Effect of ADHD medication in male C57BL/6J mice performing the rodent Continuous Performance Test.

RATIONALE: The rodent Continuous Performance Test (rCPT) is a novel rodent paradigm to assess attention and impulsivity that resembles the human CPT. This task measures the rodents' ability to discriminate between target and non-target stimuli. The effect of attention-deficit/hyperactivity disorder (ADHD) medication on rCPT performance in mice remains to be fully characterized. OBJECTIVE: To investigate the predictive validity of the mouse rCPT by studying the effects of ADHD medication methylphenidate, atomoxetine, amphetamine, guanfacine, and modafinil in four behavioral subgroups based on performance and impulsivity levels. METHODS: Two cohorts of male C57BL/6J mice were used, and the effect of treatment was tested in a variable stimulus duration probe. Performance and impulsive subgroups were made based on discriminability and percentage premature responses, respectively. RESULTS: Methylphenidate, atomoxetine, and amphetamine improved performance in the low-performing animals, with no effect in the high-performers. These improvements were a result of increased hit rate and/or decreased false-alarm rate. Furthermore, these drugs decreased percentage premature responses in the high-impulsive group. Methylphenidate, guanfacine, and modafinil increased premature responses in the low-impulsive group. Modafinil impaired performance in the high-performers by increasing false-alarm rate. CONCLUSION: The effect of ADHD treatment was dependent on baseline, as seen by increases in performance for the low-performers and decreases in impulsivity for the high-impulsive animals. These results agree with clinical data and may support the inverted U-shaped arousal-performance theory. The rCPT combined with behavioral separation into subgroups has high predictive validity, and our study is a step forward towards establishing the clinical translatability of the rCPT.

Photophysical dynamics of a binuclear Cu(i)-emitter on the fs to µs timescale, in solid phase and in solution.

Understanding subtle aspects of photophysical behavior is the key to design and synthesize new and improved luminescent materials. We contribute to this with an in-depth photophysical characterization of the binuclear copper complex Cu(i)-NHetPHOS-tris-m-tolylphosphine (1), a member of a recently established emitter class for ultra-efficient, printed organic light-emitting diodes (OLEDs). To this end we studied 1 in solution and in solid form, i.e. neat film and KBr-pellet, by means of femtosecond time-resolved transient absorption/reflectivity, time-correlated single photon counting (TCSPC), and nanosecond time-resolved step-scan FTIR spectroscopy. Using these methods, we explore the photoinduced dynamics from ultrafast Franck-Condon state deactivation until the decay of the luminescent states. Upon photoexcitation, we observed multiexponential dynamics in both solution (e.g. acetonitrile 0.8 ps, 59 ps, 3 ns, 11-13 ns) and in solid state (e.g. neat film 0.3 ps, 35 ps, 670 ps, 0.5-1 µs, 3.5-4.5 µs) with four to five time-constants that significantly depend on the type of sample. Quantum chemical calculations at the DFT level in combination with step-scan vibrational spectroscopy provided structural information about the electronic ground state S0 and the lowest lying excited state T1, and show that the latter is populated within 1 µs after photoexcitation. We found thermally activated delayed fluorescence (TADF) for this complex, which has been suggested to be the cause for its high efficiency in printed OLED devices. The results suggest that non-radiative processes, lowering the luminescence quantum yield in solution, are active on the ns to µs timescale.

Unravelling the mechanism of action of NS9283, a positive allosteric modulator of (α4)3(ß2)2 nicotinic ACh receptors.

BACKGROUND AND PURPOSE: Strong implications in major neurological diseases make the neuronal α4ß2 nicotinic ACh receptor (nAChR) a highly interesting drug target. In this study, we present a detailed electrophysiological characterization of NS9283, a potent positive allosteric modulator acting selectively at 3α:2ß stoichiometry of α2* and α4* nAChRs. EXPERIMENTAL APPROACH: The whole-cell patch-clamp technique equipped with an ultra-fast drug application system was used to perform electrophysiological characterization of NS9283 modulatory actions on human α4ß2 nAChRs stably expressed in HEK293 cells (HEK293-hα4ß2). KEY RESULTS: NS9283 was demonstrated to increase the potency of ACh-evoked currents in HEK293-hα4ß2 cells by left-shifting the concentration-response curve ~60-fold. Interestingly, this modulation did not significantly alter maximal efficacy levels of ACh. Further, NS9283 did not affect the rate of desensitization of ACh-evoked currents, was incapable of reactivating desensitized receptors and only moderately slowed recovery from desensitization. However, NS9283 strongly decreased the rate of deactivation kinetics and also modestly decreased the rate of activation. This resulted in a left-shift of the ACh window current of (α4)3(ß2)2 nAChRs in the presence of NS9283. CONCLUSIONS AND IMPLICATIONS: This study demonstrates that NS9283 increases responsiveness of human (α4)3(ß2)2 nAChR to ACh with no change in maximum efficacy. We propose that this potentiation is due to a significant slowing of deactivation kinetics. In summary, the mechanism of action of NS9283 bears high resemblance to that of benzodiazepines at the GABAA receptor and to our knowledge, NS9283 constitutes the first nAChR compound of this class.

[Freiburg intervention program for ambulatory therapy of obesity in childhood (FITOC)]. / Freiburger Interventionsprogramm zur ambulanten Therapie der Adipositas im Kindesalter (FITOC).

In this study we first try to answer the question, whether it is possible to make a successful treatment for obese children in an interdisciplinary program. Second it is asked whether a transfer of this program to further regions in Germany leads to comparable results. In FITOC children from the age of 8-11 years and over the 97. BMI-percentile are integrated in this program. The goals weight management, increased physical fitness and improvement of the cardiac risk profile are checked by weight, height, fasting blood serum, a standardized cycle ergometry and a medical measurement at the beginning, after treatment and at all check-ups. The recorded medical data show clearly that the intervention leads to a significant improvement in almost all checked parts. The successful treatment can be recorded after 8 months, likewise after 2.5 years as a long-term result. The further cornerstones of FITOC nutrition and psychology are not subject of this publication. In future the psychological part in FITOC will be evaluated by standardized inventories. The group from Düren has a success in therapy according to the definition of the program. Thereby it is shown that FITOC is extendable, if teams are trained intensively and the conditions are comparable. FITOC is able to treat obese children successfully over a long period of time. In consideration of the rising prevalence of obesity in childhood and the limited financial resources in health care this outpatient interdisciplinary program is an effective choice of treatment.

Amino acid residues of heparin cofactor II required for stimulation of thrombin inhibition by sulphated polyanions.

A variety of sulphated polyanions in addition to heparin and dermatan sulphate stimulate the inhibition of thrombin by heparin cofactor II (HCII). Previous investigations indicated that the binding sites on HCII for heparin and dermatan sulphate overlap but are not identical. In this study we determined the concentrations (IC50) of various polyanions required to stimulate thrombin inhibition by native recombinant HCII in comparison with three recombinant HCII variants having decreased affinity for heparin (Lys-173-->Gln), dermatan sulphate (Arg-189-->His), or both heparin and dermatan sulphate (Lys-185-->Asn). Pentosan polysulphate, sulphated bis-lactobionic acid amide, and sulphated bis-maltobionic acid amide resembled dermatan sulphate, since their IC50 values were increased to a much greater degree (>/=8-fold) by the mutations Arg-189-->His and Lys-185-->Asn than by Lys-173-->Gln (Gln and Lys-185-->Asn (>/=6-fold) than by Arg-189-->His (

Synthesis of apolipoprotein A-1 in pig brain microvascular endothelial cells.

In an approach toward the identification of hitherto unknown proteins involved in the function of the blood-brain barrier, we constructed a pig brain microvessel-derived cDNA library that is enriched in blood-brain barrier specific sequences by means of subtractive cloning. Sequence analysis of selected clones revealed that one of the cDNAs encoded porcine apolipoprotein (apo) A-1. The identity of apo A-1 mRNA was further confirmed by in vitro translation of RNA from brain microvascular endothelial cells and subsequent immunoprecipitation with an antibody against human apo A-1. We further investigated the expression of apo A-1 mRNA in several tissues and in endothelial cells of the pig. It is shown that cultured brain microvascular endothelial cells provide an in vitro model to study the expression and function of apo A-1 in the microvasculature of the brain.