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In the text, the synthesis and characteristics of the novel ONS-type vanadium(V) complexes with thioanilide derivatives of amino acids are described. They have shown inhibition of human protein tyrosine phosphatases (PTP1B, LAR, SHP1 and SHP2) in the submicromolar range, as well as inhibition of non-tyrosine phosphatases (CDC25A and PPA2) similar to bis(maltolato)oxovanadium(IV)(BMOV). The ONS complexes increased [14C]-deoxy-D-glucose transport into C2C12 myocytes, and one of them, VC070, also enhanced this transport in 3T3-L1 adipocytes. These complexes inhibited gluconeogenesis in hepatocytes HepG2, but none of them decreased lipid accumulation in the non-alcoholic fatty liver disease model using the same cells. Compared to the tested ONO-type vanadium complexes with 5-bromosalicylaldehyde and substituted benzhydrazides as Schiff base ligand components, the ONS complexes revealed stronger inhibition of protein tyrosine phosphatases, but the ONO complexes showed greater activity in the cell models in general. Moreover, the majority of the active complexes from both groups showed better effects than VOSO4 and BMOV. Complexes from both groups activated AKT and ERK signaling pathways in hepatocytes to a comparable extent. One of the ONO complexes, VC068, showed activity in all of the above models, also including glucose utilization in the myocytes and glucose transport in insulin-resistant hepatocytes. The discussion section explicates the results within the wider scope of the knowledge about vanadium complexes.

The synthesis and characteristics of the novel ONS-type vanadium(V) complexes with thioanilidine derivatives of aminoacids have been described. They showed inhibition of human protein tyrosine phosphatases (PTP1B, LAR, SHP1 and SHP2) in the submicromolar range and as well as inhibition of non-tyrosine phosphatases (CDC25A and PPA2) similar to bis(maltolato)oxovanadium(IV)(BMOV). The ONS complexes increased [14C]-deoxy-D-glucose transport into C2C12 myocytes, and one of them, VC070 also enhanced this transport in 3T3-L1 adipocytes. These complexes inhibited gluconeogenesis in hepatocytes HepG2, but none of them decreased lipid accumulation in the non-alcoholic fatty liver disease model using the same cells. Compared to the tested ONO-type vanadium complexes with 5-bromosalicylaldehyde and substituted benzhydrazides as components of Schiff base ligand, the ONS complexes revealed stronger inhibition of protein tyrosine phosphatases, but the ONO complexes showed greater activity in the cell models, in general. Moreover, the most of the active complexes from both groups showed better effects than VOSO4 and BMOV. Complexes from both groups activated AKT and ERK signaling pathway in hepatocytes to a comparable extent. One of the ONO complexes, VC068, showed activity in all above models, including also glucose utilization in the myocytes and glucose transport in insulin-resistant hepatocytes. The discussion has put forward explications for the results within the wider scope of the knowledge about vanadium complexes.

There is clear evidence that the presence of inflammatory factors and impaired GABA-ergic neurotransmission in depressed patients is associated with poor clinical outcome. We designed hybrid molecules, bearing the GABA molecule assembled with chemical fragments that interact with the serotonin 5-HT

Twenty-four oxidovanadium(IV,V) complexes with tridentate Schiff base ligands based on 5-nitrosalicylaldehyde, 5-methoxysalicylaldehyde, or 5-sulfosalicylaldehyde and respective hydrazide were isolated, and characterized using physicochemical and spectroscopic methods. Three of them were structurally characterized by single-crystal X-ray structure determination. The biological activity studies included inhibition of human tyrosine phosphatases, studies on myocyte C2C12, adipocyte 3T3-L1, and human hepatocyte HepG2 cell lines, glucose uptake in myocytes and adipocytes, and cytotoxicity tests. The complexes that were unstable in solutions showed biological activity typical of other V(IV) complexes, while the stable one showed much higher, ligand-dependent, activity.

Neuropsychiatric symptoms (NPS), such as psychosis, depression and anxiety are frequently observed among patients with dementia. NPS is treated by off-label psychotropic medications that are only modestly effective in dementia patients, with a high risk of adverse events and cognitive decline. Considering the above, there is an unmet need for a well-tolerated and effective therapy of NPS in dementia. We designed and synthesized a library of dual-acting compounds as phosphodiesterase type-10A inhibitors and serotonin 5-HT

Schizophrenia is a chronic mental illness, which remains difficult to treat. A high resistance to the available therapies, their insufficient efficacy, and numerous side effects are the reasons why there is an urgent need to develop new antipsychotics. This study aimed to assess the antipsychotic-like effects of JJGW08, a novel arylpiperazine alkyl derivative of salicylamide, in rodents. First, considering the JJGW08 receptor profile, we investigated the compound’s intrinsic activity towards dopamine D2 and serotonin 5-HT1A, 5-HT2A, and 5-HT7 receptors using functional assays. Next, we assessed the effect of JJGW08 on MK-801- and amphetamine-induced hyperlocomotion, its risk of inducing catalepsy and impairing motor coordination, as well as the anxiolytic-like effects in the four-plate and marble burying tests in mice. Finally, we investigated the antipsychotic-like properties of JJGW08 in rats using MK-801-induced hyperlocomotion and prepulse inhibition tests. We found that JJGW08 showed antagonistic properties at dopamine D2 and serotonin 5-HT1A, 5-HT2A, and 5-HT7 receptors. However, the effect on the 5-HT2A and 5-HT7 receptors was very weak. Moreover, the tested compound showed an antipsychotic-like effect in MK-801- and amphetamine-induced hyperlocomotion but not in a prepulse inhibition test in rats. Notably, JJGW08 demonstrated anxiolytic-like properties in both behavioral tests. Importantly, the compound did not induce catalepsy or motor coordination impairment in mice at antipsychotic-like doses. Our study suggests it is worth searching for new potential antipsychotics among arylpiperazine alkyl derivatives of salicylamide.

Among the serotonin receptors, one of the most recently discovered 5-HT6 subtype is an important protein target and its ligands may play a key role in the innovative treatment of cognitive disorders. However, none of its selective ligands have reached the pharmaceutical market yet. Recently, a new chemical class of potent 5-HT6 receptor agents, the 1,3,5-triazine-piperazine derivatives, has been synthesized. Three members, the ortho and meta dichloro- (1,2) and the unsubstituted phenyl (3) derivatives, proved to be of special interest due to their high affinities (1,2) and selectivity (3) toward 5-HT6 receptor. Thus, a broader pharmacological profile for 1–3, including comprehensive screening of the receptor selectivity and drug-like parameters in vitro as well as both, pharmacokinetic and pharmacodynamic properties in vivo, have been investigated within this study. A comprehensive analysis of the obtained results indicated significant procognitive-like activity together with beneficial drug-likeness in vitro and pharmacokinetics in vivo profiles for both, (RS)-4-[1-(2,3-dichlorophenoxy)propyl]-6-(4-methylpiperazin-1-yl)-1,3,5-triazin-2-amine (2) and (RS)-4-(4-methylpiperazin-1-yl)-6-(1-phenoxypropyl)-1,3,5-triazin-2-amine (3), but insensibly predominant for compound 2. Nevertheless, both compounds (2 and 3) seem to be good Central Nervous System drug candidates in search for novel therapeutic approach to dementia diseases, based on the 5-HT6 receptor target.

New tritarget small molecules combining Ca2+ channels blockade, cholinesterase, and H3 receptor inhibition were obtained by multicomponent synthesis. Compound 3p has been identified as a very promising lead, showing good Ca2+ channels blockade activity (IC50 = 21 ± 1 μM), potent affinity against hH3R (Ki = 565 ± 62 nM), a moderate but selective hBuChE inhibition (IC50 = 7.83 ± 0.10 μM), strong antioxidant power (3.6 TE), and ability to restore cognitive impairment induced by lipopolysaccharide.

The lack of an effective treatment makes Alzheimer's disease a serious healthcare problem and a challenge for medicinal chemists. Herein we report interdisciplinary research on novel multifunctional ligands targeting proteins and processes involved in the development of the disease: BuChE, 5-HT

This research allowed us to find the first highly potent 5-HT

The present study aimed to design and synthesize a new series of hybrid compounds with pyrrolidine-2,5-dione and thiophene rings in the structure as potential anticonvulsant and antinociceptive agents. For this purpose, we obtained a series of new compounds and evaluated their anticonvulsant activity in animal models of epilepsy (maximal electroshock (MES), psychomotor (6 Hz), and subcutaneous pentylenetetrazole (scPTZ) seizure tests). To determine the mechanism of action of the most active anticonvulsant compounds (3, 4, 6, 9), their influence on the voltage-gated sodium and calcium channels as well as GABA transporter (GAT) was assessed. The most promising compound 3-(3-methylthiophen-2-yl)-1-(3-morpholinopropyl)pyrrolidine-2,5-dione hydrochloride (4) showed higher ED50 value than those of the reference drugs: valproic acid (VPA) and ethosuximide (ETX) (62.14 mg/kg vs. 252.7 mg/kg (VPA) in the MES test, and 75.59 mg/kg vs. 130.6 mg/kg (VPA) and 221.7 mg/kg (ETX) in the 6 Hz test, respectively). Moreover, in vitro studies of compound 4 showed moderate but balanced inhibition of the neuronal voltage-sensitive sodium (site 2) and L-type calcium channels. Additionally, the antinociceptive activity of the most active compounds (3, 4, 6, 9) was also evaluated in the hot plate test and writhing tests, and their hepatotoxic properties in HepG2 cells were also investigated. To determine the possible mechanism of the analgesic effect of compounds 3, 6, and 9, the affinity for the TRPV1 receptor was investigated.

In the light of recent lines of evidence, 5-HT

New tritarget small molecules combining Ca

Molecular docking studies using appropriate 5-HT

Previously, it was found that 5-(3-chlorophenyl)-4-hexyl-2,4-dihydro-3H-1,2,4-triazole-3-thione (TP-315) effectively protects mice from maximal electroshock-induced seizures. The aim of this study was to determine possible interactions between TP-315 and different molecular targets, i.e. GABAA receptors, voltage-gated sodium channels, and human neuronal α7 and α4β2 nicotinic acetylcholine receptors. The influence of TP-315 on the viability of human hepatic HepG2 cells was also established using PrestoBlue and ToxiLight assays. It was found that the anticonvulsant activity of TP-315 results (at least partially) from its influence on voltage-gated sodium channels (VGSCs). Moreover, the title compound slightly affected the viability of human hepatic cells.

Obesity affects an increasing number of individuals in the human population and significant importance is attached to research leading to the discovery of drug which would effectively reduce weight. The search for new drugs with anorectic activity and acting within the adrenergic system has attracted the interest of researchers. This study concerns the experimental effects on body weight of α 2 -adrenoceptor antagonists from the group of pyrrolidin-2-one derivatives in rats with diet-induced obesity. Methods: The intrinsic activity of the test compounds at the α-adrenoreceptors was tested. Obesity in rats was obtained by the use of fatty diet and then the influence of the test compounds on body weight, food and water intakes, lipid and glucose profiles and glycerol and cortisol levels were determinated. The effects of the compounds on locomotor activity, body temperature, blood pressure and heart rate were tested. Results: One of the test compounds (1-(3-(4-phenylpiperazin-1-yl)propyl)pyrrolidin-2-one) reduces the animal's body weight and the amount of peritoneal adipose tissue during chronic administration, at the same time it does not cause significant adverse effects on the cardiovascular system. This compound decreases temperature and elevates glycerol levels and does not change the locomotor activity and cortisol level at anti-obese dose. Conclusions: Some derivatives of pyrrolidin-2-one that act as antagonists of the α 2 -adrenoreceptor may reduce body weight. Reducing body weight for 1-(3-(4-phenylpiperazin-1-yl)propyl)pyrrolidin-2-one can be associated with decrease in food intake, body fat reduction, reduction of blood glucose, and increased thermogenesis and lipolysis. This effect cannot be the result of changes in spontaneous activity or stress.

In the light of recent lines of evidence, 5-HT6R ligands are a promising tool for future treatment of memory impairment. Hence, this study has supplied highly potent 5-HT6R agents with procognitive effects, which represent an original chemical class of 1,3,5-triazines, different from widely studied sulfone and indole-like 5-HT6R ligands. The new compounds were rationally designed as modifications of lead, 4-(1-(2-chlorophenoxy)ethyl)-6-(4-methylpiperazin-1-yl)-1,3,5-triazin-2-amine (1), involving an introduction of: (i) two chlorines at benzene ring and (ii) varied linkers joining the triazine ring to aromatic ethers. Synthesis, in vitro and in vivo biological tests and computer-aided SAR analysis for 19 new compounds were carried out. Most of the new triazines displayed high affinity (Ki

Seventeen complexes of vanadium (III-V) with hydrazido-hydrazone Schiff bases, formed from 5-bromosalicylaldehyde and different hydrazides, are described and characterized by elemental analysis, IR, UV–Vis (in solution and as reflectance spectra) and EPR spectroscopy, cyclic voltammetry and thermogravimetric measurements. The nonoxido complexes show reversible oxidation to V(V), while oxido ones only irreversible processes. The thermogravimetric measurements indicate that Schiff base is released as its components in two separated steps. The detailed EPR measurements show distorted octahedral geometry for oxido complexes with presence of two oxidovanadium(IV) centers attributed to complexes with keto- or enol- form of hydrazide, the ratio of keto : enol form was determined. The biological activity, such as inhibition of human phosphatases (PTP1B, SHP1, SHP2, LAR and CD45), cytotoxicity and glucose uptake in myocytes (C2C12) and adipocytes (3 T3-L1) of selected complexes was tested. The obtained results indicate that the strength of tyrosine phosphatases inhibition of tested complexes does not determine the strength of their antidiabetic activity demonstrated in the glucose transport to myocytes and adipocytes. This last effectiveness is much higher than for VOSO4 and BMOV.

This research has provided the most active 5-HT

The latest results in action of vanadium compounds show important influence on adipogenesis processes and adipocytes function. Based on previously screening tests in cellular models the novel vanadium complex (N'-[(E)-(5-bromo-2-oxophenyl)methylidene]-4-methoxybenzohydrazide)oxido(1,10-phenanthroline)vanadium(IV) was selected for this study. This complex shown potent inhibition ability of tyrosine phosphatases and differences in the degree of inhibition particular phosphatases was observed. Significantly increasing of intracellular lipid accumulation and proliferative effect on 3T3-L1 preadipocytes confirmed the ability of this complex to enhancement of adipogenesis. The insulinomimetic activity of the tested complex was also demonstrated in fully differentiated 3T3-L1 adipocytes, in which glucose utilization was potentiated. Presented results support the thesis that vanadium complexes show promising possibilities for opportunities of new therapeutic strategies for the treatment of type 2 diabetes involved adipocytes.

This research has provided the most active 5-HT6R agents among 1,3,5-triazine derivatives investigated to date and has also identified the world's first selenium-containing 5-HT6R ligands. The studies are focused on design, synthesis, biological evaluation and docking-supported SAR analysis for novel 5-HT6R agents as derivatives of lead structure 4-(4-methylpiperazin-1-yl)-6-(phenoxymethyl)-1,3,5-triazin-2-amine (7). The lead modifications included an introduction of: (i) various small substituents at benzene ring, (ii) a branched ether linker or (iii) the ether oxygen replacement with other chalcogen (S, Se) or sulfonyl moiety. Hence, a series of new compounds (7–24) was synthesized and examined on their affinities for 5-HT6R and selectivity, in respect to the 5-HT1AR, 5-HT2AR, 5-HT7R and dopamine D2 receptor, in the radioligand binding assays. For representative most active compounds functional bioassays and toxicity profile in vitro and antidepressant-like activity in vivo were examined. The 2-isopropyl-5-methylphenyl derivative (10) was found as the most active triazine 5-HT6R antagonist (Ki = 11 nM). SAR analysis indicated, that an exchange of oxygen to selenium (7 vs. 22), and especially, to sulfur (7 vs. 19) was beneficial to increase both affinity and antagonistic action for 5-HT6R. Surprisingly, an introduction of SO2 caused a drastic decrease of the 5-HT6R affinity, which was explained at a molecular level based on docking studies. All in vivo tested compounds (10, 18 and 21) did not show any risk of toxicity in the safety studies in vitro.

Nine new vanadium complexes, with tridentate Schiff base ligand based on 3,5-di-tert-butyl-2-hydroxybenzaldehyde and different hydrazides, are described and characterized. The X-ray crystal structure of complex 8 shows distorted octahedral geometry of vanadium, with ONO ligand in equatorial position. The tridentate Schiff base ligand forms six membered and five-membered chelate rings at the V(V) acceptor center, with the corresponding bite angles being 82.97(9)˚ and 74.48(9)˚. The molecules are gathered by means of intermolecular O-H∙∙∙N hydrogen bond and layered by π∙∙∙π interactions involving the pyridine and phenolate rings. Such interactions expand the structure along the crystallographic a axis. The complexes were characterized by the elemental analyses, IR, UV-Vis, EPR spectroscopy, cyclic voltammetry, thermogravimetry and magnetic susceptibility measurements. The stabilization role of co-ligands is discussed. The cytotoxicity versus HepG2 hepatocytes and inhibition of human recombinant PTP1B was studied.

In our previous paper, we have reported that some 8-alkoxy-1,3-dimethyl-1H-purine-2,6(3H,7H)-dione derivatives possessed high affinity and displayed agonistic activity for the serotonin 5-HT1A receptor. In order to examine the influence of the substituent in the position 8 of the purine moiety on the affinity for the serotonin 5-HT1A , 5-HT2A , and 5-HT7 receptors, a series of 7-arylpiperazynylalkyl and 7-tetrahydroisoquinolinylalkyl (THIQ) derivatives of 8-amino-1,3-dimethyl-1H-purine-2,6(3H,7H)-dione were synthesized. All the final compounds were investigated in in vitro competition binding experiments for serotonin 5-HT1A , 5-HT2A , and 5-HT7 receptors. The structure-affinity relationships for this group of compounds were discussed. For selected compounds, functional assays for the 5-HT1A receptor were carried out. The results of the assays indicated that these groups of derivatives possessed antagonistic activity for this receptor.

Epilepsy is a chronic neurological disorder that is associated with various types of recurrent seizures, which are drug-resistant in about one third of patients. Moreover, anticonvulsant drugs are used to treat a wide range of non-epileptic conditions, including chronic pain. Here, we investigated the anticonvulsant activity of six new hybrid compounds based on the pyrrolidine-2,5-dione scaffold in the 6 Hz corneal stimulation test with 44 mA stimulus intensity in mice, which is the model of pharmacoresistant seizures. We demonstrated that two molecules, DK-10 (11) and DK-14 (14) show higher anticonvulsant activity and similar safety profile in comparison with valproic acid and much higher in comparison with levetiracetam in the aforementioned test. The second aim of this study was to examine analgesic activity of these compounds. For this purpose, the hot plate test, the formalin test, and the oxaliplatin-induced peripheral neuropathy model were performed. Among tested agents DK-11 (12) revealed prominent antinociceptive activity at non-sedative doses in the second (inflammatory) phase of the formalin test, which is the model of tonic pain and antiallodynic activity in the oxaliplatin-induced neuropathic pain, the model of painful chemotherapy-induced peripheral neuropathy. No cytotoxic effect on hepatoma cells was observed. Compound DK-10 (11) had high affinity for voltage-gated sodium channels, whereas compound DK-11 (12) showed weak binding toward sodium and calcium voltage-gated channels and the NMDA receptor. As a result, hybrid compounds reported herein seem to be very promising broad spectrum anticonvulsant molecules with collateral analgesic activity.

A series of octahydro- and 6,7-dimethoxy-3,4-dihydro- isoquinolin-2(1H)-yl-alkyl derivatives of imidazo- and pyrimidino[2,1-f]purines were synthesized and biologically evaluated in in vitro competition binding experiments for serotonin 5-HT(1A), 5-HT(6), 5-HT(7), and dopamine D2 receptors and inhibitory potencies for phosphodiesterases - PDE4B1 and PDE10A. The structure-activity relationships allowed to determine the structural features responsible for receptor and enzyme activity. Compound 5 (8-(4-(6,7-dimethoxy-3,4-dihydroiso- quinolin-2(1H)butyl)1,3-dimethyl-H-imidazo[2,1-f]purine-2,4(3H,8H)-dione) could be regarded as promising structure for further modification and detailed mechanistic study for obtained hybrid ligands.

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.

Based on our recent finding that α1 selective GABA-A receptor potentiator—zolpidem—(a hypnotic drug) exerts antipsychotic-like effects in rats, we developed a series of fluorinated imidazo[1,2-a]pyridine derivatives as potential novel antipsychotic agents. The selected compounds displayed high affinity and positive allosteric modulator properties at the GABA-A receptor, enhanced metabolic stability and lack of hepatotoxicity. The most promising compound 2-(2-(4-fluorophenyl)-6-methylimidazo[1,2-a]pyridin-3-yl)-N,N-dimethylethanamide (26) showed antipsychotic-like activity in amphetamine-induced hyperlocomotion test in rats (MED = 1 mg/kg) and was characterized by a longer duration of antipsychotic-like activity as compared to zolpidem. These results are an encouraging example of a compound with non-dopaminergic mechanism of action displaying antipsychotic activity and are a point of entry for the future studies in this field.

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.

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.

In our previous paper, we have reported that some 8-alkoxy-1,3-dimethyl-1H-purine-2,6(3H,7H)-dione derivatives possessed high affinity and displayed agonistic activity for the serotonin 5-HT1A receptor. In order to examine the influence of the substituent in the position 8 of the purine moiety on the affinity for the serotonin 5-HT1A , 5-HT2A , and 5-HT7 receptors, a series of 7-arylpiperazynylalkyl and 7-tetrahydroisoquinolinylalkyl (THIQ) derivatives of 8-amino-1,3-dimethyl-1H-purine-2,6(3H,7H)-dione were synthesized. All the final compounds were investigated in in vitro competition binding experiments for serotonin 5-HT1A , 5-HT2A , and 5-HT7 receptors. The structure-affinity relationships for this group of compounds were discussed. For selected compounds, functional assays for the 5-HT1A receptor were carried out. The results of the assays indicated that these groups of derivatives possessed antagonistic activity for this receptor.