Persona:
Pellón Suárez de Puga, Ricardo

Foto de perfil
Dirección de correo electrónico
rpellon@psi.uned.es
ORCID
0000-0002-4099-7621
Fecha de nacimiento
Proyectos de investigación
Unidades organizativas
Puesto de trabajo
Apellidos
Pellón Suárez de Puga
Nombre de pila
Ricardo
Nombre

Filtros

2017 - 201942020 - 202620
Restablecer filtros

Ajustes

Resultados de la búsqueda

Mostrando 1 - 10 de 24
  • Miniatura
    Publicación
    Delay Gradients for Spout-Licking and Magazine-Entering Induced by a Periodic Food Schedule
    (Springer Nature, 2018-03-26) Killeen, Peter R.; Pellón Suárez de Puga, Ricardo; Ibias Martín, Javier
    The present experiments studied impulsivity by manipulating the delay between target responses and presentation of a reinforcer. Food-deprived SHR, WKY, and Wistar rats were exposed to a fixed-time 30-s schedule of food pellet presentation until they developed stable patterns of water spout-licking and magazine-entering. In successive phases of the study, a resetting delay contingency postponed food delivery if target responses (licks or entries) occurred within the last 1, 2, 5, 10, 20, 25, or 28 s of the inter-food interval. Response-food delays were applied independently for the two behaviors during separate experimental phases, and order of presentation and the behavior that was punished first were counterbalanced. Licking was induced in the order of Wistar > SHR > WKY, and magazine entries were in the order of SHR > WKY > Wistar. Magazine entries showed steeper delay gradients than licking in SHR and Wistar rats but were of similar great inclination in the WKY rats. The different responses were differentially sensitive to delays. This suggests a different ordering of them in the interval between reinforcers. It also has implications for attempts to change impulsive behavior, both in terms of the nature of the response and its removal from reinforcing consequences.
  • Miniatura
    Publicación
    Environmental enrichment accelerates the acquisition of schedule-induced drinking in rats
    (Elsevier, 2023-09-15) Fuentes Verdugo, Esmeralda; López Tolsa Gómez, Gabriela Eugenia; García Pascual, Raquel; Pellón Suárez de Puga, Ricardo
    Environmental enrichment (EE) provides an improvement in the housing conditions of experimental animals, such as laboratory rats, with greater physical and social stimulation through toys and company in the home cages. Its use is known to influence performance of experimental protocols, but these effects have not been well determined in the schedule-induced drinking (SID) procedure. The main goal of this study was to investigate the effects of EE on the acquisition of SID in 24 12-week-old male Wistar rats, divided into two groups, a group with EE housed with toys and companions, and a group without enrichment in individual housing conditions without toys (social isolation and no environmental enrichment, INEE). A total of 25 sessions, under a fixed time 30 s food reinforcement schedule and with access to water in the experimental chambers were carried out. Sessions lasted 30 min. The results showed that the EE group developed faster the excessive drinking pattern of SID, and drank to higher levels, than the INEE group. The greater development of SID in the EE group contradicts the view of schedule-induced behavior as linked to stress reduction and better suits with the conception of induction related to positive reinforcement.
  • Miniatura
    Publicación
    Alcohol consumption and preference in female rats induced by reward downshift reveals sex generality of the modulatory role of physical activity
    (Lippincott, Williams & Wilkins, 2025-04-01) Castejón, Elena; Ambrosio Flores, Emilio; Pellón Suárez de Puga, Ricardo; Torres, Carmen
    Increased voluntary consumption of alcohol has been demonstrated in male rats exposed to frustrative reward downshift (the emotional self-medication effect). Access to a wheel for voluntary running abolished this effect in male rats, suggesting an attenuating effect of physical exercise on the negative affect induced by reward downshift and its consequences on drug intake. The present study analyzed this effect in female rats. Sixty-four food-deprived female Wistar rats received 32% sucrose [4% (Experiment 1) or 2% (Experiment 2) in controls] during 10, 5-min preshift sessions followed by 4% (Experiment 1) or 2% (Experiment 2) sucrose during 5 postshift sessions. Immediately after each consummatory session, animals were exposed to a 2-h, two-bottle preference test involving 32% alcohol vs. water. Half of the animals also had access to a running wheel during the preference test. The results showed (a) lower sucrose consumption in the downshifted groups (32–4% and 32–2%) compared to the unshifted controls (4–4% and 2–2%, respectively); (b) higher alcohol preference in downshifted groups without access to a wheel compared with downshifted groups with access to the wheel (Experiments 1 and 2); and (c) increased alcohol intake (g/kg) after experiencing reward downshift in animals without access to the wheel (Experiment 1). Voluntary wheel running thus reduced alcohol intake in female rats experiencing reward downshift. These findings are comparable to previous results reported in male rats and support the usefulness of physical exercise to prevent alcohol self-medication induced by frustrative nonreward.
  • Miniatura
    Publicación
    Physical activity reduces alcohol consumption induced by reward downshift
    (American Psychological Association, 2023) Castejón, Elena; Fuentes Verdugo, Esmeralda; Torres, Carmen; Pellón Suárez de Puga, Ricardo
    Increased voluntary consumption of alcohol and other anxiolytics has been demonstrated in animals after experiencing frustrative reward devaluation (downshift) or omission. These results have been interpreted in terms of emotional self-medication. In the present study, we analyzed whether voluntary physical activity reduces alcohol intake induced by reward downshift. Sixty-four male Wistar rats were divided into eight groups (n = 8). Thirty-two (downshifted) animals received 32% sucrose during 10 preshift sessions (5 min), followed by 4% sucrose during five postshift sessions, whereas 32 (unshifted) controls were always exposed to 4% sucrose. Immediately after each consummatory session, animals were exposed to a 2-hr two-bottle preference test involving 32% alcohol versus water or water versus water. Half of the animals had also access to a wheel for voluntary running during the preference test. The results showed lower sucrose consumption in downshifted groups compared with unshifted controls (the frustrative reward downshift effect). Reward downshift significantly increased alcohol intake, this effect being absent in downshifted animals with access to the wheel. These findings suggest that physical exercise could be useful to prevent alcohol self-medication induced by frustrative nonreward. Public Health Significance Human and nonhuman studies suggest that consumption-dependent reduction in negative affect promotes alcohol intake. This “self-medication behavior” has been observed in frustrating situations involving reward loss. This study showed (in rats) that increased alcohol intake induced by a reward devaluation event was abolished by voluntary wheel running. Physical exercise could therefore be useful to prevent the maladaptive effects of frustration on drug use.
  • Miniatura
    Publicación
    Repeated Δ-9-Tetrahydrocannabinol administration dose dependently increases stablished schedule-induced drinking
    (Springer Nature, 2024-02-28) Fuentes Verdugo, Esmeralda; Pellón Suárez de Puga, Ricardo; Miguens Vázquez, Miguel
    Rationale: Schedule-induced drinking (SID) reproduces an excessive and repetitive behavioural pattern that has led to propose this procedure as an animal model to study compulsive behaviours. Although it is known that cannabis can cause several adverse effects, in recent years there has been great interest in the medical application of cannabis derivatives for obsessive-compulsive related disorders. Objectives: The present study investigated the effects of repeated THC administration on rates of previously acquired SID, as well as the possible alteration of its temporal distribution along inter-food intervals. Methods: Male Wistar rats acquired SID under a 30 min fixed-time 30-sec food delivery schedule (from 30 to 43 sessions to reach a stable level). Thereafter, 5 or 10 mg/kg daily i.p. injections of THC or vehicle were repeatedly administered for 7 days to evaluate the effects on SID. Results: Repeated THC administration at a dose of 5 mg/kg resulted in an increase on licking. Surprisingly, no effects on SID were observed with the 10 mg/kg dose. However, magazine entries were reduced with both THC doses. THC also modified the temporal distributions of licking and magazine entries during inter-food intervals. Conclusions: The present results show that repeated THC administration may (i) increase induced licking at moderate doses, (ii) reduce magazine entries, and (iii) affect the temporal pattern of SID. These findings suggest that THC does not appear to be beneficial to reduce compulsive behaviour in this animal model, while another collateral effect of THC —such as a greater habitual-like behaviour— needs to be considered.
  • Miniatura
    Publicación
    Behavioral history effects on the maintenance of schedule-induced drinking in rats
    (Wiley, 2026-01-06) López Tolsa Gómez, Gabriela Eugenia; Ardoy Cuadros, Juan; Pellón Suárez de Puga, Ricardo
    Variables affecting scheduled-induced drinking (SID) have been widely studied. Previous experience with other food schedules can slow or prevent acquisition of SID, and its rate can decrease once it has developed if the conditions of the experimental sessions change. These findings conform to the idea that the distribution of behaviors during interreinforcement intervals depends on the occurrence of other behaviors. The goal here was to investigate the effect of interrupting access to water on the subsequent maintenance of SID when access to water was restored. First, in Phase A, rats developed SID under three different fixed-interval (FI) schedules. Then, in Phase B, access to water was removed in the conditioning chambers while food continued to be delivered under the same schedules. Last, when access to water was restored, rats that continued under the foodreinforcement schedule showed lower levels of SID than subjects that remained in their home cages throughout Phase B. Competition between licking and lever pressing was observed, particularly during short FI schedules. These data expand previous findings on behavioral history effects on SID and suggest that SID is part of behavioral patterns developed during interreinforcement intervals in which distribution of behaviors depends on occurrence of all other behaviors.
  • Miniatura
    Publicación
    Wheel running induced by intermittent self-administration of ethanol: A proof of concept
    (Springer, 2024-12-23) Molinés Hurtado, Fernando Antonio; Pellón Suárez de Puga, Ricardo
    Previous attempts to induce behavior with intermittent administration of reinforcing drugs have met with several shortcomings, such as failure to replicate certain features of induced behavior under intermittent administration of food. It is argued that, aside from the difference in the nature of the reinforcer used, several characteristics of previous procedures functionally depart from research in which food is used as an inducer, such as the lack of a consummatory response. In this article we attempt to develop a more functionally equivalent procedure to induce behavior with intermittent administration of reinforcing drugs that might overcome these limitations. Wistar rats of both sexes were exposed to intermittent delivery of a 5% ethanol solution (v/v) using a fixed time schedule of 60 s while they had access to an activity wheel. Rats were also exposed to a massed-ethanol control condition. A progressive increase in wheel running was found during intermittent ethanol administration. Afterwards, and to dissociate the amount of running that would be function of mobility deprivation and induction, a wheel was also added to home cages. Under these circumstances, an approximately inverted U-shaped function was observed for the distribution of running within inter-reinforcement intervals. In addition, a decrease in wheel running was observed in a massed-control condition compared with intermittent ethanol administration. The developed procedure allows the study of behavior induced by the intermittent administration of reinforcing drugs, replicating core features of induced behavior not observed with previous arrangements.
  • Miniatura
    Publicación
    Influence of early maternal separation on susceptibility to the activity-based anorexia model in male and female Sprague Dawley rats
    (Elsevier, 2022-11) Kojo Morgan, Godstime Stephen; Mata, Yolanda; Carrillo Urbano, Beatriz; Pellón Suárez de Puga, Ricardo; Collado Guirao, Paloma; Gotti, Stefano; Pinos Sánchez, María Elena
    A principal animal paradigm employed in Anorexia Nervosa (AN) study is the activity-based anorexia (ABA) model. The model's efficacy in recapitulating the core features of AN in humans allows for the study of the parameters involved in the disorder. The current study examined the susceptibility to the ABA protocol in the presence of a significant stressor (maternal separation) in male and female Sprague Dawley rats. More importantly, we analysed the sex-differences on activity levels during different periods of the ABA protocol to determine the period(s) influencing the most pathological weight loss. Both components of the ABA protocol contributed to the subjects’ bodyweight loss. Stress in the first two weeks of development conferred a protective effect in males. Time spent and activity levels on the running wheel were higher in females compared to males. Hyperactivity in ABA subjects was observed during the food-anticipatory activity (FAA) and postprandial activity in males and during the FAA and nocturnal activity periods in females. This study aids in understanding the effect of intensity of activity during specific periods on the pathological weight loss in ABA rats. These observations are informative for therapies aimed at ameliorating body mass index in AN patients.
  • Miniatura
    Publicación
    Activity-Based Anorexia and Food Schedule Induction
    (Springer, 2018-05-30) Labajos López, María José; Pellón Suárez de Puga, Ricardo; Preedy, Victor; Patel, Vinood B.; https://orcid.org/0000-0003-2074-6566
    The term activity-based anorexia refers to the animal model of anorexia nervosa in humans, by which laboratory rats lose weight rapidly and progressively when submitted to a food access regime of 1 h a day and free access to an activity wheel the remainder of the time. This combination of diet and exercise eventually leads the animals into a process of self-starvation that can end up in their death, a reason by which activity-based anorexia is considered analogous of anorexia nervosa in humans, a disease that combines self-imposed food restriction with an excessive increase in physical activity. The best-studied example of schedule-induced behavior is the excessive ingestion of water in animals that are food deprived and for whom the food episodes occur intermittently. Schedule-induced polydipsia is characterized by the consumption of water around the feeding episodes, similarly to what is seen with activity in the phenomenon of activity-based anorexia. The study presented supports the relationship between both phenomena, so that the initial development of excessive drinking facilitates the subsequent development of wheel running. It is suggested that the imposition of very strict feeding episodes could play an important role during the initial stages of the development of anorexia, facilitating the development of hyperactivity that could end up interfering with food ingestion. Prevention for the development of anorexia should focus on a more efficient control of food regimes rather than limiting physical exercise. The adequate scheduling of feeding episodes should reduce hyperactivity, as it follows from its conception as induced behavior.
  • Miniatura
    Publicación
    Chronic ∆-9-Tetrahydrocannabinol administration delays acquisition of schedule-induced drinking in rats and retains long-lasting effects
    (Springer, 2021-08-26) Fuentes Verdugo, Esmeralda; López Tolsa Gómez, Gabriela Eugenia; Pellón Suárez de Puga, Ricardo; Miguens Vázquez, Miguel
    Rationale: Schedule-induced drinking (SID) is a behavioural phenomenon characterized by an excessive and repetitive drinking pattern with a distinctive temporal distribution that has been proposed as a robust and replicable animal model of compulsivity. Despite cannabis currently being the most widely consumed illicit drug, with growing interest in its clinical applications, little is known about the effects of ∆-9-Tetrahydrocannabinol (THC) on SID. Objectives: The effects of chronic and acute THC administration on SID acquisition, maintenance and extinction were studied, as were the effects of such administrations on the distinctive temporal distribution pattern of SID. Methods: THC (5 mg/kg i.p.), or the corresponding vehicle, was administered to adult Wistar rats for 14 days in a row. Subsequently, THC effects on SID acquisition were tested during 21 sessions using a 1h fixed-time 60-s food delivery schedule. Acute effects of THC were also evaluated after SID development. Finally, two extinction sessions were conducted to assess behavioural persistence. Results: The results showed that previous chronic THC treatment delayed SID acquisition and altered the distinctive behavioural temporal distribution pattern during sessions. Moreover, acute THC administration after SID development decreased SID performance in animals chronically pre-treated with the drug. No great persistence effects were observed during extinction in animals pre-treated with THC. Conclusions: These results suggest that chronic THC affects SID development, confirming that it can disrupt learning, possibly causing alterations in time estimation, and also leads to animals being sensitized when they are re-exposed to the drug after long periods without drug exposure.