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See detailBis-tetrahydroisoquinoline derivatives: AG525E1, a new step in the search for non-quaternary non-peptidic small conductance Ca2+-activated K+ channel blockers
Graulich, Amaury ULg; Lamy, Cédric ULg; Alleva, Livia ULg et al

in Bioorganic & Medicinal Chemistry Letters (2008), 18(11), 3440-3445

So far, small conductance Ca2+-activated K+ channel (SK) blockers mostly consist of quaternary ammonium derivatives or peptides. Due to their physicochemical properties, these blockers are not suitable to ... [more ▼]

So far, small conductance Ca2+-activated K+ channel (SK) blockers mostly consist of quaternary ammonium derivatives or peptides. Due to their physicochemical properties, these blockers are not suitable to study the physiological roles of SK channels in the central nervous system in vivo. Herein, we report the discovery of a chiral bis-tertiary amine with SK blocking properties from chemical modulation of laudanosine. AG525E1 has an affinity for SK channels (K-i = 293 nM) approximately 100-fold higher than the tertiary compound laudanosine (K-i similar to 30 mu M) and similar to the charged compound dequalinium (K-i = 221 nM). AG525E1 equipotently blocks SK1, SK2 and SK3 currents in transfected cell lines. Because of its basic and lipophilic properties, it can reach central SK targets. (c) 2008 Elsevier Ltd. All rights reserved. [less ▲]

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See detailSynthesis and Radioligand Binding Studies of Bis-Isoquinolinium Derivatives as Small Conductance Ca(2+)-Activated K(+) Channel Blockers
Graulich, Amaury ULg; Dilly, Sébastien ULg; Farce, Amaury et al

in Journal of Medicinal Chemistry (2007), 50(21), 5070-5075

Starting from the scaffold of N-methyllaudanosine and N-methylnoscapine, which are known small conductance Ca2+-activated K+ channel blockers, original bis-isoquinolinium derivatives were synthezised and ... [more ▼]

Starting from the scaffold of N-methyllaudanosine and N-methylnoscapine, which are known small conductance Ca2+-activated K+ channel blockers, original bis-isoquinolinium derivatives were synthezised and evaluated using binding studies, electrophysiology, and molecular modeling. These quaternary compounds are powerful blockers, and the most active ones have 10 times more affinity for the channels than dequalinium. The unsubstituted compounds possess a weaker affinity than the analogues having a 6,7-dimethoxy- or a 6,7,8-trimethoxy substitution. The length of the linker has no influence in the alkane derivatives. In relation to the xylene derivatives, the affinities are higher for the ortho and meta isomers. These results are well corroborated by a molecular modeling study. Finally, the most effective compounds have been tested in electrophysiological experiments on midbrain dopaminergic neurons and demonstrate the blocking potential of the apamin-sensitive after-hyperpolarization. [less ▲]

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See detail(+/-)-2-Benzoyl-8-ethyl-1,2-dihydro-isoquinoline-1-carbonitrile: an original Reissert compound
Graulich, Amaury ULg; Norberg, B.; Liégeois, Jean-François ULg et al

in Acta Crystallographica Section E-Structure Reports Online (2007), 63(Part 7), 3161-3073

The title compound, C19H16N2O, is a Reissert compound. The heterocyclic fragment of the molecule exhibits a 1,3-diplanar conformation. The phenyl ring is connected to the isoquinoline ring system via an ... [more ▼]

The title compound, C19H16N2O, is a Reissert compound. The heterocyclic fragment of the molecule exhibits a 1,3-diplanar conformation. The phenyl ring is connected to the isoquinoline ring system via an amide bond that adopts an anti conformation with respect to the adjacent C-N bond in the adjacent heterocyclic ring. Intra-and intermolecular C-H center dot center dot center dot O hydrogen bonds are present in the crystal structure. [less ▲]

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See detailSynthesis and in vitro binding studies of substituted piperidine naphthamides. Part II: Influence of the substitution on the benzyl moiety on the affinity for D-2L, D-4.2, and 5-HT2A receptors
Carato, P.; Graulich, Amaury ULg; Jensen, N. et al

in Bioorganic & Medicinal Chemistry Letters (2007), 17(6), 1570-1574

In continuation of our work on N-(piperidin-4-yl)-naphthamides, the effect of substituted benzyl groups on D-2L, D-4.2, and 5-HT2A receptor affinity was evaluated. In the 1-naphthamide series most ... [more ▼]

In continuation of our work on N-(piperidin-4-yl)-naphthamides, the effect of substituted benzyl groups on D-2L, D-4.2, and 5-HT2A receptor affinity was evaluated. In the 1-naphthamide series most compounds were highly selective for D-4.2 over D-2L, and 5-HT2A receptors. Halogen and methyl substitution in position 3 or 4 of the benzyl group increased D-4.2 affinity. In the 2-naphthamide series a similar high D-4.2 over D-2L selectivity was retained while 5-HT2A affinity was increased. 3-Methoxy, 3-methyl, and 4-methyl substituents were favorable for D-4.2 affinity while halogens reduced affinity. 2-Naphthamides with a 3-bromo- or a 3-methyl group were mixed D-4.2/5-HT2A ligands similar to their unsubstituted parent compound. All compounds from both series with significant affinity for D-4.2 and 5-HT2A receptors were antagonists. (c) 2007 Elsevier Ltd. All rights reserved. [less ▲]

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See detailSynthesis and in vitro binding studies of substituted piperidine naphthamides. Part I: Influence of the substitution on the basic nitrogen and the position of the amide on the affinity for D-2L, D-4.2, and 5-HT2A receptors
Carato, P.; Graulich, Amaury ULg; Jensen, N. et al

in Bioorganic & Medicinal Chemistry Letters (2007), 17(6), 1565-1569

A series of 1- and 2-naphthamides has been prepared and tested for in vitro binding to D-2L, D-4.2, and 5-HT2A receptors. Different compounds display selectivity for D-4.2 and 5-HT2A receptors versus D-2L ... [more ▼]

A series of 1- and 2-naphthamides has been prepared and tested for in vitro binding to D-2L, D-4.2, and 5-HT2A receptors. Different compounds display selectivity for D-4.2 and 5-HT2A receptors versus D-2L receptors. N-(1-Arylalkyl-piperidin-4-yl) carboxamides have higher affinities than the corresponding N-(4-arylalkylamino-piperidin-1-yl) carboxamide analogues. A benzyl moiety in position 1 of the piperidine in the 2-naphthamide series (2) appears to be the best choice for a favorable interaction with D-4.2 and 5-HT2A receptors. Increasing the linker length between the phenyl ring and the basic nitrogen led to a decreased affinity for these receptors. In the 1-naphthamide series, the most potent D-4.2 ligand (7) possesses a phenylpropyl moiety while its affinity for 5-HT2A receptors is strongly reduced. All compounds with significant affinity for D-4.2 and 5-HT2A receptors were antagonists. (c) 2007 Elsevier Ltd. All rights reserved. [less ▲]

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See detailLong-term effects of JL 13, a potential atypical antipsychotic, on Ionotropic glutamate receptors
Tarazi, Frank I.; Moran-Gates, Taylor; Gardner, Matthew P. et al

in Journal of Molecular Neuroscience (2007), 32(3), 192-198

Changes in ionotropic glutamate (Glu) N-methyl-D-aspartic acid (NMDA), and 2-amino-3-(3-hydroxy-5-methyl-isoxazol-4-yl)propionic acid (AMPA) receptors in rat forebrain regions were autoradiographically ... [more ▼]

Changes in ionotropic glutamate (Glu) N-methyl-D-aspartic acid (NMDA), and 2-amino-3-(3-hydroxy-5-methyl-isoxazol-4-yl)propionic acid (AMPA) receptors in rat forebrain regions were autoradiographically quantified after continuous infusion of JL 13 [(5-(4-methylpiperazin-1-yl)-8-chloro-pyrido[2,3-b][1,5]benzoxazepine furnarate] for 28 days using osmotic minipumps, and compared to the effects of representative typical (haloperidol) and atypical (clozapine, olanzapine, and risperidone) antipsychotic drugs from previous studies. Similar to other atypical and not typical antipsychotics, JL 13 decreased labeling of NMDA receptors in medial and lateral caudate-putamen (CPu; by 40%). These findings indicate that downregulation of NMDA receptors by JL 13 and other atypical antipsychotic agents in CPu may contribute to their low risk of extrapyramidal side effects. In addition, and similar to olanzapine and risperidone, JL 13 increased AMPA receptor binding in CPu (by 42%). Changes in AMPA receptors may contribute to psychopharmacological properties of JL 13 and other atypical agents. Similar to clozapine, JL 13 did not alter levels of NMDA and AMPA receptors in hippocampus and entorhinal cortex. Long-term effects of JL 13 on ionotropic Glu receptors, as well as on other dopamine and serotonin receptors, support the atypical antipsychotic profile of this novel agent. [less ▲]

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See detailSynthesis and radioligand binding studies of methoxylated 1,2,3,4-tetrahydroisoquinolinium derivatives as ligands of the apamin-sensitive Ca2+- activated K+ channels
Graulich, Amaury ULg; Scuvée-Moreau, Jacqueline ULg; Alleva, Livia ULg et al

in Journal of Medicinal Chemistry (2006), 49(24), 7208-7214

Several methoxylated 1,2,3,4-tetrahydroisoquinoliniums derived from N-methyl-laudanosine and N-methyl-noscapine were synthesized and evaluated for their affinity for apamin-sensitive binding sites. The ... [more ▼]

Several methoxylated 1,2,3,4-tetrahydroisoquinoliniums derived from N-methyl-laudanosine and N-methyl-noscapine were synthesized and evaluated for their affinity for apamin-sensitive binding sites. The quaternary ammonium derivatives have a higher affinity with regard to the tertiary amines. 6,7-Dimethoxy analogues possess a higher affinity than the 6,8- and 7,8- dimethoxy isomers. A 3,4-dimethoxybenzyl or a 2-naphthylmethyl moiety in C-1 position are more favorable than a 3,4-dimethoxyphenethyl group. Smaller groups such as propyl or isobutyl are unfavorable. In 6,7-dimethoxy analogues, increasing the size and lipophilicity with a naphthyl group in the C-1 position leads to a slight increase of affinity, while the same group in the 6,7,8- trimethoxy series is less favorable. The 6,7,8- trimethoxy derivative 3f is the first tertiary amine in the series to possess an affinity close to that of N-methyl-laudanosine and N-methyl-noscapine. Moreover, electrophysiological studies show that the most effective compound 4f blocks the apamin-sensitive afterhyperpolarization in rat dopaminergic neurons. [less ▲]

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See detailLong-term effects of JL 13, a potential atypical antipsychotic, on rat dopamine and serotonin receptor subtypes
Moran-Gates, Taylor; Massari, Carla; Graulich, Amaury ULg et al

in Journal of Neuroscience Research (2006), 84(3), 675-682

Changes in dopamine (DA) D-1, D-2, D-3, and D-4 receptors and serotonin 5-HT1A and 5-HT2A receptors in rat forebrain regions were autoradiographically quantified after continuous infusion of JL 13 [(5-(4 ... [more ▼]

Changes in dopamine (DA) D-1, D-2, D-3, and D-4 receptors and serotonin 5-HT1A and 5-HT2A receptors in rat forebrain regions were autoradiographically quantified after continuous infusion of JL 13 [(5-(4-methylpiperazin-1-yl)8-chloro-pyrido[2,3-b][1,5]benzoxazepine fumarate] for 28 days with osmotic minipumps and compared with the effects of other typical (fluphenazine) and atypical (clozapine, olanzapine, and risperidone) antipsychotic drugs from previous studies. Similar to other typical and atypical antipsychotics, JL 13 increased labeling of D2 receptors in medial prefrontal cortex (MPC) and hippocampus (HIP) and D-4 receptors in nucleus accumbens (NAc), caudate-putamen (CPu), and HIP In addition, JL 13 increased 5-HT1A and decreased 5-HT2A receptors in MPC and dorsolateral frontal cortex (DFC), an effect shared by atypical antipsychotics, and may contribute to their psychopharmacological properties. Clozapine and JL 13, but not other antipsychotics, spared D2 receptors in CPu, which may reflect their ability to induce minimal extrapyramidal side effects. In addition, JL 13 but not other typical and atypical antipsychotic drugs increased abundance of D, receptors in CPu and NAc. JL 13 as well as other antipsychotic agents did not alter levels of forebrain D3 receptors. An atypical-like profile of JL 13 on DA and 5-HT receptor subtypes should encourage further development of this compound as a novel atypical anti psychotic drug. (c) 2006Wiley-Liss, Inc. [less ▲]

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See detailIdentification of a pharmacophore of SKCa channel blockers
Dilly, Sébastien ULg; Graulich, Amaury ULg; Farce, Amaury et al

in Journal of Enzyme Inhibition and Medicinal Chemistry (2005), 20(6), 517-523

Small conductance calcium-activated potassium channels ( SK) are widely expressed throughout the central nervous system ( CNS) and the periphery. Three subtypes of SK channels have so far been identified ... [more ▼]

Small conductance calcium-activated potassium channels ( SK) are widely expressed throughout the central nervous system ( CNS) and the periphery. Three subtypes of SK channels have so far been identified in different parts of the brain. Activation of the SK channels by a rise in intracellular calcium leads to the hyperpolarisation of the membrane, reducing cell excitability. Blocking the SK channels might be beneficial in the treatment of depression, Parkinson's disease and cognitive disorders. However, few blockers of SK channels have been characterized. In this study, a pharmacophoric model of SK channels blockers is presented. It is based on a series of nonpeptidic compounds and apamin, a peptidic blocker. To create the pharmacophore model, the conformational space of nonpeptidic blockers was investigated to generate a series of distance constraints applied to a simulated annealing study of apamin. The resulting conformation was superimposed with the nonpeptidic blockers to give a pharmacophore. [less ▲]

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See detailSK channels control the firing pattern of midbrain dopaminergic neurons in vivo
Waroux, Olivier ULg; Massotte, Laurent ULg; Alleva, Livia ULg et al

in European Journal of Neuroscience (2005), 22(12), 3111-3121

A vast body of experimental in vitro work and modelling studies suggests that the firing pattern and/or rate of a majority of midbrain dopaminergic neurons may be controlled in part by Ca2+-activated K ... [more ▼]

A vast body of experimental in vitro work and modelling studies suggests that the firing pattern and/or rate of a majority of midbrain dopaminergic neurons may be controlled in part by Ca2+-activated K+ channels of the SK type. However, due to the lack of suitable tools, in vivo evidence is lacking. We have taken advantage of the development of the water-soluble, medium potency SK blocker N-methyl-laudanosine (CH3-L) to test this hypothesis in anaesthetized rats. In the lateral ventral tegmental area, CH3-L iontophoresis onto dopaminergic neurons significantly increased the coefficient of variation of their interspike intervals and the percentage of spikes generated in bursts as compared to the control condition. The effect of CH3-L persisted in the presence of a specific GABA(A) antagonist, suggesting a direct effect. It was robust and reversible, and was also observed in the substantia nigra. Control experiments demonstrated that the effect of CH3-L could be entirely ascribed to its blockade of SK channels. On the other hand, the firing pattern of noradrenergic neurons was much less affected by CH3-L. We provide here the first demonstration of a major role of SK channels in the control of the switch between tonic and burst firing of dopaminergic neurons in physiological conditions. This study also suggests a new strategy to develop modulators of the dopaminergic (DA) system, which could be of interest in the treatment of Parkinson's disease, and perhaps other diseases in which DA pathways are dysfunctional. [less ▲]

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See detailSynthesis and radioligand binding studies of C-5- and C-8-substituted 1-(3,4-dimethoxybenzyl)-2,2-dimethyl-1,2,3,4-tetrahydroisoquinoliniums as SK channel blockers related to N-methyl-laudanosine and N-methyl-noscapine
Graulich, Amaury ULg; Scuvée-Moreau, Jacqueline ULg; Seutin, Vincent ULg et al

in Journal of Medicinal Chemistry (2005), 48(15), 4972-4982

The synthesis and the 125 I-apamin binding studies of original C-5- and C-8-substituted 143,4-dimethoxy-benzyl)-2,2-dimethyl-1,2,3,4-tetrahydroisoquinoliniums and 1-(3,4-dimethoxy-benzyl)-6,6-dimethyl-4,5 ... [more ▼]

The synthesis and the 125 I-apamin binding studies of original C-5- and C-8-substituted 143,4-dimethoxy-benzyl)-2,2-dimethyl-1,2,3,4-tetrahydroisoquinoliniums and 1-(3,4-dimethoxy-benzyl)-6,6-dimethyl-4,5,6,7-tetrahydrothieno[2,3-c]pyridiniums were performed in order to find a reversible and selective SK channel blocker structurally related to N-methyl-laudanosine and N-methyl-noscapine. A bulky alkyl substituent in the C-8 position of the tetrahydroisoquinoline produces a clear increase in the affinity for the apamin sensitive binding sites. The presence of an electron-withdrawing group in the C-5 and C-8 positions is not a suitable substitution for the affinity of drugs structurally related to N-methyl-laudanosine. Thiophenic analogues and 8-methoxy derivatives possess a poor affinity for the apamin sensitive binding sites. Electrophysiological studies performed with the most effective compound showed a blockade of the apamin sensitive afterhyperpolarization in rat dopaminergic neurons. [less ▲]

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See detailElectrophysiological characterization of the SK channel blockers methyl-laudanosine and methyl-noscapine in cell lines and rat brain slices
Scuvée-Moreau, Jacqueline ULg; Boland, André ULg; Graulich, Amaury ULg et al

in British Journal of Pharmacology (2004), 143(6), 753-764

We have recently shown that the alkaloid methyl-laudanosine blocks SK channel-mediated afterhyperpolarizations (AHPs) in midbrain dopaminergic neurones. However, the relative potency of the compound on ... [more ▼]

We have recently shown that the alkaloid methyl-laudanosine blocks SK channel-mediated afterhyperpolarizations (AHPs) in midbrain dopaminergic neurones. However, the relative potency of the compound on the SK channel subtypes and its ability to block AHPs of other neurones were unknown. Using whole-cell patch-clamp experiments in transfected cell lines, we found that the compound blocks SK1, SK2 and SK3 currents with equal potency: its mean IC(50)s were 1.2, 0.8 and 1.8 microM, respectively. IK currents were unaffected. In rat brain slices, methyl-laudanosine blocked apamin-sensitive AHPs in serotonergic neurones of the dorsal raphe and noradrenergic neurones of the locus coeruleus with IC(50)s of 21 and 19 microM, as compared to 15 microM in dopaminergic neurones. However, at 100 microM, methyl-laudanosine elicited a constant hyperpolarization of serotonergic neurones of about 9 mV, which was inconsistently (i.e. not in a reproducible manner) antagonized by atropine and hence partly due to the activation of muscarinic receptors. While exploring the pharmacology of related compounds, we found that methyl-noscapine also blocked SK channels. In cell lines, methyl-noscapine blocked SK1, SK2 and SK3 currents with mean IC(50)s of 5.9, 5.6 and 3.9 microM, respectively. It also did not block IK currents. Methyl-noscapine was slightly less potent than methyl-laudanosine in blocking AHPs in brain slices, its IC(50)s being 42, 37 and 29 microM in dopaminergic, serotonergic and noradrenergic neurones, respectively. Interestingly, no significant non-SK effects were observed with methyl-noscapine in slices. At a concentration of 300 microM, methyl-noscapine elicited the same changes in excitability in the three neuronal types than did a supramaximal concentration of apamin (300 nM). Methyl-laudanosine and methyl-noscapine produced a rapidly reversible blockade of SK channels as compared with apamin. The difference between the IC(50)s of apamin (0.45 nM) and methyl-laudanosine (1.8 microM) in SK3 cells was essentially due to a major difference in their k(-1) (0.028 s(-1) for apamin and >or=20 s(-1) for methyl-laudanosine). These experiments demonstrate that both methyl-laudanosine and methyl-noscapine are medium potency, quickly dissociating, SK channel blockers with a similar potency on the three SK subtypes. Methyl-noscapine may be superior in terms of specificity for the SK channels. [less ▲]

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See detailA rapid synthesis of thieno[2,3-c]pyridine and 2-substituted thieno[2,3-c]pyridines
Graulich, Amaury ULg; Liégeois, Jean-François ULg

in Synthesis (2004), (12), 1935-1937

A convenient preparation of thieno[2,3-c]pyridine 3a and of several original 2-substituted-thieno [2,3-c] pyridines 3b-f is achieved by cyclization of the Schiff base resulting from the condensation ... [more ▼]

A convenient preparation of thieno[2,3-c]pyridine 3a and of several original 2-substituted-thieno [2,3-c] pyridines 3b-f is achieved by cyclization of the Schiff base resulting from the condensation between a 2-thiophenecarboxaldehyde 1a-f and aminoacetaldehyde dimethyl acetal. This procedure provides especially good yields in the case of 2-halogenated analogues. [less ▲]

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See detail8-Methyl-6-(4-methylpiperazin-1-yl)-11H-pyrido[2,3-b][1,4]benzodiazepine
Spirlet, Marie-Rose ULg; Graulich, Amaury ULg; Liégeois, Jean-François ULg

in Acta Crystallographica Section E-Structure Reports Online (2003), 59(Part 12), 1990-1991

The conformation of the title compound, C18H21N5, is very similar to that observed in other diaryldiazepine structures such as clozapine and clozapine dihydrobromide. N-H...H hydrogen-bond interactions ... [more ▼]

The conformation of the title compound, C18H21N5, is very similar to that observed in other diaryldiazepine structures such as clozapine and clozapine dihydrobromide. N-H...H hydrogen-bond interactions result in the formation of a dimer. [less ▲]

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