Design and synthesis of novel δ opioid receptor agonists with an azatricyclodecane skeleton for improving blood-brain barrier penetration.

We designed and synthesized novel δ opioid receptor (DOR) agonists 3a-i with an azatricyclodecane skeleton, which was a novel structural class of DOR agonists. Among them, 3b exhibited high values of binding affinity and potent agonistic activity for the DOR that were approximately equivalent to those of 2 which bore an oxazatricyclodecane skeleton. In vitro assays using the blood-brain barrier (BBB) permeability test kit supported the idea that 3b achieved an excellent BBB permeability by converting an oxygen atom of 2 to a carbon atom (methylene group) in the core skeleton. As a result, 3b showed potent antinociceptive effects.

Novel delta opioid receptor agonists with oxazatricyclodecane structure showing potent agonistic activities.

We recently reported oxazatricyclodecane derivatives 1 as δ opioid receptor (DOR) agonists having a novel chemotype, but their DOR agonistic activities were relatively low. Based on the working hypothesis that the dioxamethylene moiety in 1 may be an accessory site and that it may interfere with the sufficient conformational change of the receptor required for exerting the full agonistic responses, we designed and synthesized new oxazatricyclodecane derivatives 2-4 lacking the dioxamethylene moiety. As we expected, the designed compounds 2-4 showed pronouncedly improved agonistic activities for the DOR. Compound 2a with the 17-cyclopropylmethyl substituent was a potent agonist with the highest selectivity for the DOR and was expected to be a lead compound for novel and selective DOR agonists.

A novel P2X4 receptor-selective antagonist produces anti-allodynic effect in a mouse model of herpetic pain.

Accumulating evidence indicates that purinergic P2X4 receptors (P2X4R: cation channels activated by extracellular ATP) expressed in spinal microglia are crucial for pathological chronic pain caused by nerve damage, suggesting a potential target for drug discovery. We identified NP-1815-PX (5-[3-(5-thioxo-4H-[1,2,4]oxadiazol-3-yl)phenyl]-1H-naphtho[1, 2-b][1,4]diazepine-2,4(3H,5H)-dione) as a novel antagonist selective for P2X4R with high potency and selectivity compared with other P2XR subtypes. In in vivo assay for acute and chronic pain, intrathecal administration of NP-1815-PX produced an anti-allodynic effect in mice with traumatic nerve damage without affecting acute nociceptive pain and motor function (although its oral administration did not produce the effect). Furthermore, in a mouse model of herpetic pain, P2X4R upregulation in the spinal cord exclusively occurred in microglia, and intrathecal NP-1815-PX suppressed induction of mechanical allodynia. This model also showed K(+)/Cl(-) cotransporter 2 (KCC2) downregulation, which is implicated in dorsal horn neuron hyperexcitability; this downregulation was restored by intrathecal treatment with NP-1815-PX or by interfering with brain-derived neurotrophic factor (BDNF) signaling, a P2X4R-activated microglial factor implicated in KCC2 downregulation. Taken together, the newly developed P2X4R antagonist NP-1815-PX produces anti-allodynic effects in chronic pain models without altering acute pain sensitivity, suggesting that microglial P2X4R could be an attractive target for treating chronic pain.

Discovery of small-molecule nonpeptide antagonists of nociceptin/orphanin FQ receptor: The studies of design, synthesis, and structure-activity relationships for (4-arylpiperidine substituted-methyl)-[bicyclic (hetero)cycloalkanobenzene] derivatives.

Nociceptin/orphanin FQ (N/OFQ) and N/OFQ peptide (NOP) receptor are expressed and distributed in various regions such as central nervous system (CNS), peripheral nervous system, immune system, and peripheral tissues. N/OFQ and NOP receptor have important roles on a variety of physiological, pathophysiological, regulatory, and dysregulatory mechanisms in the living body. Both activation and blockade of NOP receptor function have displayed clinical potential of NOP receptor agonists and antagonists for the treatment of various diseases or pathophysiological conditions, respectively. Potent and selective NOP receptor agonists/antagonists are also useful tools to investigate the various mechanisms mediated by NOP receptor-N/OFQ system. As the present study, a series of (4-arylpiperidine substituted-methyl)-[bicyclic (hetero)cycloalkanobenzene] analogs was designed, synthesized, and biologically evaluated in vitro to seek and identify potent and selective, small-molecules of nonpeptide NOP receptor antagonists, which resulted in the discovery of novel potent small-molecule 15 with high human NOP receptor selectivity over human µ receptor. The structure-activity relationship (SAR) of the potency and selectivity, structure-metabolic stability relationship (SMR), and SAR of hERG (human ether-a-go-go related gene) potassium ion channel binding affinity for the analogs in the present studies in vitro provided or suggested significant and/or useful structural determinants and insights for the respective purposes. The superior profiles of compound 15 are discussed with a viewpoint of multisite interactions between ligand and NOP receptor, together with the results of previous NOP receptor agonist/antagonist studies.

[Development and validation of the Reality-Monitoring Error Experience Questionnaire].

This study developed a valid and reliable questionnaire measuring individual differences in reality-monitoring error experiences in everyday life. A 50-item preliminary questionnaire was constructed on the basis of the findings from a pilot diary study. In study 1, we administered the questionnaire to 316 undergraduates, along with a dissociative experience scale to examine criterion-referenced validity. Using factor analysis, we obtained the 32-item Reality-Monitoring Error Experience Questionnaire (RMEEQ). A significant positive correlation was found between scores on the RMEEQ and the dissociative experience scale, thereby which indicates the RMEEQ's criterion-referenced validity. In Study 2, we examined the test-retest reliability of the RMEEQ by administering it to 66 undergraduates on two occasions separated by three weeks. We found a significant test-retest correlation. Taken together, these results show that the RMEEQ is a valid and reliable measure of reality-monitoring error experiences in everyday life.

Novel delta opioid receptor agonists with oxazatricyclodecane structure.

We synthesized compounds 4a,c-f,h,i containing the oxazatricyclodecane structure from a novel rearrangement reaction product 2a. All the prepared compounds 4a,c-f,h,i exhibited full agonistic activities for the δ opioid receptor (DOR). Among them, the N-methyl derivative 4c was highly selective, and the most effective DOR agonist in functional assays. Subcutaneous administration of 4c produced dose-dependent and NTI (selective DOR antagonist)-reversible antinociception lacking any convulsive behaviors in the mice acetic acid writhing tests. The N-methyl derivative 4c is expected to be a promising lead compound for selective DOR agonists with a novel chemotype.

Discovery of 1-(ß-amino substituted-ß-alanyl)-N,N-dimethylindoline-2-carboxamides as novel nonpeptide antagonists of nociceptin/orphanin FQ receptor: efficient design, synthesis, and structure-activity relationship studies.

Since the discovery of endogenous nociceptin/orphanin FQ (N/OFQ) peptide and N/OFQ peptide (NOP) receptor [or opioid-receptor-like-1 (ORL1) receptor], the structures, distribution, and pharmacology have been reported in detail. N/OFQ and NOP receptor are located in the corticolimbic regions that are involved in the integration of the emotional activity, and located in the spinal cord, the peripheral nervous systems or other peripheral tissues that are related to pain as well as urinary signal transmissions, with a pattern distinct from that of classical opioid peptides and their receptors in rodents or primates. Furthermore, N/OFQ-NOP receptor system plays an important role in the regulation of various human physiologies such as depression effect, hyperphasia effect, and blood pressure effect. In this study, the structure-activity relationship of novel NOP receptor antagonist for various 1-(ß-amino substituted-ß-alanyl)-N,N-dimethylindoline-2-carboxamides was investigated in vitro to elucidate structural requisites to identify and develop potent and selective NOP receptor antagonists, which resulted in the discovery of 1-{3-[4-(substituted phenyl)piperidin-1-yl]propanoyl}-N,N-dimethylindoline-2-carboxamide analogues that display potent and selective human NOP (hNOP) receptor binding affinity and potent hNOP receptor antagonist activity. The efficient design, synthesis, and structure-activity relationship studies for potent and selective novel NOP receptor antagonists and significant findings in vitro, that include insights for binding and functional mechanisms via receptor-ligand interactions, are reported herein.

Discovery of {1-[4-(2-{hexahydropyrrolo[3,4-c]pyrrol-2(1H)-yl}-1H-benzimidazol-1-yl)piperidin-1-yl]cyclooctyl}methanol, systemically potent novel non-peptide agonist of nociceptin/orphanin FQ receptor as analgesic for the treatment of neuropathic pain: design, synthesis, and structure-activity relationships.

Neuropathic pain is a serious chronic disorder caused by lesion or dysfunction in the nervous systems. Endogenous nociceptin/orphanin FQ (N/OFQ) peptide and N/OFQ peptide (NOP) receptor [or opioid-receptor-like-1 (ORL1) receptor] are located in the central and peripheral nervous systems, the immune systems, and peripheral organs, and have a crucial role in the pain sensory system. Indeed, peripheral or intrathecal N/OFQ has displayed antinociceptive activities in neuropathic pain models, and inhibitory effects on pain-related neurotransmitter releases and on synaptic transmissions of C- and Aδ-fibers. In this study, design, synthesis, and structure-activity relationships of peripheral/spinal cord-targeting non-peptide NOP receptor agonist were investigated for the treatment of neuropathic pain, which resulted in the discovery of highly selective and potent novel NOP receptor full agonist {1-[4-(2-{hexahydropyrrolo[3,4-c]pyrrol-2(1H)-yl}-1H-benzimidazol-1-yl)piperidin-1-yl]cyclooctyl}methanol 1 (HPCOM) as systemically (subcutaneously) potent new-class analgesic. Thus, 1 demonstrates dose-dependent inhibitory effect against mechanical allodynia in chronic constriction injury-induced neuropathic pain model rats, robust metabolic stability and little hERG potassium ion channel binding affinity, with its unique and potentially safe profiles and mechanisms, which were distinctive from those of N/OFQ in terms of site-differential effects.

Combined memory and executive function tests can screen mild cognitive impairment and converters to dementia in a community: the Osaki-Tajiri project.

BACKGROUND: The borderline condition between health and dementia, defined as Clinical Dementia Rating (CDR) 0.5, should be detected for the possible prediction of dementia. Since the CDR requires information from collateral sources, it is difficult to rate people living alone. The aim is to develop a set of tests without collateral information for detecting CDR 0.5 and converters to dementia. METHODS: 625 participants were selected from the community; 412 were CDR 0 (healthy), 168 were CDR 0.5 (defined here as mild cognitive impairment; MCI), and were 45 CDR 1+ (dementia). Neuropsychological tests were administered to assess memory, orientation, attention and executive function. We analyzed various combinations of tests by receiver operating characteristic curve and area under the curve (AUC). Among the participants, 497 were randomly selected to be re-examined after 5 years to predict further decline towards dementia. RESULTS: We found that a combination of tests for orientation, memory, attention, executive function, and abstraction and judgment could discriminate subjects with MCI from healthy participants with high accuracy (AUC = 0.83). The predictive accuracy was better than that of the Mini Mental State Examination (AUC = 0.77). The same tests, except orientation, could also predict converters to dementia (AUC = 0.88). CONCLUSIONS: We consider that a combination of tests can be helpful for the early detection of individuals with MCI and converters to dementia in the community.

In vitro and in vivo pharmacological characterization of PF-01354082, a novel partial agonist selective for the 5-HT(4) receptor.

The pharmacological profile of PF-01354082, a selective 5-HT(4) receptor partial agonist, was investigated. PF-01354082 displayed high affinity for human 5-HT(4d) and dog 5-HT(4h) receptors in binding studies, having Ki values of 2.0 nM and 4.2 nM, respectively. By contrast, PF-01354082 did not show significant affinity for several other 5-HT receptors (5-HT(1A), 5-HT(1B), 5-HT(1D), 5-HT(2A), 5-HT(2B), 5-HT(2C), 5-HT(3A), and 5-HT(7)) or the dopamine D(2long) receptor. Functional assays using either cells expressing human recombinant 5-HT(4d) receptors or rat tunica muscularis mucosae demonstrated that PF-01354082 exhibited partial agonist activity at the 5-HT(4) receptor. The effects of PF-01354082 on in vitro receptor binding, ion channel activity, and sites of uptake were further investigated. PF-01354082 did not show biologically relevant binding activity at concentrations up to 10 microM except for binding to the 5-HT(4e) receptor. Furthermore, PF-01354082 decreased I(HERG) current by only 11% at a concentration of 300 microM, indicating that the compound had greater than 150,000-fold selectivity for the human 5-HT(4d) receptor over hERG channels. An in vivo study using a gastric motility model in conscious dogs demonstrated that oral administration of PF-01354082 resulted in marked and sustained stimulation of gastric motility in a dose-dependent manner. These results indicate that PF-01354082 is an orally active, highly selective, partial agonist of the human 5-HT(4) receptor that is expected to exert a favorable effect on gastrointestinal motor disorders with reduced adverse effects mediated by other related receptors.

Novel non-peptide nociceptin/orphanin FQ receptor agonist, 1-[1-(1-Methylcyclooctyl)-4-piperidinyl]-2-[(3R)-3-piperidinyl]-1H-benzimidazole: design, synthesis, and structure-activity relationship of oral receptor occupancy in the brain for orally potent antianxiety drug.

An endogenous heptadecapeptide, nociceptin/orphanin FQ (N/OFQ), and a G-protein-coupled receptor, N/OFQ peptide (NOP) receptor [or opioid-receptor-like-1 (ORL1) receptor], have been described in terms of its structure, distribution, and pharmacology. Thus, the N/OFQ and NOP receptor are located in the central nervous systems in humans, primates, and rodents, and are involved in the integration of the emotional components in the brain; e.g., N/OFQ displays anxiolytic activity in the brain. For identifying orally potent anxiolytic, drug-design studies were performed with a series of 1,2-disubstituted benzimidazole derivatives, which resulted in the identification of various chemotypes of highly potent NOP selective full agonists in vitro with high or moderate NOP receptor occupancy in the mice brain per os such as 1-[1-(1-methylcyclooctyl)-4-piperidinyl]-2-[(3R)-3-piperidinyl]-1H-benzimidazole 1 (MCOPPB), the most potent novel non-peptide NOP full agonist in vitro and an orally potent anxiolytic in the mice.

Decreased tumorigenicity in vivo when transforming growth factor beta treatment causes cancer cell senescence.

We have previously reported that transforming growth factor beta (TGF-beta) triggers two independent senescence programs, 1) replicative senescence dependent upon telomere shortening and 2) premature senescence independent of telomere shortening, in the cell line of A549 human lung adenocarcinoma. In this study, we examined the possibility that cancer cell tumor phenotypes could be suppressed by forced senescence. We used A549 cells treated with TGF-beta for a long time (over 50 days), where senescence was induced in a telomere-shortening-dependent or an independent way. Fully senescent A549 cells were elongated, acquired contact inhibition capabilities when reaching confluence, and secreted the senescence-associated cytokine IL-6. Furthermore, senescent A549 cells had no tumorigenicity in nude mice. These results indicate that the forced induction of senescence in cancer cells may be a novel and potentially powerful method for advancing anti-cancer therapy.