Lateral Habenula 5-HT2C Receptor Function Is Altered by Acute and Chronic Nicotine Exposures.

Serotonin (5-HT) is important in some nicotine actions in the CNS. Among all the 5-HT receptors (5-HTRs), the 5-HT2CR has emerged as a promising drug target for smoking cessation. The 5-HT2CRs within the lateral habenula (LHb) may be crucial for nicotine addiction. Here we showed that after acute nicotine tartrate (2 mg/kg, i.p.) exposure, the 5-HT2CR agonist Ro 60-0175 (5-640 µg/kg, i.v.) increased the electrical activity of 42% of the LHb recorded neurons in vivo in rats. Conversely, after chronic nicotine treatment (6 mg/kg/day, i.p., for 14 days), Ro 60-0175 was incapable of affecting the LHb neuronal discharge. Moreover, acute nicotine exposure increased the 5-HT2CR-immunoreactive (IR) area while decreasing the number of 5-HT2CR-IR neurons in the LHb. On the other hand, chronic nicotine increased both the 5-HT2CR-IR area and 5-HT2CR-IR LHb neurons in the LHb. Western blot analysis confirmed these findings and further revealed an increase of 5-HT2CR expression in the medial prefrontal cortex after chronic nicotine exposure not detected by the immunohistochemistry. Altogether, these data show that acute and chronic nicotine exposure differentially affect the central 5-HT2CR function mainly in the LHb and this may be relevant in nicotine addiction and its treatment.

Zinc chelator TPEN induces pancreatic cancer cell death through causing oxidative stress and inhibiting cell autophagy.

The essential trace element zinc (Zn) is widely required in cellular functions, and abnormal Zn homeostasis causes a variety of health problems including immunodeficiency and sensory dysfunctions. Previous studies had shown that Zn availability was also important for tumor growth and progression. The aim of the present study was to investigate the potential mechanisms of N,N,N,N-Tetrakis(2-pyridylmethyl)-ethylenediamine (TPEN) (a membrane permeable zinc chelator) induced pancreatic cancer cell death. The text of inductively coupled plasma-mass spectrometry (ICP-MS) showed in human pancreatic cancer samples that the zinc content in cancer was higher than that in adjacent tissues. The pancreatic cancer cell lines Panc-1, 8988T, BxPc-3, and L3.6 were used in this study. Our results indicated that TPEN markedly induced cell death, via increasing reactive oxygen species (ROS) and restraining autophagy. Our data also indicated that TPEN-stimulated mitochondrial metabolism produced much ROS. Meanwhile, TPEN reduced the levels of glutathione (GSH) and triggered ROS outbreak, which were the main causes of cell death. In addition, cell autophagy was significantly depressed in Panc-1 cells treated by TPEN, which was due to the ability of disrupting lysosomal by TPEN. Thus, we thought zinc depletion by TPEN was a potential therapeutic strategy for pancreatic cancer.

Reversal effect of Riparin IV in depression and anxiety caused by corticosterone chronic administration in mice.

Mental disorders have a multifactorial etiology and stress presents as one of the causal factors. In depression, it is suggested that high cortisol concentration contributes directly to the pathology of this disease. Based on that, the study aims to evaluate the potential antidepressant effect of Riparin IV (Rip IV) in mice submitted to chronic stress model by repeated corticosterone administration. Female Swiss mice were selected into four groups: control (Ctrl), corticosterone (Cort), Riparin IV (Cort + Rip IV) and fluvoxamine (Cort + Flu). Three groups were administrated subcutaneously (SC) with corticosterone (20 mg/kg) during twenty-one days, while the control group received only vehicle. After the fourteenth day, groups were administrated tested drugs: Riparin IV, fluvoxamine or distilled water, by gavage, 1 h after subcutaneous injections. After the final treatment, animals were exposed to behavioral models such as forced swimming test (FST), tail suspension test (TST), open field test (OFT), elevated plus maze (EPM) and sucrose preference test (SPT). The hippocampus was also removed for the determination of BDNF levels. Corticosterone treatment altered all parameters in behavioral tests, leading to a depressive- and anxious-like behavior. Riparin IV and fluvoxamine exhibit antidepressant effect in FST, TST and SPT. In EPM and OFT, treatment displayed anxiolytic effect without alteration of locomotor activity. Corticosterone administration decreased BDNF levels and Riparin IV could reestablish them, indicating that its antidepressant effect may be related to ability to ameliorate hippocampal neurogenesis. These findings suggest that Riparin IV improves the depressive and anxious symptoms after chronic stress and could be a new alternative treatment for patients with depression.

The effects of systemic administration and local microinjection into the central nervous system of the selective serotonin 5-HT2C receptor agonist RO-600175 on sleep and wakefulness in the rat.

The effects of RO-600175, a selective 5-HT2C receptor agonist, were studied in adult rats implanted for chronic sleep recordings. Intraperitoneal administration of RO-600175 (4 mg/kg) during the light phase of the light-dark cycle significantly increased wakefulness and reduced slow wave sleep and rapid-eye-movement sleep during the first 2 h of the recording period. Direct infusion of RO-600175 into the dorsal raphe nucleus (4 mmol/l), laterodorsal tegmental nucleus (4 mmol/l), or horizontal limb of the diagonal band of Broca (4 mmol/l) also decreased rapid-eye-movement sleep. It is proposed that the activation of γ-aminobutyric acid-ergic cells located in the dorsal raphe nucleus, laterodorsal tegmental nucleus, and horizontal limb of the diagonal band of Broca is responsible, at least in part, for the effects of RO-600175 on rapid-eye-movement sleep. It is suggested that the increased wakefulness observed after systemic injection of the 5-HT2C receptor ligand could be partly related to the increased release of acetylcholine in the frontal cortex and hippocampus. However, additional studies are required to characterize the neurotransmitter systems responsible for the increase in wakefulness.

Effects of ST1936, a selective serotonin-6 agonist, on electrical activity of putative mesencephalic dopaminergic neurons in the rat brain.

The serotonin-6 (5-HT6) receptor is the most recently discovered serotonin receptor, and it represents an increasingly promising target for improving cognition in both normal and disease states. Recently, a new selective 5-HT6 receptor agonist, 2-(5 chloro-2-methyl-1H-indol-3-yl)-N,N-dimethylethanamine (ST1936), with nanomolar affinity for 5-HT6 receptors was described. We performed in-vivo electrophysiological studies to investigate the physiological role of 5-HT6 receptors in the control of the function of the substantia nigra pars compacta (SNc) and ventral tegmental area (VTA). Extracellular single-unit recordings were performed from putative dopamine-containing neurons in the SNc and VTA of anesthetised rats. In the SNc, acute systemic administration of ST1936 had no effects on basal firing activity of these dopamine neurons; however, in the VTA, ST1936 induced either dose-related increases (45% of cells) or decreases in basal activity of these dopaminergic neurons. Local application of ST1936 into the VTA caused excitation in all of the dopamine neurons, but had no effects on non-dopamine VTA neurons. Both effects of systemic and microiontophoretic ST1936 were completely reversed by the potent and selective 5-HT6 receptor antagonist 5-chloro-N-(4-methoxy-3-piperazin-1-ylphenyl)-3-methyl-2- benzothiophene-sulfonamide (SB271046). Systemic application of another 5-HT6 agonist, 2-(1-{6-chloroimidazo[2,1-b] [1,3]thiazole-5-sulfonyl}-1H-indol-3-yl)ethan-1-amine (WAY-181187), induced dose-dependent inhibition of these VTA dopaminergic neurons. ST1936 and WAY-181187 appear to have different effects on these VTA dopaminergic neurons, potentially due to different mechanisms of action or to the complexity of 5-HT6 receptor functions. Our data demonstrate the need for further investigations into the use of 5-HT6 receptor agonists to control cognitive disfunction, such as in schizophrenia and depression.

Pharmacokinetics, antitumor and cardioprotective effects of liposome-encapsulated phenylaminoethyl selenide in human prostate cancer rodent models.

PURPOSE: Cardiotoxicity associated with the use of doxorubicin (DOX), and other chemotherapeutics, limits their clinical potential. This study determined the pharmacokinetics and antitumor and cardioprotective activity of free and liposome encapsulated phenyl-2-aminoethyl-selenide (PAESe). METHODS: The pharmacokinetics of free PAESe and PAESe encapsulated in liposomes (SSL-PAESe) were determined in rats using liquid chromatography tandem mass-spectrometry. The antitumor and cardioprotective effects were determined in a mouse xenograft model of human prostate (PC-3) cancer and cardiomyocytes (H9C2). RESULTS: The encapsulation of PAESe in liposomes increased the circulation half-life and area under the drug concentration time profile, and decreased total systemic clearance significantly compared to free PAESe. Free- and SSL-PAESe improved survival, decreased weight-loss and prevented cardiac hypertrophy significantly in tumor bearing and healthy mice following treatment with DOX at 5 and 12.5 mg/kg. In vitro studies revealed PAESe treatment altered formation of reactive oxygen species (ROS), cardiac hypertrophy and gene expression, i.e., atrial natriuretic peptide and myosin heavy chain complex beta, in H9C2 cells. CONCLUSIONS: Treatment with free and SSL-PAESe exhibited antitumor activity in a prostate xenograft model and mitigated DOX-mediated cardiotoxicity.

The enhanced oral response to the 5-HT2 agonist Ro 60-0175 in parkinsonian rats involves the entopeduncular nucleus: electrophysiological correlates.

Lesions of nigrostriatal dopaminergic neurons as seen in Parkinson's disease (PD) increase orofacial responses to serotonergic (5-HT) agonists in rodents. Although this response to 5-HT agonists has been related to aberrant signalling in the basal ganglia, a group a subcortical structures involved in the control of motor behaviours, it deserves additional studies with respect to the specific loci involved. Using measurements of orofacial activity, as well as single-cell recordings in vivo, we have studied the role of the entopeduncular nucleus (EPN; equivalent to the internal globus pallidus of primates), an output structure of basal ganglia, in the hypersensitized responses to a 5-HT agonist in sham- or unilaterally dopamine-depleted rats. Intra-EPN injections of Ro 60-0175 (0.3 and 1 µg/100 nl) promoted robust oral movements in 6-OHDA rats without affecting oral activity in sham-depleted rats. Peripheral administration of Ro 60-0175 (3 mg/kg ip) decreased EPN neuronal firing rate in 6-OHDA rats compared to sham-depleted rats. Such an effect was also observed when the agonist (0.2 µg/20 nl) was locally applied onto EPN neurons. These data demonstrate the contribution of EPN to hypersensitized responses to 5-HT agonists in a rat model of PD.

Pharmacological characterization of memoquin, a multi-target compound for the treatment of Alzheimer's disease.

Alzheimer's disease (AD) is characterized by progressive loss of cognitive function, dementia and altered behavior. Over 30 million people worldwide suffer from AD and available therapies are still palliative rather than curative. Recently, Memoquin (MQ), a quinone-bearing polyamine compound, has emerged as a promising anti-AD lead candidate, mainly thanks to its multi-target profile. MQ acts as an acetylcholinesterase and ß-secretase-1 inhibitor, and also possesses anti-amyloid and anti-oxidant properties. Despite this potential interest, in vivo behavioral studies with MQ have been limited. Here, we report on in vivo studies with MQ (acute and sub-chronic treatments; 7-15 mg/kg per os) carried out using two different mouse models: i) scopolamine- and ii) beta-amyloid peptide- (Aß-) induced amnesia. Several aspects related to memory were examined using the T-maze, the Morris water maze, the novel object recognition, and the passive avoidance tasks. At the dose of 15 mg/kg, MQ was able to rescue all tested aspects of cognitive impairment including spatial, episodic, aversive, short and long-term memory in both scopolamine- and Aß-induced amnesia models. Furthermore, when tested in primary cortical neurons, MQ was able to fully prevent the Aß-induced neurotoxicity mediated by oxidative stress. The results support the effectiveness of MQ as a cognitive enhancer, and highlight the value of a multi-target strategy to address the complex nature of cognitive dysfunction in AD.

Evaluation of chemically diverse 5-HT2c receptor agonists on behaviours motivated by food and nicotine and on side effect profiles.

RATIONALE: Selective 5-HT2C receptor agonists, such as lorcaserin, are being developed for the treatment of obesity. Studies suggest that they may also have therapeutic potential for addictive behaviours including nicotine dependence, although few drugs of this class have been evaluated. OBJECTIVES: The primary aim was to evaluate the highly selective 5-HT2C agonist, CP-809101, against food-motivated (operant FR5 and progressive ratio schedules, palatability-induced feeding) and nicotine-motivated (intravenous self-administration, drug discrimination) behaviours in rats and to compare with equivalent findings for the structurally distinct 5-HT2C receptor agonists lorcaserin and Ro 60-0175. The secondary aims were to evaluate the side effect profiles of lorcaserin and CP-809101 and to determine the plasma levels of lorcaserin at a dose (1 mg/kg) that reduces both food and nicotine reinforcement for comparison to plasma concentrations reported in human trials. RESULTS: CP-809101 (0.3-3 mg/kg SC) reduced responding for both nicotine and food and blocked the discriminative stimulus properties of nicotine in a similar manner to lorcaserin and Ro 60-0175. Behaviours such as hypolocomotion, chewing and ptosis became evident following both CP-809101 and lorcaserin administration at higher doses. Plasma levels of lorcaserin were of similar range to those reported in obesity trials. CONCLUSIONS: These studies support the utility of 5-HT2C agonists as a therapeutic approach to treat nicotine dependence. Plasma exposure levels after acute lorcaserin treatment suggest that equivalent dosages could be used to evaluate these drugs in obesity and smoking cessation trials. Finally, there may be differences in the side effect profiles between lorcaserin and CP-809101, raising the possibility for tolerability differences amongst 5-HT2C agonists.

Dorsal-striatal 5-HT2A and 5-HT2C receptors control impulsivity and perseverative responding in the 5-choice serial reaction time task.

RATIONAL: Prefrontal cortex (PFC) and dorsal striatum are part of the neural circuit critical for executive attention. The relationship between 5-HT and aspects of attention and executive control is complex depending on experimental conditions and the level of activation of different 5-HT receptors within the nuclei of corticostriatal circuitry. OBJECTIVE: The present study investigated which 5-HT(2A) and 5-HT(2C) receptors in the dorsomedial-striatum (dm-STR) contribute to executive attention deficit induced by blockade of NMDA receptors in the PFC. MATERIALS AND RESULTS: Executive attention was assessed by the five-choice serial reaction time task (5-CSRTT), which provides indices of attention (accuracy) and those of executive control over performance such as premature (an index of impulsivity) and perseverative responding. The effects of targeted infusion in dm-STR of 100 and 300 ng/µl doses of the selective 5-HT(2A) antagonist M100907 and 1 and 3 µg/µl doses of 5-HT(2C) agonist Ro60-0175 was examined in animals injected with 50 ng/µl dose of a competitive NMDA receptor antagonist 3-(R)-2-carboxypiperazin-4-phosphonic acid (CPP) in the mPFC. Blockade of NMDA receptors impaired accuracy as well as executive control as shown by increased premature and perseverative responding. The CPP-induced premature and perseverative over-responding were dose-dependently prevented by both M100907 and Ro60-0175. Both drugs partially removed the CPP-induced accuracy deficit but only at the highest dose tested. CONCLUSIONS: It is suggested that in the dorsal striatum, 5-HT by an action on 5-HT(2A) and 5-HT(2C) receptors may integrate the glutamate corticostriatal inputs critical for different aspects of the 5-CSRT task performance.

Preclinical anti-angiogenesis and anti-tumor activity of SIM010603, an oral, multi-targets receptor tyrosine kinases inhibitor.

OBJECTIVE: SIM010603 is a structurally novel, oral, multi-targeted receptor tyrosine kinase inhibitor. This study investigated the anti-angiogenic and anti-tumor effects of SIM010603. METHODS: A radiometric protein kinase assay was used for measuring the kinase activity of the 32 protein kinases. Receptor phosphorylation was determined by enzyme-linked immunosorbent assay (ELISA). Cell proliferation was measured by 3-(4, 5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay. Cell chemotaxis was evaluated by modified Boyden chamber assay. Effect of SIM010603 on angiogenesis was examined by mouse cornea angiogenesis assay. Effect of SIM010603 on xenografts was assessed by tumor growth delay. Effects of SIM010603 on tumor microvascular density (MVD), recruitment of pericytes, and pericyte encapsulation of tumor vessels were analyzed by immunofluorescent staining technique. RESULTS: SIM010603 inhibited stem cell factor receptor (Kit), vascular endothelial growth factor receptor-2 (VEGFR-2), platelet-derived growth factor receptor-ß (PDGFR-ß), glial cell line-derived neurotrophic factor receptor (Rearranged during Transfection; RET), and Fms-like tyrosine kinase-3 (FLT3) with IC(50) values between 5.0 and 68.1 nmol/l. SIM010603 inhibited the phosphorylation of PDGFR-ß and VEGFR-2. Moreover, SIM010603 inhibited endothelial cell proliferation, endothelial cells chemotaxis, and corneal angiogenesis. Although SIM010603 exhibited lower activity in regard to proliferation of NCI-H460, MDA-MB-435, and T241-VEGF-A cells (IC(50) > 1 µmol/l), SIM010603 inhibited tumor growth in these xenograft tumor growth models. SIM010603 reduced tumor MVD in T241-VEGF-A tumor xenograft models and decreased positive signals of CD31, NG2 in MDA-MB-435, and LLC-SW-44 xenograft tumor models. CONCLUSIONS: These results support the clinical assessment of SIM010603 as a therapeutic agent for cancer.

An ex vivo, assessor blind, randomised, parallel group, comparative efficacy trial of the ovicidal activity of three pediculicides after a single application--melaleuca oil and lavender oil, eucalyptus oil and lemon tea tree oil, and a "suffocation" pediculicide.

BACKGROUND: There are two components to the clinical efficacy of pediculicides: (i) efficacy against the crawling-stages (lousicidal efficacy); and (ii) efficacy against the eggs (ovicidal efficacy). Lousicidal efficacy and ovicidal efficacy are confounded in clinical trials. Here we report on a trial that was specially designed to rank the clinical ovicidal efficacy of pediculicides. Eggs were collected, pre-treatment and post-treatment, from subjects with different types of hair, different coloured hair and hair of different length. METHOD: Subjects with at least 20 live eggs of Pediculus capitis (head lice) were randomised to one of three treatment-groups: a melaleuca oil (commonly called tea tree oil) and lavender oil pediculicide (TTO/LO); a eucalyptus oil and lemon tea tree oil pediculicide (EO/LTTO); or a "suffocation" pediculicide. Pre-treatment: 10 to 22 live eggs were taken from the head by cutting the single hair with the live egg attached, before the treatment (total of 1,062 eggs). TREATMENT: The subjects then received a single treatment of one of the three pediculicides, according to the manufacturers' instructions. Post-treatment: 10 to 41 treated live eggs were taken from the head by cutting the single hair with the egg attached (total of 1,183 eggs). Eggs were incubated for 14 days. The proportion of eggs that had hatched after 14 days in the pre-treatment group was compared with the proportion of eggs that hatched in the post-treatment group. The primary outcome measure was % ovicidal efficacy for each of the three pediculicides. RESULTS: 722 subjects were examined for the presence of eggs of head lice. 92 of these subjects were recruited and randomly assigned to: the "suffocation" pediculicide (n = 31); the melaleuca oil and lavender oil pediculicide (n = 31); and the eucalyptus oil and lemon tea tree oil pediculicide (n = 30 subjects). The group treated with eucalyptus oil and lemon tea tree oil had an ovicidal efficacy of 3.3% (SD 16%) whereas the group treated with melaleuca oil and lavender oil had an ovicidal efficacy of 44.4% (SD 23%) and the group treated with the "suffocation" pediculicide had an ovicidal efficacy of 68.3% (SD 38%). CONCLUSION: Ovicidal efficacy varied substantially among treatments, from 3.3% to 68.3%. The "suffocation" pediculicide and the melaleuca oil and lavender oil pediculicide (TTO/LO) were significantly more ovicidal than eucalyptus oil and lemon tea tree oil pediculicide (EO/LTTO) (P < 0.0001). Ranking: 1. "Suffocation" pediculicide (68.3% efficacy against eggs); 2. Melaleuca oil and lavender oil (44.4%) pediculicide; 3. Eucalyptus oil and lemon tea tree oil (3.3%) pediculicide. The "suffocation" pediculicide and TTO/LO are also highly efficacious against the crawling-stages. Thus, the "suffocation" pediculicide and TTO/LO should be recommended as first line treatments.

Compound A, a plant origin ligand of glucocorticoid receptors, increases regulatory T cells and M2 macrophages to attenuate experimental autoimmune neuritis with reduced side effects.

Experimental autoimmune neuritis (EAN) is a helper T cell-mediated autoimmune demyelinating inflammatory disease of the peripheral nervous system and serves as the animal model for human inflammatory demyelinating polyneuropathies. Compound A, a plant-derived phenyl aziridine precursor, was reported to activate glucocorticoid receptors to exert transrepression but not transactivation properties. In this study, we investigated the effects of Compound A in EAN rats. Compound A greatly suppressed paraparesis in EAN, even when administrated after the appearance of the first neurological signs. Accumulation of macrophages and lymphocytes, demyelination, and mRNA levels of inflammatory molecules in sciatic nerves of EAN were greatly attenuated by Compound A. In addition, Compound A inhibited progression of neuropathic pain and repressed microglia but not astrocyte activation and IL-1beta and TNF-alpha up-regulation in EAN spinal cords. In EAN sciatic nerves, Compound A treatment increased numbers of anti-inflammatory M2 macrophages. Furthermore, Compound A induced the switch of macrophages from inflammatory M1 type to anti-inflammatory M2 type in vitro. In lymph nodes of EAN rats, Compound A depressed Th1 and Th17 cytokines, but increased Th2 cytokine and Foxp3 expression. An increase of Foxp3(+)/CD4(+) regulatory T cells was seen in peripheral blood of EAN rats following Compound A treatment. In addition, Compound A did not cause a hyperglycemia effect in EAN rats as compared with the immunosuppressive steroid prednisolone. Therefore, our data demonstrated that Compound A could effectively suppress EAN with reduced side effects by attenuating inflammation, suggesting that Compound A could be a potent candidate for treatment of autoimmune neuropathies.

Characterizing the effects of 5-HT(2C) receptor ligands on motor activity and feeding behaviour in 5-HT(2C) receptor knockout mice.

5-HT(2C) receptor agonists have considerable therapeutic potential, however there is little in vivo data to compare the potency and selectivity of 5-HT(2C) receptor agonists. Since 5-HT(2C) receptor agonists reduce locomotor activity and food intake, changes in these drug-induced behaviours in 5-HT(2C) receptor knockout mice could provide a means to examine receptor selectivity in-vivo. Initially this study compared older 5-HT(2C) agonists mCPP and MK212, to newer, apparently more selective compounds: Ro 60-0175, WAY161503, CP809,101 and lorcaserin (APD356) on motor activity in wild-type, and 5-HT(2C) receptor knockout mice. Two 5-HT(2C) receptor antagonists SB242084 and SDZ SER 082 were also examined. mCPP did not significantly alter activity in wild-type mice, but enhanced activity in knockout animals. MK212 (3 and 10 mg/kg) and Ro 60-0175 (1 and 3 mg/kg) reduced activity in wild-type but not knockout animals. At 10 mg/kg, Ro 60-0175 reduced activity in knockout animals, suggesting loss of 5-HT(2C) receptor selectivity. CP809,101 and lorcaserin reduced activity in wild-type but not knockout mice. In subsequent feeding studies, Ro 60-0175 and lorcaserin reduced food intake in wild-type animals only. Selectivity of effect for mCPP was marginal. The antagonist SB242084 increased activity in wild-type animals but not in knockout mice; SB242084 did not alter feeding in either genotype. SDZ SER 082 reduced activity in both genotypes implying poor selectivity for 5-HT(2C) receptors. The data demonstrate that studying food intake, and particularly motor behaviour, in the 5-HT(2C) receptor knockout mouse is a useful and relatively simple approach for screening 5-HT(2C) receptor ligands in vivo.

A plant-derived ligand favoring monomeric glucocorticoid receptor conformation with impaired transactivation potential attenuates collagen-induced arthritis.

The glucocorticoid receptor (GR) is a transcription factor regulating its target genes either positively, through direct binding to the promoter of target genes, or negatively by the interference with the activity of transcription factors involved in proinflammatory gene expression. The well-known adverse effects of glucocorticoids are believed to be mainly caused by their GR-mediated gene-activating properties. Although dimerization of GR is thought to be essential for gene-activating properties, no compound has yet been described which selectively imposes GR monomer formation and interference with other transcription factors. In the present study, we report on a GR-binding, plant-derived compound with marked dissociative properties in rheumatoid arthritis fibroblast-like synoviocytes, which are important effector cells in inflammation and matrix degradation in rheumatoid arthritis. In addition, these findings could be extended in vivo in murine collagen-induced arthritis, in which joint inflammation was markedly inhibited without inducing hyperinsulinemia. Therefore, we conclude that GR monomers are sufficient for inhibition of inflammation in vivo.

Differential regulation of the mesoaccumbens dopamine circuit by serotonin2C receptors in the ventral tegmental area and the nucleus accumbens: an in vivo microdialysis study with cocaine.

Stimulation of central serotonin2C receptor (5-HT(2C)R) inhibits dopamine (DA)-dependent neurochemical and behavioral effects of cocaine, while 5-HT(2C)Rs locally expressed into the ventral tegmental area (VTA) and the nucleus accumbens (NAc) exert opposite functional control over cocaine-induced behavioral effects. Using in vivo microdialysis in halothane-anesthetized rats, we tested the hypothesis that this functionally opposite regulation of the mesoaccumbens DA pathway relies on the ability of 5-HT(2C)Rs in the VTA and the NAc to inhibit and enhance respectively cocaine-induced accumbal DA outflow. Intra-VTA injection of the 5-HT(2C)R agonist Ro 60-0175 at 5 microg/0.2 microl, but not 1 microg/0.2 microl, attenuated the increase in accumbal DA outflow induced by the systemic administration of 10 mg/kg of cocaine. Intra-VTA injection of the 5-HT(2C)R antagonist SB 242084 at either dose (0.1 or 0.5 microg/0.2 microl) did not modify the effects of cocaine. Intra-NAc application of Ro 60-0175 dose-dependently excited (0.1 microM) and inhibited (1 microM) cocaine-induced DA outflow. In contrast, intra-NAc application of SB 242084 resulted in diametrically opposite effects when applied at these concentrations. These results further support the idea that the overall action of central 5-HT(2C)Rs on accumbal DA output is dependent, at least in part, on the functional balance between different 5-HT(2C)R populations within the NAc and within the mesoaccumbens DA pathway (VTA vs NAc).

Synthesis of poly(beta-amino ester)s with thiol-reactive side chains for DNA delivery.

The safe and efficient delivery of DNA remains the major barrier to the clinical application of non-viral gene therapy. Here, we present novel, biodegradable polymers for gene delivery that are capable of simple graft modification and demonstrate the ability to respond to intracellular conditions. We synthesized poly(beta-amino ester)s using a new amine monomer, 2-(pyridyldithio)-ethylamine (PDA). These cationic, degradable polymers contain pyridyldithio functionalities in the side chains that react with high specificity toward thiol ligands. This reactivity is demonstrated using both mercaptoethylamine (MEA) and the thiol peptide RGDC, a ligand that binds with high affinity to certain integrin receptors. These two polymer derivatives displayed strong DNA binding as determined using electrophoresis and dye exclusion assays. In addition, the MEA-based polymer and plasmid DNA were shown to self-assemble into cationic complexes with effective diameters as low as 100 nm. Furthermore, this DNA binding ability was substantially reduced in response to intracellular glutathione concentrations, which may aid in DNA unpackaging inside the cell. These complexes also displayed low cellular toxicity and were able to mediate transfection at levels comparable to PEI in human hepatocellular carcinoma cells. These results suggest that PDA-based poly(beta-amino ester)s may serve as a modular platform for polymer-mediated gene delivery.

Synthesis and pharmacological profile of an orally-active growth hormone secretagogue, SM-130686.

Hypothalamic hormones physiologically regulate pulsatile release of growth hormone (GH) from the anterior pituitary gland. Since the discovery of these hormones in the 1970s, several new chemically synthesized peptidyl and non-peptidyl derivatives have been proved to stimulate and amplify GH secretion, and this series of molecules has been named the growth hormone secretagogues (GHSs). One of these compounds led to the discovery of a GPCR-type receptor for GHSs (GHS-R), and subsequently the endogenous ligand for the receptor has been identified, and is referred to as ghrelin. The identification of GHSs as physiological regulators of GH secretion encouraged us to examine our GHSs pharmacologically. We previously reported that novel oxindole derivatives have been identified as GHS-R agonists from our internal chemical library. Among these derivatives, (+)-6-carbamoyl-3-(2-chlorophenyl)-(2-diethylaminoethyl)-4-trifluoromethyloxindole (SM-130686, 37S) was found to have potent activity in vitro with a good pharmacokinetic profile in rats (bioavailability of 28%). In this article, we review the synthesis and pharmacological evaluation of SM-130686. SM-130686 binds specifically to GHS-R and increases the Ca(2+) concentration in Chinese hamster ovary cells expressing recombinant GHS-R. Maximal enhancement of the intracellular Ca(2+) concentration induced by SM-130686 treatment was approximately 55% that induced by ghrelin, suggesting that SM-130686 may be a partial GHS-R agonist. Also, in in vivo studies, oral administration of SM-130686 increased body length and fat-free mass gain. We compare the pharmacological profile of SM-130686 with other GHSs, including GHRH and ghrelin, and discuss the therapeutic usefulness of GHSs against several disorders, as well as for treatment of GH deficiency.

Additive impairment of the barrier function and irritation by biogenic amines and sodium lauryl sulphate: a controlled in vivo tandem irritation study.

Biogenic amines are potential irritants e.g. in fish-, meat-, milk- and egg-processing professions like cooks, butchers and bakers. The aim of this study was to test the irritative and barrier-disrupting properties of the biogenic amines ammonium hydroxide (AM), dimethylamine (DMA) and trimethylamine (TMA). A repeated sequential irritation of 30 min twice per day was performed over a total of 4 days (tandem repeated irritation test) on the back of 20 healthy volunteers of both sexes with AM, DMA, TMA and sodium lauryl sulphate (SLS). The epidermal barrier function was assessed with a Tewameter TM 210, stratum corneum surface pH was measured with a Skin-pH-Meter 900, inflammation was assessed with a Chromameter CR-300 on the a* axis for redness and a visual score was recorded. All tested biogenic amines (AM, DMA and TMA) induced a barrier disruption and a pH increase paralleled with a 1-day-delayed onset of inflammatory signs. These effects were further enhanced and accelerated by a sequential application of SLS together with the biogenic amines, and inflammation occurred earlier than with the single compounds. Acetic acid (AA) in contrast did only show mild barrier disruption and no significant inflammatory signs. Our system allowed a ranking of the different compounds in their irritative potential in the tandem irritation with SLS: SLS > NaOH > TMA > AA > AM > DMA. The results are suggestive that in the food-processing industry the simultaneous contact with biogenic amines and harmful detergents like SLS should be minimized.

Novel analogs of the sigma receptor ligand BD1008 attenuate cocaine-induced toxicity in mice.

Previous studies have shown that BD1008 (N-[2-(3,4-dichlorophenyl)ethyl]-N-methyl-2-(1-pyrrolidinyl)ethylamine) and related analogs attenuate the toxicity and stimulant effects of cocaine through antagonism of sigma receptors. In the present study, six analogs of BD1008 (UMB 98-103) were synthesized and evaluated in receptor binding and behavioral studies. Competition binding studies confirmed that all six compounds have high affinity for sigma1 receptors, moderate affinity for sigma2 receptors, and low to negligible affinity for monoamine transporters, opioid, N-methyl-D-aspartate, dopamine, and 5-HT receptors. In behavioral pharmacological studies, pretreatment of mice with UMB 100, UMB 101, or UMB 103 significantly attenuated cocaine-induced convulsions and lethality. Together with earlier studies, the data suggest that analogs of BD1008 are promising medication development leads for reducing the toxicity of cocaine.