RESUMO
Nav 1.1 (SCN1A) channels primarily located in gamma-aminobutyric acid (GABA)ergic fast-spiking interneurons are pivotal for action potential generation and propagation in these neurons. Inappropriate function of fast-spiking interneurons, leading to disinhibition of pyramidal cells and network desynchronization, correlates with decreased cognitive capability. Further, reduced functionality of Nav 1.1 channels is linked to various diseases in the central nervous system. There is, at present, however no subtype selective pharmacological activators of Nav 1.1 channels available for studying pharmacological modulation of interneuron function. In the current study, we identified a small molecule Nav 1.1 activator, 3-amino-5-(4-methoxyphenyl)thiophene-2-carboxamide, named AA43279, and provided an in vitro to in vivo characterization of the compound. In HEK-293 cells expressing human Nav 1.1 channels, AA43279 increased the Nav 1.1-mediated current in a concentration-dependent manner mainly by impairing the fast inactivation kinetics of the channels. In rat hippocampal brain slices, AA43279 increased the firing activity of parvalbumin-expressing, fast-spiking GABAergic interneurons and increased the spontaneous inhibitory post-synaptic currents (sIPSCs) recorded from pyramidal neurons. When tested in vivo, AA43279 had anti-convulsive properties in the maximal electroshock seizure threshold test. AA43279 was tested for off-target effects on 72 different proteins, including Nav 1.2, Nav 1.4, Nav 1.5, Nav 1.6 and Nav 1.7 and exhibited reasonable selectivity. Taken together, AA43279 might constitute a valuable tool compound for revealing biological functions of Nav 1.1 channels.
Assuntos
Anticonvulsivantes/farmacologia , Neurônios GABAérgicos/efeitos dos fármacos , Interneurônios/efeitos dos fármacos , Canal de Sódio Disparado por Voltagem NAV1.1/metabolismo , Convulsões/tratamento farmacológico , Bloqueadores dos Canais de Sódio/farmacologia , Tiofenos/farmacologia , Potenciais de Ação , Animais , Anticonvulsivantes/síntese química , Anticonvulsivantes/uso terapêutico , Região CA1 Hipocampal/citologia , Região CA1 Hipocampal/metabolismo , Região CA1 Hipocampal/fisiologia , Potenciais Pós-Sinápticos Excitadores , Neurônios GABAérgicos/metabolismo , Neurônios GABAérgicos/fisiologia , Células HEK293 , Humanos , Interneurônios/metabolismo , Interneurônios/fisiologia , Masculino , Camundongos , Ratos , Ratos Sprague-Dawley , Bloqueadores dos Canais de Sódio/síntese química , Bloqueadores dos Canais de Sódio/uso terapêuticoRESUMO
In this Letter, we describe a chemical lead optimization campaign starting from a novel, weak α7 nicotinic acetylcholine receptor positive allosteric modulator (PAM) hit from a HTS screen. Exploration of the structure-activity relationships for α7 PAM potency, intrinsic hepatic clearance, the structure-property relationships for lipophilicity, and thermodynamic solubility, led to the identification of Lu AF58801: a potent, orally available, brain penetrant PAM of the α7 nicotinic acetylcholine receptor, showing efficacy in a novel object recognition task in rats treated subchronically with phencyclidine (PCP).
Assuntos
Encéfalo/efeitos dos fármacos , Transtornos Cognitivos/tratamento farmacológico , Ciclopropanos/farmacologia , Descoberta de Drogas , Álcool Feniletílico/análogos & derivados , Receptor Nicotínico de Acetilcolina alfa7/metabolismo , Administração Oral , Regulação Alostérica/efeitos dos fármacos , Animais , Encéfalo/metabolismo , Transtornos Cognitivos/induzido quimicamente , Ciclopropanos/administração & dosagem , Ciclopropanos/química , Relação Dose-Resposta a Droga , Humanos , Estrutura Molecular , Fenciclidina/administração & dosagem , Álcool Feniletílico/administração & dosagem , Álcool Feniletílico/química , Álcool Feniletílico/farmacologia , Ratos , Ratos Endogâmicos , Relação Estrutura-AtividadeRESUMO
TRPV1 is a non-selective cation channel gated by noxious heat, vanilloids and extracellular protons, and act as an important signal integrator in sensory nociceptors. Because of its integrative signaling properties in response to inflammatory stimuli, TRPV1 antagonists are predicted to inhibit the sensation of ongoing or burning pain that is reported by patients suffering from chronic pain, therefore offering an unprecedented advantage in selectively inhibiting painful signaling from where it is initiated. In this chapter, we firstly summarize the physiological and pathological roles of TRPV1 and then describe the pharmacology of TRPV1 agonists and antagonists. Finally, we give an update and the status on TRPV1 therapies that have progressed into clinical trials.
Assuntos
Dor/fisiopatologia , Canais de Cátion TRPV/efeitos dos fármacos , Microscopia Crioeletrônica , Humanos , Conformação Proteica , Canais de Cátion TRPV/fisiologia , Canais de Cátion TRPV/ultraestruturaRESUMO
Ion channels are challenging targets in the early phases of the drug discovery process, especially because of the lack of technologies available to screen large numbers of compounds in functionally relevant assays. The electrophysiological patch-clamp technique, which is the gold standard for studying ion channels, has low throughput and is not amenable to screening large numbers of compounds. However, for random high-throughput screening (HTS) of compounds against ion channel targets, a number of functional cellular assays have become available during the last few years. Here we use the sodium channel NaV1.7 stably expressed in human embryonic kidney 293 cells and compare three HTS assays-a Li flux atomic absorption spectroscopy (AAS) assay, a fluorescent imaging plate reader (FLIP, Molecular Devices, Sunnyvale, CA) membrane potential assay, and a fluorescence resonance energy transfer (FRET)-based membrane potential assay-to an automated electrophysiological assay (the Ionworks HT [Molecular Devices] platform) and characterize 11 known NaV inhibitors. Our results show that all three HTS assays are suitable for identification of NaV1.7 inhibitors, but as an HTS assay the Li-AAS assay is more robust with higher Z' values than the FLIPR and FRET-based membrane potential assays. Furthermore, there was a better correlation between the Ionworks assay and the Li-AAS assay regarding the potency of the NaV inhibitors investigated. This paper describes the first comparison between all the HTS assays available today to study voltage-gated NaVs, and the results suggest that the Li-AAS assay is more suited as a first HTS assay when starting an NaV drug discovery campaign.
Assuntos
Avaliação Pré-Clínica de Medicamentos/métodos , Bloqueadores dos Canais de Sódio/farmacologia , Canais de Sódio/efeitos dos fármacos , Linhagem Celular , Células Cultivadas , Interpretação Estatística de Dados , Eletrofisiologia , Transferência Ressonante de Energia de Fluorescência , Corantes Fluorescentes , Humanos , Lítio/química , Lítio/metabolismo , Potenciais da Membrana/efeitos dos fármacos , Potenciais da Membrana/fisiologia , Canal de Sódio Disparado por Voltagem NAV1.7 , Espectrofotometria AtômicaRESUMO
Voltage-gated sodium channels (Nav) are crucial to the initiation and propagation of action potentials (APs) in electrically excitable cells, and during the past decades they have received considerable attention due to their therapeutic potential. Here, we report for the first time the synthesis and the electrophysiological evaluation of 16 ligands based on a 2-methylbenzamide scaffold that have been identified as Nav1.1 modulators. Among these compounds, N,N'-(1,3-phenylene)bis(2-methylbenzamide) (3a) has been selected and evaluated in ex-vivo experiments in order to estimate the activation impact of such a compound profile. It appears that 3a increases the Nav1.1 channel activity although its overall impact remains moderate. Altogether, our preliminary results provide new insights into the development of small molecule activators targeting specifically Nav1.1 channels to design potential drugs for treating CNS diseases.
Assuntos
Benzamidas/química , Moduladores de Transporte de Membrana/farmacologia , Canal de Sódio Disparado por Voltagem NAV1.1/metabolismo , Animais , Região CA1 Hipocampal/efeitos dos fármacos , Região CA1 Hipocampal/fisiologia , Avaliação Pré-Clínica de Medicamentos , Células HEK293 , Humanos , Interneurônios/efeitos dos fármacos , Interneurônios/fisiologia , Potenciais da Membrana/efeitos dos fármacos , Moduladores de Transporte de Membrana/síntese química , Moduladores de Transporte de Membrana/química , Estrutura Molecular , Ratos , Técnicas de Cultura de TecidosRESUMO
Ion channels are at present the third biggest target class in drug discovery. Primary research is continually uncovering potential new ion channel targets in indications such as cancer, diabetes and respiratory diseases, as well as the more established fields of pain, cardiovascular disease, and neurological disorders. Despite the physiological significance and therapeutic relevance in a wide variety of biological systems, ion channels still remain under exploited as drug targets. This is to a large extent resulting from the historical lack of screening technologies to provide the throughput and quality of data required to support medicinal chemistry. Although technical challenges still lie ahead, this historic bottleneck in ion channel drug discovery is now being overcome by novel technologies that can be integrated into lead generation stages of ion channel drug discovery to allow the development of novel therapeutic agents. This review describes the variety of technologies available for ion channel screening and discusses the opportunities these technologies provide. The challenges that remain to be addressed are highlighted.