Compulsive-Like Sufentanil Vapor Self-Administration in Rats.

Opioid misuse is at historically high levels in the United States, with inhalation (ie, smoking and vaping) being one of the most common routes of consumption. We developed and validated a novel preclinical model of opioid self-administration by inhalation that does not require surgery and reliably produces somatic and motivational signs of dependence. Rats were trained to perform an operant response (nosepoke) to receive 10 s of vaporized sufentanil, a potent opioid, in 2 h daily sessions. Rats readily and concentration-dependently self-administered vaporized sufentanil. Rats exhibited a significant increase in responding for sufentanil when given the preferential µ-opioid receptor inverse agonist naloxone, suggesting the participation of µ-opioid receptors in the reinforcing properties of sufentanil vapor. Serum sufentanil concentrations significantly correlated with the number of sufentanil vapor deliveries. Rats that were given long access (LgA; 12 h/day) but not short access (ShA; 1 h/day) to vaporized sufentanil escalated their drug intake over time and exhibited both naloxone-precipitated somatic signs of opioid withdrawal and spontaneous withdrawal-induced mechanical hypersensitivity. After 6 months of forced drug abstinence, LgA rats returned to pre-escalation baseline levels of responding for sufentanil and mechanical sensitivity. Upon subsequent re-escalation (ie, after the return to extended access to sufentanil vapor), LgA rats again developed naloxone-precipitated somatic signs of withdrawal and spontaneous withdrawal-induced mechanical hypersensitivity. These findings demonstrate that the operant sufentanil vapor self-administration model has both face and construct validity and therefore will be useful for investigating the neurobiological basis of opioid addiction.

L'hypophyse et ses traitements : comment peuvent-ils influer sur le comportement ?: The pituitary and its treatments: how can they influence behaviour?

Behaviour may be influenced by pituitary hormones or treatments. Dopamine agonist (DA) indicated in prolactinomas treatment can cause side effects, and especially impulse control disorders. In the context of prolactinomas treatment, impulse control disorders (ICD) have been reported like gambling, compulsive shopping, but mostly hypersexuality. These ICD can occur with low AD doses, and seem to be independent of type of molecule and psychiatric medical history. The main pathophysiologic hypothesis is a dysregulation of dopaminergic pathway involved in reward system. Given the possible devastating social impact of these ICD, they have to be screened in patients treated with DA. Our social behaviour can also be impacted by oxytocin. This hormone secreted on physiologic state at posterior pituitary, but also by others areas of brain and brainstem, has an impact on attachment in pair partners and in parent-child relationship, but also in empathy behaviour. Oxytocin affects as well eating behaviour with an anorexigenic impact. Studies on small populations assessed the relevance of an oxytocin treatment in several endocrine and nutritional pathologies like post-surgery craniopharyngioma, panhypopituitarism and obesity. Despite promising results, several pitfalls prevent yet the oxytocin use in clinical practice.

Chronic pramipexole treatment induces compulsive behavior in rats with 6-OHDA lesions of the substantia nigra and ventral tegmental area.

Dopamine replacement therapy (DRT) reduces motor symptoms in Parkinson's disease (PD), but also induces impulsive-compulsive behavior (ICB) in up to 25% of PD patients. These non-motor side effects of DRT generally follow a gradual transition from impulsive to compulsive-like-i.e. repetitive, compelled, and non-pleasurable-behavior. Here, we investigated the effect of chronic pramipexole (PPX) treatment on the onset of compulsive-like behavior, measured via the post-training signal attenuation (PTSA) procedure, in rats with dopaminergic lesions. Accordingly, we aimed to mimic chronic DRT in a PD context, and obtain data on the brain regions that potentially sustain this type of compulsive behavior pattern in rats. We observed that the lesion or treatment alone did not induce compulsive lever pressing in rats. However, rats with lesions of the substantia nigra and ventral tegmental area as well as with chronic PPX treatment developed strong compulsive lever-pressing behavior, as measured via PTSA. Furthermore, when chronic PPX treatment was discontinued before the PTSA test, the lesioned rats showed the same level of compulsive behavior as sham-operated rats. In fact, lesioned, treated, and compulsive-like rats showed significantly higher Fos expression in the orbitofrontal cortex and dorsal striatum. Thus, chronic PPX treatment in PD rats induced a strong compulsive-like behavior. Furthermore, Fos expression mapping suggests that the behavior was sustained via the activation of the orbitofrontal cortex and dorsal striatum.

[Aripiprazole, gambling disorder and compulsive sexuality]. / Aripiprazole, jeu pathologique et sexualité compulsive.

INTRODUCTION: Aripiprazole, an atypical or second-generation antipsychotic, is usually well tolerated. It is an approved treatment for schizophrenia and mania in bipolar disorder type 1. Unlike the other antipsychotics, it has high affinity agonist properties for dopamine D2 and D3 receptors. It has also 5-HT1A partial agonist and 5-HT2A antagonist properties. Aripiprazole is a first or second line treatment frequently used because it has reduced side effects such as weight gain, sleepiness, dyslipidemia, insulin resistance, hyperprolactinemia and extrapyramidal symptoms. CASE-REPORT: We report the case of a 28-year-old male patient diagnosed with schizoid personality disorder. He was a moderate smoker with occasional social gambling habits. After several psychotic episodes, he was first treated with risperidone, but he experienced excessive sedation, decreased libido, erectile dysfunction and was switched to 15 mg aripiprazole. He developed an addiction habit for gambling at casino slot machines. Due to large gambling debts, he requested placement on a voluntary self-exclusion list. Thereafter, he turned his attention towards scratch card gambling. The patient described his experience of gambling as a "hypnotic state". He got several personal loans to obtain money to continue gambling. He was then referred to an addiction unit. Before being treated with aripiprazole, he was an exclusive heterosexual with a poor sexual activity. Under treatment, he switched to a homosexual behavior with hypersexuality, unprotected sex and sadomasochistic practices. The craving for gambling and compulsive sexual behavior ceased two weeks after aripiprazole was discontinued and he was switched to amisulpride. Thereafter, he reported a return to a heterosexual orientation. DISCUSSION: Compulsive behaviors such as gambling, hypersexuality and new sexual orientation are common in patients with Parkinson's disease treated with dopaminergic agonists. These behaviors involve the reward system, with an enhanced dopaminergic activity in the mesolimbic pathways and occur more frequently in young subjects, males with previous gambling habits and tobacco use. A few cases of aripiprazole-induced pathological gambling as well as aripiprazole-induced hypersexuality have been reported. To our knowledge, we are the first to report a case of gambling disorder associated with hypersexuality and change of sexuality orientation. Aripiprazole is the only antipsychotic with agonist properties for the D2 dopamine receptor. It may also act as an enhancer in the mesolimbic dopaminergic pathways. Aripiprazole also has 5-HT1A partial agonist and 5-HT2A antagonist properties that may promote sexual activity. CONCLUSION: Aripiprazole is an antipsychotic associated with reduced side effects compared to other antipsychotics. We report the case of a patient who experienced gambling disorder, hypersexuality and a new sexual orientation under treatment. These side effects are little known. They are usually difficult for patients to mention due to feelings of guilt. The consequences on social life, family and health may be serious. Clinicians and patients should be aware about the possible issue of these behavior disorders with aripiprazole.

Prenatal exposure to psychostimulants increases impulsivity, compulsivity, and motivation for rewards in adult mice.

Given the widespread use and misuse of methamphetamine (METH) and methylphenidate (MPD), especially in relation to women of childbearing age, it is important to consider the long-lasting effects of these drugs on the brain of the developing fetus. Male and female C57Bl/6J mice were prenatally exposed to METH (5mg/kg), MPD (10mg/kg), or saline. Following a 3-month washout, behavioral analysis using the 5-Choice Serial Reaction Time Task (5CSRTT) was performed on adult mice. After reaching training criteria, performance on a pseudo-random intertrial interval test session revealed decrements in 5CSRTT behavior. Prenatally-treated METH and MPD mice demonstrated significant increases in impulsivity, compulsivity, and motivation for reward compared to their saline controls. There were sex by drug interactions indicating a possible sexually dimorphic response to these prenatal drug exposures. Of particular clinical interest, we find that mice prenatally exposed to METH or MPD express characteristics of both inhibitory control decrements and heightened motivation for rewards, which represent core symptoms of addiction and other impulse control disorders.

Cannabinoid hyperemesis syndrome: a case series and review of previous reports.

BACKGROUND: Cannabis is the most commonly used illicit substance worldwide. Cannabinoids or cannabinoid receptor agonists are often used to treat nausea, vomiting, and anorexia. However, in recent years, several medical journals have published reports of patients with nausea and vomiting thought to be induced by chronic cannabis use. OBJECTIVE: The authors seek to inform readers about Cannabinoid Hyperemesis Syndrome (CHS). METHOD: The authors describe four patients with chronic cannabis abuse, episodic, intractable nausea and vomiting, and compulsive hot water bathing. Previous cases of CHS are reviewed, pathophysiology is hypothesized, and difficulties with making the diagnosis are discussed. CONCLUSION: CHS should be strongly considered in the differential diagnosis of patients with intractable vomiting and/or compulsive hot water bathing.

Impulse control disorders associated with dopaminergic medication in patients with pituitary adenomas.

OBJECTIVE: Impulse control disorders (ICDs) such as pathological gambling, compulsive shopping, compulsive eating, and hypersexuality are a matter of growing interest, especially in patients with Parkinson disease who are on dopamine replacement therapy. It was recently reported that ICDs are associated with other disorders also treated with dopaminergic drugs (dopamine agonists) such as restless legs syndrome, multiple system atrophy, progressive supranuclear palsy, and fibromyalgia. The aim of this study was to determine the prevalence of ICDs in patients with pituitary adenomas who take dopamine agonists (DAs). METHODS: Twenty consecutive patients with pituitary adenomas (mostly prolactinomas) taking DAs were assessed. All participated in a structured interview focused on ICDs, which was conducted by a physician. RESULTS: Two (10%) of 20 subjects had a condition diagnosed as ICD. The first patient is a 35-year-old man with giant macroprolactinoma who was alternately treated with different types of DAs (cabergoline, bromocriptine, and quinagolide). He developed compulsive eating and pathological gambling. The second patient is a 53-year-old man with macroprolactinoma who suffered from severe hypersexuality after cabergoline was begun. CONCLUSIONS: This study demonstrates the importance of systematic screening for ICDs in patients taking dopaminergic medication regardless of their primary condition.

Features of compulsive checking behavior mediated by nucleus accumbens and orbital frontal cortex.

The quinpirole sensitization model of obsessive-compulsive disorder was used to investigate the functional role that brain regions implicated in a neuroanatomical circuit of obsessive-compulsive disorder may play in compulsive checking behavior. Following repeated injections of saline or quinpirole (0.5mg/kg, twice per week, ×8 injections) to induce compulsive checking, rats received N-methyl-d-aspartate lesions of the nucleus accumbens core (NAc), orbital frontal cortex (OFC) and basolateral amygdala, or sham lesions. When retested at 17days post-surgery, the results showed effects of NAc and OFC but not basolateral amygdala lesion. NAc lesions affected measures indicative of the amount of checking behavior, whereas OFC lesions affected indices of staying away from checking. The pattern of results suggested that the functional roles of the NAc and OFC in checking behavior are to control the vigor of motor performance and focus on goal-directed activity, respectively. Furthermore, similarities in behavior between quinpirole sham rats and saline NAc lesion rats suggested that quinpirole may drive the vigor of checking by inhibition of NAc neurons, and that the NAc may be a site for the negative feedback control of checking.

Dopamine agonist: pathological gambling and hypersexuality.

(1) Pathological gambling and increased sexual activity can occur in patients taking dopaminergic drugs. Detailed case reports and small case series mention serious familial and social consequences. The frequency is poorly documented; (2) Most affected patients are being treated for Parkinson's disease, but cases have been reported among patients prescribed a dopamine agonist for restless legs syndrome or pituitary adenoma; (3) Patients treated with this type of drug, and their relatives, should be informed of these risks so that they can watch for changes in behaviour. If such disorders occur, it may be necessary to reduce the dose or to withdraw the drug or replace it with another medication.

High frequency stimulation and temporary inactivation of the subthalamic nucleus reduce quinpirole-induced compulsive checking behavior in rats.

Obsessive-compulsive disorder (OCD) represents a highly prevalent and impairing psychiatric disorder. Functional and structural imaging studies implicate the involvement of basal ganglia-thalamo-cortical circuits in the pathophysiology of this disorder. In patients remaining resistant to pharmaco- and behavioral therapy, modulation of these circuits may consequently reverse clinical symptoms. High frequency stimulation (HFS) of the subthalamic nucleus (STN), an important station of the basal ganglia-thalamo-cortical circuits, has been reported to reduce obsessive-compulsive symptoms in a few Parkinson's disease patients with comorbid OCD. The present study tested the effects of bilateral HFS of the STN and of bilateral pharmacological inactivation of the STN (via intracranial administration of the GABA agonist muscimol) on checking behavior in the quinpirole rat model of OCD. We demonstrate that both HFS and pharmacological inactivation of the STN reduce quinpirole-induced compulsive checking behavior. We conclude that functional inhibition of the STN can alleviate compulsive checking, and suggest the STN as a potential target structure for HFS in the treatment of OCD.

Repeated N-acetylcysteine administration alters plasticity-dependent effects of cocaine.

Cocaine produces a persistent reduction in cystine-glutamate exchange via system x(c)- in the nucleus accumbens that may contribute to pathological glutamate signaling linked to addiction. System x(c)- influences glutamate neurotransmission by maintaining basal, extracellular glutamate in the nucleus accumbens, which, in turn, shapes synaptic activity by stimulating group II metabotropic glutamate autoreceptors. In the present study, we tested the hypothesis that a long-term reduction in system x(c)- activity is part of the plasticity produced by repeated cocaine that results in the establishment of compulsive drug seeking. To test this, the cysteine prodrug N-acetylcysteine was administered before daily cocaine to determine the impact of increased cystine-glutamate exchange on the development of plasticity-dependent cocaine seeking. Although N-acetylcysteine administered before cocaine did not alter the acute effects of cocaine on self-administration or locomotor activity, it prevented behaviors produced by repeated cocaine including escalation of drug intake, behavioral sensitization, and cocaine-primed reinstatement. Because sensitization or reinstatement was not evident even 2-3 weeks after the last injection of N-acetylcysteine, we examined whether N-acetylcysteine administered before daily cocaine also prevented the persistent reduction in system x(c)- activity produced by repeated cocaine. Interestingly, N-acetylcysteine pretreatment prevented cocaine-induced changes in [35S]cystine transport via system x(c)-, basal glutamate, and cocaine-evoked glutamate in the nucleus accumbens when assessed at least 3 weeks after the last N-acetylcysteine pretreatment. These findings indicate that N-acetylcysteine selectively alters plasticity-dependent behaviors and that normal system x(c)- activity prevents pathological changes in extracellular glutamate that may be necessary for compulsive drug seeking.

The transition from controlled to compulsive drug use is associated with a loss of sensitization.

Rats provided limited daily access to cocaine (1 h) maintain stable levels of drug self-administration over time while those switched to longer access (6 h or more) exhibit escalating patterns of drug intake. These results are reminiscent of human recreational and compulsive drug-taking behavior, respectively. We found that the brains of cocaine-self-administering rats were also qualitatively different in subjects having experienced 6-h (Coc6h) daily access compared to 1-h (Coc1h) access. Fourteen days after an eight-day protocol of cocaine self-administration, all subjects received one infusion of cocaine. Coc1h animals showed enhanced c-Fos reactivity in dopaminergic mesocorticolimbic brain regions and a sensitized locomotor response to IV cocaine. In contrast, both the neural and behavioral sensitization to cocaine was diminished in Coc6h animals. These data suggest that the transition to escalating patterns of drug use is associated with neuroadaptive changes that counteract those initially associated with controlled stable patterns of drug use.