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Soil erosion is one of the most recurrent environmental problems of public interest today. The western Mediterranean is an area sensitive to the effects of Climate Change, according to the latest IPCC Sixth Assessment Report, due to the proven increase in extreme events such as heat waves, extreme rainfall and droughts. Within this, the importance of competition in the territory between tourism and agriculture will be the result of radical changes in land use that are affecting the ecomorphological system to the point of making it even more susceptible due to the emergence and increase of high risks in the Mediterranean basins. Therefore, it will be essential to determine the levels of susceptibility of the basins under study with respect to erosive processes in order to create new mitigation measures to improve soil management and reduce these risks. Through this study we intend to analyze changes in land use and territorial susceptibility in several basins in southern Spain, in Malaga. The main objective is to determine the incidence and susceptibility of these basins and to analyse how they have been affected by land use changes through an observation of land use changes and the application of the RUSLE model. This project will look at the differences between two contrasting basins. One basin with steep slopes and the emergence of more sensitive crops, such as vineyards, which will increase the fragility of Mediterranean basins after torrential events, causing the appearance of a higher risk of erosion, while the other basin will be differentiated with the appearance of clearings that decrease the steep slopes together with changes to more competitive crops, such as subtropical crops. The results demonstrate the correlation between land use and torrential events in Mediterranean basins with respect to their susceptibility in their ecogeomorphological system.

La rápida expansión de la ocupación urbana en las últimas décadas está provocando un crecimiento de la impermeabilización del suelo no justificable por el valor del crecimiento de la población, con injustificables agresiones medioambientales. Por ello, se debería optar por una mayor integración de los espacios urbanos con su entorno naturalizado, generando menor huella ecológica, y el mayor valor de resiliencia frente a los fenómenos naturales catastróficos, que se incrementarán según se presentan en los diferentes escenarios de cambio climático. El objetivo del estudio es valorar la intensidad del sellado de suelo como medida de la fragmentación ecológica, y con la finalidad de aportar algunas medidas que pudieran mejorar la conectividad ecológica a diferentes escalas en Madrid (España). Se utiliza una metodología fácilmente actualizable y gratuita, mediante el libre acceso a las imágenes satelitales Sentinel y a diversas fuentes cartográficas. En 2018, la conurbación de Madrid ya consumió de media el 18,5 % del suelo, con grandes variaciones espaciales (13,33 % al N y 41,41 % al S), por lo que las propuestas de mitigación deberán ser también dispares.

This paper aims to update the exposure to flood risk in a catchment area of the Community of Madrid (Spain) linked to primary sector activities, albeit affected by the urban expansion of the capital. This research starts with the updating of the flood inventory, encompassing episodes documented between 1629 and 2020. The inadequate occupation of the territory means that floods continue to cause significant damage nowadays. It is worth highlighting the two recent floods (2019) that occurred just 15 days apart and caused serious damage to several towns in the basin. The areas at risk of flooding are obtained from the National Floodplain Mapping System, and the maximum and minimum floodable volume in the sector of the Tajuña River basin with the highest exposure to flooding has been calculated. The Sentinel 2 image in false colour (RGB bands 11-2-3, 11-8-3 and 12-11-8) and its transformation to colour properties (Intensity, Hue and Saturation) has made it possible to determine the extension of the riparian vegetation and the irrigated crops located in the alluvial plain. The SPOT 6 image with higher spatial resolution has allowed us to update the mapping of buildings located in areas at risk of flooding. Finally, based on cadastral data, a detailed cartography of built-up areas in areas at risk of flooding is provided. They affect buildings built mainly between the 1960s and 1990s, although the most recent buildings are built on agricultural land in the alluvial plain, even though current regulations prevent the occupation of these lands.

The aim of this paper is to integrate different sources of spatial information (cadastres, orthophotographies and satellite images), which also require different treatments, in order to be able to measure and evaluate the sealing of soils in a recent urban development project in the southeast of the city of Madrid, in order to establish a methodology of space-time monitoring of this parameter. Another objective is to show if the current urbanization process respects the European environmental guidelines in which waterproofed or sealed soil, inherent in economic development, coexists with natural spaces that allow to maintain some ecological functions such as softening the urban microclimate, setting growth levels of CO2 in stable figures in line with European environmental quality and standards, damping floods and preserving biodiversity. The sealing values of soils measured from different sources and using complementary techniques generate similar results when the waterproofing is higher than 60%. However, the calculations obtained from satellite images vary according to their spatial resolution and the type of treatment applied. With the Spot satellite the sealing values are close to 24%, while with the Sentinel-2 the percentage rises to 30%. Orthophotographies offer greater spatial precision, so sealing levels ( 60%) have been established, but their low temporal resolution prevents continuous monitoring, at least annually. Therefore, it is necessary to use different cartographic sources when carry out a study of urban areas, since the different temporal, spatial and spectral resolutions allow to visualize different characteristics in each of them. Consequently, their complementarity helps to correct the possible inadequacies of each of them.

The main goal of this study is the mapping of saline soils (solonchaks, solonetzs and luvisols with salic phases) in «Tierra de Medina» (Valladolid) using images of the TM and ETM sensors of the Landsat satellites. The spectral signatures of these soils show very high digital values, which allows to differentiate them from other types of soils and superficial covers. The highest values correspond to those which have salt efflorescences and the lowest values to soils affected by hydromorphic processes. The images obtained with the NDVI do not allow a clear discrimination of saline soils, but they allow to interpret the changes in their use. In these soils the values of NDVI are very low, due to their scarce vegetation. There is a remarkable vegetation reduction between years 1987 and 2001, which implies a structure deterioration and a great loss of vegetal cover; many of soils affected by salinization have not been cultivated any more., El objetivo del estudio es cartografiar los suelos salinos (solonchaks, solonetzs y luvisoles con fases sálicas) en la Tierra de Medina (Valladolid) utilizado imágenes de los sensores TM y ETM de los satélites Landsat. Las signaturas espectrales de estos suelos muestran valores digitales muy altos, lo que permite diferenciarlos de otros tipos de suelos y cubiertas superficiales. Los valores más altos corresponden a los que tienen eflorescencias salinas en superficie y los más bajos a los suelos afectados por hidromorfismo. Las imágenes obtenidas con el NDVI no permiten una clara discriminación de los suelos salinos, pero sí interpretar los cambios en su uso. En estos suelos los valores de NDVI son muy bajos, acordes con su escasa vegetación. Hay un notable descenso entre los años 1987 y 2001, lo que implica un deterioro de su estructura y una gran pérdida de cubierta vegetal; muchos de los suelos afectados por salinización se han dejado de cultivar. [fr] L’objectif de l’étude est cartographier les sols salins (solonchaks, solonetzs et luvisoles avec des phases saliques) dans la «Tierra de Medina» (Valladolid) avec l’aide des senseurs TM et ETM des satellites Landsat. Les signes spectraux de ces sols montrent des valeurs numériques très hautes, ce qui permet de les différencier d’autres types de sols et couvertures superficielles. Les valeurs plus hautes correspondent auxquelles ont efflorescences salines en surface et ceux plus faibles aux sols perturbés par hydromorphisme. Les images obtenues avec le NDVI ne permettent pas une discrimination claire des sols salins, mais d’interpréter les changements dans leur utilisation. Dans ces sols les valeurs de NDVI sont très faibles, en accord avec leur faible végétation. Il y a une diminution remarquable entre les années 1987 et 2001, ce qui implique une détérioration de sa structure et une grande perte de couverture végétale; beaucoup des sols perturbés par salinización ont été cessés de cultiver.

The spatial variability of the quality of the soil on the shores of a lagoon affected by hydromorphy and/or salinity can be identified (Laguna de Villacanas, Castilla La Mancha) by the use of multitemporal Landsat images in order to analyse these changes. For this purpose, TM and ETM images along with field observations and certain edaphic laboratory parameters are used. In order to identify saline-hydromorphic soils, the spatial variability of chemical and physical properties of a transect, which includes from Solonchaks to Regosols and Cambisols, have been correlated with the Normalised Difference Vegetation Index (NDVI). This index, chosen for specific dates, has proven to be very useful in detecting halophytic vegetation and relating it to the variability of the quality of these soils.

El sellado de suelos provocado por el crecimiento urbano produce una pérdida irreversible del ecosistema edáfico, que pocas veces es considerado en los proyectos de expansión urbanística. Aquí el proceso de consumo de suelo se analiza utilizando diversas fuentes de representación espacial, que son tratadas con técnicas de teledetección y SIG. Los nuevos proyectos urbanísticos del N de Madrid mantienen hasta la fecha entre el 41-64 % del suelo sin sellar, minimizando los impactos negativos de la impermeabilización del suelo, si bien responde en parte a la ralentización de las obras durante la crisis. Este estudio establece una metodología de trabajo para detectar y medir la pérdida de suelos en cuatro PAUs en la Comunidad Autónoma de Madrid, como un ejemplo de trabajo a escala local. La accesibilidad de bases de datos, material cartográfico e imágenes de satélite facilita la actualización de la cartografía temática. Los PAUS han sido construidos en suelos que corresponden principalmente a Luvisoles, con inclusiones menores de Calcisoles, Leptosoles, Cambisoles y Regosoles. La baja capacidad agrológica de estos suelos, implica que el sellado de suelos no afecta a suelos muy fértiles, por lo que la pérdida agronómica no es muy importante.

The role of endogenously produced nitric oxide (NO) in the regulation of basal catecholamine (CA) secretion was studied in chromaffin cells. Treatment of chromaffin cells with nitric oxide synthase (NOS) inhibitors produced a dose-dependent increase in basal catecholamine secretion, which paralleled their ability to inhibit NOS activity. This inhibitory profile was similar to that found in neurons, suggesting the constitutive expression of neuronal NOS (nNOS) in these cells, which was confirmed by Western blot analysis. A study of the kinetics and pharmacology of nNOS activity expressed in chromaffin cells in culture indicated that NOS activity is calcium-dependent, increases with time, and is highly dependent on both intracellular concentrations of L-arginine (K(m) approximately 4 microM, V(max) = 908 +/- 60 pmol/hr x 10(6) cells) and transport of L-arginine into the cells (exhibiting two affinity constants of k(1) = 3.2 +/- 0.3 microM and k(2) = 126 +/- 5.5 microM). The effects of NOS inhibitors on CA secretion were mediated by the L-arginine-NO-cGMP pathway, insofar as exogenous L-arginine was able to partially block the increase in CA secretion evoked by them, and 1H-[1,2,4]oxadiazolo[4,3-a]quinoxaline-1-one (ODQ), a specific inhibitor of guanylate cyclase, and zaprinast, an inhibitor of the cGMP phosphodiesterase, were able to increase and inhibit, respectively, basal CA secretion in a dose-dependent manner. These results suggest that chromaffin cells exhibit a tonic production of NO by nNOS that keeps the basal CA secretion at low levels, and this could be necessary for maintaining a normotensive state.

El objetivo del trabajo es revisar el concepto de sellado de suelo y destacar los diferentes enfoques metodológicos utilizados en la U.E. y especialmente en España. El concepto de sellado de suelo ha evolucionado desde el punto de vista meramente físico (suelo compactado e impermeable) hasta considerarse un grave problema medioambiental, de origen antrópico, y como tal, con posibilidades de mitigación, pues se destruyen las funciones vitales del suelo y se modifica negativamente el ecosistema. Este trabajo propone unificar criterios metodológicos, destacando al menos la superficie afectada por unidad territorial (municipio, comunidad autónoma, región o país) y señalar la escala de trabajo más conveniente en cada caso. Atendiendo al impacto del sellado de suelos en el medioambiente se proponen diferenciar tipologías para grandes ciudades, desde las más invasivas a las de mejor adaptación con el entorno. The aim of this paper is to review the concept of soil sealing and highlight the different methodological approaches used in the EU and especially in Spain. The soil sealing concept has developed from merely physical standpoint (compacted and impermeable soil) to be considered a serious anthropogenic environmental problem, and with mitigation options, as they destroy the vital functions of soil and adversely modifies the ecosystem. This paper proposes unifying methodological criteria, highlighting at least the area affected by territorial unit (municipality, autonomous community, region or country) and most convenient scale in each case. Considering the impact of soil sealing on the environment are proposed typologies for differentiating large cities, from the more invasive to the best adapted to the environment. L'objectif de cet article est d'examiner le concept de l'imperméabilisation des sols et mettre en évidence les différentes approches méthodologiques utilisées dans l'UE et surtout en Espagne. Le concept de l'imperméabilisation des sols a évolué de la simple point de vue physique (sol compacté et imperméable) pour être considéré comme un grave problème environnemental, d'origine anthropique, et comme, options d'atténuation, car ils détruisent les fonctions vitales du sol et modifie négativement l'écosystème. Ce document propose des critères méthodologiques unifier, mettant en évidence au moins la zone affectée par unité territoriale (commune, communauté autonome, région ou pays) et le point sur le niveau de travail plus pratique dans chaque cas. Compte tenu de l'impact de l'imperméabilisation des sols sur l'environnement sont proposées typologies permettant de différencier les grandes villes, à partir de la plus invasive pour le meilleur ajustement à l'environnement.

Previous work from our group stated that nitric oxide (NO), via cytokines, induces apoptosis in chromaffin cells by a mechanism involving iNOS, nNOS, and NF-κB. In this paper the involvement of glutamate as a possible intracellular trigger of neurosecretion and NO-mediated apoptosis has been evaluated. We show that chromaffin cells express different ionotropic and metabotropic glutamate receptors, this exerting different effects on the regulation of basal and glutamate-induced catecholamine secretion, via NO/cGMP. In addition, we studied the effects of endogenously generated NO, both basal and glutamate-stimulated, on apoptosis of chromaffin cells. Our results show that glutamate agonists are able to induce cell death and apoptosis in bovine chromaffin cells, parallel to an increase in NO production. Such effects were reversed by NOS inhibitors and glutamate receptor antagonists. Under basal conditions, iNOS inhibitors did not have any effect on apoptosis, whereas nNOS inhibitors induced apoptosis, indicating a neuroprotective effect of constitutive nNOS-generated NO. In contrast, glutamate-induced apoptosis was strongly reversed by nNOS inhibitors and weakly by iNOS inhibitors, thus indicating nNOS involvement in glutamate-mediated apoptosis. These results were confirmed by the fact that nNOS expression, but not iNOS, is specifically activated by glutamate. Finally, our results suggest the participation of PKG, PKA, PKC, and MAPK pathways in glutamate-mediated nNOS activation in chromaffin cells and point out the involvement of both PKA and PKC signaling pathways in the apoptotic effect of glutamate.

Data processing and satellite images are a useful tool for the study of land degradation. We have selected images from different sensors to analyze some cases of erosion and loss of soil quality: pollution, loss of organic matter (fire, deforestation), salinization, sealing, erosion and hydromorphic process. The sensors used for this type of study are the average spectral and spatial resolution (embarked in Landsat, Spot, Aster, EO, etc. satellites), high temporal resolution (embarked in MODIS, NOAA, etc. satellites) and radar satellites (embarked in Envisat, ERS, etc. satellites).

1. Muscimol, the specific GABAA receptor agonist, increased the secretion of catecholamines by chromaffin cells with an EC50 of 2.9 +/- 0.4 microM. 2. GABAA receptors of these cells were modulated by the same drugs which modulate GABAA receptors in brain tissue. 3. Benzodiazepines enhanced muscimol-evoked catecholamine secretion by between 20 and 80%. This effect seems to be mediated by binding to a central type of benzodiazepine receptor because it was completely blocked by the specific antagonist, Ro 15 1788. This antagonist was able to displace [3H]-flunitrazepam binding with an EC50 of 0.26 +/- 0.05 nM. 4. beta-Carbolines weakly inhibited muscimol-induced catecholamine secretion and were able to displace [3H]-flunitrazepam binding with an EC50 between 0.2 and 0.9 nM, depending on the beta-carboline used. 5. Pregnanolone and related neuroactive steroids enhanced muscimol-evoked catecholamine secretion by up to 87%, in a dose-dependent fashion. In contrast pregnenolone weakly inhibited muscimol-evoked catecholamine secretion. 6. Zn2+ did not affect GABAA receptor-induced catecholamine secretion. 7. These pharmacological results are absolutely concordant with the theoretical properties given by the GABAA receptor subunit composition of bovine adrenal medulla -alpha 1, alpha 4, beta 1-3, gamma 2-previously characterized by Western blot analysis.

The activation of GABAB receptors of adrenal chomaffin cells produces an increase of [Ca2+]i measured by fura-2 AM techniques. GABAB agonists 3-aminopropylphosphinic acid or (-)baclofen, at concentrations of 0.5 mM, increased basal Ca2+ values 332 +/- 60.9 and 306 +/- 40.5 nM, respectively, in cells suspended in a 2.5 mM Ca2+ buffer. The GABAB-induced increase of [Ca2+]i seemed to have two different components. The first was due to an entry from the extracellular medium mainly through L-type voltage-dependent Ca2+ channels as the dihydropiridine nifedipine 50 microM was able to decrease it more than 60%, while omega-conotoxin, which blocks N-type channels, did not produce any change in the GABAB-evoked Ca2+ increment. The second component was due to a release of Ca2+ from intracellular pools and was about one-third of the total GABAB-induced increase of [Ca2+]i. GABAB receptors stimulated inositol 1,4,5-trisphosphate-sensitive and not the caffeine-sensitive Ca2+ store. In a low-Ca2+ buffer after treatment with 2 microM angiotensin II, neither 0.5 mM 3-APPA nor baclofen were able to produce an additional increase of [Ca2+]i, whereas 4 mM caffeine had no effect on GABAB response. This intracellular Ca2+ mobilization could be due to inositol 1,4,5-trisphosphate accumulation produced by the activation of GABAB receptors. In fact, the specific agonists after 10 minutes incubation produced a dose-dependent increase of inositol 1,4,5-trisphosphate. The maximal effect was obtained at 100 microM baclofen and 3-APPA, and it was 3.63 +/- 0.75 and 3.2 +/- 1.5 times the basal levels (7.3 +/- 0.3 pmol/10(6) cells), respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

1. The role of adenosine 3':5'-cyclic monophosphate (cyclic AMP) in the regulation of catecholamine (CA) secretion in chromaffin cells remains equivocal from previous studies. 2. In the present study the effect of this cyclic nucleotide on basal CA secretion, as well as on intracellular calcium and membrane potential has been examined. 3. Forskolin and the permeable cyclic AMP analogue, 8-(4-chlorphenylthio)-adenosine-3'-5' monophosphate cyclic (pClpcAMP), increased basal CA secretion in a dose-dependent manner. The EC50s were 0.43 +/- 0.10 microM for forskolin and 39 +/- 9 microM for pClpcAMP. Other agonists with adenylate cyclase activity such as stimulants of adenosine receptors, beta-adrenoceptors, GABAB receptors and intestinal vasoactive peptide (VIP), also increased basal CA secretion in a highly significant manner. However, when they were added together with forskolin, CA secretion was not affected although an additive increase in cyclic AMP levels was produced. 4. Statistical analysis of the correlation between cyclic AMP levels and CA secretion evoked by these cyclic AMP increasing compounds showed that a significant direct correlation between both parameters existed only when low levels of cyclic AMP were produced by secretagogue stimulation. When the increase in intracellular cyclic AMP concentrations exceeded approximately 8 times the basal cyclic AMP levels the correlation was not significant. These results indicate a dual dose-dependent effect of cyclic AMP on basal CA secretion. 5. The stimulatory effect of low cyclic AMP on basal CA secretion was accompanied by an increase in membrane potential and in intracellular calcium concentrations ([Ca2+]j), the latter mainly being due to an increase in intracellular Ca2+ entry through L-type voltage-dependent Ca2" channels.6. The possible mechanisms involved in these cyclic AMP effects are discussed.

The action of (Z)-N-(2-bromo-5-hydroxy-4-methoxybenzylidene)-2-methylpropan-2-amine oxide (RP6) on rat cortical neurons in culture, under oxygen-glucose-deprivation conditions, is reported. Cortical neurons in culture were treated during 1 h with OGD. After, they were placed under normal conditions during 24 h (reperfusion) in absence and presence of RP6. Different parameters were measured under each condition (control, 1 h OGD and 1 h OGD + reperfusion in absence and presence of RP6). RP6 protects neurons against ROS generation, lipid peroxidation levels, LDH release and mitochondrial membrane potential alteration, when administered during reperfusion after the OGD damage. Consequently, these results show that nitrone RP6 protects cells against ischemia injury produced during the reoxygenation, and could be a potential drug for the ictus therapy.

The synthesis, pharmacological analysis and molecular modeling of the readily available racemic tacrine analogs 21-30, bearing the 7-aryl-9,10,11,12-tetrahydro-7H-benzo[7,8]chromeno[2,3-b]quinolin-8-amine heterocyclic ring system (II), prepared by Friedlander reaction of 2-amino-4-aryl-4H-benzo[h]chromene-3-carbonitriles (11-20) with cyclohexanone, are described in this paper. Molecules 21-30 are potent and selective inhibitors of hAChE, in the low micromolar range, one of the most potent inhibitors, 4-(8-amino-9,10,11,12-tetrahydro-7H-benzo[7,8]chromeno[2,3-b]quinolin-7-yl)-2-methoxyphenol (25), showing a IC(50) (hAChE) = 0.33 ± 0.04 μM. Kinetic studies of compound 25 proved that this compound is a mixed type inhibitor for EeAChE (K(i) = 81 nM). Accordingly, molecular modeling of inhibitor 25 showed that both enantiomers have two major predicted binding modes at the active and at the peripheral anionic sites of AChE. Inhibitor 25 has an excellent antioxidant profile as determined in the ORAC experiment (1.47 ± 0.10 Trolox equiv). Inhibitors 26-28 and 30 are permeable to BBB as determined in the PAMPA assay. Compared to tacrine, selected compounds 26-28 and 30 showed less hepatic toxicity in HepG2 cells. Moreover, cell viability-related studies in cortical neurons in primary cultures show that compounds 26-28 and 30 (0.1-50 μM) have significant neuroprotective effects against mitochondrial chain blockers-induced cell death, and, unlike tacrine, are not neurotoxic at concentrations lower than 50 μM. It is worth highlighting that compound 27 has the best neuroprotective properties out of all assayed compounds and shows no neurotoxicity. To sum up, these tacrine analogs can be considered as attractive multipotent therapeutic molecules on pharmacological receptors playing key roles in the progress of Alzheimer's disease.

The GABA A receptor subunits expressed in adrenal medulla have been characterized by radioligand binding and by immunological methods. The receptors were purified by both benzodiazepine affinity chromatography and anti- α 1 413–429 GABA A receptor antibody immunoaffinity chromatography. These preparations were screened by immunoblotting using GABA receptor α subunit sequence-specific antibodies. Results showed the existence of the α 1 subunit. Thus, the GABA A receptors expressed in adrenal medulla are homogeneous with respect to their α subunit complement and consistent with type BZI benzodiazepine receptor pharmacology.

A series of new 5,6 dihydro-1H,4H-pyrazolo[4,3-f]pyrrolo[1,2-a][1,4]diazepines was synthesized and tested for acute toxicity and CNS activity in mice. Some of these compounds were shown to possess anxiolytic activity similar to that of diazepam, with weak anticonvulsant and sedative action.

1. The function of gamma-aminobutyric acidB (GABAB) receptors in modulation of catecholamine secretion by chromaffin cells and the possible mechanism involved in this action have been examined. 2. The GABAB agonists (-)-baclofen and 3-aminopropylphosphinic acid (3-APPA) were found to induce a dose-dependent increase of basal catecholamine secretion. The EC50s were 151 +/- 35 microM and 225 +/- 58 microM for baclofen and 3-APPA, respectively. This stimulatory effect was specific since it could be blocked by 0.5 mM of the specific GABAB antagonist CGP-35348. 3. In contrast, preincubation of chromaffin cells with the GABAB agonists was found to inhibit, in a dose-dependent manner, the catecholamine secretion evoked by 10 microM nicotine and 200 microM muscimol. 4. The effects of GABAB agonists on both basal and evoked catecholamine secretion were found to be accompanied by parallel changes in intracellular calcium concentration ([Ca2+]i). GABAB agonists produced a dose-dependent increase in [Ca2+]i which was partially blocked by CGP 35348, but they produced a strong inhibition of the [Ca2+]i increase induced by nicotine and muscimol. 5. The GABAB agonists also produced a dose-dependent increase in intracellular cyclic AMP levels, there being a direct correlation between both increase in catecholamine secretion and in intracellular cyclic AMP levels. 6. The pretreatment of chromaffin cells with pertussis toxin doubled the catecholamine secretion and increased by four times the intracellular cyclic AMP levels evoked by GABAB agonists. 7. The possible involvement of adenylate cyclase in the mechanism of GABAA receptor modulation of catecholamine secretion is discussed.

The study of the functional expression of glutamate signaling molecules in peripheral tissues has received relatively little attention. However, evidence is increasing for a role of glutamate as an extracellular signal mediator in endocrine systems, in addition to having an excitatory amino acid neurotransmitter role in the CNS. Chromaffin cells are good models of catecholaminergic neurons, in which previous work from our group demonstrated the existence of both functional glutamate receptors and specific exocytotic and nonexocytotic glutamate release. In this work, the presence of specific plasma membrane (EAATs) and vesicular glutamate (VGLUTs) transporters has been investigated by using confocal microscopy, flow cytometric analysis, Western blot, and qRT-PCR techniques. We found specific expression of EAAT3, EAAT2, VGLUT1, and VGLUT3 in about 95%, 65%, 55%, and 25%, respectively, of the whole chromaffin cell population. However, chromaffin cells do not express VGLUT2 and have a very low expression of EAAT1. VGLUTs are localized mainly in the membrane fraction, and EAATs share their subcellular location between membrane and cytosolic fractions. Their estimated molecular weights were about 70 kDa for EAAT2, about 65 kDa for EAAT3, about 50 kDa for VGLUT1, and about 60 kDa for VGLUT3. RT-qPCR techniques confirm the expression of these glutamate transporters at the mRNA level and show a different regulation by cytokines and glucocorticoids between VGLUT1 and 3 and EAAT2 and -3 subfamilies. These interesting results support the participation of these glutamate transporters in the process of glutamate release in chromaffin cells and in the regulation of their neurosecretory function in adrenal medulla. V V C 2010 Wiley-Liss, Inc.

The actions and mechanism of GABAergic modulation of catecholamine secretion from isolated bovine chromaffin cells were investigated. The GABAA receptor agonist muscimol induced a fast rise in cytosolic [Ca2+ ]. The mean peak increase was 290 ± 30nM over basal levels. The increase in cytosolic [Ca2+ ] was abolished in the absence of extracellular [Ca2+ ] and was blocked by the GABAA antagonist bicuculline and the dihydropiridine nifedipine. Muscimol also elicited the release of catecholamines and increased the bisoxonol fluorescence indicating a cell depolarization. The [Ca2+ ] entry was well correlated with muscimol-evoked catecholamine secretion. When cells were treated with muscimol and a second secretagogue, a biphasic behavior was revealed. Muscimol enhanced the catecholamine release evoked by low concentrations of nicotine or K+, whereas release obtained at high concentrations of nicotine or K+ was actually inhibited. When the muscimol effect on membrane potential was studied in the presence of low K+ or nicotine concentrations, an enhancement of the bisoxonol fluorescence was observed. This effect was reversed at high concentrations of both K+ and nicotine. Measurement of 36Cl− fluxes showed an increase in membrane permeability to Cl− during muscimol stimulation. The influx or efflux in Cl− was dependent on membrane potential. In normal conditions, with a K+ concentration of 5.4 mM, a Cl− efflux was observed by both radiometric techniques, with 36Cl− and by the use of the chloride-sensitive fluorescent probe 6-methoxy-N-(3-sulphopropil)quinolinium, as indicator of intracellular Cl−. At high nicotine (20 mM) or K+ concentrations (105 mM) a Cl− influx was observed using 6-methoxy-N-(3-sulphopropil)quinolinium. Equilibrium potential for Cl− was placed at −51.4 ± 2.1mV by independent estimation of 36Cl−distribution across membrane. These results suggest a dual, modulatory role for GABA in the adrenal medulla. Its probable mechanism and implications are discussed.

The basal and evoked [3H] γ‐aminobutyric acid (GABA) release from chromaffin cells in primary cultures was studied and compared with that of [3H]NA. [3H]GABA was found to be released, in a dose‐dependent fashion, by different secretagogues known to induce noradrenaline (NA) release, that is, the cholinergic agonist nicotine, high‐potassium chloride, veratridine, and calcium ionophores. In general, there was a parallelism between percentages of release of both [3H]GABA and [3H]NA, although in all circumstances the former were lower. The nicotine‐and high‐potassium‐evoked [3H]GABA release was absolutely calcium dependent, thus indicating the existence of a exocytotic‐like mechanism, whereas in the veratridine‐induced release, a calcium‐independent component was also detected. This latter component was sodium dependent, as it showed an absolute requirement for extracellular sodium and was enhanced by ouabain. Moreover, it was inhibited by known GABA uptake inhibitors, which indicate that this component of [3H]GABA release induced by veratridine could be due to GABA outflow through the membrane carrier. The above results, together with that obtained from studies about subcellular localization of [3H]GABA taken up by chromaffin cells, seem to support the existence of two mechanisms for [3H]GABA release by chromaffin cells: one calcium‐dependent, exocytotic‐like, and another calcium‐independent and sodium‐dependent, possibly mediated by the GABA carrier. Both processes could have a functional role on the regulation of extracellular GABA levels and so in the control of catecholamine release by chromaffin cells. Copyright © 1990 Wiley‐Liss, Inc.

Resumen El analisis multitemporal de imagenes de satelite y la disponibilidad de datos de campo permiten conocer las amplias fluctuaciones hidricas de la laguna de Gallocanta y las variaciones medioambientales de este humedal. El incremento de las precipitaciones entre 2003 y 2010 pone fin al largo periodo de sequia, que llega a desecar la laguna durante anos y facilita la recuperacion de la lamina de agua a niveles similares a los anos ochenta. A partir de las imagenes Landsat la laguna de Gallocanta es claramente identificable en cualquier fecha, aunque presente fases de inundacion (1987, 2009 y 2010) y desecacion muy marcadas (2000 y 2001) correspondientes a anos humedos y secos. Resume L’analyse multitemporelle de l’imagerie satellitaire et la disponibilite de donnees sur le terrain nous permettent de connaitre les fluctuations dans l’eau de la lagune de Gallocanta et les variations de l’environnement de cette zone humide. L’augmentation des precipitations entre 2003 et 2010 met fin a la longue periode de secheresse qui a seche la lagune depuis des annees et facilite la recuperation de la surface de l’eau a des niveaux similaires aux annees quatre-vingt. En images Landsat la lagune de Gallocanta est clairement identifiable a tout moment, mais elle a des etapes d’inondation (1987, 2009 et 2010) et de sechage tres marquees (2000 et 2001) pour les annees humides et seches. Abstract Multitemporal analysis of satellite images and field data availability allow us to know the wide fluctuations in water of the Gallocanta wetland and environmental variations of this wetland. The increase in rainfall between 2003 and 2010, ending the long period of drought, dry reaching the wetland for years and facilitates the recovery of the water surface at levels similar to the eighties. From the Landsat images Gallocanta wetland is clearly identifiable at any time, although this stage of flooding (1987, 2009 and 2010) and drying very marked (2000 and 2001) for wet and dry years. Palabras clave/Mots cle/Keywords Teledeteccion, Gallocanta, ciclo hidrologico, humedal. Teledetection, Gallocanta, cycle hydrologique, zones humides. Remote sensing, Gallocanta, hydrological fluctuations, wetland.

Previous work indicated that glutamate could be involved in the regulation of catecholamine secretion in bovine chromaffin cells. Thus, the question arises on the source of this putative regulatory glutamate. In this work we have examined the possibility that glutamate could be released from chromaffin cells. Data from this study indicate that chromaffin cells are able to release glutamate when they are stimulated by different depolarising agents such as 60 mM KCl, 1 mM 4-aminopyridine or 50 microM veratridine. The amount of glutamate released by these compounds was 0.32 nmol/10(6) cells (9.24% of cellular glutamate content), 0.275 (7.86%) and 0.158 (4.52%) for KCl, 4-AP and veratridine stimulation, respectively. All these catecholamine-secretagogues induced glutamate secretion by two mechanisms: 1) a Ca(2+)-dependent, probably exocytotic, mechanism and 2) a Ca(2+)-independent mechanism mediated by reversion of the electrogenic glutamate transporter. Analysis of Ca(2+)-dependent and independent releases for different compounds carried out by several experimental approaches, indicate that Ca(2+)-dependent release was the predominant mechanism for release induced by 4-aminopyridine (84% of total release) and high KCl (63%) whilst Ca(2+)-independent release was predominant for veratridine (67%). The Ca(2+)-dependent glutamate release evoked by depolarisation of chromaffin cells with high KCl and 4-AP could be split into both a fast and a slow kinetic component, which might correspond to the release of docked and mobilised chromaffin granules, respectively. On the other hand, depolarisation of cells with veratridine result in glutamate release with only the fast kinetic component. In the case of 60 mM KCl-evoked glutamate release, the fast component exhibited a decay time of

GABA stimulates the basal catecholamine release from adrenal bovine chromaffin cells in a calciumdependent manner. This release represents about 70% of that obtained by similar doses of nicotine under similar experimental conditions. This effect is mediated by GABAA receptor sites present in chromaffin cells, since it was mimicked by muscimol and reversed by bicuculline. In addition, GABA, through its GABAA receptors, increases the catecholamine release evoked by submaximal doses of aicotine, but it has no effect on nicotine‐evoked secretion of catecholamines when nicotine was given at maximal doses. These results seem to indicate that both nicotine and GABA release catecholamines from the same intracellular pool. In contrast, baclofen, a GABAB receptor agonist, depressed both basal and nicotineevoked catecholamine release; this result indicates that in addition to GABAA control of catecholamine secretion by chromaffin cells, there is a GABAB control of this function. These results support the existence of a dual regulation of catecholamine secretion by both the GABAA and GABAB receptors in a similar way as that proposed for muscarinic and nicotinic cholinergic receptors. Copyright © 1989 Alan R. Liss, Inc.

The effect of several ligands and Ca2+ ions on [3H]GABA binding to bovine adrenal medulla membranes was investigated. Without any blockade, the [3H]GABA binding showed two components, one of low affinity (Kd = 139 +/- 22 nM and Bmax = 3.2 +/- 0.4 pmol/mg protein) and the other of high affinity (Kd = 41 +/- 6 nM and Bmax = 0.35 +/- 0.26 pmol/mg protein). Muscimol specifically blocked low-affinity sites, and (-)baclofen blocked high-affinity components. Ca2+ ions were strictly necessary for maximum binding to high-affinity sites, whereas they did not significantly affect sites of the lower affinity. These results show that the bovine adrenal medulla has a GABAA receptor population of low affinity together with a GABAB receptor of high affinity.