Beata Bystrowska

Zinc and Propolis Reduces Cytotoxicity and Proliferation in Skin Fibroblast Cell Culture: Total Polyphenol Content and Antioxidant Capacity of Propolis

It has been demonstrated that zinc exerts its beneficial influence on skin fibroblasts. Propolis, a complex mixture of plant-derived and bees’ products, was reported to stimulate cicatrization processes in skin and prevent infections. The aim of this study was to find out how zinc and propolis influence human skin fibroblasts in cell culture and to compare the effect of individual compounds to the effect of a mixture of zinc and propolis. In this study, zinc, as zinc aspartate, at a concentration of 16xa0μM, increased human fibroblasts proliferation in cell culture, whereas propolis at a concentration of 0.01xa0% (w/v) revealed antiproliferative and cytotoxic action followed by mild cell necrosis. In culture, zinc was effectively transported into fibroblasts, and propolis inhibited the amount of zinc incorporated into the cells. An addition of propolis to the medium caused a decrease in the Zn(II) amount incorporated into fibroblasts. The obtained results also indicate an appreciable antioxidant property of propolis and revealed its potential as a supplement when applied at doses lower than 0.01xa0% (w/v). In conclusion, the present study showed that zinc had a protective effect on human cultured fibroblasts’ viability, although propolis revealed its antiproliferative action and caused mild necrosis.

Investigation of the GPR39 zinc receptor following inhibition of monoaminergic neurotransmission and potentialization of glutamatergic neurotransmission.

Zinc can regulate neural function in the brain via the GPR39 receptor. In the present study we investigated whether inhibition of serotonin, noradrenaline and dopamine synthesis and potentialization of glutamate, via administration of p-chlorophenylalanine (pCPA), α-methyl-p-tyrosine (αMT) and N-methyl-D-aspartatic acid (NMDA), respectively, would cause changes in GPR39 levels. Western blot analysis showed GPR39 up-regulation following 3-day administration of αMT and NMDA in the frontal cortex, and GPR39 down-regulation following 10-day administration of pCPA, αMT, and NMDA in the hippocampus of CD-1 mice. There were no changes in serum zinc levels. Additionally, we investigated tryptophan, tyrosine and glutamate concentrations in the hippocampus and frontal cortex of GPR39 knockout (GPR39 KO) mice. Liquid chromatography-mass spectrometry (LC-MS) showed a significant decrease in tryptophan and tyrosine, but not in glutamate concentrations in the hippocampus of GPR39 KO mice. There were no changes in the frontal cortex between GPR39 KO and wild type. These results indicate a possible role of the GPR39 receptor in monoaminergic and glutamatergic neurotransmission, which plays an important role in the pathophysiology of depression.

Evaluation of the role of NMDA receptor function in antidepressant-like activity. A new study with citalopram and fluoxetine in the forced swim test in mice

BACKGROUNDnThe NMDA/glutamate receptors are involved in the mechanism of antidepressant activity.nnnMETHODSnThe present study was designed to investigate the effect of NMDA receptor ligands (agonists and antagonists of glutamate sites) on the antidepressant-like activity of selective serotonin reuptake inhibitors (SSRIs), citalopram and fluoxetine, in the forced swim test in mice.nnnRESULTSnThe antidepressant activity (reduction in immobility time) of citalopram but not of fluoxetine was antagonized by N-methyl-D-aspartate acid and enhanced by CGP37849 (antagonist of the NMDA receptor).nnnCONCLUSIONSnThe present literature data indicate that the antidepressant-like activity of conventional antidepressants is generally affected by the NMDA receptor, although by modulation from different sites of the complex. Thus, it supports the issue of the ability of NMDA receptor antagonists to enhance the antidepressant action in human depression.

Docosahexaenoic acid attenuates in endocannabinoid synthesis in RAW 264.7 macrophages activated with benzo(a)pyrene and lipopolysaccharide

Endocannabinoids are synthetized as a results of demand from membrane phospholipids. The formation and actions of these lipid mediators depend to a great extent on the prevalence of precursor fatty acid (FA), and can be influenced by diet or supplementation. The purpose of this study was to evaluate the interactive effects of lipopolysaccharide (LPS) and benzo(a)pyrene (BaP) in RAW 264.7 cells supplemented with docosahexaenoic acid (DHA). After LPS and/or BaP treatment in macrophages pre-incubated with DHA, a significant decrease in the amount of fatty acid was observed. The highest content of monounsaturated fatty acids was detected in RAW 264.7 cells co-treated with LPS and BaP. Significant interactions between LPS and BaP co-treatment in terms of endocannabinoid levels were observed in RAW 264.7 cells after DHA supplementation. The highest amount of endocannabinoids was detected in macrophages supplemented with DHA and co-treated with BaP and LPS: arachidonoyl ethanolamine AEA (5.9μg/mL), docosahexaenoyl ethanolamide DHEA (10.6μg/mL) and nervonoyl ethanolamide NEA (16.5μg/mL). The highest expression of cyclooxygenase (COX-2) and cannabinoid receptor 2 (CB2) was noted in macrophages supplemented with DHA and activated with LPS and BaP. Our data suggested a novel, CB2 receptor-dependent, environmental stress reaction in macrophages co-treated with LPS and BaP after supplementation with DHA. Despite the synergistic LPS and BaP action DHA potentiates the anti-inflammatory response in RAW 264.7 cells.

Cocaine self-administration, extinction training and drug-induced relapse change metabotropic glutamate mGlu5 receptors expression: evidence from radioligand binding and immunohistochemistry assays.

Several behavioral findings highlight thexa0importance of glutamatergic transmission and its metabotropic receptor type 5 (mGlu5) in the controlling of cocaine reward and seeking behaviors. The molecular or neurochemical nature of such interactions is not well recognized, so in the present paper we determine if cocaine self-administration and extinction/reinstatement models with the yoked triad control procedure alter mGlu5 receptor density in rats. [³H]MPEP was used to evaluate mGlu5 receptors density and affinity in selected brain structures, while immunofluorescence analysis was used to detect changes in mGlu5 receptors brain location. Cocaine self-administration and yoked cocaine delivery evoked a significant elevation in mGlu5 receptors density in the dorsal striatum, while receptor protein expression was importantly elevated in the substantia nigra and reduced in the nucleus accumbens shell. Cocaine administration followed by 10 extinction training sessions resulted in biphasic mGlu5 receptor density changes in the prefrontal cortex-nucleus accumbens pathway. mGlu5 receptors up-regulation was noted for cocaine self-administration and extinction training in the hippocampus and in yoked cocaine controls following drug abstinence in the dorsal striatum. A cocaine priming dose (but not a saline priming) resulted in a significant decrease of mGlu5 receptors density in the nucleus accumbens of rats previously treated with the drug and in the hippocampus of rats previously self-administered cocaine. The latter decrease in mGlu5 receptors density and protein expression in the hippocampus was parallel to an increase in [³H]MPEP affinity and opposite to a rise observed after single cocaine administration (ip) to drug-naïve yoked saline controls. Additionally, we also observed a significant elevation in the protein expression of the tested receptors in the limbic cortex in both cocaine groups. The present results shown modality dependent and brain-region specific changes in mGlu5 receptors localization and membrane specific binding.

Effects of Cocaine Self-Administration and Its Extinction on the Rat Brain Cannabinoid CB1 and CB2 Receptors

The aim of this study was to evaluate changes in the expression of cannabinoid type 1 (CB1) and 2 (CB2) receptor proteins in several brain regions in rats undergoing cocaine self-administration and extinction training. We used a triad-yoked procedure to distinguish between the motivational and pharmacological effects of cocaine. Using immunohistochemistry, we observed a significant decrease in CB1 receptor expression in the prefrontal cortex, dorsal striatum, and the basolateral and basomedial amygdala following cocaine (0.5xa0mg/kg/infusion) self-administration. Increased CB1 receptor expression in the ventral tegmental area in rats with previous cocaine exposure was also found. Following cocaine abstinence after 10xa0days of extinction training, we detected increases in the expression of CB1 receptors in the substantia nigra in both cocaine groups and in the subregions of the amygdala for only the yoked cocaine controls, while any method of cocaine exposure resulted in a decrease in CB2 receptor expression in the prefrontal cortex (pu2009<u20090.01), nucleus accumbens (pu2009<u20090.01), and medial globus pallidus (pu2009<u20090.01). Our findings further support the idea that the eCB system and CB1 receptors are involved in cocaine-reinforced behaviors. Moreover, we detected a cocaine-evoked adaptation in CB2 receptors in the amygdala, prefrontal cortex, and globus pallidus.