RESUMEN
Maternal Embryonic Leucine-zipper Kinase (MELK) is a current oncotarget involved in a diverse range of human cancers, with the usage of MELK inhibitors being explored clinically. Here, we aimed to discover new MELK inhibitor chemotypes from our in-house compound library with a consensus-based virtual screening workflow, employing three screening concepts. After careful retrospective validation, prospective screening and inâ vitro enzyme inhibition testing revealed a series of [1,2,4]triazolo[1,5-b]isoquinolines as a new structural class of MELK inhibitors, with the lead compound of the series exhibiting a sub-micromolar inhibitory activity. The structure-activity relationship of the series was explored by testing further analogs based on a structure-guided selection process. Importantly, the present work marks the first disclosure of the synthesis and bioactivity of this class of compounds.
Asunto(s)
Inhibidores de Proteínas Quinasas/farmacología , Proteínas Serina-Treonina Quinasas/antagonistas & inhibidores , Relación Dosis-Respuesta a Droga , Evaluación Preclínica de Medicamentos , Humanos , Simulación del Acoplamiento Molecular , Estructura Molecular , Inhibidores de Proteínas Quinasas/síntesis química , Inhibidores de Proteínas Quinasas/química , Proteínas Serina-Treonina Quinasas/metabolismo , Relación Estructura-ActividadRESUMEN
BACKGROUND: The most common mechanism that reduces the efficacy of anticancer agents is overexpression of ATP-binding cassette (ABC) drug transporters. Phenothiazines and structurally-related compounds can sensitize multidrug-resistant (MDR) cells to chemotherapeutics. MATERIALS AND METHODS: Phenothiazine derivatives were investigated regarding their anticancer and MDR-reversing effect on colonic adenocarcinoma cells. The anti-proliferative and cytotoxic effects of the derivatives were assessed by the thiazolyl blue tetrazolium bromide (MTT) method, the modulation of the ABCB1 activity was measured by rhodamine 123 accumulation assay using flow cytometry. RESULTS: All phenothiazines exhibited potent cytotoxic effect on the sensitive and MDR colon adenocarcinoma cell lines. The inhibition of the ABCB1 transporter was greater in the presence of the phenothiazine derivatives than for the known ABCB1 inhibitor verapamil. CONCLUSION: It can be concluded that these derivatives show synergism in the presence of doxorubicin and could have potential as ABCB1 inhibitors.
Asunto(s)
Adenocarcinoma/genética , Neoplasias del Colon/genética , Resistencia a Antineoplásicos/genética , Subfamilia B de Transportador de Casetes de Unión a ATP/antagonistas & inhibidores , Subfamilia B de Transportador de Casetes de Unión a ATP/genética , Adenocarcinoma/tratamiento farmacológico , Adenocarcinoma/patología , Apoptosis/efectos de los fármacos , Línea Celular Tumoral , Neoplasias del Colon/tratamiento farmacológico , Neoplasias del Colon/patología , Doxorrubicina/administración & dosificación , Resistencia a Múltiples Medicamentos/efectos de los fármacos , Resistencia a Múltiples Medicamentos/genética , Resistencia a Antineoplásicos/efectos de los fármacos , Humanos , Fenotiazinas/administración & dosificación , Rodamina 123/administración & dosificación , Verapamilo/administración & dosificaciónRESUMEN
Reaction of aryl- and benzylsulfanopyridinium amidates bearing a methyl group in position 6 with 2 equiv of diphenylketene afforded a spiro-fused ring system: azoniabenzo[de]fluorine. By use of an excess amount of ketene, a distinct reaction was observed via which a 1H-pyrrolo[3,2-b]pyridin-2(3H)-one derivative was furnished. The structure of the tetracyclic spiro-fused ring system was unambiguously confirmed by X-ray diffraction, and its formation was rationalized by DFT calculations.
RESUMEN
BACKGROUND/AIM: Bacterial resistance to antibiotics has become a serious problem in antibacterial chemotherapy and resistance of bacteria to chemically-unrelated anti-microbial agents can be associated with the over-expression of efflux pumps. The simultaneous therapy with efflux pump inhibitors (EPIs) could be a solution to improve the effectiveness of antibiotics. The response of an organism to an EPI often depends on how that molecule fits a particular site of a protein. Because enantiomers of a given compound rotate plane-polarized light in a solution by the same angle but in opposite directions, the rational drug design should take the chirality into account if there is a difference between the racemic compound and its enantiomers. MATERIALS AND METHODS: The main goal of the present study was to elucidate the role of chirality of N-hydroxyalkyl-2-aminophenothiazines as effective EPIs by an automated method that uses the general efflux pump substrate ethidium bromide (EB) for the assessment of AcrAB-TolC system of wild-type Escherichia coli K-12 AG100. It has been shown that the most active EPIs among the N-hydroxyalkyl-2-aminophenothiazines were the compounds rac-3i, (+)-3i, and (-)-3i by modulating the AcrAB-TolC efflux pump. CONCLUSION: Comparison of effects of enantiomeric pairs revealed that their activities were similar to that of racemic derivatives. Moreover, there was no significant difference between the racemic compounds and their enantiomers related to their antibacterial and efflux pump inhibiting effects.
Asunto(s)
Proteínas Portadoras/antagonistas & inhibidores , Proteínas de Escherichia coli/antagonistas & inhibidores , Fenotiazinas/química , Fenotiazinas/farmacología , Antibacterianos/farmacología , Farmacorresistencia Bacteriana , Escherichia coli K12/efectos de los fármacos , Escherichia coli K12/metabolismo , Pruebas de Sensibilidad MicrobianaRESUMEN
BACKGROUND: Phenothiazines have anticancer properties and are able to reverse the multidrug resistance of neoplastic cells by inhibiting the ATP-binding cassette, sub-family B (MDR/TAP), member 1 protein (ABCB1 or P-glycoprotein) activity. MATERIALS AND METHODS: A series of new phenothiazine derivatives was investigated regarding their ABCB1-modulating effect on multidrug resistant mouse T-lymphoma cells by rhodamine 123 accumulation assay and real-time ethidium bromide accumulation assay. RESULTS: The phenothiazine derivatives exhibited a potent anticancer effect on the parental cell line and on its multidrug-resistant mouse T-lymphoma subline overexpressing the ABCB1 transporter. The inhibition of the ABCB1 transporter in the presence of the newly-developed phenothiazines was greater than that for the known ABCB1 inhibitors thioridazine and verapamil. CONCLUSION: Based on the chemical structures and biological activity, compounds with bivalent sulfur atom in the phenothiazine ring demonstrated marked ABCB1-modulating effect, however, other derivatives with halogen or amide substitutions were ineffective.
Asunto(s)
Subfamilia B de Transportador de Casetes de Unión a ATP/metabolismo , Antineoplásicos/farmacología , Resistencia a Múltiples Medicamentos , Resistencia a Antineoplásicos , Linfoma de Células T/metabolismo , Fenotiazinas/farmacología , Subfamilia B de Transportador de Casetes de Unión a ATP/genética , Animales , Antineoplásicos/química , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Expresión Génica , Linfoma de Células T/genética , Ratones , Fenotiazinas/química , Rodamina 123/metabolismoRESUMEN
C2 toxin from Clostridium botulinum represents the prototype of clostridial binary actin ADP-ribosylating toxins which destroy the actin-cytoskeleton of mammalian cells and cause severe enteric diseases in humans and animals. After receptor-mediated endocytosis of the C2 toxin complex, the binding/translocation component C2IIa forms a heptameric transmembrane pore in membranes of acidified endosomal vesicles. The separate ADP-ribosyltransferase component C2I translocates through this C2IIa-pore from the endosomal lumen into the cytosol. Here we demonstrate that positively charged heterocyclic azolopyridinium salts which were developed as pore blockers for the anthrax toxins, efficiently protect cultured mammalian cells from intoxication with C2 toxin. The inhibitors had no effects on enzyme activity of C2I or receptor binding of C2 toxin but inhibited the pH-dependent membrane translocation of C2I in living cells, most likely by blocking the C2IIa-translocation pores. In vitro, the substances blocked C2IIa-pores in black lipid bilayer membranes when applied to the cis-side of the membrane which corresponds to the endosomal lumen of cells. Thus, heterocyclic azolopyridinium salts could represent lead compounds for development of novel therapeutics against binary clostridial toxins.
Asunto(s)
Toxinas Botulínicas/toxicidad , Membrana Celular/metabolismo , Compuestos Heterocíclicos/farmacología , Compuestos de Piridinio/farmacología , Toxinas Botulínicas/metabolismo , Escherichia coli/metabolismo , Células HeLa , Compuestos Heterocíclicos/química , Humanos , Concentración de Iones de Hidrógeno , Transporte de Proteínas , Compuestos de Piridinio/químicaRESUMEN
BACKGROUND: Several intracellular acting bacterial protein toxins of the AB-type, which are known to enter cells by endocytosis, are shown to produce channels. This holds true for protective antigen (PA), the binding component of the tripartite anthrax-toxin of Bacillus anthracis. Evidence has been presented that translocation of the enzymatic components of anthrax-toxin across the endosomal membrane of target cells and channel formation by the heptameric/octameric PA63 binding/translocation component are related phenomena. Chloroquine and some 4-aminoquinolones, known as potent drugs against Plasmodium falciparium infection of humans, block efficiently the PA63-channel in a dose dependent way. METHODOLOGY/PRINCIPAL FINDINGS: Here we demonstrate that related positively charged heterocyclic azolopyridinium salts block the PA63-channel in the µM range, when both, inhibitor and PA63 are added to the same side of the membrane, the cis-side, which corresponds to the lumen of acidified endosomal vesicles of target cells. Noise-analysis allowed the study of the kinetics of the plug formation by the heterocycles. In vivo experiments using J774A.1 macrophages demonstrated that the inhibitors of PA63-channel function also efficiently block intoxication of the cells by the combination lethal factor and PA63 in the same concentration range as they block the channels in vitro. CONCLUSIONS/SIGNIFICANCE: These results strongly argue in favor of a transport of lethal factor through the PA63-channel and suggest that the heterocycles used in this study could represent attractive candidates for development of novel therapeutic strategies against anthrax.
Asunto(s)
Antibacterianos/farmacología , Bacillus anthracis/inmunología , Toxinas Bacterianas/antagonistas & inhibidores , Imidazoles/farmacología , Piridinas/farmacología , Animales , Antígenos Bacterianos/fisiología , Línea Celular , Supervivencia Celular/efectos de los fármacos , Membrana Dobles de Lípidos , Potenciales de la Membrana , Ratones , Modelos Biológicos , Unión Proteica , Transporte de Proteínas , Volumetría , Factor de Necrosis Tumoral alfa/metabolismoRESUMEN
Novel N-hydroxyalkyl-2-aminophenothiazines implying a tetrazole moiety at the alkyl chain have been synthesized by hydroboration-oxidation of dienes followed by Buchwald-Hartwig cross-coupling reaction. Also, some sulfoxide and sulfone derivatives have been prepared by selective oxidations. MDR inhibition studies on rat hepatocyte cell culture revealed that some derivatives exhibit marked biological efficacy exceeding that of the standard verapamil (e.g., 3h, 4h, 16). Selected derivatives were subjected to chemical resolution to provide both enantiomers which were shown of similar activity on P-gp interaction measurements. The new compounds exhibited no toxicity.
Asunto(s)
Resistencia a Múltiples Medicamentos/efectos de los fármacos , Hepatocitos/efectos de los fármacos , Fenotiazinas/química , Fenotiazinas/farmacología , Miembro 1 de la Subfamilia B de Casetes de Unión a ATP/antagonistas & inhibidores , Miembro 1 de la Subfamilia B de Casetes de Unión a ATP/metabolismo , Aminación , Animales , Células Cultivadas , Masculino , Fenotiazinas/síntesis química , Ratas , Ratas Wistar , Relación Estructura-Actividad , Sulfonas/síntesis química , Sulfonas/química , Sulfonas/farmacología , Sulfóxidos/síntesis química , Sulfóxidos/química , Sulfóxidos/farmacologíaAsunto(s)
Antituberculosos/farmacología , Mycobacterium tuberculosis/efectos de los fármacos , Piperazinas/farmacología , Siloxanos/farmacología , Tuberculosis Resistente a Múltiples Medicamentos/microbiología , Humanos , Pruebas de Sensibilidad Microbiana , Mycobacterium tuberculosis/aislamiento & purificaciónRESUMEN
N-dienylphenothiazines synthesized from tetrazolo[1,5-a]pyridinium salts by treatment with phenothiazine were subjected to catalytic hydrogenation to yield N-butylphenothiazines, whereas transformation of these dienes with borane dimethyl sulfide (BH(3) × Me(2)S) resulted in selective hydroboration of one double bond and full reduction of the other double bond to give 2-hydroxybutylphenothiazines. Position of the hydroxyl group was supported by NMR spectroscopy and verified by X-ray analysis. Comparison of MDR modulatory activity of the new derivatives revealed that the hydroxybutyl compounds are promising candidates for development of novel MDR inhibitors.
Asunto(s)
Aminas/química , Fenotiazinas/química , Miembro 1 de la Subfamilia B de Casetes de Unión a ATP/antagonistas & inhibidores , Miembro 1 de la Subfamilia B de Casetes de Unión a ATP/metabolismo , Animales , Boranos/química , Células Cultivadas , Cristalografía por Rayos X , Resistencia a Múltiples Medicamentos/efectos de los fármacos , Hepatocitos/efectos de los fármacos , Masculino , Conformación Molecular , Fenotiazinas/síntesis química , Fenotiazinas/farmacología , Pirimidinas/química , Ratas , Ratas WistarRESUMEN
6-Methyl substituted 2-aryl- and 2-benzylthiopyridinium N-imides reacted with an excess of isocyanates to give N,N-disubstituted exocyclic1H-imidazo[4,5-b]pyridin-2(3H)-ones. The products easily underwent spontaneous [1,5] hydrogen shift to provide the heteroaromatic imidazopyridinone isomers. The transformation implied the initial formation of [1,2,4]triazolo[2,3-a]pyridinium salt, followed by deprotonation and carbamoylation of the methylene moiety, and, finally, a rearrangement following a [1,3] sigmatropic pattern. Mechanistic considerations suggest and some experimental findings reveal the nonconcerted two-step mechanism of the ring transformation step.
RESUMEN
BACKGROUND: Because phenothiazines inhibit efflux pumps of bacteria, forty new phenothiazine derivatives were tested for their inhibition of the efflux pump systems of Gram-positive and Gram-negative pathogenic bacteria. MATERIALS AND METHODS: Detection of efflux pump activity was conducted by a previously described automated fluorimetric method. RESULTS: Although many of the compounds significantly inhibited efflux by distinct bacteria, four compounds had exceptional activity against the efflux pump systems of the pathogenic wild type bacteria Escherichia coli, Salmonella Enteritidis, Enterococcus faecalis and Staphylococcus aureus. These four compounds were then evaluated for ability to reduce or reverse resistance of multi-drug resistant members of Escherichia coli, Salmonella and Staphylococcus aureus whose MDR phenotypes are mediated by specific over-expressed efflux pumps. One of the compounds, 2173, significantly reduced resistance of MDR Staphylococcus aureus. CONCLUSION: These results suggest possible use of compound 2173 for therapy of infections caused by this organism.
Asunto(s)
Antibacterianos/farmacología , Proteínas Bacterianas/metabolismo , Enterococcus faecalis/efectos de los fármacos , Escherichia coli/efectos de los fármacos , Proteínas de Transporte de Membrana/metabolismo , Fenotiazinas/farmacología , Salmonella enteritidis/efectos de los fármacos , Staphylococcus aureus/efectos de los fármacos , Farmacorresistencia Bacteriana Múltiple , Sinergismo Farmacológico , Enterococcus faecalis/metabolismo , Escherichia coli/metabolismo , Etidio/metabolismo , Colorantes Fluorescentes/metabolismo , Pruebas de Sensibilidad Microbiana , Oxacilina/farmacología , Salmonella enteritidis/metabolismo , Staphylococcus aureus/metabolismoRESUMEN
Based on the indoloquinoline alkaloids cryptolepine (1), neocryptolepine (2), isocryptolepine (3) and isoneocryptolepine (4), used as lead compounds for new antimalarial agents, a series of tricyclic and bicyclic analogues, including carbolines, azaindoles, pyrroloquinolines and pyrroloisoquinolines was synthesized and biologically evaluated. None of the bicyclic compounds was significantly active against the chloroquine-resistant strain Plasmodium falciparum K1, in contrast to the tricyclic derivatives. The tricyclic compound 2-methyl-2H-pyrido[3,4-b]indole (9), or 2-methyl-beta-carboline, showed the best in vitro activity, with an IC(50) value of 0.45 microM against P. falciparum K1, without apparent cytotoxicity against L6 cells (SI>1000). However, this compound was not active in the Plasmodium berghei mouse model. Structure-activity relationships are discussed and compared with related naturally occurring compounds.
Asunto(s)
Antimaláricos/farmacología , Antineoplásicos/farmacología , Alcaloides Indólicos/química , Alcaloides Indólicos/farmacología , Animales , Ratones , Plasmodium berghei/efectos de los fármacos , Plasmodium falciparum/efectos de los fármacos , Relación Estructura-ActividadRESUMEN
2-Pyrazinyl (2) and 3-pyridazinylketone arylhydrazones (6) and their benzologues undergo a ring closure reaction to yield pyrazolo[3,4- b]pyrazines (4) and pyrazolo[4,3- c]pyridazines (7), respectively, in acceptable to good yields. The reaction was found to be accelerated by using acidic or basic conditions. Quantum chemical calculations suggest the key step of the mechanism to be a direct cyclization; analysis of aromaticity based on computed magnetic properties revealed its medium-dependent pericyclic or pseudopericyclic character. The cyclization reaction has also been extended for the synthesis of related ring systems ( 9, 12, 14).
Asunto(s)
Simulación por Computador , Pirazoles/síntesis química , Teoría Cuántica , Ciclización , Modelos Moleculares , Estructura Molecular , Pirazoles/química , EstereoisomerismoRESUMEN
N-oleoyldopamine (OLDA) has been identified as an agonist of the transient receptor potential vanilloid type 1 (TRPV1) receptor. A related fatty acid amide, N-oleoylethanolamide (OEA), was found to excite sensory neurons and produce visceral hyperalgesia via activation of the TRPV1 receptor, however, a recent study described this agent as an antinociceptive one. The aim of the present paper was to characterize two newly synthesized derivatives of N-oleoyldopamine, 3-methyl-N-oleoyldopamine (3-MOLDA) and 4-methyl-N-oleoyldopamine (4-MOLDA) as well as OEA with regard to their effects on the TRPV1 receptor. Radioactive 45Ca2+ uptake was measured in HT5-1 cells transfected with the rat TRPV1 receptor and intracellular Ca2+ concentration was monitored by fura-2 microfluorimetry in cultured trigeminal sensory neurons. Thermonociception was assessed by determining the behavioral noxious heat threshold in rats. 3-MOLDA induced 45Ca2+ uptake in a concentration-dependent manner, whereas 4-MOLDA and OEA were without effect. 4-MOLDA and OEA, however, concentration-dependently reduced the 45Ca2+ uptake-inducing effect of capsaicin. In trigeminal sensory neurons, 3-MOLDA caused an increase in intracellular Ca2+ concentration and this effect exhibited tachyphylaxis upon repeated application. Again, 4-MOLDA and OEA failed to alter intracellular Ca2+ levels. Upon intraplantar injection, 3-MOLDA caused an 8-10 degrees C drop of the noxious heat threshold in rats which was inhibited by the TRPV1 receptor antagonist iodo-resiniferatoxin. 4-MOLDA and OEA failed to alter the heat threshold but inhibited the threshold drop induced by the TRPV1 receptor agonist resiniferatoxin. These data show that 3-MOLDA behaves as an agonist, whereas 4-MOLDA and OEA appear to be antagonists, at the rat TRPV1 receptor.
Asunto(s)
Dopamina/análogos & derivados , Ácidos Oléicos/metabolismo , Canales Catiónicos TRPV/metabolismo , Animales , Calcio/metabolismo , Radioisótopos de Calcio/metabolismo , Capsaicina/metabolismo , Células Cultivadas , Dopamina/química , Dopamina/genética , Dopamina/metabolismo , Endocannabinoides , Estructura Molecular , Neuronas/citología , Neuronas/metabolismo , Ácidos Oléicos/química , Ácidos Oléicos/genética , Ratas , Fármacos del Sistema Sensorial/metabolismo , Canales Catiónicos TRPV/agonistas , Canales Catiónicos TRPV/antagonistas & inhibidores , Ganglio del Trigémino/citologíaRESUMEN
Thioridazine (TZ) has previously been shown by us to have in vitro and ex vivo activity against antibiotic-susceptible and multidrug-resistant Mycobacterium tuberculosis (MDRTB). Because current therapy of MDRTB is highly problematic even when all five 'first line of defence' drugs are employed, there is a need for effective antituberculosis drugs. New derivatives of TZ were synthesised and their in vitro activity against a reference strain of M. tuberculosis was evaluated with the aid of the BACTEC 460 system. Derivatives that presented significant activity were evaluated by ex vivo studies and were shown to enhance the killing of intracellular M. tuberculosis.
Asunto(s)
Antituberculosos/farmacología , Mycobacterium tuberculosis/efectos de los fármacos , Tioridazina/análogos & derivados , Farmacorresistencia Bacteriana Múltiple , Humanos , Técnicas In Vitro , Macrófagos/microbiología , Fagocitosis , Tioridazina/farmacologíaRESUMEN
Multidrug resistance in yeast results from overexpression of genes encoding drug efflux transporters owing to gain-of-function mutations in transcription factors regulating their expression. We have screened a library of synthetic compounds for modulators of drug resistance using the multidrug-resistant Saccharomyces cerevisiae pdr3-9 mutant strain. One of the compounds, 7-chlorotetrazolo[5,1-c]benzo[1,2,4]triazine (CTBT), displayed weak antifungal activity and strongly inhibited the growth of yeast cells in combination with subinhibitory concentrations of other antifungals with a different mode of action. Biological activity of CTBT was demonstrated in Saccharomyces, Kluyveromyces and Candida yeast species grown on solid and in liquid media. The chemosensitising effect of CTBT, manifested as increased antifungal activity of fluconazole, was demonstrated in yeast mutant strains with deleted genes encoding the major multidrug resistance transcription factors Yap1p, Pdr1p and Pdr3p as well as the drug efflux pumps Pdr5p and Snq2p in S. cerevisiae or their counterparts in Candida albicans and Candida glabrata, named Cdr1p and Mdr1p, respectively. Importantly, CTBT also increased the sensitivity to fluconazole in multidrug-resistant cells overexpressing the efflux pumps. Yeast cells grown in the presence of subinhibitory concentrations of CTBT exhibited an altered sterol composition and a slightly enhanced accumulation of Rhodamine 6G, which suggests that the plasma membrane plays a role in sensitisation. This novel chemosensitisation by CTBT that can overcome multidrug resistance in yeast may prove useful in combined treatment of infections caused by drug-resistant fungal pathogens.
Asunto(s)
Antifúngicos/farmacología , Saccharomyces cerevisiae/efectos de los fármacos , Triazinas/farmacología , Farmacorresistencia Fúngica , Pruebas de Sensibilidad Microbiana , Rodaminas/metabolismo , Esteroles/análisisRESUMEN
2-Arylsulfanyl- and benzylsulfanylpyridinium N-arylimides (2), easily available from tetrazolo[1,5-b]pyridinium salts (1), participate in 1,3-dipolar cycloaddition with aryl isothiocyanates and aryl isocyanates to result in formation of fused thioxo- and oxo[1,2,4]triazolium salts (5 and 12), respectively. This transformation is interpreted as a regular 1,3-cycloaddition followed by spontaneous elimination of the aryl- or benzylsulfanyl group. Formation of these triazolium salts can be followed--under appropriate reaction conditions--by ring-opening reactions to afford some new triazolyldienes (6). Recognition of the intermediate participation of the thiolate anion along the pathway 1 --> 5 allowed elaboration of a simple procedure to 5 implying a tandem reaction sequence.
RESUMEN
Structurally related sets of triazino-quinoline, triazino-isoquinoline and pyrido-triazine derivatives were synthesised and their binding interactions with central (CBR)- and peripheral-type (PBR) benzodiazepine binding sites have been characterised. Of 33 compounds tested, a new compound, 2-(4-methylphenyl)-3H- [1,2,4] triazino [2, 3-a] quinolin-3-one (1 g) showed the lowest CBR binding inhibition constant (K(i) = 42 +/- 9 nM) and the highest CBR over PBR selectivity (>1300). All but the 4-methylphenyl (1 g) structural modifications decreased the affinity and selectivity of the parent compound, 2-phenyl-3H- [1,2,4]triazino[2,3-a]quinolin-3-one (1d) (K(i) = 69 +/- 9 nM, selectivity >890). Molecular interactions between selected ligands (standards and triazine derivatives) and alpha(1)gamma(2) subunit-interface residues in a GABA(A) receptor extracellular domain homology model have been calculated. Comparing data with calculations confirmed hydrogen bonding to gamma(2)Thr142 and hydrophobic interaction with alpha(1)His101 as being essential for high-affinity CBR binding.
Asunto(s)
Sistema Nervioso Central/efectos de los fármacos , Sistema Nervioso Periférico/efectos de los fármacos , Receptores de GABA-A/efectos de los fármacos , Triazinas/síntesis química , Triazinas/farmacología , Animales , Unión Competitiva/efectos de los fármacos , Corteza Cerebral/efectos de los fármacos , Corteza Cerebral/metabolismo , Cromatografía en Capa Delgada , Flunitrazepam/farmacocinética , Moduladores del GABA/farmacocinética , Técnicas In Vitro , Isoquinolinas/farmacocinética , Espectroscopía de Resonancia Magnética , Masculino , Modelos Moleculares , Mutación Puntual , Prosencéfalo/efectos de los fármacos , Prosencéfalo/metabolismo , Ratas , Ratas Wistar , Receptores de GABA-A/química , Receptores de GABA-A/genética , Espectrofotometría Infrarroja , Relación Estructura-Actividad , Membranas Sinápticas/efectos de los fármacos , Membranas Sinápticas/metabolismoRESUMEN
Partial hepatectomy results in the loss of cytochrome P450 enzymes. During regeneration, the levels of cytochrome P450 activities, apoproteins and mRNA are reduced. Our present study investigated CYP1A, CYP2E1 and CYP3A induction in the cells of rat liver regenerating for 1, 3, 7, or 14 days. Hepatocytes were isolated from regenerating liver of hepatectomized rats and treated with enzyme inducers: 3-methylcholanthrene, imidazole and dexamethasone. CYP1A enzymes of the cells isolated from regenerating liver were inducible by 3-methylcholanthrene. The rate of induction of the cells from 3-day regenerating liver by 3-methylcholanthrene was three times higher than that of the hepatocytes of sham-operated rats. Dexamethasone caused about two- or three-fold stronger elevation of CYP3A in the cells of 1-, 3- and 7-day regenerating liver than in hepatocytes of sham-operated animals. However, the degree of CYP2E1 induction by imidazole was the same (about 2.5-fold) at each regenerating time as it was detected in the hepatocytes of sham-operated animals. In conclusion, the inducibility of the cells was retained at each regenerating time, but the degree of induction showed some differences.