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4.
Pain ; 155(10): 2097-107, 2014 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-25083927

RESUMEN

Menthol has historically been used topically to alleviate various pain conditions. At low concentrations, this non-selective TRPM8 agonist elicits a cooling sensation, however higher concentrations result in cold hyperalgesia in normal subjects and paradoxically analgesia in neuropathic patients. Through behavioural and electrophysiological means, we examined whether this back-translated into a pre-clinical rodent model. Menthol was applied topically to the hind paws of naive and spinal nerve-ligated (SNL) rats. In behavioural assays, menthol did not affect withdrawal thresholds to mechanical stimulation and 10% and 40% menthol rarely sensitised withdrawals to innocuous cooling in naïve rats. However, in SNL rats, 10% and 40% menthol alleviated cold hypersensitivity. This was partly corroborated by in vivo electrophysiological recordings of dorsal horn lamina V/VI neurones. As several studies have implicated TRPM8 in analgesia, we examined whether a novel systemically available TRPM8 agonist, M8-Ag, had more potent anti-hyperalgesic effects than menthol in neuropathic rats. In vitro, M8-Ag activates TRPM8, expressed in HEK293 cells, with an EC50 of 44.97 nM. In vivo, M8-Ag inhibited neuronal responses to innocuous and noxious cooling in SNL rats with no effect in sham-operated rats. This effect was modality selective; M8-Ag did not alter neuronal responses to mechanical, heat or brush stimulation. In addition, M8-Ag attenuated behavioural hypersensitivity to innocuous cooling but not mechanical stimulation. These data suggest that menthol induced hyperalgesia is not consistently replicable in the rat and that the analgesic properties are revealed by injury. Systemic TRPM8 agonists might be beneficial in neuropathy without affecting normal cold sensitivity.


Asunto(s)
Analgésicos/uso terapéutico , Hiperalgesia/tratamiento farmacológico , Mentol/uso terapéutico , Morfolinas/agonistas , Neuralgia/tratamiento farmacológico , Canales Catiónicos TRPM/agonistas , Triazoles/agonistas , Analgésicos/administración & dosificación , Animales , Frío , Modelos Animales de Enfermedad , Hiperalgesia/etiología , Masculino , Mentol/administración & dosificación , Neuralgia/etiología , Umbral del Dolor/efectos de los fármacos , Traumatismos de los Nervios Periféricos/complicaciones , Ratas , Ratas Sprague-Dawley
5.
Bioorg Med Chem Lett ; 17(2): 558-61, 2007 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-17079144

RESUMEN

The synthesis of a series of novel C-linked nucleotide triphosphates is reported. These exhibit excellent agonist potency and selectivity for the P2Y2 receptor with a number of examples having EC50 values below 10 nM. Representative compounds from the N-linked and C-linked series showed enhanced metabolic stability compared with that of the natural ligand UTP.


Asunto(s)
Nucleótidos/síntesis química , Nucleótidos/farmacología , Agonistas del Receptor Purinérgico P2 , Uridina Trifosfato/química , Línea Celular Tumoral , Cromatografía Liquida , Humanos , Indicadores y Reactivos , Ligandos , Espectroscopía de Resonancia Magnética , Espectrometría de Masas , Nucleótidos/química , Receptores Purinérgicos P2Y2 , Proteínas Recombinantes , Espectrofotometría Ultravioleta , Uridina Trifosfato/farmacología
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