Publications by authors named "Kathryn R Starr"

Glycine can act as either an inhibitory neurotransmitter or as a potentiator of NMDA-dependent excitatory neurotransmission. There is some evidence that glycine can have both pro- and anticonvulsant properties in various rodent models of epilepsy. In the present study we tested several glycine transporter 1 (GlyT1) inhibitors including NFPS, SSR 504734, Lu AA21279, Org 25935, SB-710622, GSK931145, as well as the glycine agonist d-serine, in the maximal electroshock threshold (MEST) test in the rat.

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Novel 2-methyl-5-quinolinyl-1-piperazinylalkyl-3,4-dihydro-2H-1,4-benzoxazin-3-ones showing high affinities for the 5-HT(1A/1B/1D) receptors coupled with potent 5-HT reuptake inhibitory activity have been discovered. This is the first report describing docking of the lead compound 6-{2-[4-(2-methyl-5-quinolinyl)-1-piperazinyl]ethyl}-2H-1,4-benzoxazin-3(4H)-one 1, into a model of the 5-HT transporter and the 5-HT(1A) receptor model.

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5-HT1 receptor antagonists have been discovered with good selectivity over the 5-HT transporter. This is the first report of highly potent, selective ligands for the 5-HT1A/B/D receptors with low intrinsic activity, which represent a useful set of molecules for further understanding the roles of the 5-HT1 receptor subtypes and providing new approaches for the treatment of depression.

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Aberrant glutamatergic neurotransmission may underlie the pathogenesis of schizophrenia and metabotropic glutamate receptors (mGluRs) have been implicated in the disease. We have established the localization of the group III mGluR subtype, mGluR8, in the human body and investigated the biological effects of the selective mGluR8 agonist (S)-3,4-dicarboxyphenylglycine ((S)-3,4-DCPG) in schizophrenia-related animal models. The mGlu8 receptor has a widespread CNS distribution with expression observed in key brain regions associated with schizophrenia pathogenesis including the hippocampus.

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Article Synopsis
  • - Preclinical studies show that combining an SSRI with a 5-HT autoreceptor antagonist can speed up the onset of anxiety relief, as supported by clinical evidence when SSRIs are used with pindolol.
  • - The novel compound SB-649915-B demonstrated significant anxiolytic effects in animal models, reducing anxiety behaviors in rat pups and marmosets without affecting their locomotion.
  • - After chronic use, SB-649915-B continued to show anxiolytic-like effects more rapidly than paroxetine in social interaction tests, with both compounds inhibiting serotonin uptake similarly.
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Rationale: The delay in onset and treatment resistance of subpopulations of depressed patients to conventional serotonin reuptake inhibitors has lead to new drug development strategies to produce agents with improved antidepressant efficacy.

Objectives: We report the in vivo characterization of the novel 5-HT(1A/1B) autoreceptor antagonist/5-HT transporter inhibitor (6-[(1-{2-[(2-methyl-5-quinolinyl)oxy]ethyl}-4-piperidinyl)methyl]-2H-1,4-benzoxazin-3(4H)-one), SB-649915-B.

Materials And Methods: Ex vivo binding was used to ascertain 5-HT(1A) receptor and serotonin transporter occupancy.

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Investigation of halogen substitution in lead compound 1 has led to the identification of analogues which combine high affinity for 5-HT(1A) receptors and potent serotonin reuptake inhibitory activity. Several compounds show an improved selectivity over 5-HT(1B) and 5-HT(1D) receptors and a superior pharmacokinetic profile in the rat.

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The 5-HT1B receptor has attracted significant interest as a potential target for the development of therapeutics for the treatment of affective disorders such as anxiety and depression. Here we present the in vivo characterisation of a novel, selective and orally bioavailable 5-HT1B receptor antagonist, SB-616234-A (1-[6-(cis-3,5-dimethylpiperazin-1-yl)-2,3-dihydro-5-methoxyindol-1-yl]-1-[2'-methyl-4'-(5-methyl-1,2,4-oxadiazol-3-yl)biphenyl-4-yl]methanone hydrochloride). SB-616234-A reversed the 5-HT1/7 receptor agonist, SKF-99101H-induced hypothermia in guinea pigs in a dose related manner with an ED50 of 2.

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Article Synopsis
  • - SB-616234-A shows strong affinity for human 5-HT1B receptors with a pKi of 8.3, and is highly selective, being over 100 times more specific for these receptors compared to others, including rat and guinea pig versions, which have similar high affinity.
  • - The compound acts as a high affinity antagonist in both human and rat systems, indicating it blocks receptor activity without activating them, as shown by the absence of agonist effects in various binding studies.
  • - In practical experiments, SB-616234-A increases the release of serotonin (5-HT) in guinea pig and rat brain slices and inhibits binding to 5-HT1B receptors in a dose-dependent manner after oral
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Rationale: Hyperprolactinaemia is a common side effect of antipsychotic treatment and the clinical consequences associated with this, e.g. sexual dysfunction, can have a negative impact on patient compliance.

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Bisaryl cyclic ureas have been identified as high affinity 5-HT2C receptor antagonists with selectivity over 5-HT2A and 5-HT2B. Compounds such as 8 and 22 have shown oral activity in a centrally mediated pharmacodynamic model of 5-HT2C function in rodents.

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Vilazodone has been reported to be an inhibitor of 5-hydoxytryptamine (5-HT) reuptake and a partial agonist at 5-HT1A receptors. Using [35S]GTPgammaS binding in rat hippocampal tissue, vilazodone was demonstrated to have an intrinsic activity comparable to the 5-HT1A receptor agonist 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT). Vilazodone (1-10 mg/kg p.

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Starting from a high throughput screening hit, a series of 3,4-dihydro-2H-benzoxazinones has been identified with both high affinity for the 5-HT(1A) receptor and potent 5-HT reuptake inhibitory activity. The 5-(2-methyl)quinolinyloxy derivative combined high 5-HT(1A/1B/1D) receptor affinities with low intrinsic activity and potent inhibition of the 5-HT reuptake site (pK(i)8.2).

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