CyPPA, a Positive SK3/SK2 Modulator, Reduces Activity of Dopaminergic Neurons, Inhibits Dopamine Release, and Counteracts Hyperdopaminergic Behaviors Induced by Methylphenidate1

Dopamine (DA) containing midbrain neurons play critical roles in several psychiatric and neurological diseases, including schizophrenia and attention deficit hyperactivity disorder, and the substantia nigra pars compacta neurons selectively degenerate in Parkinson’s disease. Pharmacological modulation of DA receptors and transporters are well established approaches for treatment of DA-related disorders. Direct modulation of the DA system by influencing the discharge pattern of these autonomously firing neurons has yet to be exploited as a potential therapeutic strategy. Small conductance Ca2+-activated K+ channels (SK channels), in particular the SK3 subtype, are important in the physiology of DA neurons, and agents modifying SK channel activity could potentially affect DA signaling and DA-related behaviors. Here we show that cyclohexyl-[2-(3,5-dimethyl-pyrazol-1-yl)-6-methyl-pyrimidin-4-yl]-amine (CyPPA), a subtype-selective positive modulator of SK channels (SK3 > SK2 > > > SK1, IK), decreased spontaneous firing rate, increased the duration of the apamin-sensitive afterhyperpolarization, and caused an activity-dependent inhibition of current-evoked action potentials in DA neurons from both mouse and rat midbrain slices. Using an immunocytochemically and pharmacologically validated DA release assay employing cultured DA neurons from rats, we show that CyPPA repressed DA release in a concentration-dependent manner with a maximal effect equal to the D2 receptor agonist quinpirole. In vivo studies revealed that systemic administration of CyPPA attenuated methylphenidate-induced hyperactivity and stereotypic behaviors in mice. Taken together, the data accentuate the important role played by SK3 channels in the physiology of DA neurons, and indicate that their facilitation by CyPPA profoundly influences physiological as well as pharmacologically induced hyperdopaminergic behavior

3-Alkyl- and 3-amido-isothiazoloquinolin-4-ones as ligands for the benzodiazepine site of GABA(A) receptors.

Based on a pharmacophore model of the benzodiazepine binding site of the GABA(A) receptors, developed with synthetic flavones and potent 3-carbonylquinolin-4-ones, 3-alkyl- and 3-amido-6-methylisothiazoloquinolin-4-ones were designed, prepared and assayed. The suggestion that the interaction between the hydrogen bond donor site H1 with the 3-carbonyl oxygen in 3-carbonylquinolin-4-ones can be replaced by an interaction between H1 and N-2 in the isothiazoloquinolin-4-ones, was confirmed. As with the 3-carbonylquinolin-4-ones, the length of the chain in position 3 is critical for an efficient interaction with the lipophilic pockets of the pharmacophore model. The most potent 3-alkyl derivative, 3-pentyl-6-methylisothiazoloquinolin-4-one, has an affinity (K(i) value) for the benzodiazepine binding site of the GABA(A) receptors of 13nM. However, by replacing the 3-pentyl with a 3-butyramido group an even more potent compound was obtained, with a K(i) value of 2.8nM, indicating that the amide function facilitates additional interactions with the binding site

Opgørelse af passagerregularitet i S-tog

Hidtil er regularitet (aflyste tog) og punktlighed (forsinkede tog) i DSB S-TOG A/S alene opgjort på togniveau. Imidlertid har DSB S-TOG længe ønsket også at kunne opgøre passagerregulariteten, det vil sige de forsinkelser som passagerne oplever i form af samlet forsinkelse på deres tur. Dette giver dels et bedre planlægningsgrundlag for DSB S-TOG, dels muliggør det en mulig mere detaljeret afrapportering af regularitet i forhold til Trafikministeriet. Passagerers regularitet adskiller sig fra tog regularitet af en række årsager; Antallet af passagerer per tog varierer – typisk er passager intensiteten større i myldretiden, hvor togtætheden og derved også forsinkelserne er hyppigere. Hvis passagererne skifter mellem linier, vil en forsinkelse betyde mindre, såfremt næste linie alligevel nås, mens den vil betyde mere, hvis korrespondancen mistes. Dette overses ved opgørelse af togregularitet. I særlige tilfælde kan passagerne opnå en bedre korrespondance i et irregulært system. I dele af nettet vil passagerer på korte ture ofte blot kunne tage en anden linie, såfremt hele systemet er forsinket. Dette gælder i særlig grad ”røret” fra Hovedbanegården til Østerport. ANVENDTE METODER, ANALYSER OG FREMGANGSMÅDEIdéen med projektet er, at passagerregulariteten opgøres ved en beregning af passagernes rutevalg i den realiserede køreplan. Dette sammenlignes med et optimalt rutevalg i referencekøreplanen (f.eks. den annoncerede publikumskøreplan). Opgørelsen skal gennemføres dagligt, hvorfor et yderligere krav til modellen er, at den har en rimelig regnetid. Som reference blev der implementeret en traditionel rutevalgsmodel, hvor ruterne beregnes ud fra fuld information (allerede fra det øjeblik en rute starter, er der taget hensyn til evt. forsinkelser der måtte forekomme på et senere tidspunkt under rejsen). Dette resulterer i en optimistisk (for lav) opgørelse af passagerforsinkelserne. Som et alternativ er der implementeret en rutevalgsmodel, der resulterer i en pessimistisk opgørelse. Løst formuleret, beskriver modellen, at de rejsende planlægger deres rejse i forhold til en reference-køreplan (f.eks. publikumskøreplanen), og så vidt muligt forsøger at gennemføre rejsen som planlagt. For at lette formuleringen af rutevalgsmodellen, betragter den særskilt følgende to situationer: Ingen skift er planlagt Skift er planlagt DET EMPIRISKE GRUNDLAGModellen er implementeret, så den kan køre på DSB S-TOGS datawarehouse. I praksis betyder det, at den kan køres om natten efter at dagens køreplan er realiseret. Forsinkelser og aflysninger registreres i datawarehouset, hvorfor beregningen foretages på den sande realiserede køreplan. Resultatet er således en daglig opgørelse over passagerregularitet. Som input benyttes indtil videre Østtællingens stationsmatrix, hvor efterspørgslen inden for det enkelte tidsinterval i Østtællingen fordeles uniformt ud på mindre tidsintervaller – f.eks. 5 min. Ønskede afgangstider for passagerer simuleres derefter tilfældigt inden for dette interval. Differencen mellem ønsket afgangstidspunkt og realiseret afgangstidspunkt opgøres som ”skjult ventetid”. RESULTATERArbejdet viser først og fremmest at det er muligt at modellere passagerregularitet på et detaljeringsniveau, hvor alle afgange og vognløb modelleres. Artiklen viser eksempler på sådanne opgørelser, og diskuterer resultaterne heraf. Det vises, at passagerregulariteten – som forventet – er ringere, når man ikke blot benytter det optimistiske rutevalg (fuld information, nytteoptimering), men i stedet først lader passagererne ændre planlagte ruter, når de selv oplever forsinkelser. Der er forholdsvis stor forskel på resultatet, afhængig af hvor hurtig reaktion passagerne viser i forhold til forsinkede køreplaner

Azaflavones compared to flavones as ligands to the benzodiazepine binding site of brain GABA(A) receptors.

A series of azaflavone derivatives and analogues were prepared and evaluated for their affinity to the benzodiazepine binding site of the GABA(A) receptor, and compared to their flavone counterparts. Three of the compounds, the azaflavones 9 and 12 as well as the new flavone 13, were also assayed on GABA(A) receptor subtypes (alpha(1)beta(3)gamma(2s), alpha(2)beta(3)gamma(2s), alpha(4)beta(3)gamma(2s) and alpha(5)beta(3)gamma(2s)), displaying nanomolar affinities as well as selectivity for alpha1- versus alpha2- and alpha3-containing receptors by a factor of between 14 and 26

Triazoloquinazolinediones as novel high affinity ligands for the benzodiazepine site of GABA(A) receptors

Based on a pharmacophore model of the benzodiazepine-binding site of GABA(A) receptors, a series of 2-aryl-2,6-dihydro[1,2,4]triazolo[4,3-c]quinazoline-3,5-diones (structure type I) were designed, synthesized, and identified as high-affinity ligands of the binding site. For several compounds, K(i) values of around 0.20nM were determined. They show a structural resemblance with the previously described 2-phenyl-2H-pyrazolo[4,3-c]quinolin-3(5H)-ones (II) and 2-phenyl-[1,2,4]triazolo[1,5-a]quinoxalin-4(5H)-one (III). The 9-bromo substituted compounds 8a-d were prepared in an 8-step synthesis in an overall yield of approximately 40%, and a library of 9-substituted analogues was prepared by cross-coupling reactions. Compound 8e, 21, 22, and 24 were tested on recombinant rat α(1)β(3)γ(2), α(2)β(3)γ(2), α(3)β(3)γ(2), and α(5)β(3)γ(2) subtypes, and displayed selectivity for the α(1)β(3)γ(2) isoform