Both Stereoselective (R)- and (S)-1-Methyl-1,2,3,4-tetrahydroisoquinoline Enantiomers Protect Striatal Terminals Against Rotenone-Induced Suppression of Dopamine Release

1-Methyl-1,2,3,4-tetrahydroisoquinoline (1MeTIQ) is present in the human and rodent brain as a mixture of stereospecific (R)- and (S)-1MeTIQ enantiomers. The racemate, (R,S)-1MeTIQ, exhibits neuroprotective activity as shown in the earlier study by the authors, and In addition, it was suggested to play a crucial physiological role in the mammalian brain as an endogenous regulator of dopaminergic activity. In this article, we investigated the influence of stereospecific enantiomers of 1MeTIQ, (R)- and (S)-1MeTIQ (50 mg/kg i.p.) on rotenone-induced (3 mg/kg s.c.) behavioral and neurochemical changes in the rat. In behavioral study, in order to record dynamic motor function of rats, we measured locomotor activity using automated locomotor activity boxes. In biochemical studies, we analyzed in rat striatum the concentration of dopamine (DA) and its metabolites: intraneuronal DOPAC, extraneuronal 3-MT, and final HVA using HPLC with electrochemical detection. Otherwise, DA release was estimated by in vivo microdialysis study. The behavioral study has demonstrated that both acute and repeated (3 times) rotenone administration unimportantly depressed a basic locomotor activity in rat. (R)- and (S)-1MeTIQ stereoisomers (50 mg/kg i.p.) produced a modest behavioral activation both in naïve and rotenone-treated rats. The data from ex vivo neurochemical experiments have shown stereospecificity of 1MeTIQ enantiomers in respect of their effects on DA catabolism. (R)-1MeTIQ significantly increased both the level of the final DA metabolite, HVA (by about 70%), and the rate of DA metabolism (by 50%). In contrast to that, (S)-1MeTIQ significantly depressed DOPAC, HVA levels (by 60 and 40%, respectively), and attenuated the rate of DA metabolism (by about 60%). On the other hand, both the enantiomers increased the concentrations of DA and its extraneuronal metabolite, 3-MT in rat striatum. In vivo microdialysis study has shown that repeated but not acute administration of rotenone produced a deep and significant functional impairment of striatal DA release. Both (R)- and (S)- stereospecific enantiomers of 1MeTIQ antagonized rotenone-induced suppression of DA release; however, the effect of (R)-1MeTIQ was more strongly expressed in microdialysis study. In conclusion, we suggest that both chiral isomers of 1MeTIQ offer neuroprotection against rotenone-induced disturbances in the function of dopaminergic neurons and (R,S)-1MeTIQ will be useful as a drug with marked neuroprotective activity in the brain

Rapid recycling of glutamate transporters on the astroglial surface.

Glutamate uptake by astroglial transporters confines excitatory transmission to the synaptic cleft. The efficiency of this mechanism depends on the transporter dynamics in the astrocyte membrane, which remains poorly understood. Here, we visualise the main glial glutamate transporter GLT1 by generating its pH-sensitive fluorescent analogue, GLT1-SEP. Fluorescence recovery after photobleaching-based imaging shows that 70-75% of GLT1-SEP dwell on the surface of rat brain astroglia, recycling with a lifetime of ~22 s. Genetic deletion of the C-terminus accelerates GLT1-SEP membrane turnover while disrupting its surface pattern, as revealed by single-molecule localisation microscopy. Excitatory activity boosts surface mobility of GLT1-SEP, involving its C-terminus, metabotropic glutamate receptors, intracellular Ca2+, and calcineurin-phosphatase activity, but not the broad-range kinase activity. The results suggest that membrane turnover, rather than lateral diffusion, is the main 'redeployment' route for the immobile fraction (20-30%) of surface-expressed GLT1. This finding reveals an important mechanism helping to control extrasynaptic escape of glutamate

Extractos de brotes de soja desecados : Propiedades antioxidantes

En los últimos años, la industria de alimentos ha enfocados sus mayores esfuerzos a satisfacer las crecientes demandas de los consumidores por alimentos saludables. La incorporación de antioxidantes de origen natural sustituyendo parcial o totalmente los sintéticos constituye un paso importante en este sentido. El objetivo del presente trabajo fue evaluar el efecto del tratamiento térmico de deshidratación sobre las propiedades antioxidante de extractos hidroalcohólicos de brotes deshidratados de soja (BDS). El extracto crudo de BDS, obtenido por extracción con una mezcla de etanol absoluto:agua en una proporción previamente optimizada para tal fin, fue sometido a un proceso de eliminación del solvente a 50 ºC a presión reducida, hasta la obtención de un residuo sólido de coloración amarillenta (extracto seco), el cual fue pulverizado y almacenado a -18 °C en atmosfera de nitrógeno. Posteriormente el extracto seco fue reconstituido para ser analizado en su contenido de polifenoles, flavonoides, poder reductor, capacidad quelante de metales, y capacidad de captura de radicales hidroxilo, DPPH y ABTS. Fueron utilizados como estándares ácido gálico (AG), quercetina (Q), ácido ascórbico (AA) y ácido etilendiaminotetraacético (EDTA). Los resultados obtenidos mostraron que las propiedades antioxidantes del extracto deshidratado (por g de materia seca) no fueron afectadas significativamente (p<0,05) en cuanto al contenido de polifenoles (30,4±1,8 mg equivalentes AG), poder reductor (15,5±6,7 mg equivalentes AA), capacidad de captura de radicales ABTS y DPPH (98,5±1,8 y 4,8±0,1 mg equivalentes AA respectivamente). Por el contrario, en el extracto desecado, se observaron incrementos (p<0,05) en el contenido de flavonoides (de 9,1±0,7 a 12,5±0,2 mg equivalentes de Q), en la capacidad capturadora de radicales hidroxilo (de 12,6±5,2 a 56,2±0,3 %) y en la capacidad quelante de metales (de 17,6±0,8 a 43,0±2,1 mg equivalentes EDTA). Una probable explicación a este último comportamiento sería que el proceso de eliminación del solvente ejerció una pequeña purificación parcial del extracto crudo (rendimiento aproximadamente 90 %) y que el proceso de deshidratación al hidrolizar los glicósidos de los isoflavonoides liberó más sitios reactivos frente al Al³⁺, Fe²⁺ y OH●. En conclusión, el tratamiento térmico aplicado en la eliminación del solvente de extractos hidroalcohólicos de BDS no ejerció un efecto nocivo sobre la actividad antioxidante, mejorando las posibilidades de conservación y de aplicaciones tecnológicas.Centro de Investigación y Desarrollo en Criotecnología de Alimento

Human neutrophils communicate remotely via calcium-dependent glutamate-induced glutamate release

Summary Neutrophils are white blood cells that are critical to acute inflammatory and adaptive immune responses. Their swarming-pattern behavior is controlled by multiple cellular cascades involving calcium-dependent release of various signaling molecules. Previous studies have reported that neutrophils express glutamate receptors and can release glutamate but evidence of direct neutrophil-neutrophil communication has been elusive. Here, we hold semi-suspended cultured human neutrophils in patch-clamp whole-cell mode to find that calcium mobilization induced by stimulating one neutrophil can trigger an N-methyl-D-aspartate (NMDA) receptor-driven membrane current and calcium signal in neighboring neutrophils. We employ an enzymatic-based imaging assay to image, in real time, glutamate release from neutrophils induced by glutamate released from their neighbors. These observations provide direct evidence for a positive-feedback inter-neutrophil communication that could contribute to mechanisms regulating communal neutrophil behavior

Recubrimiento comestible activo sobre hamburguesas de pescado cocidas y refrigeradas

En este trabajo se estudió el efecto de un recubrimiento comestible activo, aplicado en la superficie de hamburguesas cocidas de pescado, sobre la pérdida de peso y la oxidación lipídica durante el almacenamiento refrigerado. La solución formadora de películas (SFP) fue elaborada en base a proteína de suero de quesería concentrada (WPC) y plastificada con glicerol (Gly) en concentraciones de 8,7 g proteína/100 g de solución formadora y 38 g Gly/100 g proteína. La SFP fue adicionada con un extracto liofilizado de brotes de soja (ELBS) con 31,5 mg equivalentes de ácido gálico por g de materia seca de polifenólicos, en una concentración de 0,8% (p/p) en la SFP y de 6,5% en la película formada. Como sistema modelo del recubrimiento se elaboraron películas con y sin el agregado de ELBS que fueron analizadas para determinar contenido de compuestos reductores liberados a un medio acuoso (método Folin-Ciocalteu) y permeabilidad al oxígeno (Mocon OX-Tran 2/20). Las hamburguesas cocidas fueron cubiertas por medio de pincelado y secado de la SFP sobre toda la superficie de las mismas dos veces. Luego fueron almacenadas a 10 °C durante 8 días. A los 0, 4 y 8 días se retiraron para su análisis dos muestras de las Hamburguesas con Recubrimiento (HR), Hamburguesas con Recubrimiento Activo (HRA) y Hamburguesas sin recubrir (HC). La pérdida de peso de dichas muestras fue analizada por gravimetría y la oxidación lipídica fue evaluada a través del valor peróxido (FIL/IDF- 74A:1991) y las sustancias reactivas al ácido 2-tiobarbiturico (TBARS). Los resultados obtenidos indicaron que las películas liberaron sustancias reductoras desde la matriz. Las permeabilidades al oxígeno de las películas con y sin adición de ELBS no fueron significativamente diferentes (p<0,05) siendo sus valores de 145,06±26,13 y 151,19±58,05 (cm³.μm/m².d.kPa), respectivamente. Las pérdidas de peso durante el almacenamiento de las HR (5,46±3,1%) y las HRA (4,74±2,5%) fueron significativamente menores respecto a las HC (18,6±0,6%). Con respecto a la oxidación lipídica, tanto la formación de peróxidos como la formación de TBARS fueron inhibidas en las hamburguesas con recubrimiento presentando a los 4 días de almacenamiento los mayores porcentajes de reducción, 59,0±2,3% y 71,6±0,4%; y 17,8±5,2% y 26,1±0,9% para HR y HRA respectivamente. Es decir, los recubrimientos comestibles elaborados sobre la base de proteína de suero de quesería adicionada con extracto de brotes de soja protegen las pérdidas de peso y la oxidación lipídica de las hamburguesas de pescado cocidas durante la refrigeración.Centro de Investigación y Desarrollo en Criotecnología de Alimento

Promjene citokroma P450 jetre i mozga nakon višekratne primjene kokaina, samog ili u kombinaciji s nifedipinom

The objective of this study was to evaluate possible changes caused by multiple cocaine administration, alone and in combination with 1,4-dihydropiridine calcium channel blocker nifedipine, on cytochrome P450 levels both in the brain and liver. The experiment was done on male Wistar rats divided in four groups: control, treated with nifedipine (5 mg kg-1 i.p. for five days), treated with cocaine (15 mg kg-1 i.p. for five days), and treated with nifedipine and 30 minutes later with cocaine (also for five days). Total cytochrome P450 was measured spectrometrically in liver and brain microsomes. Multiple administration of cocaine alone and in combination with nifedipine did not change the brain P450 significantly. In the liver, nifedipine significantly increased P450 by 28 % vs. control. In contrast, cocaine significantly decreased P450 by 17 % vs. control. In animals treated with nifedipine and cocaine, cytochrome P450 increased 11 % (p<0.01) vs. control, decreased 12.5 % (p<0.001) vs. nifedipine group and increased 34 % (p<0.0001) vs. cocaine group. These results suggest that the cocaine and nifedipine interact at the metabolic level.Cilj je ovog istraživanja bio ocijeniti moguće promjene uzrokovane višestrukom primjenom kokaina kao jedinog agensa odnosno u kombinaciji s nifedipinom, 1,4-dihidropiridinskim blokatorom kalcijevih kanala, na razine citokroma P450 u mozgu i jetri štakora. Životinje (mužjaci Wistar štakora) podijeljene su u četiri skupine: kontrolnu skupinu, skupinu koja je primala nifedipin (5 mg kg-1 ip. pet dana), skupinu koja je primala kokain (15 mg kg-1 ip. pet dana) i skupinu koja je primala nifedipin te pola sata kasnije kokain (također pet dana). Ukupna količina citokroma P450 mjerena je spektrofotometrijski u mikrosomima jetre i mozga. Višestruka primjena samo kokaina odnosno u kombinaciji s nifedipinom nije značajno promijenila razine citokroma P450 u mozgu. U jetri je međutim nifedipin u odnosu na kontrolnu skupinu uzrokovao povišenje razina P450, za statistički značajnih 28 %. Kokain je uzrokovao statistički značajan pad razine P450 za 17 % u odnosu na kontrolnu skupinu. U životinja koje su primale kombinaciju nifedipina i kokaina razina citokroma P450 narasla je za 11 % (p<0.01) u odnosu na kontrolu, bila je 12.5 % (p<0.001) niža u odnosu na skupinu koja je primala nifedipin te viša za 34 % (p<0.0001) u odnosu na skupinu koja je primala samo kokain. Rezultati ovog istraživanja upućuju na interakcije ovih spojeva koje se odvijaju na razini metabolizm

Synaptic Remodeling Depends on Signaling between Serotonin Receptors and the Extracellular Matrix

Rewiring of synaptic circuitry pertinent to memory formation has been associated with morphological changes in dendritic spines and with extracellular matrix (ECM) remodeling. Here, we mechanistically link these processes by uncovering a signaling pathway involving the serotonin 5-HT7 receptor (5-HT7R), matrix metalloproteinase 9 (MMP-9), the hyaluronan receptor CD44, and the small GTPase Cdc42. We highlight a physical interaction between 5-HT7R and CD44 (identified as an MMP-9 substrate in neurons) and find that 5-HT7R stimulation increases local MMP-9 activity, triggering dendritic spine remodeling, synaptic pruning, and impairment of long-term potentiation (LTP). The underlying molecular machinery involves 5-HT7R-mediated activation of MMP-9, which leads to CD44 cleavage followed by Cdc42 activation. One important physiological consequence of this interaction includes an increase in neuronal outgrowth and elongation of dendritic spines, which might have a positive effect on complex neuronal processes (e.g., reversal learning and neuronal regeneration)

Effect of an organic pesticide on mortality and learning in Africanized honey bees (Apis mellifera L.) in Brasil

Seven experiments were conducted. First, the influence of the consumption of different concentrations of the organic pesticide Bioganic® on mortality was assessed at 11 different time intervals in Africanized honey bees (Apis mellifera L.) as was direct application of the pesticide to the abdomen. Results indicated that the pesticide was not lethal to bees regardless of concentration at any intervals tested whether consumed directly or applied to the abdomen. Second, the effects of different concentrations of the pesticide on Pavlovian conditioning and complex learning were examined in harnessed foragers. Results suggest that the pesticide affected learning; however, this conclusion may be erroneous because the bees would not feed on the pesticide, thus making it impossible to properly assess Pavlovian conditioning and complex learning. Consequently, the effect of the agrochemical on complex learning was examined in free flying bees trained to land on targets. The results of free flying experiments indicated that bees did not avoid a target associated with the smell of the pesticide but did avoid the target if they had to drink the pesticide.Peer reviewedPsychologyZoolog