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Dive into the research topics where Santiago Monleón is active.

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Featured researches published by Santiago Monleón.


Psychopharmacology | 1995

Attenuation of sucrose consumption in mice by chronic mild stress and its restoration by imipramine

Santiago Monleón; Paolo S. D'Aquila; Andrés Parra; Vicente M. Simón; Paul F. Brain; Paul Willner

Chronic exposure to mild unpredictable stressors (CMS) has previously been found to reduce the consumption of palatable, sweet solutions in rats. In the present study, the utility of this procedure was assessed in mice. Male AP mice subjected to CMS showed reduced consumption of a 2% or 4% sucrose solution. This effect was reversed by chronic (3 weeks) treatment with the tricyclic antidepressant imipramine (20 mg/kg per day). These results extend previous reports of a generalized decrease in sensitivity to reward (anhedonia) in rats caused by CMS and the efficacy of antidepressant treatment in this paradigm. Chronic unpredictable mild stress in mice appears to provide a realistic animal model of depression.


Genes, Brain and Behavior | 2002

Evidence for general cognitive ability (g) in heterogeneous stock mice and an analysis of potential confounds

M J Galsworthy; Jose Luis Paya-Cano; Santiago Monleón; Robert Plomin

The heterogeneous stock (HS) is a genetically outbred line of mice established more than 30 years ago from an 8‐way cross of C57BL/6, BALB/c, RIII, AKR, DBA/2, I, A/J and C3H inbred mouse strains. The present study compared the performance of 40 HS mice across a battery of diverse cognitive tasks under a variety of motivations. Indices of emotionality were also included in order to assess their influence on performance. All measures of ability loaded positively on an unrotated first principal component that accounted for 31% of the variance, suggesting the presence of a common factor of general cognitive ability (g) underlying all tasks. A first factor derived from anxiety indices correlated nonsignificantly with all cognitive tasks and nonsignificantly with this g factor, supporting the hypothesis that the factor is cognitive rather than temperamental in nature. The factor was also robust in relation to outliers and sex differences, accounting for 28% of the variance after removal of outlier individuals and also after correcting for variance owing to sex differences. A general cognitive ability (g) appears to underlie the performance of HS mice on a battery tapping diverse cognitive demands.


European Journal of Pharmacology | 1997

Anti-anhedonic actions of the novel serotonergic agent flibanserin, a potential rapidly-acting antidepressant

Paolo S. D'Aquila; Santiago Monleón; Franco Borsini; Paul F. Brain; Paul Willner

Chronic exposure to mild unpredictable stress has previously been found to depress the consumption of palatable sweet solutions and to block the formation of conditioned place preferences; these effects are reversed by chronic treatment with tricyclic or atypical antidepressant drugs. The present study was designed to evaluate the antidepressant-like activity in this model of flibaserin (BIMT-17), a novel serotonergic agent with 5-HT1A receptor agonist and 5-HT2 receptor antagonist properties. Two experiments were conducted, using rats (experiment 1) and mice (experiment 2). In experiment 1, decreases in sucrose intake were seen in rats exposed to chronic mild stress, but the effect was unreliable in this study, and sucrose testing was terminated after 7 weeks of stress. Beginning after 5 weeks of stress, groups of control and stressed animals were treated daily with vehicle, fluoxetine (5 mg/kg) or flibanserin (5, 10 or 20 mg/kg). After 6 weeks of treatment, all animals were tested for acquisition of food-reinforced place preference conditioning. Conditioning was seen in all groups other than the vehicle-treated stressed animals. We also tested the locomotor stimulant effect of a single injection of the dopamine D2/D3 receptor agonist quinpirole (0.2 mg/kg). The effect of quinpirole was potentiated by fluoxetine in control animals, and by both fluoxetine and flibanserin (all doses) in stressed animals. In experiment 2, long-lasting decreases in sucrose intake were seen in mice exposed to chronic mild stress. The effects were reversed by chronic (4 weeks) treatment with fluoxetine (5 mg/kg) or flibanserin (2.5 or 5 mg/kg); the full effect of flibanserin was seen after the first injection. All animals received a single injection of raclopride (0.1 mg/kg) immediately prior to a sucrose intake test on day 27 of drug treatment. Raclopride decreased sucrose intake only in the three drug-treated stressed groups. The results support a rapid antidepressant-like action of flibanserin, and suggest that this effect involves sensitization of dopamine D2/D3 receptor-mediated transmission.


European Neuropsychopharmacology | 2008

Antidepressant drugs and memory: insights from animal studies.

Santiago Monleón; Concepción Vinader-Caerols; M. Carmen Arenas; Andrés Parra

This is a selective review of the literature concerning the effects of antidepressant drugs on animal memory, which was performed with the aid of the PubMed database. Monoamine oxidase inhibitors tend to either have no effect on memory or result in its improvement. Studies with cyclic antidepressants have reported no effect or, more often, memory impairments. Pre-training administration of selective serotonin reuptake inhibitors (SSRIs) has been shown to have either no effect on memory or undermine it (with some isolated exceptions, in which improvements have been recorded), while post-training administration of SSRIs has been demonstrated to improve memory or have no effect. A small group formed by the remaining antidepressants has been shown to improve memory, with the exception of trazodone, which impairs memory. These findings are discussed in the light of knowledge regarding the actions of antidepressants on several neurotransmission systems. The possibility that the effects of antidepressants on memory are the core of the therapeutic effects of these drugs is also considered.


Behavioural Brain Research | 2002

Chronic administration of fluoxetine impairs inhibitory avoidance in male but not female mice

Santiago Monleón; Adoración Urquiza; M. Carmen Arenas; Concepción Vinader-Caerols; Andrés Parra

The effects of chronic administration of fluoxetine (20 mg/kg/day i.p.) on a one-trial step-through inhibitory avoidance task were investigated in male and female CD1 mice. In Experiment 1, treatment was administered for 21 days before the training session, whereas in Experiment 2, other subjects were subjected to the same treatment starting 24 h after the training session. The comparison of test versus training latencies showed memory deterioration with pre-training administration of fluoxetine (Experiment 1), which affected males but not females. Sex differences in this task were also observed in Experiment 1, with females showing a better performance. Sex differences were evident in controls as well as in treated animals. The locomotor activity of the animals was also tested in Experiment 1. Due to the absence of sex differences in the drug effects on this measure, the sex differences in the effects of fluoxetine on inhibitory avoidance were hardly attributable to non specific effects on locomotor activity. The lack of effect of post-training administration of fluoxetine (Experiment 2) constitutes additional support of the idea that the observed effect on inhibitory avoidance in Experiment 1 is specifically related to learning and memory.


Pharmacology, Biochemistry and Behavior | 1999

Sex Differences in the Effects of Neuroleptics on Escape-Avoidance Behavior in Mice: A Review

Andrés Parra; M. C. Arenas; Santiago Monleón; Concepción Vinader-Caerols; Vicente M. Simón

The literature of the effects of dopamine antagonists on escape-avoidance, focusing on data obtained in our laboratory with male and female mice, is reviewed. The acute administration of haloperidol, raclopride, clozapine, and SCH 23390 impaired escape-avoidance behavior more in males than in females, and the subchronic administration of haloperidol had a similar effect. This appeared to be a reliable phenomenon, because it was observed in both kinds of administration, in two mouse strains, and with several drugs and doses. The observed results were dose dependent, although the dose-effect relationship was not the same in all drugs. The sex differences in escape avoidance did not seem related to sex differences in the well-known deteriorating effects of these drugs on motor activity. In addition, an analysis of all our studies showed that there were no sex differences in the variability of responses, reinforcing the idea that female subjects should be included in these types of studies.


Behavioural Brain Research | 2006

Are the effects of the antidepressants amitriptyline, maprotiline, and fluoxetine on inhibitory avoidance state-dependent?

M. Carmen Arenas; Concepción Vinader-Caerols; Santiago Monleón; Ana Martos; Estrella Everss; Aránzazu Ferrer-Añó; Andrés Parra

State-dependent learning (SDL) is a phenomenon in which the retrieval of newly acquired information is possible if the subject is in the same physiological state as during the encoding phase. SDL makes it possible to separate the effects of drugs per se on learning from the effects due to changes in drug state during the task. The present work was designed to investigate whether the antidepressants amitriptyline (30 mg/kg), maprotiline (25 mg/kg), and fluoxetine (15 mg/kg) produce SDL of the inhibitory avoidance conditioning in male and female CD1 mice. In three separate experiments, independent groups were used for each pharmacological treatment and for each sex using a 2 x 2 experimental design. The results do not show SDL in any of the drugs. In the case of amitriptilyline, the data can be attributed to a memorization deficit, while the maprotiline results are interpreted as simultaneously influenced by memorization deficit and performance facilitation due to motor impairment. Fluoxetine treatment did not produce any deteriorating effect on the conditioning. Drugs had some different effects on the performance of males and females, males showing a slightly higher deterioration than females with administration of amitriptyline and maprotiline. This study shows that these antidepressants affect the acquisition/consolidation but not the retrieval process in the inhibitory avoidance learning.


Behavioural Brain Research | 2005

Piracetam counteracts the effects of amitriptyline on inhibitory avoidance in CD1 mice.

Estrella Everss; M. Carmen Arenas; Concepción Vinader-Caerols; Santiago Monleón; Andrés Parra

The purpose of the present work was to study the effects of amitriptyline on animal cognition in relation to some characteristics of its therapeutic effects. The modulation of acute and chronic effects of amitriptyline on inhibitory avoidance in male and female mice by piracetam was investigated. In Experiment 1, mice were subjected to the training phase of inhibitory avoidance conditioning 60 min after acute piracetam (100 mg/kg) or physiological saline administration. Immediately after the behavioural task, they received a single injection of the tricyclic antidepressant amitriptyline (30 mg/kg) or physiological saline. Twenty-four hours later, subjects were tested for avoidance. In Experiment 2, the same doses of amitriptyline and piracetam were chronically administered. Mice were subjected to the training phase of inhibitory avoidance on the 22nd day, and to the test phase 24 h later. Forty-five minutes after test, subjects explored the elevated plus-maze for 5 min in order to assess whether the effects of amitriptyline on avoidance performance may reflect general behavioural changes. Results obtained were that: (a) acute and chronic amitriptyline impaired inhibitory avoidance of male and female mice, (b) piracetam counteracted the effect of acutely administered amitriptyline on inhibitory avoidance, and (c) piracetam counteracted the effects of chronically administered amitriptyline in males but not females in the same learning task. These effects do not seem to be mediated by non-specific drug effects on spontaneous motor activity or anxiety.


Behavioural Brain Research | 2000

Effects of acute and chronic maprotiline administration on inhibitory avoidance in male mice

Andrés Parra; Ana Martos; Santiago Monleón; M. C. Arenas; Concepción Vinader-Caerols

The effects of acute and chronic administration of maprotiline (5, 10 or 20 mg/kg, intraperitoneally) were assessed on inhibitory avoidance in male mice. Acute administration of maprotiline before training did not effect training phase latencies, but impaired performance (i.e. produced shorter latencies) in the test at doses of 5 and 20 mg/kg. When given after training, the drug did not modify test latencies at any of the doses used. Chronic administration for 21 days (interrupted 24 h before training) also shortened latencies in the test but not in training. An experiment on the acute effects of maprotiline on analgesia (determination of flinch and jump thresholds for increasing electric foot shock levels), at the doses stated, was carried out on naive animals. No analgesic effect of the drug was found. Taken together, the results indicate that acute maprotiline produces anterograde amnesia, and tolerance does not appear after 21 days of treatment.


Pharmacology, Biochemistry and Behavior | 2008

Changes in brain oxidative metabolism induced by inhibitory avoidance learning and acute administration of amitriptyline

Héctor González-Pardo; Nélida M. Conejo; Jorge L. Arias; Santiago Monleón; Concepción Vinader-Caerols; Andrés Parra

The effects of antidepressant drugs on memory have been somewhat ignored, having been considered a mere side effect of these compounds. However, the memory impairment caused by several antidepressants could be considered to form part of their therapeutic effects. Amitriptyline is currently one of the most prescribed tricyclic antidepressants, and exerts marked anticholinergic and antihistaminergic effects. In this study, we evaluated the effects of inhibitory avoidance (IA) learning and acute administration of amitriptyline on brain oxidative metabolism. Brain oxidative metabolism was measured in several limbic regions using cytochrome oxidase (CO) quantitative histochemistry. Amitriptyline produced a clear impairment in the IA task. In animals exposed only to the apparatus, amitriptyline decreased CO activity in nine brain regions, without affecting the remaining regions. In animals that underwent the IA training phase, amitriptyline reduced CO activity in only three of these nine regions. In animals treated with saline, IA acquisition increased CO activity in the medial prefrontal cortex, the prelimbic cortex, and the medial mammillary body, and diminished it in the medial septum and the nucleus basalis of Meynert with respect to animals exposed only to the IA apparatus. In animals treated with amitriptyline, IA acquisition did not modify CO activity in any of these regions, but increased it in the anteromedial nucleus of the thalamus, the diagonal band of Broca, and the dentate gyrus. The results reveal a pattern of changes in brain oxidative metabolism induced by IA training in saline-treated animals that was clearly absent in animals submitted to the same behavioural training but treated with amitriptyline.

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