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BACKGROUND AND PURPOSE: Antidepressants, which raise the CNS concentrations of 5-HT and noradrenaline, are frequently used in the treatment of chronic pain; however, it is not known if increasing CNS noradrenaline levels alone is sufficient for efficacy, in part resulting from a lack of small molecules with sufficient selectivity. EXPERIMENTAL APPROACH: In this report, we present the in vitro pharmacological and in vivo pharmacokinetic and pharmacological properties of the novel, orally available and CNS penetrant inhibitor of the noradrenaline transporter (NET), WAY-318068 (1-[(1S,2R)-1-(3,5-difluorophenyl)-2-hydroxy-3-(methylamino)propyl]-7-fluoro-3,3-dimethyl-1,3-dihydro-2H-indol-2-one). KEY RESULTS: WAY-318068 is a potent and effective inhibitor of the NET with a K(i) of 8.7 nM in a binding assay, and an IC(50) of 6.8 nM in an assay of transporter function, without significant binding to the dopamine transporter. Furthermore, the compound has only weak activity at the 5-HT transporter, leading to a functional selectivity of greater than 2500-fold. It is orally bioavailable with substantial quantities of the compound found in the CNS after oral dosing. As measured by microdialysis in rats, the compound causes a robust and significant increase in cortical noradrenaline levels without affecting 5-HT. WAY-318068 was effective in models of acute, visceral, inflammatory, osteoarthritic, neuropathic, diabetic and bone cancer pain, as well as in traditional models of depression at doses that do not cause motor deficits. CONCLUSIONS AND IMPLICATIONS: Collectively, the present results support the conclusion that selectively increasing CNS levels of noradrenaline is sufficient for efficacy in models of depression and pain.

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Ionizable groups were introduced onto the 10,11-dihydro-5H-pyrrolo[2,1-c][1,4]benzodiazepine scaffold of the vasopressin V2-antagonist WAY-VPA-985 in the search for molecules optimized for parenteral formulation. The synthesis and structure activity relationships (SAR) are presented together with solubility data in a model parenteral system. The amine, WAY-140288 (4f), was chosen for further development. p6

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We examined the effects of quinidine on a slow delayed rectifier K current induced by a human IsK cDNA (hlsK) in Xenopus oocytes. The apparent blocking potency of quinidine was lowered by membrane depolarization but enhanced by membrane hyperpolarization. After block had been established at a negative membrane voltage, depolarization induced unblock. A quaternary analog of quinidine (Q+1C) was not effective when applied extracellularly, but induced prominent and sustained hlsK suppression when injected intracellularly. The voltage dependence of hlsK suppression by intracellular Q+1C was similar to that seen with extracellular quinidine. Therefore, the quinidine binding site was accessible only from the intracellular side of the membrane. Our data can be explained by proposing that quinidine binds to an intracellular domain of the hisK or an associated subunit preferentially in the rested state, and that conformational changes associated with channel activation induce drug dissociation. Such a mechanism of action predicts that hlsK suppression by quinidine will display a "reverse use dependence" (less current suppression at more frequent depolarizations), and it can at least partly explain the rate dependence in the degree of action potential prolongation induced by quinidine.

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Previous pharmacological studies of methylated oxotremorine derivatives bearing substituents at the 3-, 4-, and 5-positions of the pyrrolidinone ring have been conducted using racemic mixtures, and not with optically active compounds. The synthesis and radioligand binding data of optically active, methylated oxotremorine derivatives at the 3- and 4-positions are described. There are significant pharmacological differences between the 3- and 4-position derivatives. The 4-position enantiomers have weak, approximately equal affinity and antagonist-like profiles, whereas the 3-position enantiomers have significantly different affinities and partial agonist-like profiles.

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A series of optically pure 2-[substituted-3-aminopropynyl]pyrrolidine derivatives, which are restricted-rotation analogues of the muscarinic agent N-methyl-N-(1-methyl-4-pyrrolidino-2-butynyl)acetamide (BM-5, compound 1), have been prepared from d- and l-proline. The compounds when tested in a series of in vitro muscarinic assays [[3H]CD (cortex), [3H]QNB (cortex), [3H]PZ (cortex), [3H]QNB (heart), [3H]QNB + GppNHp (heart)] were found to have weaker muscarinic properties than compound 1. The decrease in affinity was attributed to the increased size of the molecule resulting from the addition of a methylene group to form the pyrrolidine ring. The use of optically active compounds provided a more detailed examination of the complex pharmacological effects of the flexible muscarinic agent 1. The R enantiomers in the acetamide derivatives 12b, 12d, and 12f had a 5-10-fold greater affinity for the muscarinic receptor than the corresponding S enantiomers. A 5-fold difference or less found in the (R)- and (S)-carbamate derivatives 9, 15, and 16 suggested close overlap of the two enantiomers in the receptor binding domain. The affinity differences found in the enantiomeric acetamido derivatives when compared to those of the carbamate analogues may be the result of limited rotation of the acetamido group.

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The 2-benzazepine 9-chloro-7-(2-chlorophenyl)-5H-pyrimido[5,4-d] [2]benzazepine (1) has been selected for development as an anxiolytic agent. In support of this program, we have confirmed by chemical synthesis the structures of three in vitro (rat liver homogenate) metabolites of 1 and confirmed the structure of the major in vivo (dog and man) metabolite of 1, compound 2. Two of the metabolites, arising from hydroxylation of the pyrimidobenzazepine ring at the 5-position (2) and N-oxide formation at the 3-position of the pyrimidobenzazepine ring (3), were found to be as active as 1 in a series of pharmacological tests. The third metabolite, formed by hydroxylation of the 7-phenyl group in the 4-position (4), was found to be inactive in the same pharmacological screens.

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A series of 5H-pyrimido[5,4-d][2]benzazepines has been synthesized, starting from the corresponding 2-benzazepin-5-ones, and evaluated as potential anxiolytic agents. Selected compounds from this series show a pharmacological profile of action different than that of diazepam. They are more potent than diazepam in the anti-pentylenetetrazole test and in the [3H]diazepam binding assay, yet show less activity in the inclined screen test. A pharmacological data profile is given for 9-chloro-7-(2-chlorophenyl)-5H-pyrimido[5,4-d] [2]benzazepine (7c). The structure-activity relationships of these potential anxiolytic agents are discussed.

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The facile synthesis of [1,2,3]triazolo((4,5-d][2]benzazepines and dibenzo[c,f][1,2,3]triazolo[3,4-a]azepines by the addition of sodium azide to acetylenic benzophenones is described. Examination of the pharmacological data indicates that selected triazolobenzazepines are as potent as diazepam in the anti-pentylenetetrazole test and are weaker in the inclined screen and rotarod tests, suggesting that these compounds have antianxiety properties similar to diazepam with fewer deficits in motor coordination. In addition, a possible diazepam antagonist was found in the triazolo-benzazepine series. The dibenzotriazoloazepines were found to be inactive in four standard CNS screening procedures.

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As part of a program in the area of annelated 2-benzazepines, several thiazolo[5,4-d))[2]benzazepines were prepared. Treatment of the bromo ketones 7-9 with various thio amides gave the thiazoles 10-15, which when treated with methylamine gave the title compounds. The preliminary pharmacology of these compounds showed that they had central nervous system activity similar to the 1,4-benzodiazepines, such as diazepam. The thiazolo[5,4-d][2]benzazepines were also found to bind to the benzodiazepine-receptor complex, indicating that their pharmacological actions are probably related to the 1,4-benzodiazepines.

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The syntheses of 2-amino-N-(2-benzoyl)-4-chlorophenyl)acetamides are reported. The pharmacological properties of these compounds were compared with data obtained from the corresponding cyclized products [5-(2,6-dichlorophenyl)-1,4-benzodiazepin-2-ones]. Evidence is presented which suggests that the central nervous system activity observed for 1,4-benzodiazepines is inherent only in the closed seven-membered ring and is not due to the ring-opened form.

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