Search

Background: Inhibitors of acetylcholinesterase (AChE) are used to treat many disorders, among which are neurodegenerative upsets, like Alzheimer’s disease (AD). One of the limited licensed AChE inhibitors (AChEIs) used as drugs is the natural compound galantamine (Gal). Objective: As Gal is a toxic compound, here we expose data about its four derivatives in hybrid peptide-norgalantamine molecules, which have shown 100 times lower toxicity. Methods: Four newly synthesized galantamine derivatives have been involved in docking analysis made by Molegro Virtual Docker. Biological assessments were performed on ICR male mice. The change in short and long-term memory performance was evaluated by passive avoidance test. AChE activity and levels of main oxidative stress parameters: lipid peroxidation, total glutathione (GSH), enzyme activities of catalase (CAT), superoxide dismutase, and glutathione peroxidase were measured in brain homogenates. Results: Our experimental data revealed that the new hybrid molecules did not impair memory performance in healthy mice. Two of the compounds demonstrated better than Gal AChE inhibitory activity in the brain. None of them changed the level of lipid peroxidation products, one of the compounds increased GSH levels, and all of them increased CAT enzyme activity. Conclusion: The new galantamine-peptide hybrids demonstrated a potential for inhibition of AChE and antioxidant activity and deserve further attention.

Alzheimer’s disease (AD), a progressive neurodegenerative disorder characterized by memory loss and cognitive functions decline, is a leading cause for dementia and currently ranked as the sixth foremost cause of death. As of present, treatment of AD is symptomatic without convincing therapeutic benefits and new, effective, therapeutic agents are pursued. Due to massive loss of cholinergic neurons and decreased acetylcholine levels, cholinesterase inhibitors like galantamine, remain the backbone of pharmacological treatment of the disease. In the present study, using behavioral and biochemical methods, four newly synthesized galantamine derivatives, Gal 34, Gal 43, Gal 44, and Gal 46, were evaluated for a beneficial effect in a scopolamine model of dementia in mice. They were designed to have all the advantages of galantamine and additionally to inhibit β-secretase and exert favorable effects on plasma lipids. Behavioral tests included step-through inhibitory avoidance, T-maze, and the hole-board test, whereas biochemical evaluations involved assessment of acetylcholinesterase activity, brain monoamines levels, lipid peroxidation, catalase, glutathione peroxidase, and superoxide dismutase activities along with measurement of total glutathione. Results show that Gal 43, Gal 44, and, in particular, Gal 46 are especially effective in improving both short- and long-term memory and in the case of Gal 46 having a significant effect on exploratory activity as well. Although Gal 34 did not show behavioral effects as convincing as those of the other three galantamine derivatives, it demonstrated persuasive antioxidant and restorative capacities, making all four galantamine derivatives promising AD treatment agents and prompting further research, especially that in many of our studies they performed better than galantamine.

Three new complexes of Ni(II), Cu(II) and Zn(II) with deoxycholate anion, of the type M(DCA)2 · nH2O (M = Cu(II) n = 4, M = Ni(II) n = 3 and M = Zn(II) n = 2) have been synthesized and characterized on the basis of elemental analysis, FTIR and UV-Vis spectroscopy, thermal analysis, molar conductivity and magnetic measurements. The cytotoxicity of the synthesized complexes was tested against HT29 human colorectal cancer cells. Applied at a concentration range of 10 - 200 µg/mL, sodium deoxycholate and its metal complexes have been found to decrease viability and growth of cultured HT29 cells in a time- and concentration-dependent manner in short-term and long-term experiments. The ability of the complexes to induce pathological changes, genotoxicity and apoptosis in the treated cells has also been proved. In addition, the complexes demonstrated a cytotoxic effect in HT29-OxPt (resistant to oxaliplatin) cells, allowing to conclude that they are more pronounced cytotoxic agents as compared to the sodium deoxycholate alone.

CART (Cocaine- and Amphetamine-Regulated Transcript) peptide is a neurotransmitter naturally occurring in the CNS and found mostly in nucleus accumbens, ventrotegmental area, ventral pallidum, amygdalae and striatum, brain regions associated with drug addiction. In the nucleus accumbens, known for its significant role in motivation, pleasure, reward and reinforcement learning, CART peptide inhibits cocaine and amphetamine-induced dopamine-mediated increases in locomotor activity and behavior, suggesting a CART peptide interaction with the dopaminergic system. Thus in the present study, we examined the effect of CART (55-102) peptide on the basal, electrical field stimulation-evoked (EFS-evoked) (30V, 2Hz, 120 shocks) and returning basal dopamine (DA) release and on the release of the DA metabolites 3,4-dihydroxyphenyl acetaldehyde (DOPAL), 3,4-dihydroxyphenylacetic acid (DOPAC), homovanillic acid (HVA), 3,4-dihydroxyphenylethanol (DOPET), 3-methoxytyramine (3-MT) as well as on norepinephrine (NE) and dopamine-o-quinone (Daq) in isolated mouse nucleus accumbens, in a preparation, in which any CART peptide effects on the dendrites or soma of ventral tegmental projection neurons have been excluded. We further extended our study to assess the effect of CART (55-102) peptide on basal cocaine-induced release of dopamine and its metabolites DOPAL, DOPAC, HVA, DOPET and 3-MT as well as on NE and Daq. To analyze the amount of [3H]dopamine, dopamine metabolites, Daq and NE in the nucleus accumbens superfusate, a high-pressure liquid chromatography (HPLC), coupled with electrochemical, UV and radiochemical detections was used. CART (55-102) peptide, 0.1μM, added alone, exerted: (i) a significant decrease in the basal and EFS-evoked levels of extracellular dopamine (ii) a significant increase in the EFS-evoked and returning basal levels of the dopamine metabolites DOPAC and HVA, major products of dopamine degradation and (iii) a significant decrease in the returning basal levels of DOPET. At the same concentration, 0.1μM, CART (55-102) peptide did not have any effect on the release of noradrenaline. In the presence of CART (55-102) peptide, 0.1μM, the effect of cocaine, 30μM, on the basal dopamine release was inhibited and the effect on the basal DOPAC release substantially increased. To our knowledge, our findings are the first to show direct neurochemical evidence that CART (55-102) peptide plays a neuromodulatory role on the dopaminergic reward system by decreasing dopamine in the mouse nucleus accumbens and by attenuating cocaine-induced effects on dopamine release.

We compared the neuroprotective action of three natural bio-antioxidants (AOs): ellagic acid (EA), &alpha, lipoic acid (LA), and myrtenal (Myrt) in an experimental model of Parkinson&rsquo, s disease (PD) that was induced in male Wistar rats through an intrastriatal injection of 6-hydroxydopamine (6-OHDA). The animals were divided into five groups: the sham-operated (SO) control group, striatal 6-OHDA-lesioned control group, and three groups of 6-OHDA-lesioned rats pre-treated for five days with EA, LA, and Myrt (50 mg/kg, intraperitoneally- i.p.), respectively. On the 2nd and the 3rd week post lesion, the animals were subjected to several behavioral tests: apomorphine-induced rotation, rotarod, and the passive avoidance test. Biochemical evaluation included assessment of main oxidative stress parameters as well as dopamine (DA) levels in brain homogenates. The results showed that all three test compounds improved learning and memory performance as well as neuromuscular coordination. Biochemical assays showed that all three compounds substantially decreased lipid peroxidation (LPO) levels, and restored catalase (CAT) activity and DA levels that were impaired by the challenge with 6-OHDA. Based on these results, we can conclude that the studied AOs demonstrate properties that are consistent with significant antiparkinsonian effects. The most powerful neuroprotective effect was observed with Myrt, and this work represents the first demonstration of its anti-Parkinsonian impact.

Elevated striatal dopamine release is thought to be one of the hallmarks of schizophrenia and correlates with its positive symptoms. Cysteamine (2-aminoethane-1-thiol), a compound naturally found in mammalian cells, inhibits amphetamine-induced dopamine-mediated increases in locomotor activity and behavior and blocks amphetamine-induced deficits in sensorimotor gating, suggesting cysteamine interaction with the dopaminergic system. Therefore, in the present study, we examined, in vivo, in the striatum of awake, freely moving rats the effect of cysteamine on the basal and amphetamine-induced release of dopamine, given also the fact that amphetamine-induced psychosis is a widely accepted animal model of schizophrenia. In vivo transversal microdialysis was used to collect the striatal dialysate samples and high performance liquid chromatography (HPLC), coupled with electrochemical detection- to assess the samples dopamine levels. Amphetamine,1μM, administered locally through the microdialysis fiber, running through both the left and right striatum, produced a significant increase in the extracellular level of dopamine. The increase lasted over an hour when dopamine gradually returned to its basal levels. Cysteamine hydrochloride, perfused locally in the sriatum via the microdialysis probe, at a concentration of 100 μM did not change the basal release of dopamine. However, at the same concentration and administered together with amphetamine, 1μM, it completely inhibited the stimulant effect of amphetamine. To our knowledge, our in vivo results are the first to show direct neurochemical evidence that cysteamine is able to modulate amphetamine-induced dopamine neuronal activity in the striatum of awake, freely moving rats by suppressing the increased by amphetamine release of dopamine.

Close functional and anatomical interactions between the neurotensin (NT) and dopamine (DA) systems suggest that NT could be associated with Parkinson’s Disease (PD). However, clinical use of NT is limited due to its rapid degradation. This has led to the synthesis of a number of new NT fragment 8-13 [NT(8-13)] analogues, such as NT2 and NT4, to avoid the fast biodegradation of NT. The aim of this study was to investigate the neuroprotective effects of NT2 and NT4 on an experimental model of Parkinson’s disease in rats induced with 6-hydroxydopamine (6-OHDA) treatment, producing striatal lesions. Wistar male rats were divided into different groups: a sham-operated (SO) group, a striatal 6-OHDA-lesioned control group, two groups of 6-OHDA-lesioned rats treated for 5 days with NT2 or NT4 (10 mg/kg, intraperitoneally) and a NT-treated group as reference. During the first and second week post lesion the animals were subjected to a number of behavioral tests (apomorphine-induced rotations, rotarod, passive avoidance test), and brain tissue was evaluated histologically and also assessed for DA levels. The results showed that both the number of apomorphine-induced rotations and falls (rotarod test) increased in the 6-OHDA group relative to the SO group. At the same time, the 6-OHDA-treated group showed significant memory impairment, based on the to step-through test, compared to the SO group. Treatment with NT2 and NT4 significantly decreased the number of apomorphine-induced rotations and improved the memory of lesioned animals, with these NT analogues demonstrating better neuroprotective and neuromodulatory effects than NT. DA content in the brain of the PD rats treated with NT2 and NT4 increased, possibly due to attenuation of the loss of DA-ergic neurons. NT2 and NT4 were found to easily penetrate the blood–brain barrier and they showed a better stability than the reference NT neuropeptide. In conclusion, the NT approach represents an attractive strategy for the treatment of neurodegenerative disease.

The aim of our study was to evaluate the influence of selective non-steroidal anti-inflammatory drug meloxicam and its metal (Cu(II), Zn(II), Co(II), Ni(II)) complexes on the viability and proliferation of cultured humancarcinoma of the uterine cervix (HeLa) and glioblastoma multiforme (8MGBA) cells. The investigations were performed by short-term (24 h–96 h, with monolayer cultures) and long-term (16 d, with three-dimensional colonies of cancer cells) experiments by using methods with different molecular/cellular targets and mechanisms of action, such as thiazolyl blue tetrazolium bromide (MTT) test, neutral red uptake cytotoxicity assay, crystal violet staining, double staining with acridine orange and propidium iodide, alkaline version of single cell gel electrophoresis (comet assay) and colony-forming technique. The obtained results revealed that the application of the examined compounds at concentrations ranging from 5 µg/mL to 500 µg/mL induced cytopathological changes, including DNA damages in the ...

Cholecystokinin, a neuroactive peptide functioning as a neurotransmitter and neuromodulator in the central nervous system, mediates a number of processes and is implicated in neurological and psychiatric disorders such as Parkinson's disease, anxiety and schizophrenia. Striatum is one of the brain structures with the highest concentrations of CCK in the brain, rich in CCK receptors as well. The physiological effect of CCK on cholinergic interneurons, which are the major interneurons in striatum and the modulatory interactions which exist between dopamine, acetylcholine and cholecystokinin in this brain structure are still unclear. We studied the effect of cholecystokinin octapeptide (CCK-8) on the release of acetylcholine (ACh) from striatal slices of the rat brain. CCK-8 (0.01-0.1μM) showed no statistically significant effect on the basal but enhanced dose-dependently the electrically (2Hz)-evoked release of [(3)H]ACh. When slices were preperfused with 100μM sulpiride, a selective dopamine D(2) receptor antagonist, the CCK-8 (0.01μM) effect on electrically stimulated ACh release was increased nearly 2-fold. A similar increase was observed after depletion of endogenous dopamine (DA) from nigro-striatal dopaminergic neurons with 6-hydroxydopamine (6-OHDA) (2× 250μg/animal, i.c.v.). Furthermore in the presence of dopamine (100μM) or apomorphine (10μM), the prototypical DA receptor agonist, CCK-8 (0.01μM) failed to enhance the stimulation-evoked release of [(3)H]ACh. The D(2) receptor agonist quinpirol (1μM) abolished the CCK-8 effect on electrically stimulated ACh release as well. The increase in electrically induced [(3)H]ACh release produced by 0.01μM CCK-8 was antagonized by d,l loxiglumide (CR 1505), 10μM, a non-peptide CCK-A receptor antagonist and by Suc-Tyr-(OSO3)-Met-Gly-Trp-Met-Asp-β-phenethyl-amide (GE-410), 1μM, a peptide CCK-A receptor antagonist. The antagonistic effect of GE-410 on the CCK-8-potentiated, electrically induced release of [(3)H]ACh was studied in striatum for the first time. CAM 1028 (10μM), a CCK-B receptor antagonist, also prevented the potentiating effect of CCK-8 (0.01μM) on electrically stimulated release of [(3)H]ACh. The presented results indicate that (i) CCK-8 is capable of increasing ACh elicited by field electrical stimulation in striatum; (ii) CCK-8 is more effective in its ACh-stimulating effect when dopaminergic activity in striatum is blocked i.e. CCK-8-facilitated release of electrically induced ACh from cholinergic interneurons in the striatum is under the inhibitory control of the tonic activity of dopamine from the nigrostriatal pathway; (iii) the enhancing effect of CCK-8 on electrically evoked ACh release is mediated through both CCK-A and CCK-B cholecystokinin receptors located most likely on the cell bodies of cholinergic interneurons in striatum.

Objective: The aim of our study was to evaluate the influence of two complexes of Zn(II)/Au(I) and Zn(II)/Ag(I) with Schiff base ligand (H2Salen) obtained from the condensation reaction between salicylaldehyde and ethylenediamine (abbreviated ZnSalenAu, ZnSalenAg) on viability and proliferation of cultured human cancer cells.Methods: The following cell lines were used as model systems: Human cervical carcinoma (cervical carcinoma), A549 (non-small cell lung cancer [NSCLC]), glioblastoma multiforme (8MGBA), and A431 (squamous cell carcinoma) and its multidrug-resistant (MDR) clones A431-MDR, A431-MRP, and A431-ABCG2 that express mdr1, mrp1, or abcg2 gene, respectively. The investigations were performed by thiazolyl blue tetrazolium bromide test, neutral red uptake cytotoxicity assay, crystal violet staining, hematoxylin and eosin staining, double staining with acridine orange, and propidium iodide in short-term experiments (12–72 h, with monolayer cell cultures) as well as colony-forming method in long-term experiments (25 days, with three dimensional cancer cell colonies).Results: The results obtained revealed that ZnSalenAu and ZnSalenAg decreased significantly viability and proliferation of the treated cells in a time- and concentration-dependent manner being more active as compared to the free ligand H2Salen.Conclusion: The present study demonstrates for the 1st time the ability of two heterometallic complexes ZnSalenAu and ZnSalenAg to decrease significantly viability and proliferation of cultured cell lines established from some of the most common and aggressive human cancers (NSCLC, carcinoma of uterine cancer, 8MGBA, and squamous cell carcinoma) as well as MDR cancer cells.

The mononuclear complex, [Co(TAMEN)](ClO(4))(2) (DMSO), containing the Mannich base N,N'-tetra-(4-antipyrylmethyl)-1,2-diaminoethane (TAMEN) as ligand, was synthesized and characterised by conductometric, electronic and infrared spectroscopic properties. The single-crystal X-ray structure show the presence of two well defined units, [Co(TAMEN)](2+) and (ClO(4))(-). The complex cation contains cobalt(II) in the pseudo octahedral environment created by the N(2)O(4) donor set of TAMEN. The cobalt(II) complex have been screened for its cytotoxic activity against three cultured human cell lines established from hepatoma (Hep G2), breast (MCF-7) and lung (A549) cancers as well as on non-tumor bovine kidney (MDBK) cells. The cytotoxic activity of the ligand TAMEN was assessed on one tumor (Hep G2) and one non-tumor (MDBK) cell lines. The cobalt(II) compound was found to decrease in a time- and concentration- dependent manner the viability of tumor (A549, MCF-7, Hep G2) cell lines, while the ligand TAMEN expressed proliferative activity on hepatoma (HepG2) and bovine kidney (MDBK) cells, especially after prolonged incubation.

Vasoactive intestinal peptide (VIP) was administered in a model of zymosan-induced generalized inflammation (ZIGI). Its beneficial action was associated with reduced TNF-α and increased IL-10 production, lowered levels of creatinine, alanine aminotransferase (ALT), aspartate aminotransferase (AST) and bilirubin in circulation. VIP diminished the level of RANTES and MIP-1α in peritoneal exudate and circulation. The neuropeptide inhibited NO release from stimulated peritoneal macrophages. Decreased spleen, liver and kidney enlargement and less pathological changes in liver were observed. The effect of VIP was attenuated by pretreatment with VIP antagonist (anti-VIP) before the induction of shock.

The modulation of striatal cholinergic neurons by somatostatin (SOM) was studied by measuring the release of acetylcholine (ACh) in the striatum of freely moving rats. The samples were collected via a transversal microdialysis probe. ACh level in the dialysate was measured by the high performance liquid chromatography method with an electrochemical detector. Local administration of SOM (0.1, 0.5 and 1 microM) produced a long-lasting and concentration-dependent increase in the basal striatal ACh output. The stimulant effect of SOM was antagonized by the SOM receptor antagonist cyclo(7-aminopentanoyl-Phe-D-Trp-Lys-Thr[BZL]) (1 microM). In a series of experiments, we studied the effect of 6,7-dinitroquinoxaline-2, 3-dione (DNQX), a selective non-NMDA (N-methyl-D-aspartate) glutamatergic antagonist, on the basal and SOM-induced ACh release from the striatum. DNQX, 2 microM, perfused through the striatum had no effect on the basal ACh output but inhibited the SOM (1 microM)-induced ACh release. The non-NMDA glutamatergic receptor antagonist 1-(4-aminophenyl)-4-methyl-7,8-methylendioxy-5H-2,3- benzodiazepine (GYKI-52466), 10 microM, antagonized the SOM (1 microM)-induced release of ACh in the striatum. Local administration of the NMDA glutamatergic receptor antagonist, 2-amino-5-phosphonopentanoic acid (APV), 100 microM, blocked SOM (1 microM)-evoked ACh release. Local infusion of tetrodotoxin (1 microM) decreased the basal release of ACh and abolished the 1 microM SOM-induced increase in ACh output suggesting that the stimulated release of ACh depends on neuronal firing. The present results are the first to demonstrate a neuromodulatory role of SOM in the regulation of cholinergic neuronal activity of the striatum of freely moving rats. The potentiating effect of SOM on ACh release in the striatum is mediated (i) by SOM receptor located on glutamatergic nerve terminals, and (ii) by NMDA and non-NMDA glutamatergic receptors located on dendrites of cholinergic interneurones of the striatum.

The aim of the study was to evaluate the influence of metal [Zn(II), Cu(II), Ni(II)] complexes with ursodeoxycholic acid (UDCA) on the viability and proliferation of tumour and non-tumour cells. Cell lines established from retrovirus-transformed chicken hepatoma (LSCC-SF-Mc29) and rat sarcoma (LSR-SF-SR) as well as from human cancers of the breast (MCF-7), uterine cervix (HeLa), lung (A549) and liver (HepG2) were used as model systems. Non-tumour human embryo (Lep-3) cells were also included in some of the experiments. The investigations were carried out by the thiazolyl blue tetrazolium bromide (MTT) test, neutral red uptake cytotoxicity assay, crystal violet staining, double staining with acridine orange and propidium iodide and the colony-forming method. The results obtained revealed that: (1) UDCA and its metal complexes in the tested concentrations decreased (to a varying degree) the viability and proliferation of the treated cells in a time- and concentration-dependent manner; (2) chicken hepatoma (LSCC-SF-Mc29) cells were most sensitive to the cytotoxic and antiproliferative action of the compounds tested, followed by rat sarcoma (LSR-SF-SR) cells; (3) Cu‒UDCA and Ni‒UDCA were more effective against animal LSCC-SF-Mc29 and LSR-SF-SR cells, while Zn‒UDCA significantly decreased the viability and proliferation of human tumour cell lines; (4) applied independently, UDCA expressed lower cytotoxic/cytostatic activity as compared to metal complexes; and (5) the sensitivity of the non-tumour embryonic Lep-3 cells to the effects of UDCA and its metal complexes was comparable or even higher than those of the human tumour cells.

Neurotensin (NT) (10(-8)-10(-6)) exerted a dose-dependent increase in the tone and release of [3H]ACh in the guinea-pig gallbladder muscle strips but was inefficient in the canine gallbladder muscle strips. However, in conscious dogs NT (2.5-20 ng/kg intravenously (i.v.)) dose-dependently increased the gallbladder pressure. Similar was the effect of CCK8 (1-10 ng/kg i.v.) and carbachol (0.5-2 micrograms/kg i.v.). The NT- or CCK8-induced gallbladder pressure was inhibited by atropine (10-50 micrograms/kg i.v.) or hexamethonium (0.5-3 mg/kg i.v.). Somatostatin (1-2 micrograms/kg i.v.) or VIP (0.5-1 microgram/kg i.v.) also reduced or even abolished the NT- or CCK8-induced gallbladder pressure. The NT-induced increase of the tone of guinea-pig gallbladder preparations was accompanied by an increase of [3H]ACh release, suggesting the involvement of cholinergic innervation.

Background In animal models of postoperative ileus (POI), inflammation of the intestine plays an important role in the pathogenesis of POI. Changes in α 2 -adrenoceptors and nitrergic regulation have been proposed to be implicated. The aim of our study was to investigate the presynaptic α 2 -receptor–mediated control of cholinergic nerve activity, the nitrergic nerve activity, and the possible role of soluble guanylate cyclase (sGC) during the inflammatory phase of POI. Methods Ileus was induced by anesthesia and manipulation of the rat jejunum. Rats were treated with the sGC inhibitors methylene blue or ODQ; nonoperated animals served as controls. After 24 h, plasma and jejunal tissue were collected for biochemical assays, nitric oxide synthase-1 (NOS-1)-immunohistochemistry, acetylcholine (Ach)-release experiments, and muscle tension experiments. Results In all operated animal groups, myeloperoxidase activity was significantly increased, which indicates initiation of an inflammatory response. The α 2 -adrenoceptor agonist UK14,304 reduced electrically induced Ach-release similarly in operated and nonoperated animals. In strips of operated animals, electrically induced nitrergic relaxations were decreased, whereas relaxations induced by exogenous nitric oxide (NO) remained unchanged compared with control. The number of myenteric neurons and the percentage of NOS-1-positive neurons were not influenced. Plasmatic cyclic guanosine monophosphate (cGMP) levels were decreased in all operated groups, whereas jejunal cGMP levels were unchanged compared with nonoperated controls; treatment with sGC inhibitors did not reduce plasmatic cGMP levels. Conclusions This study demonstrates that presynaptic α 2 -receptor mediated control of intestinal cholinergic nerve activity is unchanged during manipulation-induced inflammation. However, this inflammation induces impaired nitrergic neurotransmission related to decreased NOS-1 activity in the nitrergic nerves.

Introduction: The biological role of bile acids is well known and a number of derivatives of cholic acid are regarded as suitable candidates for the establishment of conjugated agents in carrying out site-directed anti-cancer therapy. At the same time there are data about carcinogenicity of some of these acids, which requires in-depth study of their "relationship" with cancer cells. The aim of our study was to evaluate the influence of deoxycholic acid (DCA) and its metal (CuII, ZnII, NiII) complexes on viability and proliferation of cultured human tumor cells. Materials and Methods: Human cell lines established from cancers of the breast (MCF-7), uterine cervix (HeLa), lung (A549), liver (HepG2), brain (8MGBA) and colon (HT29) were used as experimental models. A complex approach involving methods with different cellular / molecular targets was applied to evaluate the putative cytotoxic/cytostatic activities of the compounds: MTT test, neutral red uptake cytotoxicity assay, crystal violet staining, double staining with acridine orange and propidium iodide, Comet assay, colony-forming method. Data were processed by statistical analyses. Results: Administered at a concentration range of 10-200 µg/ml for 24–120 h the compounds examined decrease in various degree the viability and proliferation of the treated cells in a time- and concentration dependant manner and suppress their ability to form 3D colonies in semi-solid medium. Cytopathological changes including double stranded DNA damages have also been observed. Conclusions: The compounds investigated reduce significantly the growth of cell lines established from some of the most common and aggressive human cancers. Cu(II) and Zn(II) complexes of DCA are found to express the most promising antitumor activity. Applied independently, DCA is less effective as compared to its metal complexes. Among the cell lines involved as model systems in our study, A549 non-small cell lung cancer cells show the highest sensitivity to the cytotoxic/cytostatic properties of the tested compounds. Acknowledgements: Supported by Grant DFNI-Б02/30 from 12.12.2014 from National Scientific Fund in Bulgaria and a bilateral project between Bulgarian Academy of Sciences and Romanian Academy.

This study evaluated whether a new generation antioxidant Activin derived from the grape seed proanthocyanidins, could reduce the induction of the adhesion molecules as a result of inflammatory response in the plasma of systemic sclerosis (SSc) patients. SSc patients were divided into two groups: one group was treated with Activin, a grape seed-derived proanthocyanidins, while the other group served as control. Patients were given Activin 100 mg/day orally for one month after which the blood samples were withdrawn from both groups of the patients. Blood was also taken from normal human volunteers. Plasma was obtained in fasting state between 8 to 9 A.M. from two groups of SSc patients and controls. Soluble adhesion molecules including ICAM-1, VCAM-1, E-selectin and P-selectin as well as malonaldehyde, a marker for oxidative stress, were measured. The results of our study demonstrated up-regulation of these soluble adhesion molecules except for P-selectin, in the plasma of the SSc patients compared to those obtained from human volunteers. Activin significantly attenuated the increased expression of these adhesion molecules. In addition, there was a significant increase in the amount of malondialdehyde formation in the plasma of the SSc patients, which was also attenuated by Activin. The results of this study demonstrated that Activin could reduce the inflammatory response and the oxidative stress developed in SSc patients.

The effects of the non-N-methyl-D-aspartate (NMDA) agonist quisqualate (QUIS) and selective AMPA/kainate receptor antagonist 1-(aminophenyl)-methyl-7, 8-methyilendioxy-5H-2,3-benzodiazepine (GYKI 52466) on the release of acetylcholine (ACh) from the hippocampus and striatum of freely moving rats were studied by transversal microdialysis. Acetylcholine level in the dialisate was measured by the high performance liquid chromatography (HPLC) method with an electrochemical detector. The QUIS (100 microM) perfused through the striatum induced an increase of extracellular ACh level (250%) which lasted for over 1h and gradually returned to basal values. Local perfusion of GYKI 52466 (10-100 microM) to the striatum did not change the basal release of ACh. GYKI 52466 (10 microM) administered together with QUIS (100 microM) in he striatum antagonized the stimulant effect of QUIS on the ACh release. Local administration of the QUIS (100 microM) through the microdialysis fiber implanted in the hippocampus, caused a long lasting increase of extracellular hippocampal ACh level (360%) which was reversed when the drug was withdrawn from the perfusion solution. The stimulant effect of QUIS was antagonized by concomitant perfusion of GYKI (10 microM). No effect was seen on the basal ACh release when GYKI (10-100 microM) was perfused through the hippocampus. Local perfusion with tetrodotoxin (1 microM) decrease the basal release of ACh and prevented the QUIS-induced increase of ACh both in the hippocampus and striatum. Our in vivo neurochemical results indicate that hippocampal and striatal cholinergic systems are regulated by non-NMDA (probably AMPA) glutamatergic receptors located in the hippocampus and striatum.

Vasoactive intestinal peptide (VIP) was tested for its capability to protect the intrinsic nerves of guinea-pig urinary bladder from damage due to anoxia/glucopenia and reperfusion. Guinea-pig detrusor strips were mounted for tension recording in small organ baths and the nerves were subjected to electric field stimulation. VIP (0.3 microM) improved significantly the response of strips to electrical field stimulation either during anoxia/glucopenia or thereafter during reperfusion, as compared to untreated tissues. The antioxidant activity of VIP assessed as its capability to scavenge peroxyl radicals during linoleic acid oxidation corresponded to 6.42+/-0.13 pIC(50) M, i.e. close to the concentration proved to protect strips against the anoxic--glucopenic and reperfusion damage.

2-t-butyl-4-methoxyphenol (BHA), 3,5-di-t-butyl-hydroxyanisole (DTBHA), 2,6-diisopropylphenol (propofol), alpha-tocopherol (alpha-TOC) and two newly synthesised analogues of BHA, namely 1-O-(4-hydroxy-3-t-butyl)phenyl-2,3,4,6-tetra-O-acetyl-beta-D-glucopyranose (beta-TAG) and 1-O-(4-hydroxy-3-t-butyl)phenyl-beta-D-glucopyranose (beta-GLU), were tested for their capability to protect the intrinsic nerves of guinea-pig urinary bladder from damage due to anoxia-glucopenia and re-exposure to glucose and O2. Guinea-pig detrusor strips were mounted for tension recording in small organ baths, superfused with warmed Krebs solution and the nerves stimulated electrically either under control or ischaemia-like (anoxia-glucopenia) and reperfusion-like conditions (normal medium re-superfusion). The Ca2+ antagonist activity of the compounds was assessed by their effect on the contraction of detrusor strips induced by 60 mM K+ Krebs solution in the presence of either 0.5 mM or 5 mM Ca2+. The antioxidant activity was illustrated by the ability of the compounds to scavenge peroxyl radicals generated by linoleic acid oxidation. All the compounds, except beta-GLU and alpha-TOC, inhibited in a concentration-dependent manner K+-induced contractions of detrusor muscles, the inhibition being inversely related to the Ca2+ concentration of the perfusion solution; moreover, they exhibited a marked antiperoxidant activity with pIC50 values decreasing in the order: DTBHAalpha-TOCBHAbeta-TAGpropofolbeta-GLU. alpha-TOC, BHA, DTBHA and beta-TAG improved significantly the response of the strips to electrical field stimulation either during the anoxia-glucopenia phase or thereafter when recovering during reperfusion, as compared to untreated tissues. The neuroprotection afforded by the phenol derivatives as well as by alpha-TOC was positively correlated to their antioxidant activity, but not to their Ca2+ antagonist activity.

We investigated in rats the effect NG-nitro- l -arginine methyl ester ( l -NAME) on retention of a passive avoidance response, and cortical ACh release monitored using the microdialysis technique. Post-training administration of l -NAME impaired 24 h retention of a passive avoidance and decreased cortical ACh release. Both effects of l -NAME were reversed by l -Arg. These results suggest that nitric oxide is involved in retention of the passive avoidance response through the modulation of the forebrain cholinergic system.

The present study sought to examine the interrelationship between nitric oxide (NO) and vasoactive intestinal peptide (VIP) in myocardial protection. Isolated rat hearts were perfused for 15 min with buffer only (Group I); 0.3 μM VIP (Group II); 3 μM L-arginine (a precursor of NO) (Group III); VIP and aminoguanidine (iNOS blocker) (Group IV); or L-arginine plus VIP 10-28 (VIP inhibitor) (Group V). Each heart was then made globally ischemic for 30 min followed by 2 h reperfusion. Both VIP and NO were found to provide cardioprotection during ischemia and reperfusion. However, the beneficial effects of VIP and NO were reduced by inhibition of NO and VIP, respectively, suggesting that cardioprotection by VIP is modulated by NO and vice versa. The results of this study suggested a coordinated regulation by cardioprotection by NO and VIP.

The effects of neurotensin (NT) on the release of acetylcholine (ACh), aspartate (Asp), glutamate (Glu) and gamma-aminobutyric acid (GABA) from the hippocampus of freely moving rats were studied by transversal microdialysis. ACh was detected by High Performance Liquid Chromatography (HPLC) with electrochemical detection while GABA, glutamate and aspartate were measured using HPLC with fluorometric detection. Neurotensin (0.2 and 0.5 microM) administered locally through the microdialysis probe to the hippocampus produced a long-lasting and concentration-dependent increase in the basal extracellular levels of GABA and ACh but not of glutamate and aspartate. The increase in the extracellular levels of GABA and ACh produced by 0.5 microM neurotensin in the hippocampus reached a maximum of about 310% for GABA and 250% for ACh. This stimulant effect of NT was antagonized by the NT receptor antagonist SR 48692 (100 microg/kg, i.p.). Local infusion of tetrodotoxin (1 microM) decreased the basal release of ACh, GABA, Asp, Glu and prevented the 0.2 microM NT-induced increase in GABA and ACh release. The effect of NT on the release of ACh was blocked by the GABA(A) receptor antagonist bicuculline (2-10 microM). Our findings indicate for the first time that neurotensin plays a neuromodulatory role in the regulation of GABAergic and cholinergic neuronal activity in the hippocampus of awake and freely moving rats. The potentiating effects of neurotensin on GABA and ACh release in the hippocampus are probably mediated by (i) NT receptors located on GABAergic cell bodies and (ii) through GABA(A) receptors located on cholinergic nerve terminals.