Showing papers by "National University of Cuyo published in 2003"
TL;DR: Interestingly, the results indicate that transferrin (Tf) stimulated exosome release in a Ca2+-dependent manner, suggesting that Tf might be a physiological stimulus for exosomes release in K562 cells.
699 citations
TL;DR: The morphology of all the Galápagos tomatoes is analysed, highlighting the potential for genetic contamination of the endemic tomatoes by hybridization and introgression with the two introduced species.
Abstract: The Galapagos Islands are of great conservation interest due to their high proportion of endemic species The endemic tomatoes (Solanum section Lycopersicon) of the islands have long been of interest to plant breeders We analyse the morphology of all the Galapagos tomatoes: two endemic species, Solanum cheesmaniae and S galapagense (the latter described here as new) and two introduced species, S lycopersicum and S pimpinellifolium Morphological characters were measured on greenhouse‐grown plants raised from seeds obtained from the wild and seed‐bank accessions Species boundaries were examined by cluster analysis and principal component analysis Although the four taxa are distinct and therefore regarded as bona fide species they exhibit considerable intraspecific variation A taxonomic treatment of the tomatoes in the Galapagos is provided, with keys to all solanums in the islands, descriptions, listings of representative specimens examined and full exsiccatae Field observations of plants
90 citations
TL;DR: Among the "Criollas", AFLP similarities ranged from 76 to 98% (Dice coefficient), indicating an important source of genetic diversity that can be exploited in future breeding programs.
87 citations
TL;DR: Ibanez et al. as discussed by the authors presented Ibanez, Maria Cecilia. Facultad de Ciencias Agrarias, University of Cuyo, Argentina.
84 citations
TL;DR: In this article, the interaction of external charged particles with the bulk and surface modes of cylindrical wires using classical and quantum mechanical formulations was studied, and general scaling properties of the interaction terms were presented, and various illustrative examples were given.
Abstract: We study the interaction of external charged particles with the bulk and surface modes of cylindrical wires using classical and quantum mechanical formulations. First, the dielectric function approach is used to calculate the main induced effects and to derive the average number of excited plasmons in a semiclassical way. Second, the surface and bulk plasmon fields are quantized and the corresponding processes of plasmon excitations are described in detail. The correspondence between the classical and quantum pictures is shown. General scaling properties of the interaction terms are presented, and various illustrative examples are given.
68 citations
TL;DR: Mercury was the only element accumulated in the Main Irrigation channel sediments, the highest contents occurring in the surroundings of the nowadays shut-down chlor-alkali plant, returning to background values approximately 40 km downstream the plant.
67 citations
TL;DR: This is the first report of the use of AFLP to characterize Argentinean garlic clones and could allow not only the differentiation among species, but also between botanical varieties and well-defined ecotype groups.
Abstract: Genetic diversity of eight selected Argentinean garlic clones (Allium sativum L.) were investigated at the DNA level with the amplified fragment length polymorphism DNA (AFLP) procedure. A total of 405 unambiguous bands were identified by six primer combinations of EcoR I +3 and Mse I +3, of those, 398 showed a clear polymorphism, representing 98% of the total bands. A presence/absence matrix was constructed with the polymorphic bands, and a dendrogram was obtained from it with the UPGMA method. The accessions showed different levels of similarity ranging between 0.24 and 0.97, using the coefficient of Jaccard. The dendrogram showed six arbitrary groups. Accessions typically considered as different clones show similarities between 0.97 and 0.495. The garlic clones were clustered according to the physiological group and bulb color. We could detect an association between AFLP and the geographical origin of the clones. The potential use of AFLP could allow not only the differentiation among species, but also between botanical varieties and well-defined ecotype groups. This is the first report of the use of AFLP to characterize Argentinean garlic clones.
65 citations
TL;DR: A new technique for rapid and straightforward preparation of large quantities of defined tubule fragments from mouse kidney is developed, which will facilitate further characterization of kidney function in normal and genetically manipulated animals.
Abstract: The increasing number of available genetically manipulated mice makes it necessary to develop tools and techniques for examining the phenotypes of these animals. We have developed a straightforward and rapid method for the isolation of large quantities of single tubule fragments from the mouse kidney. Immunohistochemistry, electron microscopy, and fluorescence microscopy were used to evaluate the viability, functional characteristics, and morphology of proximal tubules (PT), and collecting ducts from cortex (CCD) and inner stripe of the outer medulla (ISOMCD). Tubules were isolated using a modified collagenase digestion technique, and selected under light microscopy for experimentation. Electron microscopy and trypan blue exclusion showed that a large portion of unselected proximal tubules were damaged by the digestion procedure. The selected tubules, however, all excluded trypan blue, indicating that the plasma membrane had remained intact. Immunocytochemistry on isolated CCD showed normal distribution of H+-ATPase, pendrin, and anion exchanger-1 (AE-1) staining. The pH-sensitive dye 2′,7′-bis(2-carboxylethyl)-5(6)-carboxyfluorescein (BCECF) was used to measure Na+-dependent and -independent intracellular pH (pHi) recovery rates in PT, and in single intercalated cells of CCD and ISOMCD fragments. Na+-dependent pHi-recovery was 0.144±0.008 (PT), 0.182±0.013 (CCD), and 0.112±0.010 pH units/min. (ISOMCD). Na+-independent pHi recovery was found in all three segments (PT: 0.021±0.002, CCD: 0.037±0.002, ISOMCD: 0.033±0.002 pH units/min) and was sensitive to concanamycin. In summary, we have developed a new technique for rapid and straightforward preparation of large quantities of defined tubule fragments from mouse kidney. Using this technique, the first measurements of plasma membrane vacuolar H+-ATPase activities in mouse PT and collecting duct were made. This technique will facilitate further characterization of kidney function in normal and genetically manipulated animals.
45 citations
TL;DR: Evidence is presented that myosin motors and microtubules also participate in the Fcgamma-mediated internalization process in macrophages, suggesting that actin and micro Tubules are needed not only for phagosome biogenesis but also at other steps along the phagocytic pathway.
43 citations
15 Aug 2003-Materials Science and Engineering A-structural Materials Properties Microstructure and Processing
TL;DR: In this paper, a study of the entropy change Δ S between the β phase and the martensite in Cu-based shape memory alloys was presented, and the experimental data were analyzed within the frame of a simple model, which is based on the specific heats of the phases.
Abstract: A study of the entropy change Δ S between the β phase and the martensite in Cu-based shape memory alloys is presented. From a compilation of available experimental data, the composition dependence of Δ S was studied. The experimental data were analyzed within the frame of a simple model, which is based on the specific heats of the phases. It was demonstrated that the dependence of Δ S with composition comes only through the lattice parameter and the effective mass of the alloy. For the studied composition range, the greater vibrational entropy of β phase is mainly controlled by the high-mass Cu atoms.
38 citations
TL;DR: Correlation with histopathologic findings showed gadolinium-enhanced MRI to be useful for determining the location, pattern, and extent of necrosis caused within the prostate by minimally invasive techniques.
TL;DR: In this article, an economic model was developed to quantify the profitability of Prosopis plantations and was based on published values for basal diameter growth of unmanaged and managed native prosopis stands, and plantations derived from seed and improved clones.
TL;DR: In kidneys from children with UPJ obstruction an increased activity and expression of iNOS in medulla and cNOS-dependent eNos in cortex were demonstrated, and a role of cN OS in modulating GFR and interstitial fibrosis can be suggested.
TL;DR: In this article, the authors analyzed the relationship between the stability properties of the closed convex sets in finite dimensions and their corresponding boundaries and showed that if the boundary mapping is semicontinuous in any sense (lower or upper; Berge or Hausdorff) then the feasible set is also closed at σ.
Abstract: This paper analizes the relationship between the stability properties of the closed convex sets in finite dimensions and the stability properties of their corresponding boundaries. We consider a given closed convex set represented by a certain linear inequality system σ whose coefficients can be arbitrarily perturbed, and we measure the size of these perturbations by means of the pseudometric of the uniform convergence. It is shown that the feasible set mapping is Berge lower semicontinuous at σ if and only if the boundary mapping satisfies the same property. Moreover, if the boundary mapping is semicontinuous in any sense (lower or upper; Berge or Hausdorff) at σ, then it is also closed at σ. All the mentioned stability properties are equivalent when the feasible set is a convex body.
TL;DR: In this paper, the authors measured 210Pb, 226Ra, and 137C specific activity profiles using gamma-ray spectrometry and showed that both radioisotopes behave in the same manner in these systems concerning the processes occurred from fallout to sediment deposition.
Abstract: Unsupported 210Pb fluxes were determined from sediment core inventories in lakes located in Northern Patagonia, Argentina. Total 210Pb, 226Ra, associated with supported 210Pb, and 137Cs specific activity profiles were measured by gamma-ray spectrometry. Unsupported 210Pb fluxes showed very low values when compared to other regions, with a 12 fold variation, ranging from 4 to 48 Bq m−2.y−1. The linear correlation observed between the 210Pb fluxes and137Cs cumulative fluxes in sediment cores sampled from water bodies within a zone with similar precipitation demonstrated that both radioisotopes behave in the same manner in these systems concerning the processes occurred from fallout to sediment deposition, and that there are no appreciable local or regional sources of unsupported 210Pb. Positive correlation of 210Pb fluxes with organic matter contents of the uppermost sediment core layers was also observed.
TL;DR: In this paper, the Blattflache, spezifische Blattgewicht and the Gehalt an UV-Strahlung absorbierenden Verbindungen (gemessen als UV Absorption methanolischer Blattextrakte) gemessen.
Abstract: Entlang eines Hohengradienten im Hunsruck (Rheinland-Pfalz) wurden von Mai bis September Sonnen- und Schattenblatter der Rotbuche (Fagus sylvatica L.) gesammelt. Es wurden die Blattflache, das spezifische Blattgewicht und der Gehalt an UV-Strahlung absorbierenden Verbindungen (gemessen als UV Absorption methanolischer Blattextrakte) gemessen. Sowohl bei 280 nm als auch bei 320 nm zeigten die Sonnenblatter eine hohere Absorption pro Blattflache als die Schattenblatter. An allen drei Erntezeitpunkten wurde bei den Schattenblattern eine positive Korrelation zwischen der Absorption im UV-Bereich und der Hohenlage der beprobten Baume gefunden, bei den Sonnenblattern nur fur die Probenahmen im Juli und September. Daruber hinaus trat bei den Sonnenblattern eine positive Korrelation zwischen der Absorption in dem Wellenlangenbereich von 290 bis 400 nm und der Summe der taglichen Maxima der UV-Indices wahrend der Wachstumsperiode auf. Die Sonnenblatter zeigten in allen Hohenlagen zwischen Mai und Juli einen starken Absorptionsanstieg zwischen 280 und 320 nm. Von Juli bis September konnte keine weitere Absorptionszunahme beobachtet werden. Die Schattenblatter zeigten dagegen eine Zunahme der Absorption bei 280 nm und 320 nm wahrend der gesamten Vegetationsperiode von Mai bis September.
TL;DR: A family of single-particle anomalous velocity distribution is investigated by solving a particular class of stochastic Liouville equations and the stationary state is obtained analytically and the Maxwell-Boltzmann distribution is reobtained in a particular limit.
Abstract: We investigate a family of single-particle anomalous velocity distribution by solving a particular class of stochastic Liouville equations. The stationary state is obtained analytically and the Maxwell-Boltzmann distribution is reobtained in a particular limit. We discuss the comparison with other different methods to obtain the stationary state. Extensions when the models cannot be solved in an exact way are also pointed out in connection with the one-ficton approximation.
01 Feb 2003
TL;DR: In this paper, the Blattflache, spezifische Blattgewicht and the Gehalt an UV-Strahlung absorbierenden Verbindungen (gemessen als UV Absorption methanolischer Blattextrakte) gemessen.
Abstract: Entlang eines Hohengradienten im Hunsruck (Rheinland-Pfalz) wurden von Mai bis September Sonnen- und Schattenblatter der Rotbuche (Fagus sylvatica L.) gesammelt. Es wurden die Blattflache, das spezifische Blattgewicht und der Gehalt an UV-Strahlung absorbierenden Verbindungen (gemessen als UV Absorption methanolischer Blattextrakte) gemessen. Sowohl bei 280 nm als auch bei 320 nm zeigten die Sonnenblatter eine hohere Absorption pro Blattflache als die Schattenblatter. An allen drei Erntezeitpunkten wurde bei den Schattenblattern eine positive Korrelation zwischen der Absorption im UV-Bereich und der Hohenlage der beprobten Baume gefunden, bei den Sonnenblattern nur fur die Probenahmen im Juli und September. Daruber hinaus trat bei den Sonnenblattern eine positive Korrelation zwischen der Absorption in dem Wellenlangenbereich von 290 bis 400 nm und der Summe der taglichen Maxima der UV-Indices wahrend der Wachstumsperiode auf. Die Sonnenblatter zeigten in allen Hohenlagen zwischen Mai und Juli einen starken Absorptionsanstieg zwischen 280 und 320 nm. Von Juli bis September konnte keine weitere Absorptionszunahme beobachtet werden. Die Schattenblatter zeigten dagegen eine Zunahme der Absorption bei 280 nm und 320 nm wahrend der gesamten Vegetationsperiode von Mai bis September.
TL;DR: The concept that HSP27 and HSP70 are involved in the adaptive response of the human kidney to congenital UPJO is supported, as well as the changes to renal function and duration of obstruction.
Abstract: Unilateral ureteropelvic junction obstruction (UPJO), a condition involving injury to the kidney, leads to vasoconstriction, macrophage infiltration, oxidative stress, and tubulointerstitial fibrosis. In the present study we analyzed in 22 children, the impact of UPJO on expression of HSP27 and HSP70 and related the changes to renal function and duration of obstruction. Kidney function was evaluated, and renal biopsies were obtained for immunohistochemical and western blot analyses at the time of surgery. Kidney tissue from 5 children of similar age, removed because of various malignancies, was used as control. Increased HSP27, with an expression pattern related to the duration of the obstruction, was noted in proximal tubules (PTs), cortical collecting ducts (CCDs), and medullary collecting ducts. Strong HSP27 staining in cytoplasm and nuclei of these segments appeared in children with kidney obstruction for 2.1±0.41 years. HSP70 showed a close spatial expression pattern with that of HSP27. The increased staining of HSP70 in PTs and CCDs was related to the decreased glomerular filtration rate. The constitutive/cognate form of HSP70 (HSC72) was absent. These results support the concept that HSP27 and HSP70 are involved in the adaptive response of the human kidney to congenital UPJO.
TL;DR: In this article, the magnetic properties of the electron doped manganites Ca1−x Yx MnO3 (for 0 ≤ x ≤ 0.25) in the paramagnetic regime were studied.
Abstract: We present a study of the magnetic properties of the electron doped manganites Ca1−x Yx MnO3 (for 0 ≤ x ≤ 0.25) in the paramagnetic regime. For the less doped samples (x ≤ 0.1) the magnetic susceptibility, χ(T), follows a Curie–Weiss (CW) law only for T > 450 K and, below this temperature, χ−1 (T) shows a ferrimagnetic-like curvature. We approached the discussion of these results in terms of a simple mean-field model where double exchange, approximated by a ferromagnetic Heisenberg-like interaction between Mn3+ and Mn4+ ions, competes with classical superexchange. For higher levels of doping (x ≥ 0.15), the CW behaviour is observed down to the magnetic ordering temperature (Tmo) and a better description of χ(T) was obtained by assuming full delocalization of the eg electrons. In order to explore the degree of delocalization as a function of T and x, we analysed the problem through Monte Carlo simulations. Within this picture we found that at high T the electrons doped are completely delocalized but, when Tmo is approached, they form magnetic polarons of large spin that cause the observed curvature in χ−1 (T) for x ≤ 0.1.
TL;DR: In this paper, the authors examined the standard procedure employed to obtain peak intensities from the experimental data of deep inelastic neutron scattering experiments and concluded that the usual procedure introduces errors in the determination of the peak areas, and that the analysis must be based on an exact formalism, that was previously published.
Abstract: In this paper we examine the standard procedure employed to obtain peak intensities from the experimental data of deep inelastic neutron scattering experiments. Our analysis is focussed on the hydrogen, deuterium and oxygen peaks observed in experiments on heavy water and the D2O/H2O equimolar mixture. As a result of our analysis we conclude that the usual procedure (based on a convolution formalism) introduces errors in the determination of the peak areas, and that the analysis must be based on an exact formalism, that was previously published. The present paper brings consequences on the quantitative results of recent publications.
01 Jul 2003
TL;DR: In this clinical case, the post-scratch lesions were infected with C. hominivorax larvae, the first time that the myiasis–pediculosis association has been mentioned in the literature.
Abstract: The aim of the present investigation was to identify the fly producing myiasis in a patient with pediculosis. The patient was a male adult with a severe Pediculus humanus capitis’ infestation and a lesion on his head containing larvae. Examination of these larvae revealed that they were Cochliomyia hominivorax. In this clinical case, the post-scratch lesions were infected with C. hominivorax’ s larvae. It is the first time that the myiasis–pediculosis association has been mentioned in the literature.
TL;DR: P4 promotes the AR in capacitated cauda sperm but is unable to do so in noncapacitated or immature sperm because the availability of P4r increases during epididymal transit and after capacitation.
Abstract: The goals of the present study were to determine the availability of progesterone (P4) receptor (P4r) in mouse sperm during maturation and capacitation and to make the first steps toward a characterization of P4r It has been proposed that P4 is able to induce an acrosomal reaction (AR) by using a membrane P4r This induction was verified in sperm isolated from the cauda epididymis (fully mature) when incubated in specific conditions that capacitate sperm First, we set up the conditions in our laboratory to induce an AR in mature and capacitated sperm triggered by P4 that was detected by a chlortetracycline (CTC) assay Then, we examined sperm isolated from the caput epididymis (immature) incubated under conditions that support cauda sperm capacitation and found that the AR could not be detected Moreover, P4 was unable to induce the AR when it was applied to sperm isolated from either region and incubated under conditions that did not support capacitation These results can be explained by changes in P4r availability A suitable marker for P4r is the gold (Au)-P4 complex This marker shows a binding capacity that can be visualized directly by electron microscopy (EM) and indirectly by silver-enhanced methods with light microscopy The Au-P4 complex was localized in capacitated cauda sperm at the dorsal edge of the head Using these techniques, we observed a significant decrease in both noncapacitated cauda sperm and caput sperm (whether incubated in capacitating media or not) Genomic P4r could be responsible for the signal detected, but antibodies against the P4 nuclear receptor did not recognize any sites in the sperm by immunostaining methodology Instead, a 44-kd protein band was detected in the sperm by a ligand blot assay In conclusion, P4 promotes the AR in capacitated cauda sperm but is unable to do so in noncapacitated or immature sperm because the availability of P4r increases during epididymal transit and after capacitation The P4r responsible for this behavior is different from a classical nuclear receptor-on the basis of the immunostaining results-and is probably a protein close to 44 kd-on the basis of the ligand assay results
TL;DR: In this article, the authors investigated the response of a connection detail for coupling precast concrete walls in low to medium rise buildings, where the connection consists of a rectangular steel plate with a concentric circular perforation.
Abstract: Welded connections are extensively used by the precast concrete industry to ease construction. When the seismic resistance and ductility of a building incorporating precast concrete elements needs to be assured, the connections should be carefully designed and constructed to avoid undesirable structural performance. This paper discusses aspects related to an analytical and experimental programme conducted to investigate the response of a connection detail for coupling precast concrete walls in low to medium rise buildings. The connection consists of a rectangular steel plate with a concentric circular perforation. In this way, a weak but ductile link is introduced in the system. Using the principles of capacity design, the walls can be designed as if coupled and with energy dissipation taking place in the connection. Simplified expressions are presented to evaluate the shear stiffness and the yield and ultimate strength of the perforated steel plates, based on theory and the experimental data collected du...
TL;DR: It is concluded that, in the unstimulated rat distal colon epithelium, chloride secretion accounts for about 75% of ouabain-sensitive short-circuit current and oxygen consumption.
Abstract: The aerobic metabolic cost of chloride secretion was studied in rat distal colon isolated mucosa under several conditions by simultaneous measurement of short-circuit current and oxygen consumption under conditions that preserve vectorial ion transport. A low-chloride solution and the presence of bumetanide plus diphenylamine-2-carboxylate reduced short-circuit current by 75% and oxygen consumption by 25%. Ouabain decreased short-circuit current by 93% and oxygen consumption by 32%. Serotonin increased both variables by 59% and 33%, respectively. Bumetanide and diphenylamine-2-carboxylate reduced but did not abolish the effect of serotonin on short-circuit current and oxygen consumption. Changes in short-circuit current and oxygen consumption were linearly correlated under all conditions tested. It is concluded that, in the unstimulated rat distal colon epithelium, chloride secretion accounts for about 75% of ouabain-sensitive short-circuit current and oxygen consumption. Stimulated chloride secretion may demand over 40% of total oxygen consumption.
Journal Article•
TL;DR: Data confirm that changes in SMC proliferation and endothelial dysfunction at different levels of the cardiovascular system are involved in syndrome "X", and that AT1 receptor blocking can revert those changes, suggesting an important role of the RAS, possibly mediated by AT2 receptors and kinins, in the physiopathological mechanisms of this model.
Abstract: The cluster of risk factors including hyperinsulinemia, insulin resistance, hypertriglyceridemia and hypertension has been called syndrome X. Several evidences link the insulin resistance syndrome with endothelial dysfunction. Since the participation of the renin-angiotensin system (RAS) in this pathology is still unclear, the present study examined the effect of chronic administration of an angiotensin AT1 receptor antagonist, losartan (L), on endothelial nitric oxide synthase (eNOS) activity in aortic endothelium and cardiac tissue, and on the proliferation of primary cultured aortic smooth muscle cells (SMC), obtained from fructose-fed rats (FFR), an experimental model of syndrome X Male Wistar rats were used: Control, FFR and FFR+L (n = 8 in each group). After 8 weeks, tissue samples were obtained and 10% fetal calf serum (FCS) proliferative effect was examined in SMC by 3H-thymidine incorporation and cell counting. The eNOS activity was estimated in aortic endothelial lining and cardiac homogenates by conversion of 3H-arginine into 3H-citrulline. FFR aortic SMC showed a significantly increased 10% FCS-induced 3H-thymidine incorporation and cell number compared to controls. FFR aortic and cardiac eNOS activities were significantly decreased. Chronic treatment with L decreased systolic blood pressure,reverted cardiac hypertrophy, abolished the increased SMC proliferation and restoredeNOS activity. These data confirm that changes in SMC proliferation and endothelial dysfunction at different levels of the cardiovascular system are involved in syndrome "X", and that AT1 receptor blocking can revert those changes, suggesting an important role of the RAS, possibly mediated by AT2 receptors and kinins, in the physiopathological mechanisms of this model.
TL;DR: A method of propagation of G. perakii from nodal segments is reported, and Proliferating microshoot cultures were obtained by placing nodal segment on Murashige and Skoog medium supplemented with 20 g.L-1 of sucrose without growth regulators.
Abstract: Glandularia perakii is a perennial species with beautiful violet flowers that grows in the stony soil of Mendocine pedemont. A plentiful and prolonged flowering confers it an important ornamental potential. In this paper, a method of propagation of G. perakii from nodal segments is reported. Proliferating microshoot cultures were obtained by placing nodal segment on Murashige and Skoog medium (MS) supplemented with 20 g.L-1 of sucrose without growth regulators. In this medium multiplication rate after 20 days was 7.9. Rooted plants were acclimatized successfully.
Journal Article•
TL;DR: A bodega productora de vinos tintos ubicada en Maipu (Mendoza, Argentina) and se propusieron alternativas for mejorar la situacion actual organizando and reduciendo el consumo de agua and disminuyendo el impacto ambiental que causan los efluentes.
Abstract: Se estudio la gestion de efluentes y el consumo de agua en una bodega productora de vinos tintos ubicada en Maipu (Mendoza, Argentina) y se propusieron alternativas para mejorar la situacion actual organizando y reduciendo el consumo de agua y disminuyendo el impacto ambiental que causan los efluentes. La empresa no mide con precision el consumo de agua, estimandolo por las veces que se llena y vacia la pileta que recoge los efluentes. Con ese dato, y en funcion del volumen elaborado de vino, se infirio que el gasto de agua quintuplica aproximadamente al de un establecimiento similar en Francia. Tampoco son medidas la salinidad y la toxicidad de las aguas residuales.
TL;DR: The responses of the substantia nigra neurons to hypoxia are regionalized and potential neuroprotective effects may depend on the vulnerability of each neuronal type.
TL;DR: Examination of the effect of GABA-A-benzodiazepine (BZD) receptor manipulation on aggression, emotion, feeder control, and eating behavior in high- and low-aggression female pigeons maintained at 80% of their normal weight and exposed to food competition interactions showed that the emotional and aggressive responses to DZP were neutralized by FZL.
Abstract: The food competition interaction test performed with food-restricted pigeons with previously consolidated dominance is a useful tool for the study of offensive and defensive social aggression. In the present study, we examined the effect of GABA-A-benzodiazepine (BZD) receptor manipulation on aggression, emotion, feeder control, and eating behavior in high- and low-aggression female pigeons maintained at 80% of their normal weight and exposed to food competition interactions. The pigeons were divided into pairs by previously ranked high-aggression females (total time spent in aggression over 60 s/5 min; n=6 pairs) and low-aggression females (time spent in aggression less than 10 s/5 min; n=6 pairs). In Experiment 1, a pigeon in each pair of high- and low-aggression subjects were treated daily with an oral dose of diazepam (DZP, 0.6 mg/kg/0.3 ml) for 8 days. The other animal received the vehicle. On Day 8, food competition trials (10 min) were performed 30 min after treatments. In Experiment 2, pigeons were injected subcutaneously with flumazenil (FZL, 0.1 mg/kg/1 ml) or saline and exposed to a food competition trial 30 min after injections. In Experiment 3, one animal in each pair received DZP for 8 days. The other animal received the vehicle. On Day 8, the DZP-treated subjects were injected subcutaneously with FZL (0.1 mg/ kg/1 ml) 30 min before the oral dose of DZP. Trials were performed 30 min after DZP or vehicle administration. In Experiment 1, it was found that the DZP group of high-aggression pigeons showed lower scores of aggression (P<.05) and emotional responses (P<.05) than controls. The other group-scored behaviors were not affected. The DZP low-aggressions, however, showed scores of aggression eightfold higher than their controls (P<.05) but the other scored behaviors were not changed. In Experiment 2, FZL injection did not induce intrinsic effects on aggression either in the high- or in the low-aggression group. Experiment 3 showed that the emotional and aggressive responses to DZP were neutralized by FZL. This shows that GABA-A-BZD receptor mechanisms are implicated in the DZP responses in high- and low-aggression pigeons.