Pacenta polypeptide injection alleviates the fibrosis and inflammation in cigarette smoke extracts-induced BEAS-2B cells by modulating MMP-9/TIMP-1 signaling.

Chronic obstructive pulmonary disease (COPD) has high morbidity and mortality. Here, we aimed to explore the roles and potential correlation of placenta polypeptide injection (PPI) and MMP-9/TIMP-1 signaling pathway in COPD. BEAS-2B cells were treated with cigarette smoke extract (CSE) to establish a COPD cell model in vitro. The cell survival and cytotoxic effect were measured by CCK-8, LDH release and flow cytometry assays. The inflammatory responses were determined by western blot and ELISA assay. Cell fibrosis was assessed by immunofluorescence and western blot assays. PPI treatment had no cytotoxic effect on BEAS-2B cells until the final concentration reached to 10%. In the range of 0%-8% final concentration, PPI treatment weakened CSE-induced the decrease of cell viability and the increase of LDH level in a concentration-dependent manner. Four percent PPI treatment enhanced cell viability and decreased cell apoptosis of CSE-treated cells in a time-dependent manner. Moreover, 4% PPI treatment significantly decreased inflammatory responses and fibrosis induced by CSE, while AMPA (MMPs agonist) had opposite effects. Notably, AMPA reversed the protective roles of PPI on CSE-induced inflammation and fibrosis. Mechanistically, 4% PPI treatment significantly suppressed MMP-1, MMP-2, MMP-3, MMP-9, MMP-13, and MMP-19 levels, but enhanced TIMP-1, TIMP-2, TIMP-3, and TIMP-4 levels. Among them, MMP-9 and TIMP-1 might be the main target of PPI. PPI effectively attenuated CSE-induced inflammation and fibrosis in vitro by regulating MMP-9/TIMP-1 signaling pathway.

Rutin prevents seizures in kainic acid-treated rats: evidence of glutamate levels, inflammation and neuronal loss modulation.

Rutin, a naturally derived flavonoid molecule with known neuroprotective properties, has been demonstrated to have anticonvulsive potential, but the mechanism of this effect is still unclear. The current study aimed to investigate the probable antiseizure mechanisms of rutin in rats using the kainic acid (KA) seizure model. Rutin (50 and 100 mg kg-1) and carbamazepine (100 mg kg-1) were administered daily by oral gavage for 7 days before KA (15 mg kg-1) intraperitoneal (i.p.) injection. Seizure behavior, neuronal cell death, glutamate concentration, excitatory amino acid transporters (EAATs), glutamine synthetase (GS), glutaminase, α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor subunits GluA1 and GluA2, N-methyl-D-aspartate (NMDA) receptor subunits GluN2A and GluN2B, activated astrocytes, and inflammatory and anti-inflammatory molecules in the hippocampus were evaluated. Supplementation with rutin attenuated seizure severity in KA-treated rats and reversed KA-induced neuronal loss and glutamate elevation in the hippocampus. Decreased glutaminase and GluN2B, and increased EAATs, GS, GluA1, GluA2 and GluN2A were observed with rutin administration. Rutin pretreatment also suppressed activated astrocytes, downregulated the protein levels of inflammatory molecules [interleukin-1ß (IL-1ß), interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), high mobility group Box 1 (HMGB1), interleukin-1 receptor 1 (IL-1R1), and Toll-like receptor-4 (TLR-4)] and upregulated anti-inflammatory molecule interleukin-10 (IL-10) protein expression. Taken together, the results indicate that the preventive treatment of rats with rutin attenuated KA-induced seizures and neuronal loss by decreasing glutamatergic hyperactivity and suppressing the IL-1R1/TLR4-related neuroinflammatory cascade.

Respiratory Effects of the Atypical Tricyclic Antidepressant Tianeptine in Human Models of Opioid-induced Respiratory Depression.

BACKGROUND: Animal data suggest that the antidepressant and α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor modulator tianeptine is able to prevent opioid-induced respiratory depression. The hypothesis was that oral or intravenous tianeptine can effectively prevent or counteract opioid-induced respiratory depression in humans. METHODS: Healthy male and female volunteers participated in two studies that had a randomized, double blind, placebo-controlled, crossover design. First, oral tianeptine (37.5-, 50-, and 100-mg doses with 8 subjects) pretreatment followed by induction of alfentanil-induced respiratory depression (alfentanil target concentration, 100 ng/ml) was tested. Primary endpoint was ventilation at an extrapolated end-tidal carbon dioxide concentration of 55 mmHg (V̇E55). Next, the ability of four subsequent and increasing infusions of intravenous tianeptine (target tianeptine plasma concentrations 400, 1,000, 1,500, and 2,000 ng/ml, each given over 15 min) to counteract remifentanil-induced respiratory depression was determined in 15 volunteers. Ventilation was measured at isohypercpania (baseline ventilation 20 ± 2 l/min). The primary endpoint was minute ventilation during the 60 min of tianeptine versus placebo infusion. RESULTS: Alfentanil reduced V̇E55 to 13.7 (95% CI, 8.6 to 18.8) l/min after placebo pretreatment and to 17.9 (10.2 to 25.7) l/min after 50-mg tianeptine pretreatment (mean difference between treatments 4.2 (-11.5 to 3.0) l/min, P = 0.070). Intravenous tianeptine in the measured concentration range of 500 to 2,000 ng/ml did not stimulate ventilation but instead worsened remifentanil-induced respiratory depression: tianeptine, 9.6 ± 0.8 l/min versus placebo 15.0 ± 0.9 l/min; mean difference, 5.3 l/min; 95% CI, 2.5 to 8.2 l/min; P = 0.001, after 1 h of treatment. CONCLUSIONS: Neither oral nor intravenous tianeptine were respiratory stimulants. Intravenous tianeptine over the concentration range of 500 to 2000 ng/ml worsened respiratory depression induced by remifentanil.

Tetanus toxin C-fragment protects against excitotoxic spinal motoneuron degeneration in vivo.

The tetanus toxin C-fragment is a non-toxic peptide that can be transported from peripheral axons into spinal motoneurons. In in vitro experiments it has been shown that this peptide activates signaling pathways associated with Trk receptors, leading to cellular survival. Because motoneuron degeneration is the main pathological hallmark in motoneuron diseases, and excitotoxicity is an important mechanism of neuronal death in this type of disorders, in this work we tested whether the tetanus toxin C-fragment is able to protect MN in the spinal cord in vivo. For this purpose, we administered the peptide to rats subjected to excitotoxic motoneuron degeneration induced by the chronic infusion of AMPA in the rat lumbar spinal cord, a well-established model developed in our laboratory. Because the intraspinal infusion of the fragment was only weakly effective, whereas the i.m. administration was remarkably neuroprotective, and because the i.m. injection of an inhibitor of Trk receptors diminished the protection, we conclude that such effects require a retrograde signaling from the neuromuscular junction to the spinal motoneurons. The protection after a simple peripheral route of administration of the fragment suggests a potential therapeutic use of this peptide to target spinal MNs exposed to excitotoxic conditions in vivo.

Design, synthesis and pharmacological evaluation of N3 aryl/ heteroaryl substituted 2-((benzyloxy and phenylthio) methyl) 6,7- dimethoxyquinazolin-4(3H)-ones as potential anticonvulsant agents.

Novel N3 aryl/heteroaryl substituted 2-((benzyloxy and phenylthio) methyl) 6,7-dimethoxyquinazolin-4(3H)- ones (8a-8l) were synthesized and evaluated for their anticonvulsant activity using various models of epilepsy, such as maximal electroshock (MES), subcutaneous pentylenetetrazole (scPTZ) and intracerebroventricular AMPA (α-amino-3- hydroxy-5-methyl-4-isoxazolepropionic acid)-induced seizures in mice. The rotarod test has been used to determine the acute neurotoxicity. Further, the serum enzymatic activities of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) were assessed along with histopathological examination of liver. Among all the derivatives, compound 8f displayed significant activity profile based on the overall magnitude of activity and minimum neurotoxicity.

Examination of Org 26576, an AMPA receptor positive allosteric modulator, in patients diagnosed with major depressive disorder: an exploratory, randomized, double-blind, placebo-controlled trial.

Org 26576 acts by modulating ionotropic AMPA-type glutamate receptors to enhance glutamatergic neurotransmission. The aim of this Phase 1b study (N=54) was to explore safety, tolerability, pharmacokinetics, and pharmacodynamics of Org 26576 in depressed patients. Part I (N=24) evaluated the maximum tolerated dose (MTD) and optimal titration schedule in a multiple rising dose paradigm (range 100 mg BID to 600 mg BID); Part II (N=30) utilized a parallel groups design (100 mg BID, 400 mg BID, placebo) to examine all endpoints over a 28-day dosing period. Based on the number of moderate intensity adverse events reported at the 600 mg BID dose level, the MTD established in Part I was 450 mg BID. Symptomatic improvement as measured by the Montgomery-Asberg Depression Rating Scale was numerically greater in the Org 26576 groups than in the placebo group in both study parts. In Part II, the 400 mg BID dose was associated with improvements in executive functioning and speed of processing cognitive tests. Org 26576 was also associated with growth hormone increases and cortisol decreases at the end of treatment but did not influence prolactin or brain-derived neurotrophic factor. The quantitative electroencephalogram index Antidepressant Treatment Response at Week 1 was able to significantly predict symptomatic response at endpoint in the active treatment group, as was early improvement in social acuity. Overall, Org 26576 demonstrated good tolerability and pharmacokinetic properties in depressed patients, and pharmacodynamic endpoints suggested that it may show promise in future well-controlled, adequately powered proof of concept trials.

Maximum tolerated dose evaluation of the AMPA modulator Org 26576 in healthy volunteers and depressed patients: a summary and method analysis of bridging research in support of phase II dose selection.

BACKGROUND: A key challenge to dose selection in early central nervous system (CNS) clinical drug development is that patient tolerability profiles often differ from those of healthy volunteers (HVs), yet HVs are the modal population for determining doses to be investigated in phase II trials. Without clear tolerability data from the target patient population, first efficacy trials may include doses that are either too high or too low, creating undue risk for study participants and the development program overall. Bridging trials address this challenge by carefully investigating safety and tolerability in the target population prior to full-scale proof-of-concept trials. OBJECTIVE: Org 26576 is an alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) receptor positive allosteric modulator that acts by modulating ionotropic AMPA-type glutamate receptors to enhance glutamatergic neurotransmission. In preparation for phase II efficacy trials in major depressive disorder (MDD), two separate phase I trials were conducted to evaluate safety, tolerability, and pharmacokinetics in HVs and in the target patient population. METHODS: Both trials were randomized and placebo controlled, and included multiple rising-dose cohorts (HV range 100-400 mg bid; MDD range 100-600 mg bid). HVs (n = 36) and patients with MDD (n = 54) were dosed under similarly controlled conditions in an inpatient facility, HVs for up to 14 days and MDD patients for up to 28 days. Safety, tolerability, and pharmacokinetics were assessed frequently. RESULTS: Despite comparable pharmacokinetic profiles, the maximum tolerated dose (MTD) in depressed patients was 450 mg bid, twice the MTD established in HVs. No clinically relevant safety issues associated with Org 26576 were noted. CONCLUSION: This article presents safety, tolerability, and pharmacokinetic data from two different populations examined under similar dosing conditions. The important implications of such bridging work in phase II dose selection are discussed, as are study design and data interpretation challenges.

A translational approach to evaluate the efficacy and safety of the novel AMPA receptor positive allosteric modulator org 26576 in adult attention-deficit/hyperactivity disorder.

BACKGROUND: It has been posited that glutamate dysregulation contributes to the pathophysiology of attention-deficit/hyperactivity disorder (ADHD). Modulation of glutamate neurotransmission may provide alternative therapeutic options. The novel 2-amino-3-(5-methyl-3-oxo-1,2-oxazol-4-yl)propanoic acid receptor positive allosteric modulator Org 26576 was investigated with a translational approach including preclinical and clinical testing. METHODS: Neonatal rat 6-hydroxydopamine lesion-induced hyperactivity was used as preclinical model. Seventy-eight ADHD adults entered a multicenter, double-blind, placebo-controlled, two-period crossover trial. After 1 week placebo lead-in, 67 subjects were randomized into one of four treatment sequences: sequence A (n = 15) Org 26576 (100 mg b.i.d.) for 3 weeks, followed by a 2-week placebo crossover and 3 weeks placebo; sequence B (n = 16) 5 weeks placebo followed by 3 weeks Org 26576 (100 mg b.i.d.); sequence C (n = 18) Org 26576 flexible dose (100-300 mg b.i.d.) for 3 weeks, then 5 weeks placebo; sequence D (n = 18) 5 weeks placebo followed by 3 weeks Org 26576 (100-300 mg b.i.d.). The Adult ADHD Investigator Symptom Rating Scale was used to assess changes in ADHD symptomatology. RESULTS: Org 26576 (1, 3, 10 mg/kg intraperitoneal) produced dose-dependent inhibition of locomotor hyperactivity in 6-hydroxydopamine-lesioned rats. Org 26576 (100 mg b.i.d.) was superior to placebo in treating symptoms of adult ADHD subjects. The primary Adult ADHD Investigator Symptom Rating Scale results were supported by some secondary analyses. However, Org 26576 (100-300 mg b.i.d.) did not confirm these results. Most frequently reported adverse events were nausea, dizziness, and headache. CONCLUSIONS: These preclinical and clinical findings suggest that Org 25676 may have utility in the treatment of ADHD.

Glyphosate in northern ecosystems.

Glyphosate is the main nonselective, systemic herbicide used against a wide range of weeds. Its worldwide use has expanded because of extensive use of certain agricultural practices such as no-till cropping, and widespread application of glyphosate-resistant genetically modified crops. Glyphosate has a reputation of being nontoxic to animals and rapidly inactivated in soils. However, recent evidence has cast doubts on its safety. Glyphosate may be retained and transported in soils, and there may be cascading effects on nontarget organisms. These processes may be especially detrimental in northern ecosystems because they are characterized by long biologically inactive winters and short growing seasons. In this opinion article, we discuss the potential ecological, environmental and agricultural risks of intensive glyphosate use in boreal regions.

Activation of somatostatin receptor (sst 5) protects the rat retina from AMPA-induced neurotoxicity.

In a recent study, we employed an in vivo model of retinal excitotoxicity to investigate the neuroprotective effect of somatostatinergic agents. Intravitreal administration of somatostatin and sst(2) selective agonists protected the retina from (RS)-alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid hydrobromide (AMPA) induced excitotoxicity. The sst(1) and sst(4) selective ligands had no effect (Kiagiadaki and Thermos, 2008). The presence of sst(5) receptors in rat retina was only recently reported (Ke and Zhong, 2007). Synthetic agonists that activate sst(2) receptors also bind with high affinity to the sst(5) subtype. In the present study the putative neuroprotective effects of sst(5) receptor activation were investigated. Adult female and male Sprague-Dawley (250-350g) rats were employed. Groups of animals received intravitreally PBS (50mM) or AMPA (42 nmol/eye) alone or in combination with L-817,818 (sst(5), 10(-5), 10(-4)M). To exclude neuroprotective effects via the activation of sst(2) receptors, L-817,818 (10(-4)M) was coinjected with the sst(2) antagonist CYN-154806 (10(-4)M). Immunohistochemistry (IHC) studies using the anti-retinal marker choline acetyltransferase (ChAT) and TUNEL staining were employed to examine retinal cell loss and protection. IHC and Western blot analysis were also employed to assess whether the sst(5) receptors are viable in the AMPA treated tissue as compared to control retina. sst(5) receptors were not affected by AMPA. L-817,818 protected the retina from the AMPA insult in the dose of 10(-4)M, while CYN-154806 (10(-4)M) had no effect on the sst(5) neuroprotection. TUNEL staining confirmed the AMPA-induced retinal toxicity and the L-817,818 neuroprotection. These results demonstrate for the first time that sst(5) receptors are functional in the retina, and that sst(5) analogs administered intravitreally protect the retina from excitotoxicity. Further studies are essential to ascertain the therapeutic relevance of these results.

The analgesic action of topical diclofenac may be mediated through peripheral NMDA receptor antagonism.

The analgesic mechanism underlying the efficacy of topical diclofenac in the treatment of musculoskeletal pain is incompletely understood. The present study investigated whether intramuscular injection of diclofenac (0.1mg/ml, approximately 340microM) could attenuate jaw-closer muscle nociceptor discharge and mechanical sensitization induced by activation of peripheral 5-hydroxytryptamine (serotonin) or excitatory amino acid receptors in anesthetized Sprague-Dawley rats. Diclofenac inhibited nociceptor discharge evoked by NMDA, but had no effect on nociceptor discharge evoked by 5-hydroxytryptamine or AMPA. Subsequent experiments revealed that diclofenac-mediated inhibition of NMDA-evoked nociceptor discharge was competitive. Intramuscular injection of 5-hydroxytryptamine, NMDA and AMPA also decreased nociceptor mechanical threshold, however, only the mechanical sensitization produced by NMDA was reversed by diclofenac. Co-administration of the proinflammatory prostaglandin PGE(2) did not alter the ability of diclofenac to significantly attenuate NMDA-evoked nociceptor discharge or NMDA-induced mechanical sensitization. Intramuscular injection of either diclofenac or the competitive NMDA receptor antagonist DL-2-amino-5-phosphonovalerate (50mM) alone could elevate nociceptor mechanical threshold for a 30min period post-injection. The present study indicates that in vivo, diclofenac can exert a selective, competitive inhibition of peripheral NMDA receptors at muscle concentrations achievable after topical administration of diclofenac containing preparations. This property may contribute to the analgesic effect of topical diclofenac when used for muscle pain.

Functional recovery of hearing following ampa-induced reversible disruption of hair cell afferent synapses in the avian inner ear.

Hair cells in the avian inner ear can regenerate after acoustic trauma or ototoxic insult, and significant functional recovery from hearing loss occurs. However, small residual deficits remain, possibly as a result of incomplete reestablishment of the hair cell neural synaptic contacts. The aim of the present study was to determine if intracochlear application of alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA), an excitotoxic glutamate agonist, causes reversible disruption of hair cell neural contacts in the bird, and to what extent functional recovery occurs if synaptic contacts are reestablished. Compound action potential (CAP) responses to tone bursts were recorded to determine hearing thresholds during a recovery period of up to 4 months. Subsequently, the response properties of single auditory nerve fibers were analyzed in the same animals. Instillation of AMPA into the perilymph of the scala tympani led to immediate abolition of CAP thresholds. Partial recovery occurred over a period of 2-3 weeks, without further improvement of thresholds thereafter. High-frequency thresholds did not reach control values even after 3-4 months of recovery. Single-ganglion cell response properties, obtained 3-4 months after AMPA treatment, showed elevated thresholds at the fiber's characteristic frequency (CF) for units with CF above 0.3 kHz. Sharpness of tuning (Q(10 dB)) was reduced in units with CF above 0.4 kHz. The spontaneous firing rate was higher in units with CF above 0.18 kHz. The maximum sound-evoked discharge rate was also increased. Transmission electron micrographs of the basilar papilla showed that, following AMPA treatment, the nerve endings went through a sequence of swelling, degeneration and recovery over a period of 3-7 days. The process of neosynaptogenesis was completed 14 days after exposure. The present findings are strong evidence for a role of glutamate or a related excitatory amino acid as the afferent transmitter in the avian inner ear. In addition they show that functional recovery after disruption and regeneration of hair cell neural synapses, without apparent damage to the hair cells, is incomplete.

Excitotoxicity-induced expression of amyloid precursor protein (beta-APP) in the hippocampus and cortex of rat brain. an electron-microscopy and biochemical study.

After stereotaxic microinjection of N-methyl-D-aspartate (NMDA) or alpha-amino-3-hydroxy-5-methyl isoxazole-4-propionic acid (AMPA) to CA1 of rat hippocampus, the animals were sacrificed: 0 h, 2 h, 12 h, 24 h and 3 days after the insult. Other groups of animals before microinjection of the excitotoxins received intraperitoneal injection of dizocilpine (MK-801). Expression of beta-APP was assessed by immunohistochemical and immunobiochemical methods, and the results were correlated with changes in tissue ultrastructure observed in the electron microscopy. The results of the immunochemical analyses study demonstrated that application of NMDA and AMPA resulted in the increase of the expression of beta-APP in the CA1 of hippocampus and to a less extent in the cortex. Pretreatment with MK-801 strongly suppressed this effect. Beta-amyloid release was not detected. Morphological and cytochemical study revealed that NMDA injection induced massive damage of hippocampal and cortical neurones, associated with mitochondrial calcium sequestration and unusual accumulation of neurofilaments. Ultrastructural changes after AMPA application were limited to the brain cortex. These data indicate that although excitotoxic insult induces hyperexpression of beta3-APP, there is no relation between this effect and neurodegeneration, and excitotoxicity does not induce amyloidogenic processing of beta-APP.

Basal forebrain cholinergic lesions enhance conditioned approach responses to stimuli predictive of food.

This study examined the effects of lesions to different neuronal populations within the basal forebrain on reward-related learning. Rats received bilateral alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) or quinolinate lesions that preferentially destroy the cholinergic nucleus basalis magnocellularis (NBM) or noncholinergic ventral pallidal neurons, respectively. Both lesions enhanced conditioned approach responses to stimuli predictive of food but did not increase the locomotor stimulating effect of d-amphetamine. Although both lesions disrupted the discriminative control over behavior by a conditioned stimulus, they did not impair the subsequent acquisition of instrumental responding with conditioned reinforcement (CR). Indeed, both lesions were associated with an increased responding with CR following intra-accumbens infusions of d-amphetamine (0, 1, 3, 10, and 20 microg). Quinolinate lesions also increased responses on an inactive control lever. Neither lesion altered consummatory responses to food or sucrose. Results suggest that NBM lesions may disrupt the balance between cortical and subcortical dopamine levels, and/or produce a deficit in attentional mechanisms that is manifested as increased responding to specific stimuli.

Pharmacological characterization of AMPA-induced biting behaviour in mice.

The spinal cord dorsal horn contains neural mechanisms which can greatly facilitate pain. It is well established that excitatory amino acids, aspartate and glutamate, are involved in the spinal transmission of nociceptive information and in the development of hyperalgesia. In the present study, intrathecal (i.t.) administration of alpha-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid (AMPA), a structural analog of L-glutamate, produced a dose-dependent behavioural syndrome characterized by caudally directed biting in mice. We demonstrated that peripheral pre-administration of the AMPA receptor antagonists 2,3-dihydroxy-6-nitro-7-sulfamoylbenzo(F)quinoxaline (NBQX, 10-100 mg/kg s.c.) and 1-(4-aminophenyl)-3-methylcarbamoyl-4-methyl-3,4-dihydro-7, 8-methylene-dioxy-5H-2,3-benzo-diazepine-HCl (GYKI 53655, 3-10 mg/kg s.c.), and also of the NMDA receptor antagonist 5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5, 10-imine maleate (MK 801, 0.3-1 mg/kg s.c.) reversed this effect. These findings suggest that the hyperalgesia induced by the i.t. injection of AMPA in mice involves the activation of both NMDA and non-NMDA excitatory amino acid receptor sites.