2-arachidonoylglycerol metabolism is differently modulated by oligomeric and fibrillar conformations of amyloid beta in synaptic terminals

Alzheimer´s disease (AD) is the most prevalent disorder of senile dementia mainly characterized by amyloid-beta peptide (Aβ) deposits in the brain. Cannabinoids are relevant to AD as they exert several beneficial effects in many models of this disease. Still, whether the endocannabinoid system is either up- or down-regulated in AD has not yet been fully elucidated. Thus, the aim of the present paper was to analyze endocannabinoid 2-arachidonoylglycerol (2-AG) metabolism in cerebral cortex synaptosomes incubated with Aβ oligomers or fibrils. These Aβ conformations were obtained by "aging" the 1-40 fragment of the peptide under different agitation and time conditions. A diminished availability of 2-AG resulting from a significant decrease in diacylglycerol lipase (DAGL) activity was observed in the presence of large Aβ1-40 oligomers along with synaptosomal membrane damage, as judged by transmission electron microscopy and LDH release. Conversely, a high availability of 2-AG resulting from an increase in DAGL and lysophosphatidic acid phosphohydrolase activities occurred in the presence of Aβ1-40 fibrils although synaptosomal membrane disruption was also observed. Interestingly, neither synaptosomal mitochondrial viability assayed by MTT reduction nor membrane lipid peroxidation assayed by TBARS formation measurements were altered by Aβ1-40 oligomers or fibrils. These results show a differential effect of Aβ1-40 peptide on 2-AG metabolism depending on its conformation.Fil: Pascual, Ana Clara. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones Bioquímicas de Bahía Blanca. Universidad Nacional del Sur. Instituto de Investigaciones Bioquímicas de Bahía Blanca; Argentina. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia; ArgentinaFil: Gaveglio, Virginia Lucía. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones Bioquímicas de Bahía Blanca. Universidad Nacional del Sur. Instituto de Investigaciones Bioquímicas de Bahía Blanca; ArgentinaFil: Giusto, Norma Maria. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones Bioquímicas de Bahía Blanca. Universidad Nacional del Sur. Instituto de Investigaciones Bioquímicas de Bahía Blanca; ArgentinaFil: Pasquaré, Susana Juana. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones Bioquímicas de Bahía Blanca. Universidad Nacional del Sur. Instituto de Investigaciones Bioquímicas de Bahía Blanca; Argentin

The endocannabinoid system in the visual process

An increasing number of articles have been published in recent years on the role of the endocannabinoid system (ECS) in different cellular processes. Here we review and discuss findings on the ECS in visual processing and present the structure of the retina. We focus on the photoreceptor cell and the events that occur in the phototransduction process, considering the conformational light-induced changes in rhodopsin and in particular its chromophore (11-cis retinal). Advances in the distribution and function of the endocannabinoid system in the retina with special reference to its function in the physiological light process are also addressed, as is the relationship between rhodopsin, retinal pathologies and the ECS.Fil: Pasquaré, Susana Juana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones Bioquímicas de Bahía Blanca. Universidad Nacional del Sur. Instituto de Investigaciones Bioquímicas de Bahía Blanca; Argentina. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia; ArgentinaFil: Chamorro Aguirre, Estefania. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones Bioquímicas de Bahía Blanca. Universidad Nacional del Sur. Instituto de Investigaciones Bioquímicas de Bahía Blanca; ArgentinaFil: Gaveglio, Virginia Lucía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones Bioquímicas de Bahía Blanca. Universidad Nacional del Sur. Instituto de Investigaciones Bioquímicas de Bahía Blanca; Argentina. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia; Argentin

Towards a better method of cannabinoid extraction and preservation for cannabis-based products

Recombinant human erythropoietin (Epo) has been successful in the treatment of anemia of different etiologies but high Epo doses, used to reduce the frequency of administration or to treat refractory anemia, have been linked with adverse outcomes. Previously, we observed a decreased effect of high Epo concentrations on endothelial cell migration. Here, we studied the antiapoptotic effect of Epo on erythroleukemia K562 cells exposed to TNF-a (T), after incubation with increasing concentrations of Epo (10, 100 and 400 U/mL) and erythroid differentiation with hemin. While Epo10 prevented the increase in the percentage of apoptotic nuclei observed with TNF-a, Epo100 and Epo400 did not show that protection. Considering that this effect could be related to the decreased availability of the Epo receptor, we investigated the activity of protein tyrosine phosphatase 1B (PTP1B) and the process of proteasomal degradation in this cell model. PTP1B activity, which regulates many aspects of the signaling pathways elicited by Epo upon EpoR activation, showed no significant differences between cultures with low and high Epo concentrations. Then, we used the proteasome inhibitor MG132 to evaluate if EpoR internalization could affect the antiapoptotic effect of Epo against TNF-a. In the presence of MG132, the results with high concentrations of Epo were similar to those observed with Epo10T (Hoechst staining, C 13.5 ± 0.7, T 31.5 ± 1.5*, Epo10T 22.1 ± 1.1*, Epo100T 29.4 ± 1.4*, Epo400T 29.9 ± 2.2*, Epo100TMG 21.7 ± 19, and Epo400TMG 22 ± 1.3 %, *P<0.05, n= 6). Based on this, it can be suggested that the kinetics of EpoR internalization/degradation, mediated by the proteasome, could explain, at least in part, the lack of antiapoptotic effect of high concentrations of Epo. The present results give new insights that may contribute to understand Epo behavior when cells of different tissues are activated by a high concentration of the hormone, and may help to adequate therapeutic strategies.Fil: Chamorro Aguirre, Estefania. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones Bioquímicas de Bahía Blanca. Universidad Nacional del Sur. Instituto de Investigaciones Bioquímicas de Bahía Blanca; ArgentinaFil: Pascual, Ana Clara. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones Bioquímicas de Bahía Blanca. Universidad Nacional del Sur. Instituto de Investigaciones Bioquímicas de Bahía Blanca; ArgentinaFil: Milano, Pablo Gustavo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones Bioquímicas de Bahía Blanca. Universidad Nacional del Sur. Instituto de Investigaciones Bioquímicas de Bahía Blanca; ArgentinaFil: Bocetti, Marisol Claudia. Provincia de Buenos Aires. Municipalidad de Bahía Blanca; ArgentinaFil: Pasquaré, Susana Juana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones Bioquímicas de Bahía Blanca. Universidad Nacional del Sur. Instituto de Investigaciones Bioquímicas de Bahía Blanca; ArgentinaReunión Anual de Sociedades de BiocienciaMar del PlataArgentinaSociedad Argentina de Investigación ClínicaAsociación Argentina de Farmacología ExperimentalSociedad Argentina de BiologíaAsociación Argentina de Nanomedicina

Proliferative glioblastoma cancer cells exhibit persisting temporal control of metabolism and display differential temporal drug susceptibility in chemotherapy

Even in immortalized cell lines, circadian clocks regulate physiological processes in a time-dependent manner, driving transcriptional and metabolic rhythms, the latter being able to persist without transcription. Circadian rhythm disruptions in modern life (shiftwork, jetlag, etc.) may lead to higher cancer risk. Here, we investigated whether the human glioblastoma T98G cells maintained quiescent or under proliferation keep a functional clock and whether cells display differential time responses to bortezomib chemotherapy. In arrested cultures, mRNAs for clock (Per1, Rev-erbα) and glycerophospholipid (GPL)-synthesizing enzyme genes, 32 P-GPL labeling, and enzyme activities exhibited circadian rhythmicity; oscillations were also found in the redox state/peroxiredoxin oxidation. In proliferating cells, rhythms of gene expression were lost or their periodicity shortened whereas the redox and GPL metabolisms continued to fluctuate with a similar periodicity as under arrest. Cell viability significantly changed over time after bortezomib treatment; however, this rhythmicity and the redox cycles were altered after Bmal1 knock-down, indicating cross-talk between the transcriptional and the metabolic oscillators. An intrinsic metabolic clock continues to function in proliferating cells, controlling diverse metabolisms and highlighting differential states of tumor suitability for more efficient, time-dependent chemotherapy when the redox state is high and GPL metabolism low.Fil: Wagner, Paula Micaela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigaciones en Química Biológica de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Centro de Investigaciones en Química Biológica de Córdoba; ArgentinaFil: Sosa Alderete, Lucas Gastón. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Biología Molecular; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Gorne, Lucas Damián. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Gaveglio, Virginia Lucía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones Bioquímicas de Bahía Blanca. Universidad Nacional del Sur. Instituto de Investigaciones Bioquímicas de Bahía Blanca; ArgentinaFil: Salvador, Gabriela Alejandra. Universidad Nacional de Córdoba; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones Bioquímicas de Bahía Blanca. Universidad Nacional del Sur. Instituto de Investigaciones Bioquímicas de Bahía Blanca; ArgentinaFil: Pasquaré, Susana Juana. Universidad Nacional del Sur; ArgentinaFil: Guido, Mario Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigaciones en Química Biológica de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Centro de Investigaciones en Química Biológica de Córdoba; Argentin

Daily rhythms of glycerophospholipid synthesis in fibroblast cultures involve differential enzyme contributions

Circadian clocks regulate the temporal organization of several biochemical processes including lipid metabolism and their disruption leads to severe metabolic disorders. Immortalized cell lines acting as circadian clocks display daily variations in [32P]-phospholipid labeling; however, the regulation of glycerophospholipid (GPL) synthesis by internal clocks remains unknown. Here we found that arrested NIH 3T3 cells synchronized with a 2 h-serum shock exhibited temporal oscillations in: a) the labeling of total [3H]- GPLs, with lowest levels around 28 and 56 h, and b) the activity of GPL-synthesizing and -remodeling enzymes such as phosphatidate phosphohydrolase 1 (PAP-1) and lysophospholipid acyltransferases (LPLAT) respectively, with antiphase profiles. In addition, we investigated the temporal regulation of phosphatidylcholine (PC) biosynthesis. PC is mainly synthesized through the Kennedy pathway with Choline Kinase (ChoK) and CTP:phosphocholine cytidylyltranferase (CCT) as key regulatory enzymes. We observed that the PC labeling exhibited daily changes with the lowest levels every ~28 h that were accompanied by brief increases in CCT activity and the oscillation in ChoK mRNA expression and activity. Results demonstrate that the metabolisms of GPLs and particularly of PC in synchronized fibroblasts are subject to a complex temporal control involving concerted changes in the expression and/or activities of specific synthesizing enzymes.Fil: Acosta Rodríguez, Victoria América. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Centro de Investigaciones En Química Biológica de Córdoba (p); ArgentinaFil: Marquez, Sebastian. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Centro de Investigaciones En Química Biológica de Córdoba (p); ArgentinaFil: Salvador, Gabriela Alejandra. Consejo Nacional de Investigaciones Cientí­ficas y Técnicas. Centro Científico Tecnológico Bahí­a Blanca. Instituto de Investigaciones Bioquímicas Bahí­a Blanca (i); ArgentinaFil: Pasquaré, Susana Juana. Consejo Nacional de Investigaciones Cientí­ficas y Técnicas. Centro Científico Tecnológico Bahí­a Blanca. Instituto de Investigaciones Bioquímicas Bahí­a Blanca (i); ArgentinaFil: Gorne, Lucas Damián. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Centro de Investigaciones En Química Biológica de Córdoba (p); ArgentinaFil: Garbarino Pico, Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Centro de Investigaciones En Química Biológica de Córdoba (p); ArgentinaFil: Giusto, Norma Maria. Consejo Nacional de Investigaciones Cientí­ficas y Técnicas. Centro Científico Tecnológico Bahí­a Blanca. Instituto de Investigaciones Bioquímicas Bahí­a Blanca (i); ArgentinaFil: Guido, Mario Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Centro de Investigaciones En Química Biológica de Córdoba (p); Argentin

Diacylglyceride lipase activity in rod outer segments depends on the illumination state of the retina

We have demonstrated that the competition between phosphatidic acid (PA) and lysophosphatidic acid (LPA), sphingosine 1-phosphate (S1P) and ceramide 1-phosphate (C1P) for lipid phosphate phosphatases (LPP) generates different levels of diacylglycerol (DAG) depending on the illumination state of the retina. The aim of the present research was to determine the diacylglyceride lipase (DAGL) activity in purified rod outer segments (ROS) obtained from dark-adapted retinas (DROS) or light-adapted retinas (BLROS) as well as in ROS membrane preparations depleted of soluble and peripheral proteins. [2-3H]monoacylglycerol (MAG), the product of DAGL, was evaluated from [2-3H]DAG generated by LPP action on [2-3H]PA in the presence of either LPA, S1P or C1P. MAG production was inhibited by 55% in BLROS and by 25% when the enzymatic assay was carried out in ROS obtained from dark-adapted retinas and incubated under room light (LROS). The most important events occurred in DROS where co-incubation of [2-3H]PA with LPA, S1P or C1P diminished MAG production. A higher level of DAGL activity was observed in LROS than in BLROS, though this difference was not apparent in the presence of LPA, S1P or C1P. DAGL activity in depleted DROS was diminished with respect to that in entire DROS. LPA, S1P and C1P produced a similar decrease in MAG production in depleted DROS whereas only C1P significantly diminished MAG generation in depleted BLROS. Sphingosine and ceramide inhibited MAG production in entire DROS and stimulated its generation in BLROS. Sphingosine and ceramide stimulated MAG generation in both depleted DROS and BLROS. Under our experimental conditions the degree of MAG production depended on the illumination state of the retina. We therefore suggest that proteins related to phototransduction phenomena are involved in the effects observed in the presence of S1P/sphingosine or C1P/ceramide.Fil: Pasquaré, Susana Juana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones Bioquímicas de Bahía Blanca. Universidad Nacional del Sur. Instituto de Investigaciones Bioquímicas de Bahía Blanca; ArgentinaFil: Giusto, Norma Maria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones Bioquímicas de Bahía Blanca. Universidad Nacional del Sur. Instituto de Investigaciones Bioquímicas de Bahía Blanca; Argentin

Phospholipase D and phosphatidate phosphohydrolase activities in rat cerebellum during aging

Aging is a process that affects different organs, of which the brain is particularly susceptible. PA and DAC are central intermediates in the phosphoglyceride as well as in the neutral lipid biosynthetic pathway, and they have also been implicated in signal transduction. Phospholipase D (PLD) and phosphatidate phosphohydrolase (PAP) are the enzymes that generate PA and DAG. The latter can be transformed into MAC by diacylglycerol lipase (DGL). In the present study, we examine how aging modulates the PLD, PAP, and DGL isoforms in cerebellar subcellular fractions from 4- (adult), 28-, and 33-mon-old (aged) rats. PI-4,5-bisphosphonate (PIP2)-dependent PLD, PAP1, and DCL1 were distributed in different percentages in all cerebellum subcellular fractions. On the other hand, PAP2 and DGL2 activities were observed in all subcellular fractions except in the cytosolic fraction. Aging modified the enzyme distribution pattern. In addition, aging decreased nuclear (45%), mitochondrial-synaptosomal (55%), and cytosolic (71%) PAP1 activity and increased (28%) microsomal PAP1 activity. DGL1 activity was decreased in nuclear (85%) and mitochondrial-synaptosomal (63%) fractions by aging. On the other hand, PIP2-dependent PLD activities were increased in the mitochondrial-synaptosomal fraction. PAP2 and DGL2 were increased in the microsomal fraction by 87 and 114%, respectively, and they were decreased in the nuclear fraction. The changes observed in cerebellum PAP1 and DCL1 activities from aged rats with respect to adult rats could be related to modifications in lipid metabolism. Differential PA metabolization during aging through PIP2-dependent PLD/PAP2/DGL2 activities could be related to alterations in the neural signal transduction mechanisms.Fil: Pasquaré, Susana Juana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones Bioquímicas de Bahía Blanca. Universidad Nacional del Sur. Instituto de Investigaciones Bioquímicas de Bahía Blanca; ArgentinaFil: Salvador, Gabriela Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones Bioquímicas de Bahía Blanca. Universidad Nacional del Sur. Instituto de Investigaciones Bioquímicas de Bahía Blanca; ArgentinaFil: Giusto, Norma Maria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones Bioquímicas de Bahía Blanca. Universidad Nacional del Sur. Instituto de Investigaciones Bioquímicas de Bahía Blanca; Argentin

Insulin receptor activation effects on synaptosomal 2-AG hydrolysis in an amyloidosis model induced by AB oligomers

Insulin (Ins) plays an important role in synaptic plasticity and is tightly related to Alzheimer´s disease (AD). Aβ oligomers (AβO), which are responsible for synaptic dysfunction in AD, can bind to Ins receptor (IR) and can therefore be internalized into neurons. AβO also disrupt the synaptic membrane and diminish 2-AG availability, the main neuroprotective cannabinoid. Ins can prevent AβO binding to IR, thus attenuating its neurotoxicity. Here, we hypothesized that Ins prevent AβO deleterious effects on 2-AG metabolism. To this end, we isolated cerebral cortex synaptosomes (syn) by differential centrifugation purified in ficoll gradients and preincubated them with 10 µM LY294002 (phosphatidylinositol-3-kinase -PI3K- inhibitor) or 100 µM genistein (tyrosine kinase inhibitor) for 10 min, and subsequently incubated with 0.2 mM vanadate (protein-tyrosine phosphatase inhibitor), 100 nM Ins, or 0.2 mM vanadate plus 100 nM Ins, for 30 min. Syn were then incubated for 10 min with or without 0.1 µM AβO. After this incubation, activation of IR signaling by Western Blot, released LDH activity, and 2-AG hydrolysis activity were evaluated. It was observed that a 30 min incubation with Ins and vanadate activated IR and Akt (p0.05). As to syn membrane damage, neither of the pretreatments could prevent AβO effect on LDH release (p>0.05). On the other hand, Ins and vanadate decreased 2-AG hydrolysis (p0.05). However, in the presence of AβO, Ins and vanadate failed to alter 2-AG hydrolysis (p>0.05) and LY increased this activity (p<0.001). Our results show a regulation of 2-AG hydrolysis by Ins, possibly increasing its availability via IR and involving PI3K pathway, which is abolished by AβO. The effect of AβO appears to be independent of IR and to involve PI3K activity. Ins also failed in preventing AβO damage in synaptic membrane.Fil: Pascual, Ana Clara. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones Bioquímicas de Bahía Blanca. Universidad Nacional del Sur. Instituto de Investigaciones Bioquímicas de Bahía Blanca; ArgentinaFil: Salas, Sabrina Rosicler. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones Bioquímicas de Bahía Blanca. Universidad Nacional del Sur. Instituto de Investigaciones Bioquímicas de Bahía Blanca; ArgentinaFil: Pasquaré, Susana Juana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones Bioquímicas de Bahía Blanca. Universidad Nacional del Sur. Instituto de Investigaciones Bioquímicas de Bahía Blanca; ArgentinaReunión Anual de Sociedades de BiocienciaMar del PlataArgentinaSociedad Argentina de Investigación ClínicaAsociación Argentina de Farmacología ExperimentalSociedad Argentina de BiologíaSociedad Argentina de ProtozoologíaAsociación Argentina de NanomedicinasAsociación Argentina de Ciencia y Tecnología de Animales de Laboratori

Age-related changes in the metabolization of phosphatidic acid in cerebral cortex synaptosomes

In this study, phosphatidic acid (PA) metabolization is found to generate diacylglycerol (DAG), monoacylglycerol (MAG) and glycerol by the sequential action of lipid phosphate phosphatase (LPP), diacylglycerol lipase (DAGL), and monoacylglycerol lipase (MAGL) in cerebral cortex (CC) synaptosomes. It is also demonstrated that PA is metabolized by phospholipases A (PLA)/lysophosphatidic acid phosphohydrolase (LPAPase) in synaptic endings. Age-related changes in the metabolization of PA have been observed in rat cerebral cortex synaptosomes in the presence of the alternative substrates for LPP, namely LPA, sphingosine 1-phosphate (S1P) and ceramide 1-phosphate (C1P). In addition, LPA and C1P up to concentrations of about 50 μM favor the metabolism in the direction of MAG and glycerol in aged and adult synaptosomes, respectively. At equimolecular concentrations with PA, LPA decreases DAG formation in adult and aged synaptosomes, whereas S1P decreases it and C1P increases it only in aged synaptosomes. Sphingosine (50 μM) or ceramide (100 μM) increase PA metabolism by the pathway that involves LPP/DAGL/MAGL action in aged membranes. Using RHC-80267, a DAGL inhibitor, we could observe that 50% and 33% of MAG are produced as a result of DAGL action in adult and aged synaptosomes, respectively. Taken together, our findings indicate that the ageing modifies the different enzymatic pathways involved in PA metabolization.Fil: Pasquaré, Susana Juana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones Bioquímicas de Bahía Blanca. Universidad Nacional del Sur. Instituto de Investigaciones Bioquímicas de Bahía Blanca; ArgentinaFil: Gaveglio, Virginia Lucía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones Bioquímicas de Bahía Blanca. Universidad Nacional del Sur. Instituto de Investigaciones Bioquímicas de Bahía Blanca; ArgentinaFil: Giusto, Norma Maria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones Bioquímicas de Bahía Blanca. Universidad Nacional del Sur. Instituto de Investigaciones Bioquímicas de Bahía Blanca; Argentin

El sistema endocannabinoide en los fotorreceptores de la retina bovina

Las células fotorreceptoras son las responsables de registrar la luz. Un estímulo lumínico intenso o prolongado compromete la función visual por muerte de las células fotorreceptoras. El Sistema Endocannabinoide (SEC) actúa como neuromodulador y neuroprotector, de allí la importancia de abordar su estudio en el proceso visual y en la injuria neuronal. El objetivo del presente trabajo fue evaluar si el SEC es modulado por luz en los segmentos externos (ROS) de los bastones, lugar donde se inicia el proceso de fototransducción. Se encontró que las enzimas de síntesis (diacilglicerol lipasa (DAGL) y lisofosfatidato fosfohidrolasa (LPAPasa) y de hidrólisis (monoacilglicerol lipasa (MAGL)) del endocannabinoide 2-araquidonoil glicerol (2-AG) están presentes y son activas en el ROS. Además se expresan los receptores cannabinoides CB1, CB2 y GPR55. El balance entre la síntesis y la hidrólisis del 2-AG por estímulo lumínico (3000 luxes por 30 min) demuestra un aumento en su producción por incremento de la actividad de síntesis (DAGL). La luz, además, aumenta la expresión de los receptores cannabinoides CB1 y CB2 y disminuye la del GPR55. Nuestro trabajo evidencia por primera vez la presencia de elementos del SEC en segmentos externos de células fotorreceptoras (ROS) y su modificación por luz, sugiriendo que las proteínas relacionadas con el fenómeno de fototransducción están involucradas en los efectos observados.Fil: Chamorro Aguirre, Estefania. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones Bioquímicas de Bahía Blanca. Universidad Nacional del Sur. Instituto de Investigaciones Bioquímicas de Bahía Blanca; Argentina. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia; ArgentinaFil: Gaveglio, Virginia Lucía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones Bioquímicas de Bahía Blanca. Universidad Nacional del Sur. Instituto de Investigaciones Bioquímicas de Bahía Blanca; Argentina. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia; ArgentinaFil: Pasquaré, Susana Juana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones Bioquímicas de Bahía Blanca. Universidad Nacional del Sur. Instituto de Investigaciones Bioquímicas de Bahía Blanca; Argentina. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia; Argentina2° Taller Latinoamericano de Ciencias de la VisiónSan Miguel de TucumánArgentinaUniversidad Nacional de Tucumá