Search results for "Agoni"
showing 10 items of 2493 documents
Effects of several degrees of chronic social defeat stress on emotional and spatial memory in CD1 mice
2015
In the present study, the effects of several degrees of CSDS (Chronic Social Defeat Stress) on emotional and spatial memory in mice were evaluated in separate experiments. Male CD1 mice were randomly assigned to four experimental groups (n=10-12) for each experiment: NS (non-stressed), S5, S10 and S20 (5, 10 and 20 sessions of CSDS, respectively). The S groups underwent the corresponding number of agonistic encounters (10min each) over a 20-day period. 24h after the last session of CSDS, mice performed the inhibitory avoidance (Experiment 1) or the Morris water maze test (Experiment 2). In both experiments, animals were also evaluated in the elevated plus maze for 5min to obtain complementa…
Effects of acute social stress on the conditioned place preference induced by MDMA in adolescent and adult mice
2014
Exposure to social defeat stress increases the rewarding effects of psychostimulants in animal models, but its effect on 3,4-methylenedioxymethylamphetamine (MDMA) reward has received little attention. In the present study, we evaluated the influence of social defeat on the rewarding effects of MDMA in adolescent [postnatal day (PND) 29-40] and adult (PND 50-61) male mice using the conditioned place preference paradigm. Experimental mice were exposed to social defeat in an agonistic encounter before each session of conditioning with 1.25 or 10 mg/kg of MDMA. The effects of social defeat on corticosterone levels and the motor or the anxiogenic effects of MDMA were also evaluated. Mice expose…
Inhibitory avoidance learning in CD1 mice: Effects of chronic social defeat stress
2015
Chronic social defeat stress (CSDS) is an animal model widely used to determine the neurobiological mechanisms of stress and its associated pathologies. In this study, the effects of CSDS on inhibitory avoidance (IA) were evaluated in post-pubertal and adult male CD1 mice, instead of the C57BL/6J strain used in the CSDS standard protocol. CSDS consisted of daily 5-min (experiments 1 and 2) or 10-min (experiment 3) agonistic encounters on 21 consecutive days. Twenty four hours after the last session of CSDS, all the mice were tested for IA. They were also evaluated in an elevated plus-maze, obtaining complementary measures of locomotor activity and emotionality. In experiments 1 and 2, IA le…
Rewarding effects of 3,4-methylenedioxymethamphetamine (“Ecstasy”) in dominant and subordinate OF-1 mice in the place preference conditioning paradigm
2006
We tested the ability of 3,4-methylenedioxymethamphetamine (MDMA) to induce conditioned place preference (CPP) in dominant and subordinate OF-1 mice subjected to cohabitation and repeated sessions of agonistic confrontation, as well as in non-confronted mice. We selected doses of MDMA (2, 6, 10 mg/kg) previously reported to induce CPP in mice and we measured expression of c-Fos evoked by the treatments in non-confronted mice. MDMA induced c-Fos protein in several corticolimbic regions involved in drug-induced reward. Mice were exposed to brief sessions of agonistic confrontation on 5 consecutive days. Determinations of circulating hormones and drug conditioning tests were carried out on com…
Uso de antagonistas de la hormona liberadora de gonadotrofinas (GnRH) en la preparación endometrial de las receptoras de ovocitos
2015
INTRODUCCIÓN: La donación de ovocitos está bien establecida como técnica de reproducción asistida y ofrece la oportunidad única de tratar a mujeres con diferentes entidades clínicas, tanto con función ovárica como sin ella. En las pacientes con función ovárica conservada, se utilizan análogos de la GnRH (a-GnRH) para provocar una supresión hipofisaria, lo que permite conseguir una sincronización entre la donante y la receptora, evitando picos ovulatorios espontáneos que abrirían la ventana de implantación de la receptora en asincronía con la donante. OBJETIVO: El objetivo principal del estudio fue comparar los resultados obtenidos con el empleo de antagonistas de la GnRH (ant-GnRH) en la si…
Functional feature of a novel model of blood brain barrier: Studies on permeation of test compounds
2001
Drug delivery to the central nervous system (CNS) is subject to the permeability limitations imposed by the blood-brain barrier (BBB). Several systems in vitro have been described to reproduce the physical and biochemical behavior of intact BBB, most of which lack the feature of the in vivo barrier. We developed a fully formed monolayer of RBE4.B immortalized rat brain microvessel endothelial cells (ECs), grown on top of polycarbonate filter inserts with cortical neuronal cells grown on the outside. Neurons induce ECs to synthesize and sort occludin to the cell periphery. Occludin localization is regulated by both compositions of the substratum and soluble signals released by cortical co-cu…
Reduction of red-green discrimination by dopamine D1 receptor antagonists and retinal dopamine depletion
1996
AbstractReduction of wavelength discrimination ability in the 560–640 nm range, but not in the 404–540 nm range, has been demonstrated in goldfish after intravitreal injection of D1-dopamine receptor antagonists. Intravitreal injection of the dopaminergic neurotoxin 6-OH-dopamine severely reduced wavelength discrimination ability in the 540–661 nm range within 3 days. Discrimination ability could be reconstituted by the Dl-agonist SKF 38393. Animals recovered from injection of 6-OH-dopamine within 14–16 days. No change of wavelength discrimination was induced by 6-OH-dopamine in the 461–540 nm range. We conclude that under photopic conditions dopamine modulates retinal mechanisms involved i…
Effekte von Ketamin bei globaler zerebraler Ischämie
1997
This review focuses on the significance of S-(+)-ketamine as a neuroprotective agent. Evidence in the literature supporting or contradicting a neuroprotective or even therapeutic role of ketamine in global cerebral ischaemia is critically reviewed, and data from an ongoing study in a rat global cerebral ischaemia model (15 min ischaemia with S(+)-ketamine administered 15 min after reperfusion) are reported. The number of experimental studies available so far limited, however, and therefore results cannot be considered conclusive at the present time. Only at higher ketamine dosages was protection found reliably, especially in models of complete forebrain ischaemia lasting over 10 min. In our…
Role of NK1 and NK2 receptors in mouse gastric mechanical activity
2006
1. The aim of the present study was to examine the role of NK1 and NK2 receptors in the control of mechanical activity of mouse stomach. In this view, the motor effects induced by NK1 and NK2 receptor agonists and antagonists were analyzed, measuring motility as intraluminal pressure changes in mouse-isolated stomach preparations. In parallel, immunohistochemical studies were performed to identify the location of NK1 and NK2 receptors on myenteric neurons and smooth muscle cells. 2. Substance P (SP) induced biphasic effects: a contraction followed by relaxation; neurokinin A (NKA) and [beta-Ala8]-NKA(4-10), selective agonist of NK2 receptors, evoked concentration-dependent contractions, whe…
NMDA receptor antagonist treatment increases the production of new neurons in the aged rat hippocampus
2002
The production of new neurons declines during adulthood and persists, although at very low levels, in the aged hippocampus. Since neurogenesis in young adults has been related to learning and memory, its reduction may contribute to the age-related impairments in these abilities. Adrenalectomy (ADX) enhances neurogenesis in the aged hippocampus, although it also induces neuronal cell death. Since the administration of an NMDA receptor antagonist enhances neurogenesis in young adult rats without deleterious morphological effects, we have tested whether neurogenesis could be reactivated in aged rats. Our study shows that cell proliferation, cell death, neurogenesis and the number of radial gli…