Search results for " place"
showing 10 items of 656 documents
Involvement of nitric oxide synthesis in sensitization to the rewarding effects of morphine
2009
Abstract Knowledge about the specific brain changes and neural plasticity processes produced by repeated exposure to a drug is essential to progress in the field of neurobiology of addiction and the development of effective medication. In the present study, the influence of nitric oxide synthesis on sensitization to the rewarding effects of morphine has been evaluated. The effects of pre-treatment of mice with saline or 20 mg/kg of morphine plus the nitric oxide synthase inhibitor 7-nitroindazole (7NI) (12.5 or 25 mg/kg) on the place conditioning induced by a low dose of morphine (2 mg/kg) were assessed. The dose of 2 mg/kg of morphine was ineffective in animals pre-treated with saline but …
Memantine blocks sensitization to the rewarding effects of morphine
2009
Knowledge regarding the specific brain changes and neural plasticity processes produced by repeated drug exposure may be used to advance the understanding of the neurobiology of addiction in order to design appropriate medications. In the present study, the influence of N-methyl-d-aspartate (NMDA) glutamatergic receptors on sensitization to the motor and rewarding effects of morphine was evaluated. The effects of pre-exposure to saline or 20 mg/kg morphine plus the NMDA receptor antagonist memantine (10 or 20 mg/kg) on motor activity and place conditioning induced by a low dose of morphine (2 mg/kg) were assessed. The dose of 2 mg/kg of morphine was ineffective in mice pre-exposed to saline…
Effect of adolescent exposure to MDMA and cocaine on acquisition and reinstatement of morphine-induce CPP
2007
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…
Reinstatement of Morphine-Induced Conditioned Place Preference in Mice by Priming Injections
2004
To construct a model of relapse of drug abuse in mice, the induction, we evaluated the extinction and reinstatement of morphine-induced place preference. In Experiment 1, we examined the effects of morphine (0, 2, 3, 5, 10, 20 and 40 mg/kg) in the conditioned place preference (CPP) paradigm. Mice showed CPP with 5, 10, 20 and 40 mg/kg. In Experiment 2, we evaluated the effects of two different extinction procedures. After conditioning with 40 mg/kg of morphine, the mice underwent daily extinction sessions of 60 or 15 min of duration. CPP was extinguished after seven and nine sessions, respectively. In Experiment 3, we tested the reinstating effects of several priming doses of morphine. Mice…
Isolation decreases physical and motivational aspects of morphine withdrawal
2005
Environmental manipulations such as social housing conditions of animals may play a role in the expression of individual differences in response to drugs. This study aimed to evaluate whether isolated and grouped mice develop different degrees of morphine dependence. Isolated and grouped mice were rendered morphine dependent employing two different methods of induction: a fast or slow protocol, both reaching the same maximum daily dose (100 mg/kg). Naloxone-induced morphine withdrawal was assessed using a modified Gellert-Holtzman scale and a conditioned place aversion (CPA) procedure. Isolated animals manifested fewer signs of physical dependence than grouped mice and only those receiving …
Role of CB2 cannabinoid receptors in the rewarding, reinforcing, and physical effects of nicotine.
2013
This study was aimed to evaluate the involvement of CB2 cannabinoid receptors (CB2r) in the rewarding, reinforcing and motivational effects of nicotine. Conditioned place preference (CPP) and intravenous self-administration experiments were carried out in knockout mice lacking CB2r (CB2KO) and wild-type (WT) littermates treated with the CB2r antagonist AM630 (1 and 3 mg/kg). Gene expression analyses of tyrosine hydroxylase (TH) and α3- and α4-nicotinic acetylcholine receptor subunits (nAChRs) in the ventral tegmental area (VTA) and immunohistochemical studies to elucidate whether CB2r colocalized with α3- and α4-nAChRs in the nucleus accumbens and VTA were performed. Mecamylamine-precipitat…
The dopamine uptake inhibitor 3 alpha-[bis(4'-fluorophenyl)metoxy]-tropane reduces cocaine-induced early-gene expression, locomotor activity, and con…
2009
Benztropine (BZT) analogs, a family of high-affinity dopamine transporter ligands, are molecules that exhibit pharmacological and behavioral characteristics predictive of significant therapeutic potential in cocaine addiction. Here, we examined in mice the effects of 3 alpha-[bis(4'-fluorophenyl)metoxy]-tropane (AHN-1055) on motor activity, conditioned place preference (CPP) and c-Fos expression in the striatum. AHN-1055 produced mild attenuation of spontaneous locomotor activity at a low dose (1 mg/kg) and weak stimulation at a higher dose (10 mg/kg). In parallel, the BZT analog significantly increased c-Fos expression in the dorsolateral caudoputamen at the high dose, whereas producing ma…
Intraspecific Communication Through Chemical Signals in Female Mice: Reinforcing Properties of Involatile Male Sexual Pheromones
2006
In rodents, social and reproductive behaviors critically depend on chemical signals, including sexual pheromones that have been suggested (but not demonstrated) to be rewarding. In this work, we analyze this issue by studying the chemoinvestigatory behavior of adult female mice (without experience with male-derived chemicals) toward 1) the synthetic odorant citralva, 2) bedding soiled by different conspecifics (females, males, and castrated males), and 3) volatiles derived from bedding soiled by males and castrated males (confronted in 2-choice tests). We also study whether these chemical signals are able to induce conditioned place preference, a reliable test for rewarding properties of st…
The relationship between workload and burnout among nurses: The buffering role of personal, social and organisational resources
2021
Workload in the nursing profession is high, which is associated with poor health. Thus, it is important to get a proper understanding of the working situation and to analyse factors which might be able to mitigate the negative effects of such a high workload. In Germany, many people with serious or life-threatening illnesses are treated in non-specialized palliative care settings such as nursing homes, hospitals and outpatient care. The purpose of the present study was to investigate the buffering role of resources on the relationship between workload and burnout among nurses. A nationwide cross-sectional survey was applied. The questionnaire included parts of the Copenhagen Psychosocial Qu…
Non-readmission decisions in the intensive care unit: A qualitative study of physicians' experience in a multicentre French study.
2021
Purpose Deciding not to re-admit a patient to the intensive care unit (ICU) poses an ethical dilemma for ICU physicians. We aimed to describe and understand the attitudes and perceptions of ICU physicians regarding non-readmission of patients to the ICU. Materials and methods Multicenter, qualitative study using semi-directed interviews between January and May 2019. All medical staff working full-time in the ICU of five participating centres (two academic and three general, non-academic hospitals) were invited to participate. Participants were asked to describe how they experienced non-readmission decisions in the ICU, and to expand on the manner in which the decision was made, but also on…