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Although the activation of extrasynaptic GluN2B-containing N-methyl-d-aspartate (NMDA) receptors has been implicated in neurodegenerative diseases, such as Alzheimer’s and Huntington’s disease, their physiological function remains unknown. In this study, we found that extrasynaptic GluN2B receptors play a homeostatic role by antagonizing long-term potentiation (LTP) induction under conditions of prolonged synaptic stimulation. In particular, we have previously found that brief theta-pulse stimulation (5 Hz for 30 s) triggers robust LTP, whereas longer stimulation times (5 Hz for 3 min) have no effect on basal synaptic transmission in the hippocampal CA1 region. Here, we show that prolonged stimulation blocked LTP by activating extrasynaptic GluN2B receptors via glutamate spillover. In addition, we found that this homeostatic mechanism was absent in slices from the SAP102 knockout, providing evidence for a functional coupling between extrasynaptic GluN2B and the SAP102 scaffold protein. In conclusion, we uncovered a rapid homeostatic mechanism that antagonizes LTP induction via the activation of extrasynaptic GluN2B-containing NMDA receptors. NEW & NOTEWORTHY Although long-term potentiation (LTP) is an attractive model for memory storage, it tends to destabilize neuronal circuits because it drives synapses toward a maximum value. Unless opposed by homeostatic mechanisms operating through negative feedback rules, cumulative LTP could render synapses unable to encode additional information. In this study, we uncovered a rapid homeostatic mechanism that antagonizes LTP induction under conditions of prolonged synaptic stimulation via the activation of an extrasynaptic GluN2B-SAP102 complex.

Fue evaluado el efecto de cuatro niveles de cama de pollos (C) y harina de subproductos de maíz (H), con bagazo de caña amonificado (B, a un 40% de la ración ofrecida) en raciones para corderos (14,82 ± 2,41 kg, 120 días (d) de edad), mestizos West African x Dorset, en crecimiento manejados en confinamiento total. Este experimento fue conducido con el fin de estimar la respuesta productiva en condiciones de una explotación comercial. Las raciones fueron C (11,4; 20,4; 29,4 y 38,4%) y H (48, 39, 30 y 21%, respectivamente) evaluadas durante 112 d, en un diseño completamente al azar con tres repeticiones por tratamiento y cuatro corderos por repetición (2 machos y 2 hembras), total 48 corderos. Los resultados permiten concluir que la C (20,4 a 29,4%), H (39 a 30%) y B (40%) pueden ser utilizados para levantar y terminar corderos, con ganancias de peso vivo (PV) de 100 y 83 g/cordero/d, con un costo de la ración de 709 a 683 Bs/kg de PV y sin comprometer la salud de los animales, cuyos hígados (393 y 364 g) y riñones (63 y 68 g) fueron normales. El peso de la canal caliente (11,67 y 10,27 kg), el rendimiento en canal (49,1 y 45,2%), el peso de los muslos (3,62 y 3,11 kg) y de las paletas (2,53 y 2,51 kg) con tamaño y proporción semejantes al grado estándar de canales de corderos. Esto hace posible el uso de dichas raciones en la producción intensiva de corderos en confinamiento total en las áreas de influencia de la agroindustria del maíz, avícola y caña de azúcar, con costos de las raciones que garantizan el beneficio comercial. The effect of four levels of poultry litter (C) and corn by-product meal (H) with ammoniated sugar cane bagasse (B, to 40% of the ration offered) in rations for growing lambs (14.82 ± 2.41 kg, 120 days (d) old), crossbred West African x Dorset, total confinement managed, were evaluated. This experiment was conducted in order to estimate the productive in terms of commercial exploitation. The rations were C (11.4, 20.4, 29.4 and 38.4%) and H (48, 39, 30 and 21%, respectively) evaluated for 112 d, in a completely randomized design with three replications per treatment and four lambs per replicate (2 males and 2 females), all 48 lambs. The results suggest that the C (20.4 to 29.4%), H (39-30%) and B (40%) can be used to lift and finish lambs, with gains of body weight (BW) of 100 and 83 g / lamb / d, with a ration cost of 709- 683 Bs / kg BW and without compromising the health of the animals, whose livers (393 and 364 g) and kidneys (63 and 68 g) were normal. The hot carcass weight (11.67 and 10.27 kg), carcass yield (49.1 and 45.2%), weight of thighs (3.62 and 3.11 kg) and pallets (2.53 and 2.51 kg) with size and proportions similar to standard grade lamb carcasses. This enables the use of these rations in the intensive production of lambs in total confinement in the areas of influence of agribusiness corn, poultry and sugarcane, with costs of rations that ensure commercial benefit. 520 - 530 Bimestral

This paper deals with an ethnography aimed at describing and ­understanding the gendered organization of schopería life and masculinity in northern Chile. Schoperías are characterized physically and socially and the effects these ­premises have on gender relations and masculinity assigned to them by waitresses and clients are studied. Schoperías are beer halls, mainly for men, ­served by women, located in cities near copper mines in Chile. They are strongly ­gendered and classed places. Schoperías are reference scenarios for men and their performance; they are premises that privilege masculine socialization and heterosexual ­hegemonic masculine performance. Paradoxically, they are at the same time unique places where male friendship and complicity take place, allowing homosociability and the expression of a certain type of affection and feelings among men. O artigo baseia-se numa etnografia com a qual se pretendeu descrever e compreender a organização das schoperías em função do género e a masculinidade no Norte do Chile. As schoperías são caraterizadas física e socialmente e são estudados os efeitos que estes locais produzem nas relações de género e na masculinidade que lhes é atribuída pelas empregadas e pelos clientes. As schoperías são cervejarias destinadas sobretudo aos homens, que são servidos por mulheres, localizadas em cidades próximas de minas de cobre no Chile. São lugares fortemente marcados pelo género e pela classe. As schoperías são cenários de referência para os homens e a sua performance; são locais que privilegiam a socialização masculina e a performance masculina heterossexual e hegemónica. Paradoxalmente, são ao mesmo tempo lugares singulares onde a amizade e a cumplicidade masculinas têm lugar, permitindo a homossociabilidade e a expressão de um certo tipo de afeto e sentimentos entre homens.

Resumen El Modelo de Estrés de las Minorías (Meyer, 2003) ha permitido explicar de qué forma el prejuicio sexual produce efectos negativos en la salud y bienestar de personas pertenecientes a las minorías sexuales, a través de la identificación de estresores de tipo distales y proximales. Este estudio buscó indagar los efectos del prejuicio sexual en la salud mental de personas transgénero en Chile desde un enfoque cualitativo. Se realizaron entrevistas semi-estructuradas a 17 personas transgénero femeninas y masculinas en cuatro ciudades del país. Los resultados nos permite identificar la presencia de factores distales asociados a discriminación manifiesta y factores proximales asociados a la vivencia del estigma y su relación con el autoconcepto. Finalmente, se describen efectos en la salud mental, entre los que destacan la presencia de sintomatología ansioso-depresiva, ideación e intentos suicidas, conductas autolesivas y consumo de alcohol y otras sustancias. Abstract The Minority Stress Model (Meyer, 2003) has made it possible to explain how sexual prejudice produces negative effects on the health and wellbeing of people belonging to sexual minorities, through distal and proximal stressors. A qualitative study was conducted to investigate the effects of sexual prejudice on the mental health of transgender adults in Chile. Semi-structured interviews were conducted with 17 transgender people, both male and female, in four cities of the country. The results allow us to identify the presence of distal factors associated with overt discrimination, as well as, proximal factors associated with the experience of stigma and its effects on self-concept. Finally, effects on mental health are described, among which the presence of anxious-depressive symptomatology, suicidal ideation and attempts, self-injurious behavior and consumption of alcohol and other substances.