Anti-hyperalgesic effects of a novel TRPM8 agonist in neuropathic rats: a comparison with topical menthol.

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.

IRAK-4 inhibitors. Part II: a structure-based assessment of imidazo[1,2-a]pyridine binding.

A potent IRAK-4 inhibitor was identified through routine project cross screening. The binding mode was inferred using a combination of in silico docking into an IRAK-4 homology model, surrogate crystal structure analysis and chemical analogue SAR.

IRAK-4 inhibitors. Part 1: a series of amides.

The synthesis and profile of a series of amides are described. Some of these compounds were potent IRAK-4 inhibitors and two examples were evaluated in vivo.

IRAK-4 inhibitors. Part III: a series of imidazo[1,2-a]pyridines.

Following the identification of a potent IRAK inhibitor through routine project cross screening, a novel class of IRAK-4 inhibitor was established. The SAR of imidazo[1,2-a]pyridino-pyridines and benzimidazolo-pyridines was explored.

Novel nucleotide triphosphates as potent P2Y2 agonists with enhanced stability over UTP.

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.

Novel nucleotide triphosphates as potent P2Y2 agonists.

The synthesis and P2Y2 activities of a novel series of nucleoside triphosphates are described. Many of these compounds were potent agonists of the P2Y2 receptor.

Low molecular weight indole fragments as IMPDH inhibitors.

The study of non-oxazole containing indole fragments as inhibitors of inosine monophosphate dehydrogenase (IMPDH) is described. The synthesis and in vitro inhibitory values for IMPDH II are discussed.

Novel indole inhibitors of IMPDH from fragments: synthesis and initial structure-activity relationships.

The elaboration of previously reported indole fragments as inhibitors of inosine monophosphate dehydrogenase (IMPDH) is described. The synthesis, in vitro inhibitory values for IMPDH II, PBMC proliferation and physicochemical properties are discussed.