/isolamento & purificação , Cromatografia Líquida , Flavonoides/química , Flavonoides/isolamento & purificação , Frutas/química , Espectrometria de Massas , Estrutura Molecular , Fenóis/isolamento & purificação , Folhas de Planta/química , Raízes de Plantas/química , Caules de Planta/química , Sementes/química
4.
Plant Dis ; 96(1): 141, 2012 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30731884

RESUMO

Fruit rot disease (FRD), an emerging problem of tinda (Praecitrullus fistulosus) in India. FRD epidemics begin during rainy and warm weather and often spoil marketable produce. Symptoms appear as numerous, pale brown-to-dark brown, deeply penetrating circular soft rot lesions on fleshy fruit tissues. Noneffervescent bacterial exudates occasionally form on lesions. Repeated isolations from FRD-affected tinda fruits consistently yielded the same bacterial species. Inoculation of the isolated bacterium into asymptomatic tinda fruits produced identical soft rot symptoms. Fruits were inoculated with the isolate ITCC B0030 (0.1 OD) by removing a 2.0-cm deep tissue plug with a sterile cork borer (5 mm in diameter) and injecting the inoculum with a syringe in the cylindrical cavity. After inoculation, the plug (upper 5 mm) was reinserted, sealed with sterile paraffin, and covered with a small piece of wet absorbent cotton to prevent dehydration. High humidity (>90%) and 30 to 33°C temperature was maintained after inoculation in a glasshouse. After 4 to 10 days, fruits showed FRD symptoms. The reisolated bacterium from artificially inoculated symptomatic fruits was identical with the original inoculated bacterium. Identity of the bacterial pathogen for FRD was confirmed by phenotypic and genotypic methods. The causal bacterium was a gram-negative, non-sporing motile rod with a single polar flagellum. The bacterium produced yellowish green and blue-green diffusible pigments on King's B (KB) medium. On yeast dextrose calcium carbonate agar at 30°C, the colonies produced abundant, blue, diffusible pigment within 48 h. The bacterium grew at temperatures up to 42°C but not at 4°C. Excellent growth occurred on Salmonella-Shigella agar and MaConkey's medium, as reported also for Pseudomonas aeruginosa strain P8. The bacterium produced ammonia, hydrogen sulfide, arginine dihydrolase, urease, lipase, catalase, gelatinase, and casinase but not amylase, indole, or acetyl methyl carbinol. The bacterium was identified as P. aeruginosa using Biolog based Bacterial Identification System version 4.2 (Biolog Inc., Hayward, CA). The bacterium did not utilize cellobiose, dulcitol, maltose, sorbitol, sucrose, arabinose, and starch. Upon infiltration on tobacco leaves (Nicotiana tabacum cv. Xanthi) at 107 or more cells ml-1, the bacterium gave a strong hypersensitive reaction within 24 h. Transmission electron micrographs (TEM, KYKY 1000B, Japan) of the causal bacterium revealed a single, polar flagellum. Identity was further confirmed as P. aeruginosa based on 16S rRNA sequence (1,491 nt) analysis with universal primers F1 (5'-GAGTTTGATCCTGGCTCAG-3') and R13 (5'-AGAAAGGAGGTGATCCAGCC-3'). A blastN search of GenBank revealed a >99% nt identity with P. aeruginosa strain TAUC 7 (HQ914782). The 16S rRNA gene sequence (1,491 nt) was deposited in Bankit GenBank (JF797204). To our knowledge, this is the first report of fruit rot of tinda caused by P. aeruginosa in India (ITCC B0030) and a new record of bacterial rot of Praecitrullus fistulosus induced by a fluorescent and blue-green pigment producing P. aeruginosa. To date, P. syringae pv. lachrymans and a nonfluorescent P. pseudoalcaligenes subsp. citrulli were reported to infect Citrullus lanata (1) and Praecitrullus fistulosus (2), respectively. References: (1) D. L. Hopkins and N. C. Schenck. Phytopathology 62:542, 1972. (2) N. W. Schaad et al. Int. J. Syst. Bacteriol. 28:117, 1978.

5.
Osteoarthritis Cartilage ; 18(8): 1027-35, 2010 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-20472083

RESUMO

OBJECTIVE: To identify the methods used in population-based epidemiological studies to diagnose radiographic foot osteoarthritis (OA) and to estimate the population prevalence of radiographic foot OA. METHOD: Electronic databases searched included Medline, Embase, CINAHL and Ageline (inception to May 2009). The search strategy combined search terms for radiography, OA, foot, and specific foot joints. Predetermined selection criteria were applied. Data extracted from each paper included: sample population, radiographic views taken, foot joints examined, scoring system used, definition of OA applied, reliability of radiographic scoring and prevalence of radiographic OA in the foot. RESULTS: Titles and abstracts of 1035 papers were reviewed and full-texts of 21 papers were obtained. Fifteen papers met inclusion criteria and a further 12 papers were included after screening references. Radiographic views were frequently not specified (NS) but a combination of antero-posterior (AP) and lateral (Lat) views was most commonly reported. The first metatarsophalangeal (MTP) joint was the most commonly examined joint (n=20, 74%). Nineteen studies (70%) used the Kellgren and Lawrence (K&L) grading system, 95% of which defined OA as K&L grade> or =2. Estimates of the prevalence of radiographic first MTP joint OA (defined as K&L> or =2) in middle-aged to older adults ranged from 6.3 to 39%. Significant statistical heterogeneity prevented pooling of prevalence estimates. CONCLUSION: There are comparatively few studies examining radiographic foot OA. Existing studies mainly focus on the first MTP joint and use the K&L grading system. Future studies are needed to quantify the prevalence of radiographic OA at the different joint complexes within the foot.


Assuntos
Articulações do Pé/diagnóstico por imagem , Osteoartrite/epidemiologia , Humanos , Osteoartrite/diagnóstico por imagem , Osteoartrite/fisiopatologia , Prevalência , Radiografia , Índice de Gravidade de Doença
6.
Bioorg Med Chem Lett ; 17(13): 3630-5, 2007 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-17512197

RESUMO

Recent literature has suggested the benefit of selective PPARdelta agonists for the treatment of atherosclerosis and other disease states associated with the metabolic syndrome. Herein we report the synthesis and structure-activity relationships of a series of novel and selective PPARdelta agonists. Our search began with identification of a novel benzothiophene template which was modified by the addition of various thiazolyl, isoxazolyl, and benzyloxy-benzyl moieties. Further elucidation of the SAR led to the identification of benzofuran and indole based templates. During the course of our research, we discovered three new chemical templates with varying degrees of affinity and potency for PPARdelta versus the PPARalpha and PPARgamma subtypes.


Assuntos
Benzofuranos/química , Química Farmacêutica/métodos , Indóis/química , PPAR delta/agonistas , Tiofenos/química , Animais , Benzofuranos/síntese química , Desenho de Fármacos , Avaliação Pré-Clínica de Medicamentos , Humanos , Indóis/síntese química , Concentração Inibidora 50 , Ligantes , Modelos Químicos , Relação Estrutura-Atividade , Tiazóis/química , Tiofenos/síntese química
7.
Kidney Int ; 69(3): 560-4, 2006 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-16395253

RESUMO

Anemia is a common complication of chronic kidney disease (CKD), but the outcomes associated with lower hemoglobin (Hgb) levels in patients with CKD not yet on dialysis are not well characterized. Analyses exploring outcomes associated with a single baseline Hgb value also do not account for the longitudinal variation of this measure. After collecting all Hgb measurements (N=17 194, median (range): 12 (1-168)) over a median follow-up period of 2.1 years in a historical prospective cohort of 853 male US veterans with CKD Stages 3-5 not yet on dialysis, we examined the association of time-averaged Hgb levels with predialysis all-cause mortality, end-stage renal disease (ESRD), and a composite end point of both. Kaplan-Meier survival analysis and Cox models adjusted for age, race, body mass index, smoking status, blood pressure, diabetes mellitus, cardiovascular disease, categories of estimated glomerular filtration rate, serum concentrations of albumin and cholesterol, and proteinuria were examined. Lower time-averaged Hgb was associated with significantly higher hazard of the composite end point (hazard ratio (95% confidence interval) in the adjusted model for time-averaged Hgb of <110, 111-120 and 121-130, compared to >130 g/l: 2.57 (1.85-3.58), 1.97 (1.45-2.66), 1.19 (0.86-1.63), P(trend)<0.001). Lower time-averaged Hgb was associated with both significantly higher pre-dialysis mortality and higher risk of ESRD, when analyzed separately. Anemia (especially time-averaged Hgb <120 g/l) is associated with both higher mortality and increased risk of ESRD in male patients with CKD not yet on dialysis.


Assuntos
Anemia/complicações , Anemia/fisiopatologia , Nefropatias/complicações , Nefropatias/fisiopatologia , Falência Renal Crônica/etiologia , Idoso , Anemia/sangue , Doença Crônica , Estudos de Coortes , Seguimentos , Hemoglobinas/análise , Humanos , Nefropatias/sangue , Nefropatias/mortalidade , Falência Renal Crônica/sangue , Falência Renal Crônica/epidemiologia , Falência Renal Crônica/fisiopatologia , Masculino , Pessoa de Meia-Idade , Modelos de Riscos Proporcionais , Estudos Prospectivos , Fatores de Risco , Índice de Gravidade de Doença , Análise de Sobrevida
8.
Pharmacol Biochem Behav ; 69(3-4): 571-8, 2001.
Artigo em Inglês | MEDLINE | ID: mdl-11509218

RESUMO

Behavioral effects of desamino-3-iodozacopride (DAIZAC) [(S)-5-chloro-3-iodo-2-methoxy-N-(1-azabicyclo[2.2.2]oct-3-yl)benzamide], a selective high-affinity 5-HT(3) receptor antagonist (K(D) 0.14 nM), were evaluated in the mouse elevated plus-maze using the anxiolytic benzodiazepine, diazepam, as a positive control. DAIZAC treatment produced a significant dose-related increase in the time spent in the open arm. The increased total time in the open arm resulted from a significant dose-dependent increase in the number of entries into that arm. The minimum dose of DAIZAC associated with a statistically significant increase in entries and time spent in the open arm was 0.05 mg/kg ip, consistent with its high affinity for the 5-HT(3) receptor. DAIZAC did not affect the amount of time spent in the open arm after each entry. Thus, DAIZAC reduced apparent avoidance of the open arm when the animal was in the central compartment, without affecting active avoidance of that arm when the animal was in the exposed condition. The increase in the open-arm entries was accompanied by a corresponding reduction in the number of entries into the closed arm with a consequent reduction in the time spent in the closed arm. The time spent in the closed arm after each entry was not altered by DAIZAC administration. As such, the sole apparent effect of DAIZAC was to alter the choice of arm to enter when the animal was in the central compartment. Diazepam also significantly increased total time in the open arm; however, the increase was not attributable to a single behavioral factor. The anxiolytic-like effects of DAIZAC reached maximum by 20-30 min and returned to baseline levels by 90 min. Ex vivo binding studies found that levels of DAIZAC-like activity assayed in brains of mice 25 min after DAIZAC injection were significantly correlated with the behavioral parameters associated with anxiolysis. These results indicate that DAIZAC produces dose-dependent anxiolytic-like behavioral changes in the mouse elevated plus-maze that are correlated with brain DAIZAC-like activity.


Assuntos
Ansiolíticos/uso terapêutico , Ansiedade/tratamento farmacológico , Benzamidas/uso terapêutico , Compostos Bicíclicos Heterocíclicos com Pontes/uso terapêutico , Receptores de Serotonina/metabolismo , Antagonistas da Serotonina/uso terapêutico , Animais , Ansiolíticos/metabolismo , Ansiedade/metabolismo , Benzamidas/metabolismo , Benzodiazepinas/farmacologia , Encéfalo/metabolismo , Compostos Bicíclicos Heterocíclicos com Pontes/metabolismo , Relação Dose-Resposta a Droga , Masculino , Camundongos , Camundongos Endogâmicos ICR , Receptores 5-HT3 de Serotonina , Antagonistas da Serotonina/metabolismo
9.
Eur J Med Chem ; 35(12): 1121-5, 2000 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-11248411

RESUMO

This document has been elaborated by the IUPAC Medicinal Chemistry section and is backed by a large number of scientists, many of whom have had direct involvement and whose names appear at the end of the article. This work discusses the role that the discovery of new medicinal agents has in the development of societies as well as in the conservation of biodiversity in terms of work carried out on natural products. Also included are several recommendations for countries which are presently in search of their own scientific and technological development in medicinal agents. The IUPAC Medicinal Chemistry section would appreciate the collaboration of the scientific societies in every country to aid in the diffusion of this document.


Assuntos
Produtos Biológicos , Química Farmacêutica , Mudança Social , Conservação dos Recursos Naturais , Especificidade da Espécie
11.
Curr Pharm Des ; 5(1): 11-20, 1999 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-10066881

RESUMO

The disease process known as atherosclerosis is the leading cause of morbidity and mortality in the Western world. Current therapies have focused on treating the major risk factors identified to date including plasma lipid derangements, hypertension, clotting disorders, and diabetes. However, a significant number of individuals will be diagnosed with this malady in the apparent absence of known risk factors. Recent attention has turned toward treating the disease at the level of the vessel wall. In this review, we assess the relevancy of the oxygenating enzyme 15-lipoxygenase (15-LO) as a therapeutic target. In vitro studies suggest that this enzyme may be involved in processes that modify native LDL in such a way as to be avidly taken up by tissue macrophages. In support of this contention are reports demonstrating the colocalization of 15-LO with macrophage-rich arterial lesions and epitopes of modified LDL. Investigations using transgenic animals also suggest that the site of 15-LO expression may be an important factor in the development of the disease. The alteration of important cellular fatty acids may also generate intracellular signals that promote a pro-atherogenic phenotype in the absence of measurable changes in bulk lipid peroxidation. A limited number of studies have examined 15-LO inhibitors and those structural determinants necessary for inhibition of the enzyme. These include natural products and synthetic analogs. Structure activity relationships have been defined for a number of compounds including caffeic acid derivatives, propargyl ethers, and catechols. A novel, potent, specific inhibitor of 15-LO that lacks significant antioxidant activity was tested for its ability to inhibit atherosclerotic lesion formation in vivo. This benzothiopyranoindole virtually eliminated lesion formation in two animal models in the absence of significant changes in plasma lipids. Further, it prevented the progression of pre-established lesions in another study. Collectively, these data provide a strong scientific rationale for exploring the inhibition of 15-LO as a therapeutic strategy.


Assuntos
Arteriosclerose/tratamento farmacológico , Inibidores Enzimáticos/uso terapêutico , Inibidores de Lipoxigenase , Animais , Araquidonato 15-Lipoxigenase/fisiologia , Arteriosclerose/etiologia , Humanos , Relação Estrutura-Atividade
12.
J Pharmacol Exp Ther ; 288(1): 221-31, 1999 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-9862774

RESUMO

The 5-hydroxytryptamine(HT)3 receptor subtype is present in the central nervous system (CNS) in low abundance, and few selective radiolabeled antagonists with high specific activity are available to study these sites. DAIZAC [desamino-3-iodo-(S)-zacopride; (S)-5-chloro-3-iodo-2-methoxy-N-(1-azobicyclo-[2.2. 2]oct-3-yl)benzamide] is a compound with high affinity and selectivity for the 5-HT3 receptor. Scatchard analysis of specific binding to NCB-20 cell membranes gave a Bmax of 340 +/- 58 fmol/mg protein and a KD of 0.14 +/- 0.03 nM, which is in agreement with the value previously reported in rat brain (KD = 0.15 nM). Nonspecific binding of [125I]DAIZAC in NCB-20 cells was <1% of total binding at the KD for DAIZAC compared with 17% in the rat brain preparation. Unlabeled DAIZAC (10 microM) showed minimal ability to displace binding of radiolabeled ligands selected for their affinities for other CNS receptor and uptake carrier binding sites. The discrimination ratio of DAIZAC for the 5-HT3 receptor over the M1 muscarinic binding site, the non-5-HT3 site at which it was most potent, was >2800. Serotonergic antagonists at every other known CNS serotonergic binding sites (3-30 microM) were ineffective in displacing [125I]DAIZAC binding in rat brain membranes. Similarly, antagonists (3-30 microM) for other nonserotonergic receptors and uptake sites were ineffective in displacing [125I]DAIZAC binding. Autoradiographic studies showed highest specific binding in area postrema and nucleus solitarius, with intermediate levels of binding in entorhinal cortex and hippocampus. DAIZAC inhibited 5-HT3 receptor-mediated inward cation current in NCB-20 cells with an IC50 of 0.24 nM. [125I]DAIZAC is a potent and highly selective ligand for in vitro studies of the 5-HT3 receptor.


Assuntos
Benzamidas/farmacologia , Compostos Bicíclicos Heterocíclicos com Pontes/farmacologia , Receptores de Serotonina/metabolismo , Antagonistas da Serotonina/farmacologia , Animais , Autorradiografia , Benzamidas/química , Benzamidas/farmacocinética , Ligação Competitiva , Encéfalo/efeitos dos fármacos , Encéfalo/metabolismo , Compostos Bicíclicos Heterocíclicos com Pontes/química , Compostos Bicíclicos Heterocíclicos com Pontes/farmacocinética , Células Cultivadas , Eletrofisiologia , Técnicas In Vitro , Radioisótopos do Iodo , Masculino , Camundongos , Ensaio Radioligante , Ratos , Ratos Sprague-Dawley , Receptores de Serotonina/efeitos dos fármacos , Receptores 5-HT3 de Serotonina , Antagonistas da Serotonina/farmacocinética , Distribuição Tecidual
13.
J Assoc Physicians India ; 47(3): 275-9, 1999 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-10999119

RESUMO

BACKGROUND: The availability of sensitive and specific assays for evaluation of the thyroid axis has allowed definition of thyroid disorders at subclinical stage. This has almost obviated the use of thyrothrophin releasing hormone (TRH) study. We describe here a group of patients with minimal signs of hypothyroidism having normal thyroid function tests (T3, T4, thyroid stimulating hormone (TSH)) and have shown exaggerated TSH response to TRH. MATERIAL AND METHODS: Total 82 subjects were studied. Of these, 11 were age and sex matched controls, and 71 were patients. In all subjects TSH and other thyroid assays (T3, T4, FT4) were done by immunoradiometric assay (IRMA), and radioimmunoassay (RIA) respectively. Thyroid antibody was carried out by haemagglutination method. Results were compared to age and sex related normal ranges. To further investigate the status of thyroid axis, TRH study was carried out using standard protocol. RESULTS: Based on TRH study patients were grouped in three categories. Group 1 included 29 patients whose TSH response to TRH was normal. Group 2 included 20 patients with normal baseline TSH and exaggerated TSH response to TRH and Group 3 included 18 patients with baseline TSH in the range of 5 to 10 mu IU/ml and exaggerated TSH response to TRH. There was a significant difference to total T3 between group 1 and 3 (p < 0.05) but mean values were within normal limits. While no significant difference was observed in total T4 between controls and patient's group. Serum TSH values were high in group 3 as compared to controls and Group 1 and 2 (p < 0.0001). For Free T4 no statistical significance was observed between Group 1, 2 and 3. Thyroid antibodies were positive in 22.7% of patients in Group 2 and 33.33% in Group 3. CONCLUSION: We conclude from the present study that even with sensitive TSH assays TRH study still has a role to mark the early stage of hypothyroidism. Those with a normal or upper normal TSH with exaggerated response to TRH are termed as sub-biochemical hypothyroidism and can be considered for thyroid replacement therapy.


Assuntos
Hipertireoidismo/diagnóstico , Hormônio Liberador de Tireotropina , Tireotropina/sangue , Tireotropina/efeitos dos fármacos , Adolescente , Adulto , Idoso , Criança , Feminino , Humanos , Hipertireoidismo/sangue , Masculino , Pessoa de Meia-Idade , Probabilidade , Radioimunoensaio , Valores de Referência , Sensibilidade e Especificidade , Índice de Gravidade de Doença , Testes de Função Tireóidea
14.
16.
Neuron ; 21(4): 895-906, 1998 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-9808474

RESUMO

Cyclic GMP (cGMP) is a crucial intracellular messenger in neuronal, muscle, and endocrine cells. The intracellular concentration of cGMP is regulated by various neurotransmitters, including acetylcholine (ACh) and nitric oxide (NO). While much is known about the biochemical steps leading to cGMP synthesis, little is known about cGMP kinetics in intact cells. Here, we use "patch-cramming," in which an excised, inside-out membrane patch containing cyclic nucleotide-gated ion channels is used as a biosensor, to obtain the first real-time measurements of cGMP in intact cells. Patch-cramming experiments on neuroblastoma cells show that both muscarinic agonists and NO rapidly elevate cGMP. NO elicits cGMP responses repeatedly without decrement, whereas responses to muscarinic agonists exhibit a profound and prolonged desensitization. Remarkably, muscarinic agonists also cause long-term (>30 min) suppression (LTS) of cGMP responses elicited by NO. Biochemical measurements reveal that rat sympathetic neurons also exhibit LTS of cGMP, suggesting that LTS is a widespread mechanism that may contribute to synaptic plasticity.


Assuntos
Sistemas Computacionais , GMP Cíclico/metabolismo , Membranas Intracelulares/metabolismo , Lábio/fisiologia , Agonistas Muscarínicos/farmacologia , Óxido Nítrico/farmacologia , Animais , GMP Cíclico/antagonistas & inibidores , Eletrofisiologia/métodos , Cinética , Oócitos/metabolismo , Ratos , Células Tumorais Cultivadas , Xenopus
18.
Artigo em Inglês | MEDLINE | ID: mdl-9608609

RESUMO

1. Antagonists at 5-HT3 receptors have shown activity in animal models of mental illness, however, few radiolabeled 5-HT3 ligands are available for preclinical studies. MIZAC, an analogue of the selective 5-HT3 antagonist, zacopride, binds with high affinity (1.3-1.5 nM) to CNS 5-HT3 sites. The authors report here the selectivity of MIZAC for these sites in rat brain homogenates. 2. Ninety-seven percent of total specific binding of [125I]MIZAC (0.1 nM) of was displaced by bemesetron (3 microM), a selective 5-HT3 antagonist. Competition studies using ligands with known affinities for 5-HT3 sites give a high correlation with reported pKi values (r2 0.98). Bemesetron displaceable binding has a regional distribution consistent with that of the 5-HT3 receptor, i.e. highest in cortex and hippocampus, and lowest in striatum and cerebellum. 3. Potent antagonists present at concentrations sufficient to occupy 95% of other 5-HT receptor populations (1A, 1B, 1D, 2A, 2B, 2C, 5A, 5B, 6, and 7) showed minimal ability to displace [125I]MIZAC binding (3 nM). Specificity studies using radioligand binding assays selective for 5-HT4, 5-HT6, and 5-HT7 receptors, and for binding sites of other neurotransmitters indicate a high degree of selectivity of [125I]MIZAC for the 5-HT3 receptor. 4. [125I]MIZAC binds to an apparent low affinity (benzac) site having a unique pharmacology. Low affinity binding was displaceable by benztropine, but not by other muscarinic agents nor inhibitors of dopamine uptake. The regional distribution of the low affinity site differed markedly from that of the high affinity site. The apparent affinity of [125I]MIZAC for the benzac site is two orders of magnitude lower than for the 5-HT3 receptor. Given its high selectivity for 5-HT3 binding sites, [125I]MIZAC appears to be a promising ligand for labeling 5-HT3 receptors in vitro and in vivo.


Assuntos
Benzamidas/metabolismo , Encéfalo/metabolismo , Compostos Bicíclicos Heterocíclicos com Pontes/metabolismo , Receptores de Serotonina/metabolismo , Antagonistas da Serotonina/metabolismo , Animais , Ligação Competitiva , Técnicas In Vitro , Radioisótopos do Iodo , Masculino , Ratos , Ratos Sprague-Dawley , Receptores de Serotonina/efeitos dos fármacos
19.
J Med Chem ; 41(7): 1042-9, 1998 Mar 26.
Artigo em Inglês | MEDLINE | ID: mdl-9544204

RESUMO

We have designed a novel series of CCK-B receptor antagonists by combining key pharmacophores, an arylurea moiety of 1 and a quinazolinone ring of 3, from two known series. Our earlier studies showed that compounds with methylene linkers in our "target" produced moderate binding affinity and selectivity for CCK-B receptors, whereas its higher and lower homologues resulted in loss of affinity. Introduction of -NH- as a linker dramatically enhanced binding affinity and selectivity for CCK-B receptors, thus providing several compounds with single-digit nanomolar binding affinity and excellent selectivity. Analogous to the earlier studies of the series of quinazolinone derivatives 3, we also found 3-isopropoxyphenyl as a preferred substitution on the N-3 quinazolinone. Electron-withdrawing substitutions on the urea terminal phenyl ring enhanced the CCK-B potency. Representative compounds of this series were tested in the functional assay and showed pure antagonist profiles. Compounds 51 and 61 were orally active in the elevated rat X-maze test. These compounds were also evaluated for their pharmacokinetic profile. The absolute oral bioavailability of compound 61 was 22% in rats.


Assuntos
Colecistocinina/antagonistas & inibidores , Administração Oral , Animais , Comportamento Animal/efeitos dos fármacos , Masculino , Aprendizagem em Labirinto/efeitos dos fármacos , Ratos , Ratos Wistar
20.
Nucl Med Biol ; 25(2): 141-53, 1998 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-9468029

RESUMO

In an effort to develop selective, high-affinity radioligands for the 5-HT-3 receptor, a series of homologues of 5-chloro-2,3-dimethoxy-N-(1-azabicyclo[2.2.2]oct-3-yl)benzamide (2b) was prepared in which individual methoxy groups were replaced by ethoxyl, (2-fluoroethoxyl), allyloxyl, propargyloxyl, or (3-iodoallyl)oxyl groups. Affinities for the 5-HT-3 receptor were determined by displacement of the binding of [125I]MIZAC (2a), a selective 5-HT-3 receptor antagonist radioligand, in rat brain homogenates. The 3-substituted homologues were more potent than the lead compound, 2b. The homologue having the largest 3-substituent, i.e., E-(S)-N-(1-azabicyclo[2.2.2]oct-3-yl)-5-chloro-3-(3-iodo-2-propenyl)oxy- 2-methoxybenzamide (3b, THIZAC), had one of the highest affinities, Ki 0.08 nM. The 2-substituted homologues were equipotent with 2b, having Ki 0.2-0.3 nM, regardless of the size of the substituent. The corresponding iodoallyl derivative, E-(S)-N-(1-azabicyclo[2.2.2]oct-3-yl)-5-chloro-2-(3-iodo-2-propenyl)oxy- 3-methoxybenzamide (4, LIZAC), displayed a Ki of 0.29 nM. Saturation binding of [125I]-4 gave a KD of 0.31 +/- 0.04 nM and a Bmax of 2.36 +/- 0.10 fmol/mg of entorhinal cortex. In vivo biodistribution of [125I]-4 in the rat brain showed increased accumulation in hippocampus relative to that in cerebellum. Both the high-affinity ligands [125I]-3b and [125I]-4 are potentially useful radioligands for studying the 5-HT-3 receptor.


Assuntos
Benzamidas/síntese química , Quinuclidinas/síntese química , Compostos Radiofarmacêuticos/síntese química , Receptores de Serotonina/metabolismo , Animais , Benzamidas/farmacocinética , Benzamidas/farmacologia , Fenômenos Químicos , Físico-Química , Cromatografia Líquida de Alta Pressão , Radioisótopos do Iodo , Cinética , Ligantes , Masculino , Quinuclidinas/farmacocinética , Quinuclidinas/farmacologia , Compostos Radiofarmacêuticos/farmacocinética , Compostos Radiofarmacêuticos/farmacologia , Ratos , Ratos Sprague-Dawley , Receptores de Neurotransmissores/efeitos dos fármacos , Receptores de Neurotransmissores/metabolismo , Receptores de Serotonina/efeitos dos fármacos , Distribuição Tecidual , Tomografia Computadorizada de Emissão
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