0000000000289344
AUTHOR
Manuel Daza-losada
CB1 cannabinoid receptor-mediated aggressive behavior
This study examined the role of cannabinoid CB1 receptors (CB1r) in aggressive behavior. Social encounters took place in grouped and isolated mice lacking CB1r (CB1KO) and in wild-type (WT) littermates. Cognitive impulsivity was evaluated in the delayed reinforcement task (DRT). Gene expression analyses of monoaminooxidase-A (MAO-A), catechol-o-methyl-transferase (COMT), 5-hydroxytriptamine transporter (5-HTT) and 5-HT1B serotonergic receptor (5HT1Br) in the median and dorsal raphe nuclei (MnR and DR, respectively) and in the amygdala (AMY) were performed by real time-PCR. Double immunohistochemistry studies evaluated COMT and CB1r co-localization in the raphe nuclei and in the cortical (AC…
Behavioural and neurotoxic long-lasting effects of MDMA plus cocaine in adolescent mice
The poly-drug pattern is the most common among MDMA users, with cocaine being a frequently associated drug. The aim of the present work was to evaluate the behavioural and neurotoxic long-term effects of exposure during adolescence to MDMA alone or plus cocaine. Mice of 28 to 30 days of age received a treatment of two daily injections of an identical dose of MDMA (5, 10 or 20 mg/kg), alone or plus cocaine (25 mg/kg), for 3 days (6 administrations). Three weeks after receiving MDMA, an increase in the time dedicated by the animals to social contacts with their conspecifics was observed, whilst their behaviour in the elevated plus maze showed no differences from that of non-treated mice. Afte…
Effects of extended cocaine conditioning in the reinstatement of place preference.
Rats allowed extended access to cocaine self-administration develop a number of symptoms of addiction, such as greater susceptibility to drug-induced relapse. Using the conditioned place preference (CPP), the number of conditioning training sessions was increased in order to augment exposure to contextual cues associated with the effects of a drug. Mice were conditioned with a steady dose of 6 or 25 mg/kg of cocaine for 4, 8, 12, 16, 20 or 40 days. Weekly sessions of extinction followed the establishment of preference, after which a priming dose of cocaine was administered to reinstate the extinguished preference. The magnitude of the place preference effect was equal in all groups, indepen…
Role of the dopaminergic system in the acquisition, expression and reinstatement of MDMA-induced conditioned place preference in adolescent mice.
Background The rewarding effects of 3,4-methylenedioxy-metamphetamine (MDMA) have been demonstrated in conditioned place preference (CPP) procedures, but the involvement of the dopaminergic system in MDMA-induced CPP and reinstatement is poorly understood. Methodology/Principal Findings In this study, the effects of the DA D1 antagonist SCH 23390 (0.125 and 0.250 mg/kg), the DA D2 antagonist Haloperidol (0.1 and 0.2 mg/kg), the D2 antagonist Raclopride (0.3 and 0.6 mg/kg) and the dopamine release inhibitor CGS 10746B (3 and 10 mg/kg) on the acquisition, expression and reinstatement of a CPP induced by 10 mg/kg of MDMA were evaluated in adolescent mice. As expected, MDMA significantly increa…
Sex-dependent effects of early maternal deprivation on MDMA-induced conditioned place preference in adolescent rats: Possible neurochemical correlates
Abstract The early neonatal stage constitutes a sensitive period during which exposure to adverse events can increase the risk of neuropsychiatric disorders. Maternal deprivation (MD) is a model of early life stress that induces long-term behavioural and physiological alterations, including susceptibility to different drugs of abuse. In the present study we have used the conditioned place preference (CPP) paradigm to address the influence of MD on the rewarding effects of 3,4-methylenedioxymetamphetamine (MDMA) in adolescent animals of both sexes. We have previously observed in adolescent rats that MD induces modifications in the serotonergic and endocannabinoid systems, which play a role i…
High novelty-seeking predicts greater sensitivity to the conditioned rewarding effects of cocaine
Novelty-seeking in rodents, defined as enhanced specific exploration of novel situations, is considered to predict the response of animals to drugs of abuse and, thus, identify "drug-vulnerable" individuals. The main objective of this work was to determine the capacity of two animal models-the novel object recognition task and the novel environment test-for evaluating to what extent novelty-seeking can predict greater sensitivity to the rewarding properties of cocaine in young adult (PND 56) and adolescent (PND 35) OF1 mice of both sexes. Conditioned place preference, a useful tool for evaluating the sensitivity of individuals to the incentive properties of addictive drugs, was induced with…
A Methanol Extract ofBrugmansia arboreaAffects the Reinforcing and Motor Effects of Morphine and Cocaine in Mice
Previous reports have shown that several of the effects of morphine, including the development of tolerance and physical withdrawal symptoms, are reduced by extracts ofBrugmansia arborea(L.) Lagerheim (Solanaceae) (B. arborea). In the present study we evaluate the action of the methanol extract ofB. arborea(7.5–60 mg/kg) on the motor and reinforcing effects of morphine (20 and 40 mg/kg) and cocaine (25 mg/kg) using the conditioned place preference (CPP) procedure. At the doses employed,B. arboreadid not affect motor activity or induce any effect on CPP. The extract partially counteracted morphine-induced motor activity and completely blocked the CPP induced by 20 mg/kg morphine. On the othe…
Acquisition and reinstatement of MDMA-induced conditioned place preference in mice pre-treated with MDMA or cocaine during adolescence
Those who take ecstasy are more likely to consume other drugs than non-users with cocaine abuse being reported by 75.5% of high school student MDMA (+/- 3,4-methylenedioxymetamphetamine hydrochloride) users. The aim of this work was to evaluate the effects of exposure during adolescence to MDMA, cocaine or to both drugs on the MDMA-induced conditioned place preference (CPP) in adult mice. Animals received two daily administrations of saline, 10 mg/kg of MDMA, 25 mg/kg of cocaine or 10 mg/kg of MDMA plus 25 mg/kg of cocaine over 3 days (from PD28 to 30). Three weeks after pre-treatment, the MDMA-induced CPP procedure was initiated (PD52). Acquisition of CPP was induced with a sub-threshold d…
Effect of the CB1 cannabinoid agonist WIN 55212-2 on the acquisition and reinstatement of MDMA-induced conditioned place preference in mice
AbstractBackgroundNumerous reports indicate that MDMA users consume other psychoactive drugs, among which cannabis is one of the most common. The aim of the present study was to evaluate, using the conditioned place preference, the effect of the cannabinoid agonist WIN 55,212-2 on the rewarding effects of MDMA in mice.MethodsIn the first experiment adolescent mice were initially conditioned with 1.25, 2.5 or 5 mg/kg of MDMA or 0.1 or 0.5 mg/kg of WIN and subsequently with both drugs. Reinstatement of the extinguished preference by priming doses was performed in the groups that showed CPP. In the second experiment, animals were conditioned with 2.5 or 5 mg/kg of MDMA and, after extinction, r…
Acute behavioural and neurotoxic effects of MDMA plus cocaine in adolescent mice.
The poly-drug pattern is the most common among those observed in MDMA users, with cocaine being a frequently associated drug. This study evaluates the acute effects of MDMA (5, 10 and 20 mg/kg), alone or in combination with cocaine (25 mg/kg), on motor activity, anxiety (elevated plus maze and social interaction test), memory and brain monoamines in adolescent mice, Both drugs, administered alone or concurrently, produced hyperactivity and a decrease in social contacts. However, an anxiolytic effect, studied by means of the elevated plus maze and expressed as an increase in the time spent on the open arms, was observed only in those animals treated with cocaine and MDMA. The passive avoidan…
Rewarding effects and reinstatement of MDMA-induced CPP in adolescent mice.
Although the rewarding effects of 3,4-methylenedioxy-metamphetamine (MDMA) have been demonstrated in self-administration and conditioned place preference (CPP) procedures, its addictive potential (ie, the vulnerability to relapse, measured by its ability to induce reinstatement of an extinguished response), remains poorly understood. In this study, the effects of MDMA (5, 10, and 20 mg/kg) on the acquisition, extinction and reinstatement of CPP were evaluated in mice, using two different protocols during acquisition of CPP. In the first experiment, animals were trained using a two-session/day schedule (MDMA and saline for 4 consecutive days), whereas in the second experiment, they were trai…
The novelty-seeking phenotype modulates the long-lasting effects of intermittent ethanol administration during adolescence.
The aim of the present study was to investigate if a novelty-seeking phenotype mediates the long-lasting consequences of intermittent EtOH intoxication during adolescence. The hole board test was employed to classify adolescent mice as High- or Low-Novelty Seekers. Subsequently, animals were administered ethanol (1.25 or 2.5 g/kg) on two consecutive days at 48-h intervals over a 14-day period. Anxiety levels - measured using the elevated plus maze- spontaneous motor activity and social interaction test were studied 3 weeks later. A different set of mice underwent the same procedure, but received only the 2.5 g/kg dose of ethanol. Three weeks later, in order to induce CPP, the same animals w…
Effect of adolescent exposure to MDMA and cocaine on acquisition and reinstatement of morphine-induce CPP
It is well known that an elevated percentage of ecstasy users also consume cocaine. Recently, it has been reported that a high frequency of heroin smokers first consumed heroin under the effects of ecstasy with the hope of reducing the stimulant effects of the latter drug. The aim of the present study was to evaluate the effect of exposure to MDMA and cocaine during adolescence on morphine-induced conditioned place preference (CPP) and reinstatement in adulthood. In the first experiment, adolescent mice were exposed to six injections of MDMA and three weeks later their response to the reinforcing properties of 40 mg/kg of morphine was evaluated using the CPP paradigm. All the treatment grou…
Assessment of the abuse potential of MDMA in the conditioned place preference paradigm: Role of CB1 receptors
Numerous reports have highlighted the role of the endocannabinoid system in the addictive potential of MDMA (3,4-methylenedioxy-methamphetamine). A previous report showed that CB1 knockout (KOCB1) mice do not acquire MDMA self-administration, despite developing conditioned place preference (CPP). This contradiction could be due to the particular procedure of place conditioning used. The present work compares MDMA-induced CPP in KOCB1 mice using unbiased and biased procedures of place conditioning. In the unbiased procedure, MDMA induced CPP and reinstatement of the extinguished preference in wild type (WT) mice, but not in KOCB1 mice. In contrast, in a biased protocol of CPP, MDMA produced …
Acute blockade of CB1 receptor leads to reinstatement of MDMA-induced conditioned place preference
Cannabis is one of the drugs most commonly consumed in combination with ecstasy (3,4-methylenedioxymethamphetamine, MDMA). Although numerous studies have attempted to further our understanding of the role of the cannabinoid system in drug abuse, few have focused on how it influences the rewarding effects of MDMA. The aim of the present study was to evaluate the role of the CB1 cannabinoid receptor in vulnerability to reinstatement of a MDMA-induced conditioned place preference (CPP). Mice were first conditioned with 5mg/kg of MDMA. Once the preference had been extinguished, a priming dose of MDMA, alone or plus the CB1 cannabinoid agonist WIN 55,212-2 (0.1 and 0.5mg/kg) or the CB1 cannabino…
Capacity of novelty-induced locomotor activity and the hole-board test to predict sensitivity to the conditioned rewarding effects of cocaine
Novelty-seeking in rodents, defined as enhanced specific exploration of novel situations, is considered to predict the response of animals to drugs of abuse and, thus, allow "drug-vulnerable" individuals to be identified. The main objective of this study was to assess the predictive ability of two well-known paradigms of the novelty-seeking trait - novelty-induced locomotor activity (which distinguishes High- and Low-Responder mice, depending on their motor activity) and the hole-board test (which determines High- and Low-Novelty Seeker mice depending on the number of head dips they perform) - to identify subjects that would subsequently be more sensitive to the conditioned rewarding effect…
Potencial adictivo del éxtasis: una visión desde los modelos animales
Resumen La 3,4-metilendioximetanfetamina (MDMA) es el principio activo del “extasis”, un psicoestimulante de gran popularidad entre los adolescentes y los adultos jovenes. La actividad farmacologica del extasis esta mediada por la serotonina (5-HT) y la dopamina (DA), esta ultima fuertemente implicada en la modulacion de los efectos reforzantes de las drogas de abuso. Aunque escasos, los estudios realizados en consumidores de extasis indican que un porcentaje de ellos cumplirian los criterios de dependencia a esta sustancia. La presente revision analiza los resultados mas relevantes obtenidos hasta el momento sobre los efectos reforzantes de la MDMA, principalmente aquellos obtenidos a part…
Adolescent pre-exposure to ethanol and 3,4-methylenedioxymethylamphetamine (MDMA) increases conditioned rewarding effects of MDMA and drug-induced reinstatement
Many adolescents often take ethanol (EtOH) in combination with 3,4-methylenedioxymethylamphetamine (MDMA). In the present work, we used a mouse model to study the effect of repeated pre-exposure during adolescence to EtOH (2 g/kg), MDMA (10 or 20 mg/kg) or EtOH + MDMA on the rewarding and reinstating effects of MDMA in the conditioned place preference (CPP) paradigm. Pre-exposure to EtOH, MDMA or both increased the rewarding effects of a low dose of MDMA (1.25 mg/kg). These pre-treatments did not affect the acquisition of the CPP induced by 5 mg/kg of MDMA. However, the CPP was more persistent in mice pre-exposed to both doses of MDMA or to EtOH + MDMA20. After extinction of the CPP induced…