CB1 receptor blockade counters age-induced insulin resistance and metabolic dysfunction

Funding This work was supported by the BBSRC and Diabetes UK.Peer reviewedPublisher PD

Contrasting effects of selective lesions of nucleus accumbens core or shell on inhibitory control and amphetamine-induced impulsive behaviour

The core and shell subregions of the nucleus accumbens receive differential projections from areas of the medial prefrontal cortex that have dissociable effects on impulsive and perseverative responding. The contributions of these subregions to simple instrumental behaviour, inhibitory control and behavioural flexibility were investigated using a ‘forced choice’ task, various parameter manipulations and an omission schedule version of the task. Post-training, selective core lesions were achieved with microinjections of quinolinic acid and shell lesions with ibotenic acid. After a series of behavioural task manipulations, rats were re-stabilized on the standard version of the task and challenged with increasing doses of d-amphetamine (vehicle, 0.5 or 1.0 mg/kg i.p. 30 min prior to test). Neither core- nor shell-lesioned rats exhibited persistent deficits in simple instrumental behaviour or challenges to behavioural flexibility or inhibitory control. Significant differences between lesion groups were unmasked by d-amphetamine challenge in the standard version of the forced task. Core lesions potentiated and shell lesions attenuated the dose-dependent effect of d-amphetamine on increasing anticipatory responses seen in sham rats. These data imply that the accumbens core and shell subregions do not play major roles in highly-trained task performance or in challenges to behavioural control, but may have opposed effects following d-amphetamine treatment. Specifically, they suggest the shell subregion to be necessary for dopaminergic activation driving amphetamine-induced impulsive behaviour and the core subregion for the normal control of this behaviour via conditioned influences

Análisis de la opinión de estudiantes sobre conductas de riesgo de jóvenes en Puerto Rico

The main purpose of the study was to analyze the opinion that students of the University of Puerto Rico, Río Piedras Campus (UPRRP) have about some risk behaviors in teenagers of both genders between the ages of 13-18. We administered an online survey, which was taken by 1,836 students enrolled during the first semester of the 2017-18 academic year. We used mixed methods: descriptive statistics analysis and content analysis. The findings reveal that the opinion of students is that youth is a stage of confusion and turbulence; that some risk behaviors have increased during the past five years and that it tends to be associated to male youth. These results suggest that university students tend to reproduce the dominant social imaginary in terms of risk behavior in youth. Further investigations should take into consideration the consequences of youth stigmatization, since this is a heterogeneous and diverse group.El objetivo de nuestro estudio fue analizar la opinión que tienen los/as estudiantes de la Universidad de Puerto Rico, Recinto de Río Piedras (UPRRP), sobre algunas conductas de riesgo en jóvenes de ambos géneros, de 13-18 años.  Administramos un cuestionario en línea que fue contestado por 1,836 estudiantes matriculados/as durante el primer semestre del año académico 2017-18. Utilizamos un método mixto: análisis estadístico descriptivo y análisis de contenido. Los hallazgos revelan que la opinión de la mayoría de los/as estudiantes universitarios/as es que la juventud es una etapa de confusión y turbulencia; que algunas conductas de riesgo han aumentado durante los pasados cinco años y que se asocian más con los jóvenes que con las jóvenes. Estos hallazgos sugieren que los/as estudiantes tienden a reproducir los imaginarios sociales dominantes sobre la conducta de riesgo en jóvenes entre las edades de 13-18 años. Futuros trabajos deben considerar las consecuencias de la estigmatización hacia los/as jóvenes, ya que este es un grupo heterogéneo y variado

Deep Brain Stimulation Reveals a Dissociation of Consummatory and Motivated Behaviour in the Medial and Lateral Nucleus Accumbens Shell of the Rat

Following the successful application of deep brain stimulation (DBS) in the treatment of Parkinson's disease and promising results in clinical trials for obsessive compulsive disorder and major depression, DBS is currently being tested in small patient-populations with eating disorders and addiction. However, in spite of its potential use in a broad spectrum of disorders, the mechanisms of action of DBS remain largely unclear and optimal neural targets for stimulation in several disorders have yet to be established. Thus, there is a great need to examine site-specific effects of DBS on a behavioural level and to understand how DBS may modulate pathological behaviour. In view of the possible application of DBS in the treatment of disorders characterized by impaired processing of reward and motivation, like addiction and eating disorders, we examined the effect of DBS of the nucleus accumbens (NAcc) on food-directed behavior. Rats were implanted with bilateral stimulation electrodes in one of three anatomically and functionally distinct sub-areas of the NAcc: the core, lateral shell (lShell) and medial shell (mShell). Subsequently, we studied the effects of DBS on food consumption, and the motivational and appetitive properties of food. The data revealed a functional dissociation between the lShell and mShell. DBS of the lShell reduced motivation to respond for sucrose under a progressive ratio schedule of reinforcement, mShell DBS, however, profoundly and selectively increased the intake of chow. DBS of the NAcc core did not alter any form of food-directed behavior studied. DBS of neither structure affected sucrose preference. These data indicate that the intake of chow and the motivation to work for palatable food can independently be modulated by DBS of subregions of the NAcc shell. As such, these findings provide important leads for the possible future application of DBS as a treatment for eating disorders such as anorexia nervosa

P2 receptors are involved in the mediation of motivation-related behavior

The importance of purinergic signaling in the intact mesolimbic–mesocortical circuit of the brain of freely moving rats is reviewed. In the rat, an endogenous ADP/ATPergic tone reinforces the release of dopamine from the axon terminals in the nucleus accumbens as well as from the somatodendritic region of these neurons in the ventral tegmental area, as well as the release of glutamate, probably via P2Y1 receptor stimulation. Similar mechanisms may regulate the release of glutamate in both areas of the brain. Dopamine and glutamate determine in concert the activity of the accumbal GABAergic, medium-size spiny neurons thought to act as an interface between the limbic cortex and the extrapyramidal motor system. These neurons project to the pallidal and mesencephalic areas, thereby mediating the behavioral reaction of the animal in response to a motivation-related stimulus. There is evidence that extracellular ADP/ATP promotes goal-directed behavior, e.g., intention and feeding, via dopamine, probably via P2Y1 receptor stimulation. Accumbal P2 receptor-mediated glutamatergic mechanisms seem to counteract the dopaminergic effects on behavior. Furthermore, adaptive changes of motivation-related behavior, e.g., by chronic succession of starvation and feeding or by repeated amphetamine administration, are accompanied by changes in the expression of the P2Y1 receptor, thought to modulate the sensitivity of the animal to respond to certain stimuli

Non-additive effects of multiple predators alter the biological control of the coffee leaf miner (Leucoptera coffeella)

Although most prey are attacked by multiple predators, much of the ecological theory on prey suppression focuses on the effects of a single predator. The presence of multiple predators can lead to complex interactions such as trait-mediated interactions (TMIIs) and intraguild predation which can influence the suppression of pest populations. Here we explore the effect of two predators, a native anole lizard species Anolis cristatellus (Squamata: Dactyloidae) and a non-native ant species Wasmannia auropunctata (Hymenoptera: Formicidae), on the coffee leaf miner, Leucoptera coffeella (Lepidoptera: Lyonetiidae) (CLM). In a laboratory experiment we examined the effects of these two predators in isolation and when co-occurring. Our results show that when each predator is alone, they are able to consume the CLM in a comparable way. However, when they are together, their effect is not greater than when alone. This indicates that there is a negative effect when both predators co-occur. The results from this experiment have practical implications since both predators are present in coffee agroecosystems in Puerto Rico, where the CLM is considered the main insect pest. Furthermore, these results demonstrate the potential dynamics among several predators in agroecosystems and the potential implications for herbivore regulation

A Rare Case of Uterine Leiomyosarcoma with Metastasis to the Thyroid Gland

Uterine leiomyosarcomas are aggressive tumors associated with a poor prognosis. These neoplasms have high metastatic potential, more frequently affecting the lungs, liver, and peritoneum. There are very few cases of metastasis to the thyroid described in the literature. We present the case of a 47-year-old female diagnosed with uterine leiomyosarcoma metastatic to the thyroid gland. In this case report, we want to emphasize the utility of ancillary studies to help differentiate a leiomyosarcoma from anaplastic thyroid carcinoma since cytologic evaluation alone can be challenging