Anna Partyka

Quinoline- and isoquinoline-sulfonamide derivatives of LCAP as potent CNS multi-receptor-5-HT1A/5-HT2A/5-HT7 and D2/D3/D4-agents: the synthesis and pharmacological evaluation.

Two series of arylpiperazinyl-alkyl quinoline-, isoquinoline-, naphthalene-sulfonamides with flexible (13-26) and semi-rigid (33-36) alkylene spacer were synthesized and evaluated for 5-HT(1A), 5-HT(2A), 5-HT(6), 5-HT(7) and selected compounds for D(2), D(3), D(4) receptors. The compounds with a mixed 5-HT and D receptors profile 16 (N-{4-[4-(3-chlorophenyl)-piperazin-1-yl]-butyl}-3-quinolinesulfonamide) and 36 (4-(4-{2-[4-(4-chloro-phenyl)-piperazin-1-yl]-ethyl}-piperidine-1-sulfonyl)-isoquinoline), displaying antagonistic activity at 5-HT(7), 5-HT(2A), D(2) postsynaptic sites, produced antidepressant-like effects in the forced swim test in mice and showed significant anxiolytic activity in the plus-maze test in rats. The lead compound 36, a multi-receptor 5-HT(2A)/5-HT(7)/D(2)/D(3)/D(4) agent, also displayed significant antipsychotic properties in the MK-801-induced hyperlocomotor activity in mice.

Antidepressant and antipsychotic activity of new quinoline- and isoquinoline- sulfonamide analogs of aripiprazole targeting serotonin 5-HT1A/5-HT2A/5-HT7 and dopamine D2/D3 receptors

A series of new quinoline- and isoquinoline-sulfonamide analogs of aripiprazole was synthesized to explore the influence of two structural features - replacement of ether/amide moiety with sulfonamide one, and localization of a sulfonamide group in the azine moiety. In contrast to aripiprazole, compound 33 (N-(3-(4-(2,3-dichlorophenyl)piperazin-1-yl)propyl)quinoline-7-sulfonamide) and 39 (N-(4-(4-(2,3-dichlorophenyl)piperazin-1-yl)butyl)isoquinoline-3-sulfonamide) displaying multireceptor 5-HT(1A)/5-HT(2A)/5-HT(7)/D(2)/D(3) profile, and behaving as 5-HT(1A) agonists, D(2) partial agonists, and 5-HT(2A)/5-HT(7) antagonists, produced significant antidepressant activity in FST in mice. On the other hand, their 4-isoquinolinyl analog 40 (N-(4-(4-(2,3-dichlorophenyl)piperazin-1-yl)butyl)isoquinoline-4-sulfonamide), with similar receptor binding and functional profile, additionally displayed remarkable antipsychotic properties in the MK-801-induced hyperlocomotor activity in mice.

Quinoline- and isoquinoline-sulfonamide analogs of aripiprazole: novel antipsychotic agents?

The introduction of typical antipsychotics over six decades ago signaled an important milestone in psychiatry. However, second-generation antipsychotics ameliorated the positive symptoms of schizophrenia but displayed limited effectiveness for the negative and cognitive symptoms. In addition, while the newer antipsychotics produced fewer motor side effects, the atypical antipsychotics still induced weight gain and endocrinopathies. In recent years, a third generation of antipsychotics was identified. Aripiprazole was the first approved drug acting as a D2 partial agonist/functionally selective ligand. This review presents the state of the development of novel antipsychotic dopaminergic and non-dopaminergic agents, supported by an overview of the compounds evaluated under advanced preclinical and clinical development (e.g., cariprazine and brexpiprazole). In line with the recent trends in the development of modern atypical antipsychotics, we present our strategic development of long-chain arylpiperazine-derived quinoline- and isoquinoline-sulfonamide displaying a multireceptor binding profile and partial D2 receptor agonism.

Arene- and quinoline-sulfonamides as novel 5-HT7 receptor ligands

Novel arene- and quinolinesulfonamides were synthesized using different solutions and a solid-support methodology, and were evaluated for their affinity for 5-HT(1A), 5-HT(2A), 5-HT(6), and 5-HT(7) receptors. Compound 54 (N-Ethyl-N-[4-(1,2,3,4,4a,5,6,7,8,8a-decahydroisoquinolin-2-yl)butyl]-8-quinolinesulfonamide) was identified as potent 5-HT(7) antagonist (K(i)=13 nM, K(B)=140 nM) with good selectivity over 5-HT(1A), 5-HT(2A), 5-HT(6) receptors. In the FST in mice, it reduced immobility in a manner similar to the selective 5-HT(7) antagonist SB-269970.

Pharmacological evaluation of the anxiolytic-like effects of EMD 386088, a partial 5-HT6 receptor agonist, in the rat elevated plus-maze and Vogel conflict tests.

The 5-HT6 is one of the most recent additions to the 5-HT receptor family. Its pharmacological profile and anatomical distribution is suggestive of a putative role in mood disorders. Most of preclinical evidence suggests an anxiolytic-like action of 5-HT6 receptor antagonists. Evaluation the anxiolytic-like effects of EMD 386088, a partial 5-HT6receptor agonist, and its putative mechanism of action in rats. EMD 386088, administered intraperitoneally at a dose of 2.5 mg/kg evoked specific anxiolytic-like activity in the automated version of the conflict drinking Vogel and the elevated plus-maze tests visible by increasing all parameters indicating a potential anti-anxiety effect. Its activity was blocked by the selective 5-HT6 receptor antagonist SB 271046, but not by the selective GABAA/benzodiazepine receptor antagonist flumazenil. EMD 386088 did not intensify an anxiolytic-like effect produced by diazepam in the elevated plus-maze test. These findings suggest that EMD 386088, a 5-HT6 receptor agonist, produces anxiolytic-like activity after systemic administration which may result from direct stimulation of 5-HT6 receptors.

Antidepressant- and Anxiolytic-Like Effects of New Dual 5-HT1A and 5-HT7 Antagonists in Animal Models

The aim of this study was to further characterize pharmacological properties of two phenylpiperazine derivatives: 1-{2-[2-(2,6-dimethlphenoxy)ethoxy]ethyl}-4-(2-methoxyphenyl)piperazynine hydrochloride (HBK-14) and 2-[2-(2-chloro-6-methylphenoxy)ethoxy]ethyl-4-(2- methoxyphenyl)piperazynine dihydrochloride (HBK-15) in radioligand binding and functional in vitro assays as well as in vivo models. Antidepressant-like properties were investigated in the forced swim test (FST) in mice and rats. Anxiolytic-like activity was evaluated in the four-plate test in mice and elevated plus maze test (EPM) in rats. Imipramine and escitalopram were used as reference drugs in the FST, and diazepam was used as a standard anxiolytic drug in animal models of anxiety. Our results indicate that HBK-14 and HBK-15 possess high or moderate affinity for serotonergic 5-HT2, adrenergic α1, and dopaminergic D2 receptors as well as being full 5-HT1A and 5-HT7 receptor antagonists. We also present their potent antidepressant-like activity (HBK-14—FST mice: 2.5 and 5 mg/kg; FST rats: 5 mg/kg) and (HBK-15—FST mice: 1.25, 2.5 and 5 mg/kg; FST rats: 1.25 and 2.5 mg/kg). We show that HBK-14 (four-plate test: 2.5 and 5 mg/kg; EPM: 2.5 mg/kg) and HBK-15 (four-plate test: 2.5 and 5 mg/kg; EPM: 5 mg/kg) possess anxiolytic-like properties. Among the two, HBK-15 has stronger antidepressant-like properties, and HBK-14 displays greater anxiolytic-like activity. Lastly, we demonstrate the involvement of serotonergic system, particularly 5-HT1A receptor, in the antidepressant- and anxiolytic-like actions of investigated compounds.

Antidepressant- and anxiolytic-like activity of 7-phenylpiperazinylalkyl-1,3-dimethyl-purine-2,6-dione derivatives with diversified 5-HT1A receptor functional profile

Continuing our earlier study in a group of purine-2,6-dione derivatives of long chain arylpiperazines (LCAPs), a series of 8-unsubstituted 7-phenylpiperazin-4-yl-alkyl (4-14) and 7-tetrahydroisoquinolinyl-alkyl (15-17) analogues were synthesized and their serotonin 5-HT1A, 5-HT2A, 5-HT6, 5-HT7 and dopamine D2 receptor affinities were determined. The study allowed us to identify some potent 5-HT1A receptor ligands with additional moderate affinity for 5-HT2A, 5-HT7 and dopamine D2 receptors. Compounds 9, 12, 13 and 14, with the highest 5HT1A receptor affinity, were selected for further functional in vivo studies and behavioural evaluation of antidepressant- and antianxiety-like activity. Compounds 9, 12 and 13 showed features of agonists of pre- and/or post-synaptic 5-HT1A receptors, whereas 14 was classified as an antagonist of postsynaptic sites. Moreover, derivatives 9 and 14 acted as antagonists of 5-HT2A receptors. In behavioural studies, compounds 9 and 13 showed antidepressant-like activity in the mouse forced swim test, and their effects were similar or stronger than those of imipramine. Compounds 9, 12 and 14 displayed potential anxiolytic-like properties in the mouse four-plate test, similar or even greater than those of the reference anxiolytic drug, diazepam.

Partial agonist efficacy of EMD386088, a 5-HT6 receptor ligand, in functional in vitro assays

BACKGROUND Over recent years, the 5-hydroxytryptamine6 (5-HT6) receptor has emerged as a promising molecular target which interacts with several central nervous system acting drugs. In animal models, both agonists and antagonists of this receptor exhibit equivalent potency and efficacy as potential antidepressants, anxiolytics and anti-obesity or anti-dementia drugs. EMD386088 (5-chloro-2-methyl-3-(1,2,3,6-tetrahydro-4-pyridinyl)-1H-indole hydrochloride) has been described as a high affinity 5-HT6 receptor ligand with a full agonist activity and with moderate affinity for 5-HT3 sites. METHODS We have extended these data by broadening its profile for other, not yet tested, monoaminergic, GABA(A), opioid μ receptors and serotonin transporter (SERT) and we have conducted functional in vitro assays; i.e., measurement of cAMP by homogeneous TR-FRET immunoassay and HTRF method made by CEREP as well as aequorin-based calcium flux assay. RESULTS In two in vitro models based on cAMP formation, maximal efficacy values for EMD386088 were 65 and 31%, for in house and CEREP experiments, respectively. In a model based on calcium response, the studied compound showed 46% of maximal serotonin (5-HT) signal. EMD386088 antagonizes 5-HT response in increasing concentrations from 10(-9) to 10(-6) M. CONCLUSIONS The present in vitro findings confirm that EMD386088 is a selective 5-HT6 receptor ligand with moderate affinity for 5-HT3 sites only and it behaves as a potent partial agonist of 5-HT6 receptor with varying levels of agonist intrinsic activity, depending on a method employed. In view of these results, caution is recommended in the interpretation of pharmacological in vivo studies with EMD386088.

Novel 1H-Pyrrolo[3,2-c]quinoline Based 5-HT6 Receptor Antagonists with Potential Application for the Treatment of Cognitive Disorders Associated with Alzheimer’s Disease

Modulators of the serotonin 5-HT6 receptor (5-HT6R) offer a promising strategy for the treatment of the cognitive deficits that are associated with dementia and Alzheimers disease. Herein, we report the design, synthesis, and characterization of a novel class of 5-HT6R antagonists that is based on the 1H-pyrrolo[3,2-c]quinoline core. The most active compounds exhibited comparable binding affinity to the reference compound, SB-742457, and markedly improved selectivity. Lead optimization led to the identification of (S)-1-[(3-chlorophenyl)sulfonyl]-4-(pyrrolidine-3-yl-amino)-1H-pyrrolo[3,2-c]quinoline (14) (Ki = 3 nM and Kb = 0.41 nM). Pharmacological characterization of the 5-HT6Rs constitutive activity at Gs signaling revealed that 14 behaved as a neutral antagonist, while SB-742457 was classified as an inverse agonist. Both compounds 14 and SB-742457 reversed phencyclidine-induced memory deficits and displayed distinct procognitive properties in cognitively unimpaired animals (3 mg/kg) in NOR tasks. Compounds 14 and SB-742457 were also active in the Vogel test, yet the anxiolytic effect of 14 was 2-fold higher (MED = 3 mg/kg). Moreover, 14 produced, in a 3-fold higher dose (MED = 10 mg/kg), antidepressant-like effects that were similar to those produced by SB-742457 (MED = 3 mg/kg). Together, these data suggest that the 4-(pyrrolidine-3-yl-amino)-1H-pyrrolo[3,2-c]quinoline scaffold is an attractive molecular framework for the development of procognitive agents. The results are promising enough to warrant further detailed mechanistic studies on the therapeutic potential of 5-HT6R antagonists and inverse agonists for the treatment of cognitive decline and depression/anxiety symptoms that are comorbidities of Alzheimers disease.

New 8-aminoalkyl derivatives of purine-2,6-dione with arylalkyl, allyl or propynyl substituents in position 7, their 5-HT1A, 5-HT2A, and 5-HT7 receptor affinity and pharmacological evaluation

BACKGROUND Our previous studies in a group of arylpiperazine derivatives of 1,3-dimethyl-3,7-dihydro-purine-2,6-diones, aimed at chemical diversification of the purine-2,6-dione by introduction of hydrophobic substituent in a 7- or 8- position or elongation of the linker length between arylpiperazine and purine core, allowed a selection of potent 5-HT1A, 5-HT2A and 5-HT7 receptor ligands displaying anxiolytic and antidepressant properties. Continuing our research in this field, in the present studies we designed a new series of 8-aminoalkylamino (15-35) and 8-arylpiperazinylpropoxy (36-42) derivatives of 7-substituted 1,3-dimethyl-3,7-dihydropurine-2,6-dione as potential 5-HT1A, 5-HT2A and 5-HT7 receptor ligands with potential psychotropic activity. METHODS Radioligand binding assays were employed for determining the affinity and the selectivity profile of the synthesized compounds for native 5-HT1A, 5-HT2A, and cloned 5-HT6 and 5-HT7 receptors. The functional activity of the selected compounds at 5-HT1A and 5-HT2A receptors was tested in the commonly used in vivo models. Antidepressant and anxiolytic properties were evaluated in the forced swim (FST) and the four-plate test (FPT) in mice, respectively. RESULTS Among the evaluated series, selected 7-benzyl-8-((4-(4-(3-chlorophenyl)piperazin-1-yl)butyl)amino)-1,3-dimethyl-1H-purine-2,6(3H,7H)-dione (21), a mixed 5-HT1A/5-HT2A/5-HT7 receptor ligand, produced an antidepressant-like effect in FST, and exerted anxiolytic-like activity in FPT. Another pharmacologically evaluated compound 42 (a mixed 5-HT1A/5-HT7 ligand) slightly, but non-significantly attenuated the immobility time of mice in FST and was devoid of activity in FPT. CONCLUSIONS Study revealed advantage of mixed 5-HT1A/5-HT2A/5-HT7 receptor ligands over 5-HT1A/5-HT7 agents to display antidepressant- and anxiolytic-like activity. Modification of arylalkyl/allyl substituent in position 7 of purine-2,6-dione opens possibility for designing new 5-HT ligands with preserved p electron system and lower molecular weight.