Structures of human monoamine oxidase B (MAO B) in complex with safinamide and two coumarin derivatives, all sharing a common benzyloxy substituent, were determined by X-ray crystallography. These compounds competitively inhibit MAO B with Ki values in the 0.1-0.5 microM range that are 30-700-fold lower than those observed with MAO A. The inhibitors bind noncovalently to MAO B, occupying both the entrance and the substrate cavities and showing a similarly oriented benzyloxy substituent.

Ideal treatment in Parkinson's disease (PD) aims at relieving symptoms and slowing disease progression. Of all remedies, levodopa remains the most effective for symptomatic relief, but the medical need for neuroprotectant drugs is still unfulfilled. Safinamide, currently in phase III clinical trials for the treatment of PD, is a unique molecule with multiple mechanisms of action and a very high therapeutic index. It combines potent, selective, and reversible inhibition of MAO-B with blockade of voltage-dependent Na+ and Ca2+ channels and inhibition of glutamate release. Safinamide has neuroprotective and neurorescuing effects in MPTP-treated mice, in the rat kainic acid, and in the gerbil ischemia model. Safinamide potentiates levodopa-mediated increase of DA levels in DA-depleted mice and reverses the waning motor response after prolonged levodopa treatment in 6-OHDA-lesioned rats. Safinamide has excellent bioavailability, linear kinetics, and is suitable for once-a-day administration. Therefore, safinamide may be used in PD to reduce l-dopa dosage and also represents a valuable therapeutic drug to test disease-modifying potential.

Recent evidence suggests that the pathophysiology of neurodegenerative and inflammatory neurological diseases has a neuroimmunological component involving complement, an innate humoral immune defense system. The present study demonstrates the effects of experimentally induced global ischemia on the biosynthesis of C1q, the recognition subcomponent of the classical complement activation pathway, in the CNS. Using semiquantitative in situ hybridization, immunohistochemistry, and confocal laser scanning microscopy, a dramatic and widespread increase of C1q biosynthesis in rat brain microglia (but not in astrocytes or neurons) within 24 h after the ischemic insult was observed. A marked increase of C1q functional activity in cerebrospinal fluid taken 1, 24, and 72 h after the ischemic insult was determined by C1q-dependent hemolytic assay. In the light of the well-established role of complement and complement activation products in the initiation and maintenance of inflammation, the ischemia-induced increase of cerebral C1q biosynthesis and of C1q functional activity in the cerebrospinal fluid implies that the proinflammatory activities of locally produced complement are likely to contribute to the pathophysiology of cerebral ischemia. Pharmacological modulation of complement activation in the brain may be a therapeutic target in the treatment of stroke.

In an effort to discover novel selective monoamine oxidase (MAO) B inhibitors with favorable physicochemical and pharmacokinetic profiles, 7-[(m-halogeno)benzyloxy]coumarins bearing properly selected polar substituents at position 4 were designed, synthesized, and evaluated as MAO inhibitors. Several compounds with MAO-B inhibitory activity in the nanomolar range and excellent MAO-B selectivity (selectivity index SI > 400) were identified. Structure-affinity relationships and docking simulations provided valuable insights into the enzyme-inhibitor binding interactions at position 4, which has been poorly explored. Furthermore, computational and experimental studies led to the identification and biopharmacological characterization of 7-[(3-chlorobenzyl)oxy]-4-[(methylamino)methyl]-2H-chromen-2-one methanesulfonate 22b (NW-1772) as an in vitro and in vivo potent and selective MAO-B inhibitor, with rapid blood-brain barrier penetration, short-acting and reversible inhibitory activity, slight inhibition of selected cytochrome P450s, and low in vitro toxicity. On the basis of this preliminary preclinical profile, inhibitor 22b might be viewed as a promising clinical candidate for the treatment of neurodegenerative diseases.

Although most epilepsies are adequately treated by conventional antiepileptic therapy, there remains an unfulfilled need for safer and more effective anticonvulsant agents. Starting from milacemide, a weak anticonvulsant, and trying to elucidate its mechanism of action, we discovered a structurally novel class of potent and preclinically safe anticonvulsants. Here we report the structure-activity relationship (SAR) study within this series of compounds. Different parts of the structural lead 2-[[4-(3-chlorobenzoxy)benzyl]amino]acetamide (6) were thus varied (Figure 1), and many potent anticonvulsants were found. As an outcome of this study, 57 ((S)-2-[[4-(3-fluorobenzoxy)benzyl]amino]propanamide methanesulfonate, PNU-151774E) emerged as a promising candidate for further development for its potent anticonvulsant activity and outstanding therapeutic indexes (TIs) in different animal tests.

A series of derivatives of 4-phenyl-1,4-dihydropyridine bearing imidazol-1-yl or pyridin-3-yl moieties on the phenyl ring were synthesized with the aim of combining Ca2+ antagonism and thromboxane A2 (TxA2) synthase inhibition in the same molecule. Some of these compounds showed significant combined Ca2+ antagonism and TxA2 synthase inhibition in vitro, while others showed only one single activity. Structural requirements for significant single or combined activities are discussed. Theoretical conformational analysis, by molecular mechanics and semiempirical AM1 calculations, was performed for 1,4-dihydro-2,6-dimethyl-4-[3-(1H-imidazol-1-yl)phenyl]- 3,5-pyridinedicarboxylic acid, diethyl ester (FCE 24265) and two close congeners. FCE 24265, which inhibited TxB2 production in rat whole blood with IC50 = 1.7 x 10(-7) M and antagonized K+ induced contraction in guinea pig aorta with IC50 = 6.0 x 10(-8) M, was selected for further pharmacological evaluation. Our results show that this compound is less potent than nifedipine both in vitro and in vivo yet presents a favorable profile in vivo, lowering blood pressure without inducing reflex tachycardia. Moreover, its additional potent and selective TxA2 synthase inhibitory activity makes this compound an interesting pharmacologic tool in pathologies where both enhanced TxA2 synthesis and cellular Ca2+ overload are involved.

No abstract

NW-1029, a benzylamino propanamide derivative, was selected among several molecules of this chemical class on the basis of its affinity for the [(3)H]batracotoxin ligand displacement of the Na(+) channel complex and also on the basis of its voltage and use-dependent inhibitory action on the Na(+) currents of the rat DRG (dorsal root ganglia) sensory neuron. This study evaluated the analgesic activity of NW-1029 in animal models of inflammatory and neuropathic pain (formalin test in mice, complete Freund's adjuvant and chronic constriction injury in rats) as well as in acute pain test (hot-plate and tail-flick in rats). Orally administered NW-1029 dose-dependently reduced cumulative licking time in the early and late phase of the formalin test (ED(50)=10.1 mg/kg in the late phase). In the CFA model, NW-1029 reversed mechanical allodynia (von Frey test) after both i.p. and p.o. administration (ED(50)=0.57 and 0.53 mg/kg), respectively. Similarly, NW-1029 reversed mechanical allodynia in the CCI model after both i.p. and p.o. administration yielding an ED(50) of 0.89 and 0.67 mg/kg, respectively. No effects were observed in the hot-plate and tail-flick tests up to 30 mg/kg p.o. The compound orally administered (0.1-10 mg/kg) was well tolerated, without signs of neurological impairment up to high doses (ED(50)=470 and 245 mg/kg in rat and mice Rotarod test, respectively). These results indicate that NW-1029 has anti-nociceptive properties in models of inflammatory and neuropathic pain.