RESUMEN
Abnormal hippocampal activity has been linked to impaired cognitive performance in Alzheimer's disease and schizophrenia, leading to a hypothesis that normalization of this activity may be therapeutically beneficial. Our work suggests that one approach for hippocampal normalization may be through activation of the M4 muscarinic acetylcholine receptor. We used a brain penetrant M4 muscarinic acetylcholine receptor selective activator, PT-3763, to show dose-dependent attenuation of field potentials in Schaffer collateral (CA3-CA1) and recurrent associational connections (CA3-CA3) ex vivo in hippocampal slices. In vivo, systemic administration of PT-3763 led to attenuation of glutamate release in CA3 as measured by amperometry and to a dose-dependent decrease in population CA1 pyramidal activity as measured by fiber photometry. This decrease in population activity was also evident with a localized administration of the compound to the recorded site. Finally, PT-3763 reversed scopolamine-induced deficit in Morris water maze. Our results suggest that M4 muscarinic acetylcholine receptor activation may be a suitable therapeutic treatment in diseases associated with hyperactive hippocampal activity.
Asunto(s)
Enfermedad de Alzheimer , Hipocampo/fisiología , Agonistas Muscarínicos/farmacología , Receptor Muscarínico M4/agonistas , Receptor Muscarínico M4/fisiología , Esquizofrenia , Enfermedad de Alzheimer/tratamiento farmacológico , Animales , Relación Dosis-Respuesta a Droga , Hipocampo/efectos de los fármacos , Masculino , Aprendizaje por Laberinto/efectos de los fármacos , Aprendizaje por Laberinto/fisiología , Ratones , Agonistas Muscarínicos/química , Agonistas Muscarínicos/uso terapéutico , Técnicas de Cultivo de Órganos , Ratas , Ratas Long-Evans , Ratas Sprague-Dawley , Esquizofrenia/tratamiento farmacológicoRESUMEN
Recent data demonstrated that activation of the muscarinic M1 receptor by a subtype-selective positive allosteric modulator (PAM) contributes to the gastrointestinal (GI) and cardiovascular (CV) cholinergic adverse events (AEs) previously attributed to M2 and M3 activation. These studies were conducted using PAMs that also exhibited allosteric agonist activity, leaving open the possibility that direct activation by allosteric agonism, rather than allosteric modulation, could be responsible for the adverse effects. This article describes the design and synthesis of lactam-derived M1 PAMs that address this hypothesis. The lead molecule from this series, compound 1 (PF-06827443), is a potent, low-clearance, orally bioavailable, and CNS-penetrant M1-selective PAM with minimal agonist activity. Compound 1 was tested in dose escalation studies in rats and dogs and was found to induce cholinergic AEs and convulsion at therapeutic indices similar to previous compounds with more agonist activity. These findings provide preliminary evidence that positive allosteric modulation of M1 is sufficient to elicit cholinergic AEs.
Asunto(s)
Isoindoles/farmacología , Lactamas/farmacología , Oxazoles/farmacología , Receptor Muscarínico M1/agonistas , Convulsiones/inducido químicamente , Regulación Alostérica , Anfetamina/farmacología , Animales , Ataxia/inducido químicamente , Diarrea/inducido químicamente , Perros , Donepezilo , Diseño de Fármacos , Femenino , Humanos , Indanos/farmacología , Isoindoles/administración & dosificación , Isoindoles/síntesis química , Isoindoles/toxicidad , Lactamas/administración & dosificación , Lactamas/síntesis química , Lactamas/toxicidad , Masculino , Ratones Endogámicos C57BL , Microsomas Hepáticos/metabolismo , Oxazoles/administración & dosificación , Oxazoles/síntesis química , Oxazoles/toxicidad , Piperidinas/farmacología , Ratas Wistar , Receptor Muscarínico M1/antagonistas & inhibidores , Escopolamina/farmacología , Relación Estructura-Actividad , Sulfonamidas/farmacología , Tiadiazoles/farmacología , Vómitos/inducido químicamenteRESUMEN
The rationale for using M1 selective muscarinic acetylcholine receptor activators for the treatment of cognitive impairment associated with psychiatric and neurodegenerative disease is well-established in the literature. Here, we investigate measurement of inositol phosphate accumulation, an end point immediately downstream of the M1 muscarinic acetylcholine receptor signaling cascade, as an in vivo biochemical readout for M1 muscarinic acetylcholine receptor activation. Five brain penetrant M1-subtype selective activators from three structurally distinct chemical series were pharmacologically profiled for functional activity in vitro using recombinant cell calcium mobilization and inositol phosphate assays, and a native tissue hippocampal slice electrophysiology assay, to show that all five compounds presented a positive allosteric modulator agonist profile, within a narrow range of potencies. In vivo characterization using an amphetamine-stimulated locomotor activity behavioral assay and the inositol phosphate accumulation biochemical assay demonstrated that the latter has utility for assessing functional potency of M1 activators. Efficacy measured by inositol phosphate accumulation in mouse striatum compared favorably to efficacy in reversing amphetamine-induced locomotor activity, suggesting that the inositol phosphate accumulation assay has utility for the evaluation of M1 muscarinic acetylcholine receptor activators in vivo. The benefits of this in vivo biochemical approach include a wide response window, interrogation of specific brain circuit activation, an ability to model responses in the context of brain exposure, an ability to rank order compounds based on in vivo efficacy, and minimization of animal use.
Asunto(s)
Encéfalo/efectos de los fármacos , Calcio/metabolismo , Fosfatos de Inositol/metabolismo , Agonistas Muscarínicos/farmacología , Receptor Muscarínico M1/agonistas , Anfetamina/farmacología , Animales , Encéfalo/metabolismo , Encéfalo/fisiología , Células CHO , Cuerpo Estriado/efectos de los fármacos , Cuerpo Estriado/metabolismo , Cuerpo Estriado/fisiología , Cricetinae , Cricetulus , Dopaminérgicos/farmacología , Relación Dosis-Respuesta a Droga , Fenómenos Electrofisiológicos/efectos de los fármacos , Hipocampo/efectos de los fármacos , Hipocampo/metabolismo , Hipocampo/fisiología , Humanos , Masculino , Ratones , Actividad Motora/efectos de los fármacos , Agonistas Muscarínicos/clasificación , Ratas Sprague-Dawley , Receptor Muscarínico M1/metabolismoRESUMEN
It is hypothesized that selective muscarinic M1 subtype activation could be a strategy to provide cognitive benefits to schizophrenia and Alzheimer's disease patients while minimizing the cholinergic side effects observed with nonselective muscarinic orthosteric agonists. Selective activation of M1 with a positive allosteric modulator (PAM) has emerged as a new approach to achieve selective M1 activation. This manuscript describes the development of a series of M1-selective pyridone and pyridine amides and their key pharmacophores. Compound 38 (PF-06767832) is a high quality M1 selective PAM that has well-aligned physicochemical properties, good brain penetration and pharmacokinetic properties. Extensive safety profiling suggested that despite being devoid of mAChR M2/M3 subtype activity, compound 38 still carries gastrointestinal and cardiovascular side effects. These data provide strong evidence that M1 activation contributes to the cholinergic liabilities that were previously attributed to activation of the M2 and M3 receptors.
Asunto(s)
Descubrimiento de Drogas , Ácidos Picolínicos/farmacología , Receptor Muscarínico M1/agonistas , Tiazoles/farmacología , Animales , Relación Dosis-Respuesta a Droga , Femenino , Masculino , Ratones , Modelos Moleculares , Estructura Molecular , Ácidos Picolínicos/síntesis química , Ácidos Picolínicos/química , Ratas , Receptor Muscarínico M1/metabolismo , Relación Estructura-Actividad , Tiazoles/síntesis química , Tiazoles/químicaRESUMEN
Selective activation of the M1 receptor via a positive allosteric modulator (PAM) is a new approach for the treatment of the cognitive impairments associated with schizophrenia and Alzheimer's disease. A novel series of azaindole amides and their key pharmacophore elements are described. The nitrogen of the azaindole core is a key design element as it forms an intramolecular hydrogen bond with the amide N-H thus reinforcing the bioactive conformation predicted by published SAR and our homology model. Representative compound 25 is a potent and selective M1 PAM that has well aligned physicochemical properties, adequate brain penetration and pharmacokinetic (PK) properties, and is active in vivo. These favorable properties indicate that this series possesses suitable qualities for further development and studies.
Asunto(s)
Regulación Alostérica/efectos de los fármacos , Amidas/química , Amidas/farmacología , Indoles/química , Indoles/farmacología , Receptor Muscarínico M1/metabolismo , Amidas/farmacocinética , Animales , Diseño de Fármacos , Humanos , Enlace de Hidrógeno , Indoles/farmacocinética , Ratones , Simulación del Acoplamiento Molecular , Receptor Muscarínico M1/agonistasRESUMEN
A unique tetrahydrofuran ether class of highly potent α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor potentiators has been identified using rational and structure-based drug design. An acyclic lead compound, containing an ether-linked isopropylsulfonamide and biphenyl group, was pharmacologically augmented by converting it to a conformationally constrained tetrahydrofuran to improve key interactions with the human GluA2 ligand-binding domain. Subsequent replacement of the distal phenyl motif with 2-cyanothiophene to enhance its potency, selectivity, and metabolic stability afforded N-{(3S,4S)-4-[4-(5-cyano-2-thienyl)phenoxy]tetrahydrofuran-3-yl}propane-2-sulfonamide (PF-04958242, 3), whose preclinical characterization suggests an adequate therapeutic index, aided by low projected human oral pharmacokinetic variability, for clinical studies exploring its ability to attenuate cognitive deficits in patients with schizophrenia.
Asunto(s)
Evaluación Preclínica de Medicamentos/métodos , Receptores AMPA/metabolismo , Sulfonamidas/farmacología , Tiofenos/farmacología , Administración Oral , Adolescente , Adulto , Anciano , Animales , Sitios de Unión , Modelos Animales de Enfermedad , Perros , Relación Dosis-Respuesta a Droga , Descubrimiento de Drogas , Estabilidad de Medicamentos , Femenino , Humanos , Masculino , Memoria a Corto Plazo/efectos de los fármacos , Ratones Endogámicos C57BL , Persona de Mediana Edad , Conformación Proteica , Ratas Sprague-Dawley , Esquizofrenia/tratamiento farmacológico , Relación Estructura-Actividad , Sulfonamidas/química , Tiofenos/química , Adulto JovenRESUMEN
The α(2)δ auxiliary subunits (α(2)δ-1 and α(2)δ-2) of voltage-sensitive calcium channels are thought to be the site of action of pregabalin (Lyrica), a drug that has been shown to be anxiolytic in clinical trials for generalized anxiety disorder. Pregabalin and the chemically related drug gabapentin have similar binding and pharmacology profiles, demonstrating high-affinity, in vitro binding to both α(2)δ-1 and α(2)δ-2 subunits. Two independent point mutant mouse strains were generated in which either the α(2)δ-1 subunit (arginine-to-alanine mutation at amino acid 217; R217A) or the α(2)δ-2 subunit (arginine-to-alanine mutation at amino acid 279; R279A) were rendered insensitive to gabapentin or pregabalin binding. These strains were used to characterize the activity of pregabalin in the Vogel conflict test, a measure of anxiolytic-like activity. Pregabalin showed robust anticonflict activity in wild-type littermates from each strain at a dose of 10 mg/kg but was inactive in the α(2)δ-1 (R217A) mutants up to a dose of 320 mg/kg. In contrast, pregabalin was active in the α(2)δ-2 (R279A) point mutants at 10 and 32 mg/kg. The positive control phenobarbital was active in mice carrying either mutation. These data suggest that the anxiolytic-like effects of pregabalin are mediated by binding of the drug to the α(2)δ-1 subunit.
Asunto(s)
Ansiolíticos/metabolismo , Canales de Calcio/genética , Conflicto Psicológico , Ácido gamma-Aminobutírico/análogos & derivados , Alanina/genética , Animales , Ansiolíticos/uso terapéutico , Ansiedad/genética , Ansiedad/metabolismo , Ansiedad/prevención & control , Arginina/genética , Canales de Calcio/metabolismo , Masculino , Ratones , Ratones de la Cepa 129 , Ratones Congénicos , Ratones Endogámicos C57BL , Ratones Mutantes , Mutación Puntual/efectos de los fármacos , Mutación Puntual/genética , Pregabalina , Ácido gamma-Aminobutírico/metabolismo , Ácido gamma-Aminobutírico/uso terapéuticoRESUMEN
A series of oxadiazolone bioisosteres of pregabalin 1 and gabapentin 2 were prepared, and several were found to exhibit similar potency for the alpha(2)-delta subunit of voltage-gated calcium channels. Oxadiazolone 9 derived from 2 achieved low brain uptake but was nevertheless active in models of osteoarthritis. The high clearance associated with compound 9 was postulated to be a consequence of efflux by OAT and/or OCT, and was attenuated on co-administration with cimetidine or probenecid.
Asunto(s)
Aminas , Ácidos Ciclohexanocarboxílicos , Osteoartritis/tratamiento farmacológico , Oxadiazoles/química , Oxadiazoles/uso terapéutico , Ácido gamma-Aminobutírico/análogos & derivados , Animales , Encéfalo/metabolismo , Interacciones Farmacológicas , Quimioterapia Combinada , Gabapentina , Factores de Transcripción de Octámeros , Transportadores de Anión Orgánico , Oxadiazoles/farmacología , Pregabalina , RatasRESUMEN
Rational replacement of the alkyne linker of mGluR5 antagonist MPEP gave 7-arylquinolines. SAR optimization gave an orally active compound with high affinity for the MPEP binding site.
Asunto(s)
Diseño de Fármacos , Antagonistas de Aminoácidos Excitadores/química , Antagonistas de Aminoácidos Excitadores/farmacología , Quinolinas/química , Quinolinas/farmacología , Receptores de Glutamato Metabotrópico/antagonistas & inhibidores , Modelos Moleculares , Estructura Molecular , Piridinas/química , Piridinas/farmacología , Receptor del Glutamato Metabotropico 5 , Relación Estructura-ActividadRESUMEN
Several beta-amino tetrazole analogs of gabapentin 1 and pregabalin 2 were prepared by one of two convergent, highly efficient routes, and their affinity for the alpha(2)-delta protein examined. Two select compounds with potent affinity for alpha(2)-delta, 8a and 16a, were subsequently tested in vivo in an audiogenic seizure model and found to elicit protective effects.
Asunto(s)
Anticonvulsivantes/síntesis química , Anticonvulsivantes/farmacología , Ácidos Carboxílicos/química , Epilepsia Refleja/prevención & control , Ácido gamma-Aminobutírico/análogos & derivados , Aminas/síntesis química , Aminas/química , Aminas/farmacología , Animales , Anticonvulsivantes/química , Sitios de Unión , Ácidos Ciclohexanocarboxílicos/síntesis química , Ácidos Ciclohexanocarboxílicos/química , Ácidos Ciclohexanocarboxílicos/farmacología , Modelos Animales de Enfermedad , Evaluación Preclínica de Medicamentos , Gabapentina , Ratones , Ratones Endogámicos DBA , Estructura Molecular , Pregabalina , Subunidades de Proteína/efectos de los fármacos , Estereoisomerismo , Relación Estructura-Actividad , Ácido gamma-Aminobutírico/síntesis química , Ácido gamma-Aminobutírico/química , Ácido gamma-Aminobutírico/farmacologíaRESUMEN
A series of carboxylate bioisosteres of structures related to gabapentin 1 have been prepared. When the carboxylate was replaced by a tetrazole, this group was recognized by the alpha2-delta protein. Further characterization of alpha2-delta binding compounds 14a and 14b revealed a similar pattern of functional in vitro and in vivo activity to gabapentin 1.
Asunto(s)
Aminas/síntesis química , Aminas/farmacología , Anticonvulsivantes/química , Anticonvulsivantes/farmacología , Ácidos Carboxílicos/química , Ácidos Ciclohexanocarboxílicos/síntesis química , Ácidos Ciclohexanocarboxílicos/farmacología , Tetrazoles/química , Ácido gamma-Aminobutírico/síntesis química , Ácido gamma-Aminobutírico/farmacología , Aminas/química , Animales , Anticonvulsivantes/síntesis química , Ácidos Ciclohexanocarboxílicos/química , Modelos Animales de Enfermedad , Relación Dosis-Respuesta a Droga , Diseño de Fármacos , Evaluación Preclínica de Medicamentos , Gabapentina , Técnicas In Vitro , Ratones , Ratones Endogámicos DBA , Estructura Molecular , Ratas , Estereoisomerismo , Relación Estructura-Actividad , Ácido gamma-Aminobutírico/químicaRESUMEN
As part of a program aimed at generating compounds with affinity for the alpha(2)-delta subunit of voltage-gated calcium channels, several novel beta-amino acids were prepared using an efficient nitroalkane-mediated cyclopropanation as a key step. Depending on the ester that was chosen, the target amino acids could be prepared in as few as three steps. The cyclopropyl amino acids derived from ketones proved to be potent binders of the alpha(2)-delta subunit of voltage-gated calcium channels, but did not interact with the large neutral amino acid system L (leucine) transporter. Anticonvulsant effects were observed in vivo with compound 34 but only after intracerebroventricular (icv) administration, presumably due to inadequate brain concentrations of the drug being achieved following oral dosing. However, pregabalin 1 was active in the DBA/2 model after oral (and icv) dosing, supporting a hypothesis that active transport is a prerequisite for such zwitterionic species to cross the blood-brain barrier.