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The aim of this study was to explore the α 1 -adrenoceptor-independent mechanisms involved in the vasorelaxant properties of two non-quinazoline α 1 -adrenoceptors antagonists (MH-76 and MH-79). Endothelium intact and endothelium denuded rat aorta was contracted with 1 μM phenylephrine to plateau, and the vasodilatory effect of MH-76 and MH-79 was examined in the absence or presence of inhibitors of the different signal transduction pathways. cGMP concetration was measured in rat aorta (enzyme immunoassay kit). In human aortic endothelial cells (HAEC) NO production was examined using a DAF-FM DA fluorescent indicator, whereas in human aortic smooth muscle cells the influence of the title compounds on K + efflux was evaluated. The vasorelaxant effect of MH-76 and MH-79 was attenuated by endothelium removal, N ω -Nitro-l-arginine methyl ester (L-NAME) and 1H-[1,2,4]Oxadiazolo[4,3-a]quinoxalin-1-one (ODQ) pretreatment to the level characteristic for α 1 -adrenoreceptor blocking activity. In addition, the MH-76 and MH-79 induced relaxation was reduced by K + channels blockers. In endothelium intact rat aorta, MH-76 and MH-79 caused an increase in cGMP level, whereas in HAEC they increased NO generation. In contrast, the reference, quinazoline based α 1 -antagonist prazosin, did not influence NO production. Our findings suggest that the mechanisms underlying the vasodilatory properties of non-quinazoline based α 1 -adrenoceptors antagonists MH-76 and MH-79 involve not only α 1 -adrenoceptor blocking activity but also the activation of the endothelial NO-cGMP signalling pathway and the subsequent opening of K + channels. Our studies show that such double mechanism of action is superior to pure α 1 -adrenoceptor blockade, and may be considered as a promising alternative for the prevention and treatment of cardiovascular diseases., (Copyright © 2018 Elsevier Masson SAS. All rights reserved.)

Serotonin (5-HT) and adrenaline acting at platelet 5-HT 2A -serotoninergic and α 2 -adrenergic receptors are involved in platelet aggregation. We have evaluated the antagonistic potency at 5-HT 2A , α 2A -, and α 2B -adrenoceptors as well as an anti-aggregation effect of aroxyalkyl derivatives of 2-methoxyphenylpiperazine and compared them with ketanserin, sarpogrelate, prazosin, yohimbine and ARC239 (2-[2-[4-(o-methoxyphenyl)-piperazin-1-yl]-ethyl]-4,4-dimethyl-1,3-(2H,4H)-isoquinolindione). Functional bioassays at cells expressing human receptors, revealed studied compounds to be moderate antagonists of 5-HT 2A and α 2 -adrenoceptors, with around 2-7 times stronger antagonistic effect at α 2B subtype than α 2A subtype. Further, studied compounds inhibited 5-HT 2A -mediated contraction in isolated rat aortic rings and 5-HT vasopressor response in rat in vivo. Studied compounds inhibited collagen stimulated whole rat blood aggregation with compound MH-77 (1-[(2,3-dimethylphenoxy)propyl]-4-(2-methoxyphenyl)piperazine hydrochloride) being more potent than sarpogrelate or yohimbine. They also inhibited 5-HT/adrenaline-, amplified ADP- or collagen- induced platelet aggregation. Simultaneous, moderate blockade of 5-HT 2A serotonin and α 2 -adrenergic receptors is effective in preventing aggregation and could constitute alternative antiplatelet therapy., (Copyright © 2017 Elsevier B.V. All rights reserved.)

In the search for potential psychotropic agents, a new series of 3,7-dimethyl- and 1,3-dimethyl-8-alkoxypurine-2,6-dione derivatives of arylpiperazines, perhydroisoquinolines, or tetrahydroisoquinolines with flexible alkylene spacers (5-16 and 21-32) were synthesized and evaluated for 5-HT 1A /5-HT 7 receptor affinities as well as PDE4B1 and PDE10A inhibitory properties. The 1-(4-(4-(2-hydroxyphenyl)piperazin-1-yl)butyl)-3,7-dimethyl-8-propoxypurine-2,6-dione (16) and 7-(2-hydroxyphenyl)piperazinylalkyl-1,3-dimethyl-8-ethoxypurine-2,6-diones (31 and 32) as potent dual 5-HT 1A /5-HT 7 receptor ligands with antagonistic activity produced an antidepressant-like effect in the forced swim test in mice. This effect was similar to that produced by citalopram. All the tested compounds were stronger phosphodiesterase isoenzyme inhibitors than theophylline and theobromine. The most potent compounds, 15 and 16, were characterized by 51 and 52% inhibition, respectively, of PDE4B1 activity at a concentration of 10 -5  M. Concerning the above findings, it may be assumed that the inhibition of PDE4B1 may impact on the signal strength and specificity resulting from antagonism toward the 5-HT 1 and 5-HT 7 receptors, especially in the case of compounds 15 and 16. This dual receptor and enzyme binding mode was analyzed and explained via molecular modeling studies., (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

A series of new 7-arylpiperazinylalkyl-1,3-dimethyl-purine-2,6-dione derivatives with diversified 8-amino substituent in 8 position was synthesized and their 5-HT1A, 5-HT2A, 5-HT6, 5-HT7, and D2 receptor affinities were determined. The binding study allowed identifying some potent 5-HT1A/5-HT2A/5-HT7/D2 ligands. The most interesting because of their multireceptor profile were 8-piperidine (30-35) and 8-dipropylamine (45-47) analogs with four and five carbon aliphatic linkers. The selected compounds 24, 31, 34, 39, 41, 43, 45, and 46 in the functional in vitro evaluation for all targeted receptors showed significant partial D2 agonist, partial 5-HT1A agonist, and 5-HT2A antagonist properties. The advantageous in vitro affinity of compound 34 for 5-HT1A and D2 receptors has been explained by means of molecular modeling, taking into consideration its partial agonist activity towards the latter one. In behavioral studies, compounds 32 and 34 revealed antipsychotic-like properties, significantly decreasing d-amphetamine-induced hyperactivity in mice.

Xanthone derivatives possess many biological properties, including neuroprotective, antioxidant or antidepressant-like. In this study we aimed to investigate antidepressant- and anxiolytic-like properties of a new xanthone derivative - 6-methoxy-4-[4-(2-methoxyphenyl)piperazin-1-yl]-9H-xanthen-9-one (HBK-7), as well as its possible mechanism of action, and the influence on cognitive and motor function. HBK-7 in our earlier studies showed high affinity for serotonergic 5-HT1A receptor. We determined the affinity of HBK-7 for CNS receptors and transporters using radioligand assays and examined its intrinsic activity towards 5-HT1A receptor. We evaluated antidepressant- and anxiolytic-like activity of HBK-7 in the mouse forced swim test, and four-plate test, respectively. We examined the influence on locomotor activity in mice to determine if the effect observed in the forced swim test was specific. We used step-through passive avoidance and rotarod tests to evaluate the influence of HBK-7 on cognitive and motor function, respectively. HBK-7 showed moderate affinity for dopaminergic D2 receptor and very low for serotonergic 5-HT2A, adrenergic α2 receptors, as well as serotonin transporter. Functional studies revealed that HBK-7 was a 5-HT1A receptor antagonist. HBK-7 (10mg/kg) decreased immobility time in the forced swim test. Combined treatment with sub-effective doses of HBK-7 and fluoxetine reduced immobility of mice in the forced swim test. Pretreatment with p-chlorophenylalanine and WAY-100,635 antagonized the antidepressant-like effect of HBK-7. Neither of the treatments influenced locomotor activity of mice. HBK-7 at antidepressant-like dose did not impair memory or motor coordination in mice. We demonstrated that HBK-7 was a 5-HT1A receptor antagonist with potent, comparable to mianserin, antidepressant-like activity. HBK-7 mediated its effect through serotonergic system and its antidepressant-like action required the activation of 5-HT1A receptors. At active dose it did not influence cognitive and motor function. Since 5-HT1A receptor antagonists may accelerate the occurrence of antidepressant effect, our findings highlight their potential as future antidepressants., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Xanthone derivatives have been shown to posses many biological properties. Some of them act within the central nervous system and show neuroprotective or antidepressant-like properties. Taking this into account we investigated antidepressant-like activity in mice and the possible mechanism of action of 6-methoxy-2-[4-(2-methoxyphenyl)piperazin-1-yl]-9H-xanthen-9-one (HBK-11) - a new xanthone derivative. We demonstrated that HBK-11 produced antidepressant-like effects in the forced swim test and tail suspension test, comparable to that of venlafaxine. The combined treatment with sub-effective doses of HBK-11 and fluoxetine (but not reboxetine or bupropion) significantly reduced the immobility in the forced swim test. Moreover, the antidepressant-like activity of HBK-11 in the aforementioned test was blocked by p-chlorophenylalanine, and significantly reduced by serotonergic 5HT1A receptor antagonist - WAY-1006335 and 5HT2A/C receptor antagonist - ritanserin. As none of the above treatments influenced the spontaneous locomotor activity, it can be concluded that HBK-11 mediates its activity through a serotonergic system, and its antidepressant-like effect involves 5HT1A and 5HT2A/C receptor activation. Furthermore, at antidepressant-like doses HBK-11 did not cause the mice to display locomotor deficits in rotarod or chimney tests. Considering the pharmacokinetic profile, HBK-11 demonstrated rapid absorption after i.p. administration, high clearance value, short terminal half-life, very high volume of distribution and incomplete bioavailability. The compound studied had good penetration into the brain tissue of mice. Since studied xanthone derivative seems to present interesting, untypical mechanism of antidepressant-like action i.e. 5HT2A/C receptor activation, it may have a potential in the treatment of depressive disorders, and surely requires further studies., (Copyright © 2015 Elsevier B.V. All rights reserved.)

A series of novel spirohydantoin derivatives with arylpiperazinylbutyl moiety were synthesized and evaluated for serotonin 5-HT1A, 5-HT2A, 5-HT7 and dopamine D2 receptors. Based on these data, four compounds were selected for further binding affinity assays on dopamine D1, D3, D4, and 5-HT2C, 5-HT6 as well as adrenergic α1 and α2C receptors, which are involved in various CNS diseases such as schizophrenia, anxiety and/or depression. The compound 14, 1-{4-[4-(2-metoxyphe-nyl)piperazin-1-yl]butyl}-3',4'-dihydro-2H,2'H,5H-spiro[imidazolidine-4,1'-naphthalene]-2,5-dione, with the most promising functional profile, mixed 5-HT2A/D2 antagonist and 5-HT1A partial agonist, was selected. In the mouse d-amphetamine-induced locomotor hyperactivity model, compound 14 produced antipsychotic-like activity, which is devoid of cataleptogenic effects and in the forced swim test in mice, it showed a significant antidepressant-like effect unlike the reference drug aripiprazole., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

A novel series of arylpiperazinylalkyl purine-2,4-diones (4-27) and purine-2,4,8-triones (31-38) was synthesized and tested to evaluated their affinity for the serotoninergic (5-HT1A, 5-HT6, 5-HT7) and dopaminergic (D2) receptors. Compounds with purine-2,4-dione nucleus generally had affinity values higher than the corresponding purine-2,4,8-trione compounds. A spectrum of receptor activities was observed for compounds with a substituent at the 7-position of the imidazo[2,1-f]purine-2,4-dione system and some potent 5-HT1A (18, 25), 5-HT7 (14) and mixed 5-HT1A/5-HT7 (8, 9) receptor ligands with additional affinity for dopamine D2 receptors (15) has been identified. Moreover, docking studies proved that a substituent at the 7-position of 1,3-dimethyl-(1H,8H)-imidazo[2,1-f]purine-2,4-dione could be essential for receptor affinity and selectivity, especially towards 5-HT1A and 5-HT7. The results of the preliminary pharmacological in vivo studies of selected derivatives of 1,3-dimethyl-(1H,8H)-imidazo[2,1-f]purine-2,4-dione, including 9 as a potential anxiolytic, 8 and 15 as potential antidepressants, and 18 and 25 as potential antidepressant and anxiolytic agents., (Copyright © 2015 Elsevier Masson SAS. All rights reserved.)

We describe a novel class of designed multiple ligands (DMLs) combining serotonin 5-HT6 receptor (5-HT6R) antagonism with dopamine D2 receptor (D2R) partial agonism. Prototype hybrid molecules were designed using docking to receptor homology models. Diverse pharmacophore moieties yielded 3 series of hybrids with varying in vitro properties at 5-HT6R and D2R, and at M1 receptor and hERG channel antitargets. 4-(piperazin-1-yl)-1H-indole derivatives showed highest antagonist potency at 5-HT6R, with 7-butoxy-3,4-dihydroquinolin-2(1H)-one and 2-propoxybenzamide derivatives having promising D2R partial agonism. 2-(3-(4-(1-(phenylsulfonyl)-1H-indol-4-yl)piperazin-1-yl)propoxy)benzamide (47) exhibited nanomolar affinity at both 5-HT6R and D2R and was evaluated in rat models. It displayed potent antidepressant-like and anxiolytic-like activity in the Porsolt and Vogel tests, respectively, more pronounced than that of a reference selective 5-HT6R antagonist or D2R partial agonist. In addition, 47 also showed antidepressant-like activity (Porsolt's test) and anxiolytic-like activity (open field test) in aged (>18-month old) rats. In operant conditioning tests, 47 enhanced responding for sweet reward in the saccharin self-administration test, consistent with anti-anhedonic properties. Further, 47 facilitated extinction of non-reinforced responding for sweet reward, suggesting potential procognitive activity. Taken together, these studies suggest that DMLs combining 5-HT6R antagonism and D2R partial agonism may successfully target affective disorders in patients from different age groups without a risk of cognitive deficits., (Copyright © 2014 Elsevier Masson SAS. All rights reserved.)

Purpose: Earlier we demonstrated that 3-[4-(3-trifluoromethyl-phenyl)-piperazin-1-yl]-dihydrofuran-2-one (LPP1) elevates nociceptive thresholds in the mouse model of diabetic neuropathic pain. Since drug-induced impairments of glucose and lipid metabolism and the oxidative stress might diminish benefits from analgesia achieved by analgesic drugs used in diabetic neuropathy, the effect of LPP1 on glucose utilization, lipid accumulation and its antioxidant and cytotoxic potential were assessed in some in vitro and ex vivo tests., Methods: Total antioxidant capacity was evaluated spectrophotometrically using 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical method, whereas the activities of glutathione (GSH) peroxidase and reductase were measured using methods based on the oxidation of NADPH to NADP. The spectrophotometric method for the evaluation of GSH level in mouse brain tissue homogenates involved the oxidation of GSH by the sulfhydryl reagent 5,5'-dithio-bis(2-nitrobenzoic acid) (DTNB) to form a yellow derivative, 5'-thio-2-nitrobenzoic acid (TNB), measurable at 412 nm. Cytotoxicity and glucose utilization were measured in hepatoma HepG2 cells and in 3T3-L1 adipocytes. Lipid accumulation was measured in 3T3-L1 cell lines., Results: LPP1 had dose-dependent antioxidant properties in DPPH radical assay (14-22% versus control; p < 0.001). Its single administration caused an increase in GSH concentration in brain tissue homogenates of mice by 34% (versus control group; p < 0.05). LPP1 was not cytotoxic and it did not increase glucose utilization or lipid accumulation in cell cultures., Conclusions: Previously demonstrated antinociceptive properties of LPP1 are accompanied by a lack of cytotoxicity. LPP1 does not impair glucose or lipid metabolism and is an antioxidant. All these properties might be advantageous for its use in diabetic neuropathy.