RESUMEN
Optimization of the novel alpha-2-delta-1 ligand 4 provided compounds 37 and 38 which have improved DMPK profiles, good in vivo analgesic activity and in vitro selectivity over alpha-2-delta-2. An in-house P-gp prediction programme and the MetaSite software package were used to help solve the specific problems of high P-gp efflux and high in vivo clearance.
Asunto(s)
Analgésicos/química , Bloqueadores de los Canales de Calcio/química , Canales de Calcio/química , Neuralgia/tratamiento farmacológico , Pirazoles/química , Piridazinas/química , Piridinas/química , Miembro 1 de la Subfamilia B de Casetes de Unión a ATP/metabolismo , Analgésicos/síntesis química , Analgésicos/uso terapéutico , Animales , Bloqueadores de los Canales de Calcio/síntesis química , Bloqueadores de los Canales de Calcio/uso terapéutico , Canales de Calcio/metabolismo , Canales de Calcio Tipo L , Ligandos , Pirazoles/síntesis química , Piridazinas/síntesis química , Piridazinas/uso terapéutico , Piridinas/síntesis química , Ratas , Relación Estructura-ActividadAsunto(s)
Virus de la Lengua Azul/clasificación , Lengua Azul/epidemiología , Lengua Azul/transmisión , Brotes de Enfermedades/veterinaria , Vacunación/veterinaria , Animales , Animales Domésticos , Lengua Azul/prevención & control , Brotes de Enfermedades/prevención & control , Europa (Continente)/epidemiología , Factores de Riesgo , Vigilancia de Guardia/veterinaria , Serotipificación/veterinaria , Ovinos , Reino Unido/epidemiologíaRESUMEN
We report the synthesis and SAR of a series of novel azaindole CB(2) agonists. 6-Azaindole 18 showed activity in an acute pain model but was inactive in a chronic model. 18 is a Pgp substrate with low brain penetration. The template was redesigned, and the resulting 5-azaindole 36 was a potent CB(2) agonist with high CNS penetration. This compound was efficacious in the acute model and the chronic joint pain model.
Asunto(s)
Aminopiridinas/uso terapéutico , Encéfalo/metabolismo , Morfolinas/uso terapéutico , Dolor/tratamiento farmacológico , Receptor Cannabinoide CB2/agonistas , Aminopiridinas/farmacocinética , Animales , Compuestos Aza , Células CHO , Línea Celular , Enfermedad Crónica , Cricetinae , Cricetulus , Descubrimiento de Drogas , Humanos , Indoles , Morfolinas/farmacocinética , Ratas , Relación Estructura-ActividadRESUMEN
AIMS: To investigate the presence of proteinase-activated receptor 2 (PAR2) in the human tooth pulp and to determine whether there are any changes in receptor expression with caries and pain. METHODS: Forty-four mandibular first permanent molars were collected from children (n = 36, mean age 9.96 years +/- 2.11) requiring dental extractions under general anesthesia. Teeth were categorized as either intact (n = 22) or carious (n = 22). Carious teeth were further subdivided into asymptomatic (n = 10) and painful (n = 12). The coronal pulp was removed and processed for indirect immunofluorescence by using antibodies raised against PAR2 and double labeled with either a neuronal marker (protein gene product 9.5) or both a smooth muscle cell (aSMA) and endothelial (UEIL) marker, in order to examine PAR2 presence in both neuronal and vascular tissue. In addition, hemotoxylin and eosin staining was performed to identify pulpal fibroblasts. RESULTS: PAR2 expression was found to be present in pulpal nerve fibers, vascular tissue, and pulpal fibroblasts. PAR2 neuronal expression was not affected by the presence of caries (P > .05) but was significantly less in carious painful teeth than in carious asymptomatic teeth (P < .05). No changes in vascular PAR2 expression were found (P > .05); however, the number of PAR2-labeled fibroblast-like cells per mm2 was significantly greater in carious teeth (P < .05). CONCLUSION: These findings indicate that PAR2 receptors and changes in their level of expression may have relevance and clinical importance in nociception.
Asunto(s)
Caries Dental/metabolismo , Pulpa Dental/metabolismo , Receptor PAR-2/biosíntesis , Odontalgia/metabolismo , Niño , Pulpa Dental/irrigación sanguínea , Pulpa Dental/citología , Pulpa Dental/inervación , Fibroblastos/metabolismo , Técnica del Anticuerpo Fluorescente Indirecta , Humanos , Microvasos/metabolismo , Diente Molar , Fibras Nerviosas/metabolismoRESUMEN
A novel series of [4-[4-(methylsulfonyl)phenyl]-6-(trifluoromethyl)-2-pyrimidine-based cyclooxygenase-2 (COX-2) inhibitors, which have a different arrangement of substituents compared to the more common 1,2-diarylheterocycle based molecules, have been discovered. For example, 2-(butyloxy)-4-[4-(methylsulfonyl)phenyl]-6-(trifluoromethyl)pyrimidine (47), a member of the 2-pyrimidinyl ether series, has been shown to be a potent and selective inhibitor with a favourable pharmacokinetic profile, high brain penetration and good efficacy in rat models of hypersensitivity.
Asunto(s)
Aminas/síntesis química , Inhibidores de la Ciclooxigenasa 2/síntesis química , Éteres/síntesis química , Pirimidinas/síntesis química , Sulfonas/síntesis química , Aminas/farmacología , Animales , Encéfalo/efectos de los fármacos , Encéfalo/metabolismo , Química Farmacéutica/métodos , Ciclooxigenasa 2/química , Inhibidores de la Ciclooxigenasa 2/farmacología , Modelos Animales de Enfermedad , Diseño de Fármacos , Éteres/farmacología , Humanos , Inflamación , Concentración 50 Inhibidora , Ratones , Estructura Molecular , Enfermedades Neurodegenerativas/tratamiento farmacológico , Pirimidinas/farmacología , Ratas , Sulfonas/farmacologíaRESUMEN
We describe herein the medicinal chemistry approach which led to the discovery of a novel pyridine-3-carboxamide series of CB(2) receptor agonists. The SAR of this new template was evaluated and culminated in the identification of analogue 14a which demonstrated efficacy in an in vivo model of inflammatory pain.
Asunto(s)
Analgésicos/síntesis química , Piridinas/síntesis química , Piridinas/uso terapéutico , Receptor Cannabinoide CB2/agonistas , Amidas/síntesis química , Amidas/farmacología , Amidas/uso terapéutico , Analgesia/métodos , Animales , Modelos Animales de Enfermedad , Descubrimiento de Drogas/métodos , Inflamación , Dolor/tratamiento farmacológico , Piridinas/farmacología , Relación Estructura-ActividadRESUMEN
We have investigated a possible role for the ATP receptor subunit P2X(3), in the development of neuropathic pain following injury to a peripheral branch of the trigeminal nerve. In nine anaesthetised adult ferrets the left lingual nerve was sectioned and recovery permitted for 3 days, 3 weeks or 3 months (3 ferrets per group). A retrograde tracer, fluorogold, was applied to the nerve to allow identification of cell bodies in the trigeminal ganglion with axons in the injured nerve. Indirect immunofluorescence for P2X(3) and image analysis was used to quantify the percentage area of staining at the site of injury. Additionally, the proportion of fluorogold-positive cells that expressed P2X(3) was determined and compared with expression in non-fluorogold containing cells in another part of the ganglion. Comparisons were made with results from control animals that only received the tracer injection. After lingual nerve injury there was no significant change in P2X(3) expression at the site of nerve injury or within cell bodies linked to either injured (lingual) or uninjured (ophthalmic) axons, at any of the time periods investigated. Overall, this study suggests that P2X(3) expression at these sites is not involved in the development of neuropathic pain following lingual nerve injury.
Asunto(s)
Traumatismos del Nervio Lingual , Nervio Lingual/metabolismo , Receptores Purinérgicos P2/metabolismo , Animales , Femenino , Hurones , Lateralidad Funcional , Receptores Purinérgicos P2X3 , Recuperación de la Función/fisiología , Estilbamidinas , Factores de TiempoRESUMEN
Abnormal neural activity generated at a site of nerve injury is thought to contribute to the development of dysaesthesia. Vanilloid receptor 1 (TRPV1), a transducer of noxious stimuli, may be involved in the initiation of this abnormal activity and could provide a useful therapeutic target. We investigated the effect of a specific TRPV1 antagonist (SB-750364) on injury-induced discharge in the lingual nerve. In 12 anaesthetised adult ferrets the left lingual nerve was sectioned and animals were allowed to recover for 3-7 days. In terminal experiments under general anaesthesia, the nerve was re-exposed and electrophysiological recordings made from spontaneously active axons in fine filaments dissected from the nerve central to both the injury site and the junction with the chorda tympani. SB-750364 was infused via the cephalic vein in order to achieve three increasing but stable systemic blood levels of the compound (0.3, 1.0 and 3.0 microM). Twenty-eight spontaneously active units were studied, with discharge frequencies ranging from 0.02 to 4.9 Hz. There was a significant reduction in spontaneous activity in 17 units (61%) at 1.0 microM or less of SB-750364 (p<0.01; Friedman test with Dunn's multiple comparisons). A further 4 units (14%) showed a significant reduction in activity at 3.0 microM (p<0.01). In the remaining 7 units (25%) the discharge was unaffected (p>0.05). These data show that the TRPV1 antagonist SB-750364 can reduce the level of spontaneous activity initiated in some axons following lingual nerve injury.
Asunto(s)
Traumatismos del Nervio Craneal , Nervio Lingual/efectos de los fármacos , Canales Catiónicos TRPV/antagonistas & inhibidores , Potenciales de Acción/efectos de los fármacos , Animales , Traumatismos del Nervio Craneal/tratamiento farmacológico , Traumatismos del Nervio Craneal/patología , Traumatismos del Nervio Craneal/fisiopatología , Modelos Animales de Enfermedad , Relación Dosis-Respuesta a Droga , Femenino , Hurones , Nervio Lingual/fisiopatología , Traumatismos del Nervio Lingual , Masculino , Conducción Nerviosa/efectos de los fármacos , Conducción Nerviosa/fisiología , Estimulación Física , Canales Catiónicos TRPV/metabolismoRESUMEN
UNLABELLED: The role of specific nicotinic receptor (nAChR) subtypes in antinociception has not been fully elucidated because of the lack, until recently, of selective tool compounds. (R)-N-(1-azabicyclo[2.2.2]oct-3-yl)(5-(2-pyridyl)thiopene-2-carboxamide) (compound B) is reported to be an agonist selective for the alpha(7)nAChR and in the present study was found to be efficacious in inflammatory pain models in 2 species. Compound B reversed complete Freund adjuvant-induced reductions in paw withdrawal thresholds in rat and mouse in a dose-related manner, producing maximum reversals of 65% +/- 4% at 10 mg/kg and 87% +/- 15% at 20 mg/kg. When rats and mice were predosed with the centrally penetrant, broad-spectrum nicotinic receptor antagonist mecamylamine, the efficacy of the agonist was significantly inhibited, producing reversals of only 11% +/- 5% at 10 mg/kg and 5% +/- 13% at 20 mg/kg, confirming activity via nicotinic receptors. Rats were also predosed systemically with the selective low-brain penetrant alpha(7)-antagonist methyllycaconitine, which had no effect on agonist activity (90% +/- 18% at 10 mg/kg), suggesting a central involvement. This hypothesis was further established with methyllycaconitine completely inhibited the agonist effect when dosed intrathecally (1% +/- 7%). PERSPECTIVE: These studies provide good rationale for the utility of selective, central nervous system penetrant agonists at the alpha(7)-nicotinic receptor for the treatment of inflammatory pain.
Asunto(s)
Benzofuranos/farmacología , Hiperalgesia/tratamiento farmacológico , Quinuclidinas/farmacología , Receptores Nicotínicos/fisiología , Aconitina/administración & dosificación , Aconitina/análogos & derivados , Aconitina/farmacología , Animales , Conducta Animal/efectos de los fármacos , Benzofuranos/administración & dosificación , Relación Dosis-Respuesta a Droga , Femenino , Adyuvante de Freund , Hiperalgesia/inducido químicamente , Hiperalgesia/fisiopatología , Inflamación/inducido químicamente , Inflamación/metabolismo , Inflamación/fisiopatología , Inyecciones Intraperitoneales , Masculino , Mecamilamina/administración & dosificación , Mecamilamina/farmacología , Ratones , Ratones Endogámicos C57BL , Modelos Animales , Antagonistas Nicotínicos/administración & dosificación , Antagonistas Nicotínicos/farmacología , Dolor/tratamiento farmacológico , Dolor/metabolismo , Dolor/fisiopatología , Dimensión del Dolor/métodos , Quinuclidinas/administración & dosificación , Ratas , Soporte de Peso/fisiología , Receptor Nicotínico de Acetilcolina alfa 7RESUMEN
We have developed a model to study central changes following inflammation of the tooth pulp in the ferret and have examined Fos expression in the trigeminal nucleus following stimulation of non-inflamed and inflamed tooth pulps. The aim of this study was to establish the ability of this model to predict analgesic efficacy in clinical studies of inflammatory pain. We addressed this by assessing the effects of the neurokinin-1 receptor antagonist GR205171A and ibuprofen on Fos expression following stimulation of the inflamed pulp and comparing this with known analgesic efficacy. Adult ferrets were prepared under anaesthesia to allow tooth pulp stimulation, recording from the digastric muscle and intravenous injections at a subsequent experiment. In some animals pulpal inflammation was induced, by introducing human caries into a deep buccal cavity. After 5 days, animals were reanaesthetised, treated with vehicle, GR205171A or ibuprofen and the teeth were stimulated at ten times the threshold of the jaw-opening reflex. Stimulation of all tooth pulps induced ipsilateral Fos in trigeminal subnuclei caudalis and oralis. GR205171A had no significant effect on Fos expression in the trigeminal nucleus of animals with either non-inflamed or inflamed tooth pulps. Ibuprofen reduced Fos expression in the trigeminal nucleus and this effect was most marked in animals with pulpal inflammation. These results differ from those previously described using a range of other animal models, but agree with known clinical efficacy of neurokinin-1 receptor antagonists and ibuprofen. Therefore this model is likely to be of use in accurately predicting the analgesic efficacy of novel compounds.
Asunto(s)
Antiinflamatorios no Esteroideos/farmacología , Pulpa Dental/inervación , Regulación de la Expresión Génica/efectos de los fármacos , Genes fos/efectos de los fármacos , Ibuprofeno/farmacología , Proteínas del Tejido Nervioso/biosíntesis , Antagonistas del Receptor de Neuroquinina-1 , Fragmentos de Péptidos/farmacología , Proteínas Proto-Oncogénicas c-fos/biosíntesis , Pulpitis/fisiopatología , Sustancia P/análogos & derivados , Núcleos del Trigémino/metabolismo , Animales , Antiinflamatorios no Esteroideos/uso terapéutico , Diente Canino , Inhibidores de la Ciclooxigenasa/farmacología , Inhibidores de la Ciclooxigenasa/uso terapéutico , Evaluación Preclínica de Medicamentos , Estimulación Eléctrica , Hurones , Ibuprofeno/uso terapéutico , Proteínas del Tejido Nervioso/genética , Fragmentos de Péptidos/uso terapéutico , Pulpitis/tratamiento farmacológico , Pulpitis/genética , Receptores de Neuroquinina-1/fisiología , Sustancia P/farmacología , Sustancia P/uso terapéutico , Neuralgia del Trigémino/tratamiento farmacológico , Neuralgia del Trigémino/etiología , Neuralgia del Trigémino/fisiopatología , Núcleos del Trigémino/fisiopatologíaRESUMEN
Selective CB2 receptor agonists are promising potential therapeutic agents for the treatment of inflammatory and neuropathic pain. A focused screen identified a pyrimidine ester as a partial agonist at the CB2 receptor with micromolar potency. Subsequent lead optimization identified 35, GW842166X, as the optimal compound in the series. 35 has an oral ED50 of 0.1 mg/kg in the rat FCA model of inflammatory pain and was selected as a clinical candidate for this indication.
Asunto(s)
Analgésicos/síntesis química , Dolor/tratamiento farmacológico , Piranos/síntesis química , Pirimidinas/síntesis química , Receptor Cannabinoide CB2/agonistas , Analgésicos/farmacocinética , Analgésicos/farmacología , Animales , Disponibilidad Biológica , Semivida , Humanos , Inflamación/tratamiento farmacológico , Inflamación/metabolismo , Dolor/metabolismo , Piranos/farmacocinética , Piranos/farmacología , Pirimidinas/farmacocinética , Pirimidinas/farmacología , Ratas , Relación Estructura-ActividadRESUMEN
We have previously carried out detailed characterization and identification of Fos expression within the trigeminal nucleus after tooth pulp stimulation in ferrets. The aim of this study was to determine the effect of pulpal inflammation on the excitability of central trigeminal neurons following tooth pulp stimulation. Adult ferrets were prepared under anesthesia to allow tooth pulp stimulation, recording from the digastric muscle, and intravenous injections at a subsequent experiment. In some animals, pulpal inflammation was induced by introducing human caries into a deep buccal cavity. After 5 d, animals were re-anaethetized, and the teeth were stimulated at 10 times the threshold of the jaw-opening reflex. Stimulation of all tooth pulps induced ipsilateral Fos in the trigeminal subnuclei caudalis and oralis. All non-stimulated animals showed negligible Fos labeling, with no differences recorded between inflamed and non-inflamed groups. Following tooth pulp stimulation, Fos expression was greater in animals with inflamed teeth than in animals with non-inflamed teeth, with the greatest effect seen in the subnucleus caudalis. These results suggest that inflammation increases the number of trigeminal brainstem neurons activated by tooth pulp stimulation; this may be mediated by peripheral or central mechanisms.
Asunto(s)
Proteínas Proto-Oncogénicas c-fos/biosíntesis , Pulpitis/fisiopatología , Núcleo Espinal del Trigémino/metabolismo , Animales , Caries Dental/complicaciones , Pulpa Dental/inervación , Estimulación Eléctrica , Hurones , Expresión Génica , Pulpitis/etiologíaRESUMEN
The lingual nerve, a peripheral branch of the trigeminal nerve, can be damaged during the surgical removal of lower third molar teeth. This damage can lead to the development of dysaesthesia, with some patients complaining of burning pain. We investigated the hypothesis that vanilloid receptor 1 (TRPV1), a transducer of noxious heat stimuli, was involved in the development of this burning pain. Neuroma specimens were obtained from patients undergoing microsurgical repair of a damaged lingual nerve. Repair was undertaken where there was little evidence of spontaneous recovery, 7-41 months after the initial injury. Preoperatively the incidence of dysaesthesia was determined by reported symptoms and using visual analogue scales (VAS) for pain, tingling and discomfort. Nine neuromas were studied from patients with burning dysaesthesia and six from patients with a sensory deficit but no dysaesthesia. Indirect immunofluorescence for protein gene product (PGP) 9.5 and TRPV1 was used to quantify the percentage area of PGP 9.5 positive neuronal tissue that also expressed TRPV1. The results showed no significant difference between the mean percentage area of TRPV1 expression in neuromas from patients with or without burning dysaesthesia. Furthermore, there was no correlation between TRPV1 expression and the VAS scores for pain, tingling or discomfort. However, if data from all patients was pooled, there was a negative correlation between the level of TRPV1 expression and the time after initial injury. These data do not rule out involvement of TRPV1 in the aetiology of burning dysaesthesia following lingual nerve injury but suggest that TRPV1 at the injury site does not play a primary role.
Asunto(s)
Traumatismos del Nervio Lingual , Nervio Lingual/metabolismo , Neuralgia/metabolismo , Neuroma/metabolismo , Canales Catiónicos TRPV/metabolismo , Enfermedades del Nervio Trigémino/metabolismo , Adulto , Enfermedad Crónica , Femenino , Humanos , Nervio Lingual/fisiopatología , Masculino , Persona de Mediana Edad , Tercer Molar/anatomía & histología , Neuralgia/etiología , Neuralgia/fisiopatología , Neuroma/etiología , Neuroma/fisiopatología , Nociceptores/metabolismo , Procedimientos Quirúrgicos Orales/efectos adversos , Dolor Intratable/etiología , Dolor Intratable/metabolismo , Dolor Intratable/fisiopatología , Parestesia/etiología , Parestesia/metabolismo , Parestesia/fisiopatología , Complicaciones Posoperatorias/etiología , Complicaciones Posoperatorias/fisiopatología , Enfermedades del Nervio Trigémino/etiología , Enfermedades del Nervio Trigémino/fisiopatologíaRESUMEN
We have investigated a possible role for vanilloid receptor 1 (TRPV1), a transducer of noxious stimuli, in the development of neuropathic pain following injury to a peripheral branch of the trigeminal nerve. In nine adult ferrets the left lingual nerve was sectioned and recovery permitted for 3 days, 3 weeks or 3 months (3 ferrets per group). A retrograde tracer, fluorogold, was injected into the damaged nerve to identify associated cell bodies in the trigeminal ganglion. Three further ferrets, receiving only tracer injection, served as uninjured controls. Indirect immunofluorescence for TRPV1 and image analysis was used to quantify the percentage area of staining (PAS) of TRPV1 in the left and right lingual nerves. Additionally, the proportion of fluorogold positive and fluorogold negative cells expressing TRPV1 in the ganglion was determined. TRPV1 expression increased significantly at the injury site of damaged nerves 3 days after injury and this was matched by a reduction in the proportion of fluorogold positive cells expressing TRPV1 in the ganglion. At 3 weeks TRPV1 expression at the injury site was still high, while in the ganglion was significantly greater than in the controls. In the 3-month recovery group TRPV1 expression in both nerve fibres and ganglion cells, was not significantly different from controls and there were no changes in expression in the fluorogold negative cells in the ganglion at any time point studied. These data suggest that after injury there is an increase in the axonal transport of TRPV1 from the cell bodies to the damaged axons and this is followed by an increase in synthesis in the ganglion. These changes in expression may be involved in development of sensory disturbances or dysaesthesia after injury.
Asunto(s)
Traumatismos del Nervio Lingual , Nervio Lingual/metabolismo , Neuralgia/metabolismo , Canales Catiónicos TRPV/metabolismo , Ganglio del Trigémino/metabolismo , Animales , Femenino , Hurones , Técnica del Anticuerpo Fluorescente Indirecta , Colorantes Fluorescentes , EstilbamidinasRESUMEN
We have investigated the expression of TTX-sensitive (TTXs) and TTX-resistant (TTXr) sodium channel subtypes following injury to the inferior alveolar nerve (IAN), in order to determine their potential role in the development of trigeminal neuropathic pain. In seven anaesthetised ferrets, fluorogold (2%) was injected into the left IAN to identify cell bodies with axons in this nerve. In four animals, the nerve was sectioned distal to the injection site and the remaining three served as controls. After 3 days, the animals were perfused with 4% paraformaldehyde. The left and right IANs and trigeminal ganglia were processed using indirect immunofluorescence with specific primary antibodies to TTXs subtypes Na(v)1.3 and Na(v)1.7 and TTXr subtypes Na(v)1.8 and Na(v)1.9. Image analysis was used to quantify the percentage area of staining (PAS) in the nerves. In the ganglia, counts were made of positively labelled cells in the fluorogold population. PAS for Na(v)1.8 and Na(v)1.9 was significantly greater in injured nerves than in either contralateral or control nerves. After injury, significantly fewer cells in the ganglia expressed Na(v)1.3 (controls 36.9%; injured 13.1%), Na(v)1.7 (controls 17.0%; injured 8.1%) and Na(v)1.9 (controls 60.3%; injured 29.0%) (p<0.05, unpaired t test). These changes are different from those previously reported in the dorsal root ganglion following damage to peripheral nerves of spinal origin. As they occur at a time of known high abnormal neural discharge, it seems likely that changes in sodium channel expression may play a role in nerve injury-induced trigeminal pain.