Anxiolytic-like and antidepressant-like activities of MCL0129 (1-[(S)-2-(4-fluorophenyl)-2-(4-isopropylpiperadin-1-yl)ethyl]-4-[4-(2-methoxynaphthalen-1-yl)butyl]piperazine), a novel and potent nonpeptide antagonist of the melanocortin-4 receptor

We investigated the effects of a novel melanocortin-4 (MC4) receptor antagonist,1-[(S)-2-(4-fluorophenyl)-2-(4-isopropylpiperadin-1-yl)ethyl]-4-[4-(2-methoxynaphthalen-1-yl)butyl]piperazine (MCL0129) on anxiety and depression in various rodent models. MCL0129 inhibited [(125)I][Nle(4)-D-Phe(7)]-alpha-melanocyte-stimulating hormone (alpha-MSH) binding to MC4 receptor with a K(i) value of 7.9 nM, without showing affinity for MC1 and MC3 receptors. MCL0129 at 1 microM had no apparent affinity for other receptors, transporters, and ion channels related to anxiety and depression except for a moderate affinity for the sigma(1) receptor, serotonin transporter, and alpha(1)-adrenoceptor, which means that MCL0129 is selective for the MC4 receptor. MCL0129 attenuated the alpha-MSH-increased cAMP formation in COS-1 cells expressing the MC4 receptor, whereas MCL0129 did not affect basal cAMP levels, thereby indicating that MCL0129 acts as an antagonist at the MC4 receptor. Swim stress markedly induced anxiogenic-like effects in both the light/dark exploration task in mice and the elevated plus-maze task in rats, and MCL0129 reversed the stress-induced anxiogenic-like effects. Under nonstress conditions, MCL0129 prolonged time spent in the light area in the light/dark exploration task and suppressed marble-burying behavior. MCL0129 shortened immobility time in the forced swim test and reduced the number of escape failures in inescapable shocks in the learned helplessness test, thus indicating an antidepressant potential. In contrast, MCL0129 had negligible effects on spontaneous locomotor activity, Rotarod performance, and hexobarbital-induced anesthesia. These observations indicate that MCL0129 is a potent and selective MC4 antagonist with anxiolytic- and antidepressant-like activities in various rodent models. MC4 receptor antagonists may prove effective for treating subjects with stress-related disorders such as depression and/or anxiety.     

Effects of two novel D3-selective compounds, NGB 2904 [N-(4-(4-(2,3-dichlorophenyl)piperazin-1-yl)butyl)-9H-fluorene-2-carboxamide] and CJB 090 [N-(4-(4-(2,3-dichlorophenyl)piperazin-1-yl)butyl)-4-(pyridin-2-yl)benzamide], on the reinforcing and discriminative stimulus effects of cocaine in rhesus monkeys

The present study examined the effects of two novel dopamine D3 receptor compounds, NGB 2904 [N-(4-(4-(2,3-dichlorophenyl)piperazin-1-yl)butyl)-9H-fluorene-2-carboxamide], an antagonist, and CJB 090 [N-(4-(4-(2,3-dichlorophenyl)piperazin-1-yl)butyl)-4-(pyridin-2-yl)benzamide], a partial agonist, in two models of cocaine abuse in rhesus monkeys. To establish a dose range and time course of effects, both compounds were shown to block quinpirole-induced yawning when administered i.m. 15, 30, or 120 min before quinpirole. Next, rhesus monkeys were trained to discriminate i.m. injections of saline (0.5 ml) and cocaine (0.3 mg/kg). Neither D3 compound (0.03-3.0 mg/kg; n=3) substituted for cocaine in any monkey. When given in combination with cocaine, CJB 090 but not NGB 2904 attenuated the discriminative stimulus effects of cocaine, shifting the cocaine dose-response curve to the right. In a separate group of monkeys, responding was maintained under a second-order schedule of either food (1.0-g pellets; n=3) or cocaine (0.1 mg/kg/injection; n=4) presentation. When responding was stable, a dose of NGB 2904 (1.0-5.6 mg/kg i.v.) or CJB 090 (0.3-3.0 mg/kg i.v.) was administered for 5 consecutive days, immediately before the session. CJB 090, but not NGB 2904, decreased cocaine- and food-maintained responding. These data indicate that compounds with relatively high affinity and selectivity for the D3 receptor can attenuate the discriminative and reinforcing stimulus effects of cocaine while not producing cocaine-like effects. The present findings support the continued examination of D3 compounds as pharmacological tools for better understanding the role of this receptor subtype in cocaine addiction and as potential lead compounds for novel therapeutic agents.     

Development of trans-2-[1H-imidazol-4-yl] cyclopropane derivatives as new high-affinity histamine H3 receptor ligands

Previously, a novel series of 1H-4-substituted imidazole compounds were described as potent and selective histamine (HA) H3 receptor ligands (Yates et al., 1999). The present studies extend the structure-activity relationships for optimal HA H3 receptor affinity and central nervous system penetration by incorporation of a conformationally restricted cyclopropane nucleus. Moreover, the current studies extend our understanding of ligand-receptor interactions at the HA H3 receptor with the development of high affinity HA H3 receptor antagonists containing a stereochemical presentation. Structure-activity relationships were established from in vitro HA H3 receptor-binding affinities using [3H]Nalpha-methylhistamine and rat cortical tissue homogenates. Systematic optimization of multiple structural features critical for HA H3 receptor affinity provided some of the most potent HA H3 receptor agents described. For example, GT-2331 was determined to bind to a single population of HA H3 receptors with a Ki of 0.125 nM. In vivo, GT-2331 has a favorable central nervous system penetration profile with an ED50 of 0.08 mg/kg (i.p.) in rats and a long duration of action (T1/2 > 4 h). In addition, GT-2331 was extremely selective for the HA H3 receptor versus other HA receptors and a battery of neurotransmitter, neuropeptide, hormone, or enzyme systems. Several compounds were tested in vitro which suggested HA H3 receptor heterogeneity and are discussed in terms of structure-activity relationships for the HA H3 receptor.     

Calcium-dependent inhibition of synaptosomal serotonin transport by the alpha 2-adrenoceptor agonist 5-bromo-N-[4,5-dihydro-1H-imidazol-2-yl]-6-quinoxalinamine (UK14304)

Termination of serotonergic transmission is the function of the plasma membrane 5-hydroxytryptamine (serotonin, 5-HT) transporter (SERT), which is also a high-affinity target in vivo for antidepressants, amphetamines, and cocaine. Studies show that SERT is regulated by protein kinase- and phosphataselinked pathways. In contrast, receptor-linked modulation of SERT is only minimally defined. Because noradrenergic stimulation is reported to influence 5-HT release, we explored possible presynaptic adrenoceptor-mediated regulation of SERT. In mouse forebrain synaptosomes, alpha2-adrenoceptor agonists, particularly 5-bromo-N-[4,5-dihydro-1H-imidazol-2-yl]-6-quinoxalinamine (UK14304), triggered a concentration- and time-dependent decrease in 5-HT transport. In contrast, 5-HT uptake was unaffected by pharmacological alpha1-adrenoceptor activation. Kinetically, UK14304 significantly decreased the apparent substrate affinity, Km without altering transport capacity, Vmax. At concentrations of UK14304 supporting maximal inhibition of SERT in synaptosomes, no effect on SERT in transfected cells was observed, suggesting that UK14304 acts indirectly to reduce SERT activity. The effect of UK14304 on 5-HT uptake was not shared by other Na+ and Cl--dependent transporters. UK14304-mediated inhibition of SERT function was yohimbine-sensitive, as was inhibition triggered by norepinephrine, and was abolished in the absence of added Ca2+. Moreover, UK14304 effects were attenuated by voltage-sensitive Ca2+ channel antagonists, consistent with a role for Ca2+ in UK14304 effects. In agreement with altered 5-HT transport activity in vitro, in vivo chronoamperometry studies revealed that UK14304 significantly prolonged 5-HT clearance. Our findings suggest that UK14304 modulates SERT function in vitro and in vivo via signaling pathways, possibly supported by an influx of Ca2+ through voltage-sensitive Ca2+ channels.     

Peripheral phosphodiesterase 4 inhibition produced by 4-[2-(3,4-Bis-difluoromethoxyphenyl)-2-[4-(1,1,1,3,3,3-hexafluoro-2-hydroxypropan-2-yl)-phenyl]-ethyl]-3-methylpyridine-1-oxide (L-826,141) prevents experimental autoimmune encephalomyelitis

Administration of phosphodiesterase 4 (PDE4) inhibitors suppresses the pathogenesis associated with experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis (MS). In the present study, we compared the effects of rolipram and 4-[2-(3,4-bis-difluoromethoxyphenyl)-2-[4-(1,1,1,3,3,3-hexafluoro-2-hydroxypropan-2-yl)-phenyl]-ethyl]-3-methylpyridine-1-oxide (L-826,141), a novel nonbrain penetrant PDE4 inhibitor, on the onset and severity of clinical signs in a chronic, nonrelapsing/remitting model of EAE. Both rolipram (10 mg/kg p.o.) and L-826,141 (3 mg/kg p.o.) reduced the severity of EAE relative to controls, whereas L-826,141 (3 mg/kg p.o.) also delayed disease onset. To assess whether L-826,141 prevented EAE progression after the first signs of clinical onset, rolipram (10 mg/kg p.o.) or L-826,141 (3 or 30 mg/kg p.o.) were administered 24 h after the first signs of EAE were observed. Only L-826,141 at a dose of 30 mg/kg p.o. significantly decreased the clinical severity of EAE compared with vehicle controls. Immunohistochemical detection of the neuronal activity marker Fos confirmed that L-826,141 did not reach concentrations in the central nervous system sufficient to activate central neurons. Lipopolysaccharide-induced tumor necrosis factor-alpha in whole blood and plasma concentrations of L-826,141 revealed that only the 30-mg/kg dose resulted in levels sufficient to produce a near complete inhibition of PDE4 activity in immune cells. Taken together, these results demonstrate that peripheral PDE4 inhibition, produced by L-826,141, prevents the progression of EAE after the first onset of clinical signs, and suggest that similar compounds may have clinical efficacy in the treatment of MS.     

Antihyperalgesic effects of (R,E)-N-(2-hydroxy-2,3-dihydro-1H-inden-4-yl)-3-(2-(piperidin-1-yl)-4-(trifluoromethyl)phenyl)-acrylamide (AMG8562), a novel transient receptor potential vanilloid type 1 modulator that does not cause hyperthermia in rats

Antagonists of the vanilloid receptor TRPV1 (transient receptor potential vanilloid type 1) have been reported to produce antihyperalgesic effects in animal models of pain. These antagonists, however, also caused concomitant hyperthermia in rodents, dogs, monkeys, and humans. Antagonist-induced hyperthermia was not observed in TRPV1 knockout mice, suggesting that the hyperthermic effect is exclusively mediated through TRPV1. Since antagonist-induced hyperthermia is considered a hurdle for developing TRPV1 antagonists as therapeutics, we investigated the possibility of eliminating hyperthermia while maintaining antihyperalgesia. Here, we report four potent and selective TRPV1 modulators with unique in vitro pharmacology profiles (profiles A through D) and their respective effects on body temperature. We found that profile C modulator, (R,E)-N-(2-hydroxy-2,3-dihydro-1H-inden-4-yl)-3-(2-(piperidin-1-yl)-4-(trifluoromethyl)phenyl)acrylamide (AMG8562), blocks capsaicin activation of TRPV1, does not affect heat activation of TRPV1, potentiates pH 5 activation of TRPV1 in vitro, and does not cause hyperthermia in vivo in rats. We further profiled AMG8562 in an on-target (agonist) challenge model, rodent pain models, and tested for its side effects. We show that AMG8562 significantly blocks capsaicin-induced flinching behavior, produces statistically significant efficacy in complete Freund's adjuvant- and skin incision-induced thermal hyperalgesia, and acetic acid-induced writhing models, with no profound effects on locomotor activity. Based on the data shown here, we conclude that it is feasible to modulate TRPV1 in a manner that does not cause hyperthermia while maintaining efficacy in rodent pain models.     

The benzamide derivative N-[1-(7-tert-Butyl-1H-indol-3-ylmethyl)-2-(4-cyclopropanecarbonyl-3-methyl-piperazin-1-yl)-2-oxo-ethyl]-4-nitro-benzamide (SP-10) reduces HIV-1 infectivity in vitro by modifying actin dynamics

Current treatments for patients infected with HIV are suboptimal. There is a need for new HIV therapies that act through different mechanisms than current treatments. We investigated the in vitro efficacy, safety and mechanism of action of the benzamide derivative N-[1-(7-tert-Butyl-1H-indol-3-ylmethyl)-2-(4-cyclopropanecarbonyl-3-methyl-piperazin-1-yl)-2-oxo-ethyl]-4-nitro-benzamide (SP-10), a potential new HIV treatment. When HIV-1-responsive engineered HeLa cells were pre-incubated for 48 h with either SP-10 or zidovudine (AZT), SP-10 was able to inhibit viral replication at much lower concentrations (IC50 = 0.036 nM) than AZT (IC50 = 27.4 nM). In contrast to AZT, SP-10 also inhibited replication of the multidrug-resistant HIV-1 strain MDR-769 in the HeLa cell model. In co-incubation experiments, SP-10 also inhibited the CCR5-sensitive HIV-1 BaL virus replication in human peripheral blood mononuclear cells. SP-10 displayed very low toxicity compared with current antiviral treatments. Confocal laser scanning microscopy and immunoprecipitation studies showed that SP-10 reduced the expression of CD4 and CCR5 on the surface of the host cell. SP-10 also reduced the level of gp120 binding to the cell surface. Confocal laser scanning microscopy studies showed that SP-10 blocked the formation of actin filaments (F-actin) and altered actin accumulation near the cell surface. These promising results suggest that SP-10 has a novel mechanism of action that enables effective inhibition of HIV-1 binding and cell entry. Further development of SP-10 as a new HIV treatment appears warranted.     

Antinociceptive pharmacology of N-[[4-(4,5-dihydro-1H-imidazol-2-yl)phenyl]methyl]-2-[2-[[(4-methoxy-2,6-dimethylphenyl) sulfonyl]methylamino]ethoxy]-N-methylacetamide, fumarate (LF22-0542), a novel nonpeptidic bradykinin B1 receptor antagonist

The antinociceptive pharmacology of N-[[4-(4,5-dihydro-1H-imidazol-2-yl)phenyl]methyl]-2-[2-[[(4-methoxy-2,6-dimethylphenyl) sulfonyl]methylamino]ethoxy]-N-methylacetamide fumarate (LF22-0542), a novel nonpeptidic B1 antagonist, was characterized. LF22-0542 showed high affinity for human and mouse B1 receptors with virtually no affinity for the human B2 receptor; a selectivity index of at least 4000 times was obtained when LF22-0542 was profiled throughout binding or cell biology assays on 64 other G-protein-coupled receptor, 10 ion channels, and seven enzymes. LF22-0542 was a competitive B1 receptor antagonist and elicited significant antinociceptive actions in the mouse acetic acid-induced writhing assay, as well as in the second phases of formalin-induced nociception in mice and in both the first and second phases of the formalin response in rats. LF22-0542 was active after s.c. but not p.o. administration. In B1 receptor knockout (KO) mice, acetic acid and formalin responses were significantly reduced and LF22-0542 had no additional effects in these animals. LF22-0542 alleviated thermal hypersensitivity in both acute (carrageenan) and persistent inflammatory (complete Freund's adjuvant) pain models in rats. LF22-0542 produced a full reversal of experimental neuropathic thermal hypersensitivity but was inactive in reversing nerve injury-induced tactile hypersensitivity in rats. In agreement with this observation, B1 KO mice subjected to peripheral nerve injury did not show thermal hypersensitivity but developed nerve injury-induced tactile hypersensitivity normally. The data demonstrate the antihyperalgesic actions of a selective systemically administered B1 receptor antagonist and suggest the utility of this class of agents for the treatment of inflammatory pain states and for some aspects of neuropathic pain.     

Pharmacology of the urotensin-II receptor antagonist palosuran (ACT-058362; 1-[2-(4-benzyl-4-hydroxy-piperidin-1-yl)-ethyl]-3-(2-methyl-quinolin-4-yl)-urea sulfate salt): first demonstration of a pathophysiological role of the urotensin System

Urotensin-II (U-II) is a cyclic peptide now described as the most potent vasoconstrictor known. U-II binds to a specific G protein-coupled receptor, formerly the orphan receptor GPR14, now renamed urotensin receptor (UT receptor), and present in mammalian species. Palosuran (ACT-058362; 1-[2-(4-benzyl-4-hydroxy-piperidin-1-yl)-ethyl]-3-(2-methyl-quinolin-4-yl)-urea sulfate salt) is a new potent and specific antagonist of the human UT receptor. ACT-058362 antagonizes the specific binding of (125)I-labeled U-II on natural and recombinant cells carrying the human UT receptor with a high affinity in the low nanomolar range and a competitive mode of antagonism, revealed only with prolonged incubation times. ACT-058362 also inhibits U-II-induced calcium mobilization and mitogen-activated protein kinase phosphorylation. The binding inhibitory potency of ACT-058362 is more than 100-fold less on the rat than on the human UT receptor, which is reflected in a pD'(2) value of 5.2 for inhibiting contraction of isolated rat aortic rings induced by U-II. In functional assays of short incubation times, ACT-058362 behaves as an apparent noncompetitive inhibitor. In vivo, intravenous ACT-058362 prevents the no-reflow phenomenon, which follows renal artery clamping in rats, without decreasing blood pressure and prevents the subsequent development of acute renal failure and the histological consequences of ischemia. In conclusion, the in vivo efficacy of the specific UT receptor antagonist ACT-058362 reveals a role of endogenous U-II in renal ischemia. As a selective renal vasodilator, ACT-058362 may be effective in other renal diseases.     

A convenient separation method for di(2-ethylhexyl)phthalate by novel superparamagnetic molecularly imprinted polymers

Through a surface molecular imprinting technique and coating superparamagnetic Fe₃O₄ nanoparticles with molecularly imprinted polymers (MIPs), a novel magnetic molecularly imprinted polymer (MMIP) was successfully fabricated for the convenient separation of di(2-ethylhexyl)phthalate (DEHP) with methacrylic acid as functional monomer, ethylene glycol dimethacrylate as cross linker and 2,2-azobis(isobutyronitrile) as initiator. A magnetic non-molecularly imprinted polymer (MNIP) was also prepared for comparison purposes. The morphology structure and the magnetic properties of MMIP were characterized by transmission electron microscopy (TEM), Fourier transform infrared spectrometry (FT-IR), X-ray diffraction, vibrating sample magnetometry (VSM) and thermo gravimetric analysis (TGA). The adsorption properties of MMIP and MNIP were investigated by static and dynamic adsorption experiments. The results show that the diameter of the synthesized MMIP microspheres is about 300–500 nm with good dispersibility in solvent. The prepared MMIP shows superparamagnetic properties with the maximum saturation magnetic intensity of 43.97 emu g⁻¹, and it can be conveniently separated using an external magnetic field. Compared with MNIP, MMIP has a higher adsorption capacity and better adsorption selectivity for DEHP, and the imprinting factor reaches 3.012. The regeneration adsorption experiment illuminates that the novel MMIP can be reused with good separation efficiency.

Through surface molecular imprinting technique and coating superparamagnetic Fe₃O₄ nanoparticles with molecularly imprinted polymers, a novel MMIP was successfully fabricated for the convenient separation of DEHP.     

Pharmacological characterization of a new, orally active and potent allosteric metabotropic glutamate receptor 1 antagonist, 4-[1-(2-fluoropyridin-3-yl)-5-methyl-1H-1,2,3-triazol-4-yl]-N-isopropyl-N-methyl-3,6-dihydropyridine-1(2H)-carboxamide (FTIDC)

A highly potent and selective metabotropic glutamate receptor (mGluR) 1 antagonist, 4-[1-(2-fluoropyridin-3-yl)-5-methyl-1H-1,2, 3-triazol-4-yl]-N-isopropyl-N-methyl-3,6-dihydropyridine-1(2H)-carboxamide (FTIDC), is described. FTIDC inhibits, with equal potency, l-glutamate-induced intracellular Ca(2+) mobilization in Chinese hamster ovary cells expressing human, rat, or mouse mGluR1a. The IC(50) value of FTIDC is 5.8 nM for human mGluR1a and 6200 nM for human mGluR5. The maximal response in agonist concentration-response curves was reduced in the presence of higher concentrations of FTIDC, suggesting the inhibition in a noncompetitive manner. FTIDC at 10 microM showed no agonistic, antagonistic, or positive allosteric modulatory activity toward mGluR2, mGluR4, mGluR6, mGluR7, or mGluR8. FTIDC did not displace [(3)H]l-quisqualate binding to human mGluR1a, indicating FTIDC is an allosteric antagonist. Studies using chimeric and mutant receptors of mGluR1 showed that transmembrane (TM) domains 4 to 7, especially Phe801 in TM6 and Thr815 in TM7, play pivotal roles in the antagonism of FTIDC. FTIDC inhibited the constitutive activity of mGluR1a, suggesting that FTIDC acts as an inverse agonist of mGluR1a. Intraperitoneally administered FTIDC inhibited face-washing behavior elicited by a group I mGluR agonist, (S)-3,5-dihydroxyphenylglycine in mice at doses that did not produce motor impairment. Oral administration of FTIDC also inhibited the face-washing behavior. FTIDC is a highly potent and selective allosteric mGluR1 antagonist and a compound having oral activity without species differences in its antagonistic activity on recombinant human, mouse, and rat mGluR1. FTIDC could therefore be a valuable tool for elucidating the functions of mGluR1 not only in rodents but also in humans.     

Promoted adsorptive removal of chromium(vi) ions from water by a green-synthesized hybrid magnetic nanocomposite (NFe3O4Starch-Glu-NFe3O4ED)

A novel magnetic starch-crosslinked-magnetic ethylenediamine nanocomposite, NFe₃O₄Starch-Glu-NFe₃O₄ED, was synthesized via microwave irradiation. The characteristics of the assembled NFe₃O₄Starch-Glu-NFe₃O₄ED nanocomposite were evaluated via XRD, FT-IR, TGA, BET, SEM and HR-TEM analyses. Its particle size was confirmed to be in the range 11.25–17.16 nm. The effectiveness of the designed nanocomposite for the removal of Cr(vi) ions was explored using the batch adsorption technique. Equilibrium results proved that the adsorptive removal of the target metal ions from aqueous solution was highly dependent on the optimized experimental parameters. The maximum adsorptive removal percentage values (%R) of Cr(vi) ions on NFe₃O₄Starch-Glu-NFe₃O₄ED obtained at pH 2.0 were 85.27%, 91.90%, and 96.47% using 10.0, 25.0, and 50.0 mg L⁻¹ Cr(vi), respectively, for an equilibrium time of 30 min. The adsorption process was found to be strongly influenced by the presence of interfering salts including NaCl, CaCl₂, KCl, MgCl₂, and NH₄Cl. Kinetic studies were performed and it was found that the pseudo-second and Elovich models well fitted the experimental data with the possible suggested ion-pair interaction mechanism. Different isotherm models were employed to assess the adsorption equilibrium, which was revealed by fitting Langmuir, Temkin and Freundlich models. The maximum uptake capacity based on the Langmuir model was 210.741 mg g⁻¹. The effect of temperature and thermodynamics confirmed that adsorption was spontaneous, feasible, and endothermic in nature. Finally, the validity and applicability of using the NFe₃O₄Starch-Glu-NFe₃O₄ED nanocomposite to remove Cr(vi) ions from real water matrices were confirmed in the range of 91.2–94.7 ± 2.2–3.7%.

A novel magnetic starch-crosslinked-magnetic ethylenediamine nanocomposite, NFe₃O₄Starch-Glu-NFe₃O₄ED, was synthesized via microwave irradiation for the removal of Cr(vi) ions from aquous solution using the batch adsorption technique.     

Antidepressant-like pharmacological profile of a novel triple reuptake inhibitor, (1S,2S)-3-(methylamino)-2-(naphthalen-2-yl)-1-phenylpropan-1-ol (PRC200-SS)

Due to the putative involvement of dopaminergic circuits in depression, triple reuptake inhibitors are being developed as a new class of antidepressant, which is hypothesized to produce a more rapid onset and better efficacy than current antidepressants selective for serotonin or norepinephrine neurotransmission. (1S,2S)-3-(Methylamino)-2-(naphthalen-2-yl)-1-phenylpropan-1-ol (PRC200-SS), a new triple reuptake inhibitor, potently bound to the human serotonin, norepinephrine, and dopamine transporters with K(d) values of 2.3, 0.63, and 18 nM, respectively. Inhibition of serotonin, norepinephrine, and dopamine uptake by PRC200-SS was also shown in cells expressing the corresponding transporter (K(i) values of 2.1, 1.5, and 61 nM, respectively). In vivo, PRC200-SS dose-dependently decreased immobility in the forced-swim test in rats and in the tail-suspension test in mice, models predictive of antidepressant activity, with effects comparable with imipramine. These results in the behavioral models did not seem to result from the stimulation of locomotor activity. Consistent with the in vitro data and behavioral effects, peripheral administration of PRC200-SS (5 and 10 mg/kg i.p.) significantly increased extracellular levels of serotonin and norepinephrine in the medial prefrontal cortex, and of serotonin and dopamine in the core of nucleus accumbens, with reduction of levels of 3,4-dihydroxyphenylacetic acid, homovanillic acid, and 5-hydroxyindoleacetic acid compared with levels for saline control. Furthermore, PRC200-SS self-administration, which was used as a marker of abuse liability, was not observed with rats. Therefore, it seems that PRC200-SS may represent a novel triple reuptake inhibitor and possess antidepressant activity.     

{2-[1-(3-Methoxycarbonylmethyl-1H-indol-2-yl)-1-methyl-ethyl]-1H-indol-3-yl}-acetic acid methyl ester (MIAM) inhibited human hepatocellular carcinoma growth through upregulation of Sirtuin-3 (SIRT3)

{2-[1-(3-Methoxycarbonylmethyl-1H-indol-2-yl)-1-methyl-ethyl]-1H-indol-3-yl}-acetic acid methyl ester (MIAM) is a novel indole compound. Our previous studies showed that MIAM possessed activity against many cancers xenografted in mice without significant toxicity. In this study, we determined the effect of MIAM on human hepatocellular carcinoma (HCC) by both in vitro and in vivo assays. In in vitro assay, the experiments were performed in the hypoxic incubator. MIAM inhibited HCC growth with dose-dependent manner. The effects of MIAM on HCC might be due to its activities in induction of apoptosis, arrest of cell cycle in G₀/G₁ phase. Further studies showed that MIAM might exert its actions through multiple mechanisms. MIAM could reduce intracellular ATP, increase levels of p53/p21 and SIRT3/SOD2/Bax. MIAM also had the activity of reducing HIF1α and hexokinase II (HK II) in HCC. MIAM had the activity of increasing cellular reactive oxygen species (ROS) in HCC. However, the increase of ROS might not be its main mechanism in inhibition of HCC. MIAM might inhibit HepG2 growth through induction of apoptosis. We determined the relationship between level of SIRT3 and cell viability in the MIAM-treated cells. MIAM treatment resulted in increase of SIRT3 in HCC. Further, HepG2 cells infected with human SIRT3 were more sensitive to MIAM than the cells without infection of SIRT3. These results suggested that MIAM might inhibit HCC growth through upregulation of SIRT3. Importantly, the effect of MIAM was confirmed in the HepG2 xenografts bearing in mice. MIAM treatment did not induce significant toxicology to mice. Together, MIAM could be developed as potential agent for treatment of HCC.     

Studies on antifungal agents. 18. In vitro activity of 5,5-disubstituted-3-phenyl-3-(1H-imidazol-1-ylmethyl)-2-methy lisoxazol idines and related compounds

The in vitro antifungal activity of a series of novel 5,5-disubstituted-3-phenyl-3-(1H-imidazol-1-ylmethyl)-2-methyli soxazolidines and related compounds against Trichophyton rubrum, Aspergillus fumigatus and Candida albicans was studied. The screening was performed in solid agar cultures and some structure-activity relationships involving the C-5-substitution pattern are discussed.     

(-)-(1R,2R)-3-(3-dimethylamino-1-ethyl-2-methyl-propyl)-phenol hydrochloride (tapentadol HCl): a novel mu-opioid receptor agonist/norepinephrine reuptake inhibitor with broad-spectrum analgesic properties

(-)-(1R,2R)-3-(3-dimethylamino-1-ethyl-2-methyl-propyl)-phenol hydrochloride (tapentadol HCl) is a novel micro-opioid receptor (MOR) agonist (Ki = 0.1 microM; relative efficacy compared with morphine 88% in a [35S]guanosine 5'-3-O-(thio)triphosphate binding assay) and NE reuptake inhibitor (Ki = 0.5 microM for synaptosomal reuptake inhibition). In vivo intracerebral microdialysis showed that tapentadol, in contrast to morphine, produces large increases in extracellular levels of NE (+450% at 10 mg/kg i.p.). Tapentadol exhibited analgesic effects in a wide range of animal models of acute and chronic pain [hot plate, tail-flick, writhing, Randall-Selitto, mustard oil colitis, chronic constriction injury (CCI), and spinal nerve ligation (SNL)], with ED50 values ranging from 8.2 to 13 mg/kg after i.p. administration in rats. Despite a 50-fold lower binding affinity to MOR, the analgesic potency of tapentadol was only two to three times lower than that of morphine, suggesting that the dual mode of action of tapentadol may result in an opiate-sparing effect. A role of NE in the analgesic efficacy of tapentadol was directly demonstrated in the SNL model, where the analgesic effect of tapentadol was strongly reduced by the alpha2-adrenoceptor antagonist yohimbine but only moderately attenuated by the MOR antagonist naloxone, whereas the opposite was seen for morphine. Tolerance development to the analgesic effect of tapentadol in the CCI model was twice as slow as that of morphine. It is suggested that the broad analgesic profile of tapentadol and its relative resistance to tolerance development may be due to a dual mode of action consisting of both MOR activation and NE reuptake inhibition.     

Inhibition of improgan antinociception by the cannabinoid (CB)(1) antagonist N-(piperidin-1-yl)-5-(4-chlorophenyl)-1-(2,4-dichlorophenyl)-4-methyl-1H-pyrazole-3-carboxamide (SR141716A): lack of obligatory role for endocannabinoids acting at CB(1) receptors

Improgan, a nonopioid antinociceptive agent, activates descending, pain-relieving mechanisms in the brain stem, but the receptor for this compound has not been identified. Because cannabinoids also activate nonopioid analgesia by a brain stem action, experiments were performed to assess the significance of cannabinoid mechanisms in improgan antinociception. The cannabinoid CB(1) antagonist N-(piperidin-1-yl)-5-(4-chloro phenyl)-1-(2,4-dichlorophenyl)-4-methyl-1H-pyrazole-3-carboxamide (SR141716A) induced dose-dependent inhibition of improgan antinociception on the tail-flick test after i.c.v. administration in rats. The same treatments yielded comparable inhibition of cannabinoid [R-(+)-(2,3-dihydro-5-methyl-3-[(4-mor pholinyl)methyl]pyrol[1,2,3-de]-1,4-benzoxazin-6-yl)(1-naphthalenyl)methanone monomethanesulfonate, WIN 55,212-2] analgesia. Inhibition of improgan and WIN 55,212-2 antinociception by SR141716A was also observed in Swiss-Webster mice. Radioligand binding studies showed no appreciable affinity of improgan on rat brain, mouse brain, and human recombinant CB(1) receptors, ruling out a direct action at these sites. To test the hypothesis that CB(1) receptors indirectly participate in improgan signaling, the effects of improgan were assessed in mice with a null mutation of the CB(1) gene with and without SR141716A pretreatment. Surprisingly, improgan induced complete antinociception in both CB(1) (-/-) and wild-type control [CB(1) (+/+)] mice. Furthermore, SR141716A inhibited improgan antinociception in CB(1) (+/+) mice, but not in CB(1) (-/-) mice. Taken together, the results show that SR141716A reduces improgan antinociception, but neither cannabinoids nor CB(1) receptors seem to play an obligatory role in improgan signaling. Present and previous studies suggest that Delta(9)-tetrahydrocannabinol may act at both CB(1) and other receptors to relieve pain, but no evidence was found indicating that improgan uses either of these mechanisms. SR141716A will facilitate the study of improgan-like analgesics.