Neuroprotective arylpiperazine dopaminergic/serotonergic ligands suppress experimental autoimmune encephalomyelitis in rats

Arylpiperazine-based dopaminergic/serotonergic ligands exert neuroprotective activity. We examined the effect of arylpiperazine D-2/5-HT1A ligands, N-{4-[2-(4-phenyl-piperazin-1-yl)-ethyl}-phenyl]- picolinamide (6a) and N-{3-[2-(4-phenyl-piperazin-1-yl)ethyl]- phenyl}-picolinamide (6b), in experimental autoimmune encephalomyelitis (EAE), a model of neuroinflammation. Both compounds (10 mg/kg i.p.) reduced EAE clinical signs in spinal cord homogenate-immunized Dark Agouti rats. Compound 6b was more efficient in delaying the disease onset and reducing the maximal clinical score, which correlated with its higher affinity for D-2 and 5-HT1A receptors. The protectionwas retainedif treatment was limited to the effector (from day 8 onwards), but not the induction phase (day 0-7) of EAE. Compound 6b reduced CNS immune infiltration and expression of mRNA encoding the proinflammatory cytokines tumor necrosis factor, IL-6, IL-1, and GM-CSF, T(H)1 cytokine IFN-gamma, T(H)17 cytokine IL-17, as well as the signature transcription factors of T(H)1 (T-bet) and T(H)17 (ROR gamma t) cells. Arylpiperazine treatment reduced apoptosis and increased the activation of anti-apoptotic mediators Akt and p70S6 kinase in the CNS of EAE animals. The in vitro treatment with 6b protected oligodendrocyte cell line OLN-93 and neuronal cell line PC12 from mitogen-activated normal T cells or myelin basic proteinactivated encephalitogenic T cells. In conclusion, arylpiperazine dopaminergic/serotonergic ligands suppress EAE through a direct neuroprotective action and decrease inCNS inflammation

Synthesis, Biological, and Computational Evaluation of Substituted 1-(2-Methoxyphenyl)-4-(1-phenethylpiperidin-4-yl)piperazines and 1-(2-Methoxyphenyl)-4-[(1-phenethylpiperidin-4-yl)methyl]piperazines as Dopaminergic Ligands

Sixteen new 1-(2-methoxyphenyl)-4-(1-phenethylpiperidin-4-yl)piperazines and 1-(2-methoxyphenyl)-4-[(1-phenethylpiperidin-4-yl)methyl]piperazines were synthesized to be used as probes for mapping the dopamine D-2 receptor (D(2)DAR) arylpiperazine binding site. All compounds were evaluated for their affinity toward D(2)DAR in an in vitro competitive displacement assay. The most active one was 1-(2-methoxyphenyl)-4-{[1-(3-nitrophenethyl)piperidin-4-yl]methyl}piperazine (25) with an affinity of K-i = 54 nM. Docking analysis was conducted on all herein described compounds, whereas molecular dynamic simulation was performed on ligand 25 to establish its mode of interaction with D(2)DAR. Two possible docking orientations are proposed; the one with a salt bridge between the piperidine moiety and Asp114 of D(2)DAR is more stable.Supplementary material: [http://cherry.chem.bg.ac.rs/handle/123456789/3631

Synthesis and biological evaluation of 5-substituted derivatives of benzimidazole

A series of eight novel 5-substituted derivatives of benzimidazole was synthesized by condensation of the corresponding diamine with ethyl 4-[4-(2-chlorophenyl)piperazin-1-yl]butanoate in refluxing 4 M hydrochloric acid. In vitro antibacterial activity against ten strains, namely Bacillus subtilis, Clostridium sporogenes, Streptosporangium longisporum, Micrococcus flavus, Sarcina lutea, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Salmonella enteritidis and Proteus vulgaris and antifungal activity against two fungal strains, namely Candida albicans and Saccharomyces cerevisiae, were evaluated. Of all the compounds screened for activity, 2-{3-[4-(2-chlorophenyl)piperazin-1-yl]propyl}-5-iodo-1H-benzimidazole and 2-{3-[4-(2-chlorophenyl)piperazin-1-yl]propyl}-5-methyl-1H-benzimidazole were associated with higher antifungal activity than commercial drugs

Investigation of key interactions between the second extracellular loop of the dopamine D2 receptor and several hydroxy-N-\{{[}2-(4-phenylpiperazin-1-yl)ethyl]phenyl\}nicotinamides

The dopaminergic receptor system has been the focus for the development of new pharmacotherapeutic agents targeting a number of central nervous system related disorders, such as drug addiction, schizophrenia, depression, and Parkinson's disease, to name just a few. To date, the crystal structure for the human D2 receptor is not known, despite its vital function and importance as a therapeutic target. Herein, a recent advancement in the determination of key receptor ligand interactions for the available arylpiperazine-like ligands, using a D2 receptor model based on the crystal structure of the D3 receptor is presented. To determine key interactions responsible for high dopaminergic activity, computer-docking analysis was used together with experimental data. A total of 4 dopaminergic ligands showing moderate to high affinity were tested and the obtained results rationalized using ligand structures docked into the proposed D2 receptor model.Ministry for Education, Science and Technological Development of the Republic of Serbia {[}172032