Substituted thieno[2,3-d]pyrimidines as adenosine A2A receptor antagonists.

A novel series of benzyl substituted thieno[2,3-d]pyrimidines were identified as potent A2A receptor antagonists. Several five- and six-membered heterocyclic replacements for the optimized methylfuran were explored. Select compounds effectively reverse catalepsy in mice when dosed orally.

Design and characterization of optimized adenosine A2A/A1 receptor antagonists for the treatment of Parkinson's disease.

The design and characterization of two, dual adenosine A(2A)/A(1) receptor antagonists in several animal models of Parkinson's disease is described. Compound 1 was previously reported as a potential treatment for Parkinson's disease. Further characterization of 1 revealed that it was metabolized to reactive intermediates that caused the genotoxicity of 1 in the Ames and mouse lymphoma L51784 assays. The identification of the metabolites enabled the preparation of two optimized compounds 13 and 14 that were devoid of the metabolic liabilities associated with 1. Compounds 13 and 14 are potent dual A(2A)/A(1) receptor antagonists that have excellent activity, after oral administration, across a number of animal models of Parkinson's disease including mouse and rat models of haloperidol-induced catalepsy, mouse and rat models of reserpine-induced akinesia, and the rat 6-hydroxydopamine (6-OHDA) lesion model of drug-induced rotation.

Optimization of arylindenopyrimidines as potent adenosine A(2A)/A(1) antagonists.

Two reactive metabolites were identified in vivo for the dual A(2A)/A(1) receptor antagonist 1. Two strategies were implemented to successfully mitigate the metabolic liabilities associated with 1. Optimization of the arylindenopyrimidines led to a number of amide, ether, and amino analogs having comparable in vitro and in vivo activity.

Reduction of dominant or submissive behaviors as models for antimanic or antidepressant drug testing: technical considerations.

Technical variants of mania and depression models that were based on dominant-submissive relationships (DSR) have been analyzed and compared in the present paper. In these paradigms, one animal of a pair developed the behavioral trait of dominance while the other submissiveness in a food competition test after repeated interactions in a specially designed apparatus. Data collection methods and timelines have been compared in variants of the DSR-based models. In addition, different selection criteria to assign dominant or submissive status to animals and two different scoring systems were evaluated. The importance of the selection criteria for DSR stability has been emphasized. Our data showed that (1) only animals selected with the strict criteria form clear dominant and submissive relationships that hold throughout the study period, (2) submissive animals were influenced by fluoxetine and dominant animals were influenced by sodium valproate similarly in pairs scored by human observer and by a video-tracking system. These studies indicate that the model variant using stringent selection criteria and automatic scoring was the most reliable for use in depression-related studies.

Assessing activity onset time and efficacy for clinically effective antidepressant and antimanic drugs in animal models based on dominant-submissive relationships.

There is confusion in the literature on the measurement of the drug activity onset time (AOT) for both clinical and non-clinical studies of antidepressant and antimanic drugs. The questions asked are: How often and at which time points should drug effects be measured? At what level of a drug effect should AOT be determined? Is the placebo (control) effect important for consideration of drug AOT? This paper reviews approaches taken to answer these questions and to assess drug therapeutic AOT. The first part of the paper is devoted to a review of methods used in clinical trials with depression as an indication. The second part is focused on approaches taken in animal models of depression and how they could help in assessing drug AOT. Finally, a summary of pharmacological values on which the AOT depends is presented and a new statistical approach to data analysis method proposed. The allied experimental design for pre-clinical and clinical studies may help to characterize and differentiate AOT for available and new generation of antidepressants and antimanic drugs.

Levels of mRNA coding for alpha-, beta-, and gamma-synuclein in the brains of newborn, juvenile, and adult rats.

Synucleins are proteins known for their malfunction in a group of illnesses called synucleopathies, which includes Alzheimer's and Parkinson's disease. To learn more about the role of synucleins in the CNS, we have studied levels of message coding for alpha-, beta-, and gamma-synuclein using quantitative RT-PCR. Levels of synuclein mRNAs were studied in the cerebral cortex (left and right, anterior and posterior), hippocampus, striatum, and cerebellum, obtained from 5-d-old (newborn), 1-mo (juvenile)-, and 6-, and 9-mo (adult)-old rats. The mRNA levels for all synucleins varied significantly among structures. The rank order of mRNA levels in different structures was cortex = hippocampus > striatum > cerebellum for alpha-synuclein; cortex > hippocampus = cerebellum > striatum for beta-synuclein; and hippocampus = striatum > cortex = cerebellum for gamma-synuclein. There was significant effect of age for mRNA levels for all synucleins. The dynamics of these changes were different depending on type of synuclein and brain structure. Levels of mRNA for alpha-synuclein were significantly reduced with age in all structures except hippocampus. For beta- and gamma-synuclein, levels increased significantly only in the cerebral cortex and only from 5 d to 1 mo of age. In contrast, gamma-synuclein levels in the cerebellum were very high at 5 d and significantly reduced at 1 mo of age. The revealed pattern and dynamics of changes in the levels of mRNA coding for synucleins would support the conclusion for an important role of these molecules during development and the aging process.

Diarylacetylene piperidinyl amides as novel anxiolytics.

N-Phenyl-2-[1-[3-(2-pyridinylethynyl)benzoyl]-4-piperidine]acetamide (9) and related piperidine acetamide derivatives have good oral activity in the elevated plus maze, an animal model predictive of clinical efficacy for the treatment of anxiety. Modest affinity was observed for the neurokinin NK-1 and 2 receptors, which are known to be involved in the regulation of mood and emotion.

Reduction of Submissive Behavior Model for antidepressant drug activity testing: study using a video-tracking system.

Submissive animals can be defined in a food competition test as spending significantly less time on the feeder than their dominant partners. Using observer-based scoring in the Reduction of Submissive Behavior Model, submissive behavior in rats and mice has been previously shown to be sensitive and selective to antidepressant treatment. In this paper, we report the use of automated scoring by a multiple-subject video-tracking system to record similar effects of antidepressants on rat submissive behavior. Automated scoring enabled the observation of four pairs of rats during each 5-min experimental session (one set) and immediate switching to the observation of the next four pairs of animals. Studies were conducted to confirm our previous results with imipramine and fluoxetine that were obtained with manual scoring, and to extend those results to studies with other drugs, including the antidepressant maprotiline and the delta-opioid antagonist naltrindole, which is not known to have antidepressant activity. As in previous studies, treatment of the submissive animal for 5 weeks with imipramine (20 mg/kg) or fluoxetine (10 mg/kg) significantly reduced submissive behavior, with a delayed onset of antidepressant effect that was dependent on drug dose. Maprotiline (10 and 20 mg/kg), like imipramine or fluoxetine and in contrast to naltrindole, strongly reduced rat submissive behavior, further demonstrating the selectivity of this test for antidepressant activity.

The application of nuclear magnetic resonance-based metabonomics to the dominant-submissive rat behavioral model.

Nuclear magnetic resonance (NMR) methods were used to study whether there are differences in the urine content between behaviorally distinct groups of rats: dominant and submissive. The dominant-submissive relationships (DSRs) were established in rat pairs competing for access to the feeder filled with sweetened milk. Dominant rats spend significantly longer amounts of time at the feeder than do their submissive partners. During a 2-week period, rats were tested for the DSR. At the end of the second week, behavioral groups of rats were selected and urine was collected during a 3.5-h time period. Principal component analysis revealed a metabolite from milk sugar, galactose, as a discriminating factor between rats classified as dominant and those classified as submissive. Measurements of galactose showed that the amount present in the urine correlated with the time spent in the feeder zone, thereby supporting the time criterion established for the DSR model.

5-ethoxymethyl-7-fluoro-3-oxo-1,2,3,5-tetrahydrobenzo[4,5]imidazo[1,2a]pyridine-4-N-(2-fluorophenyl)carboxamide (RWJ-51204), a new nonbenzodiazepine anxiolytic.

5-ethoxymethyl-7-fluoro-3-oxo-1,2,3,5-tetrahydrobenzo[4,5] imidazo[1,2a]pyridine-4-N-(2-fluorophenyl)carboxamide) (RWJ-51204) binds selectively and with high affinity (K(i) = 0.2-2 nM) to the benzodiazepine site on GABA(A) receptors. Considering the GABA shift, the intrinsic modulatory activity of RWJ-51204 is lower than that of full agonist anxiolytics (lorazepam, diazepam, alprazolam, and clonazepam) but similar to partial agonists (bretazenil, abecarnil, panadiplon, and imidazenil). RWJ-51204 was orally active in anxiolytic efficacy tests; pentylenetetrazole induced seizure inhibition in mice (ED(50) = 0.04 mg/kg), Vogel conflict in rats (ED(50) = 0.36 mg/kg), elevated plus-maze in rats (minimal effective dose = 0.1 mg/kg), and conflict in squirrel monkeys (ED(50) = 0.49 mg/kg). RWJ-51204 attenuated chlordiazepoxide-induced motor impairment in mice. Usually, RWJ-51204 was more potent than reference anxiolytics in rodent efficacy tests but less potent in monkey conflict. Usually, the slope of the dose-response lines for RWJ-51204 was more shallow than the full agonist anxiolytics but steeper than partial agonists in efficacy tests but typically shallow in tests for central nervous system side effects. In monkeys only mild or moderate sedation was observed at doses equivalent to 20 or 40 times the anxiolytic ED(50). RWJ-51204 fits into the partial agonist class of GABA(A) receptor modulators. In conclusion, RWJ-51204 exhibits a profile in in vitro experiments and in animal models, in mice and monkeys (but not in rats), suggesting that it has a profile of anxiolytic activity associated with less sedation, motor impairment, or muscle relaxation than currently available GABA(A) receptor modulators, i.e., the benzodiazepines.