Search results for "Narcotic Antagonist"
showing 10 items of 34 documents
Improved effect of the combination naltrexone/D-penicillamine in the prevention of alcohol relapse-like drinking in rats
2014
Opioid antagonists are licensed drugs for treating alcohol use disorders; nonetheless, clinical studies have evidenced their limited effectiveness. Preclinical findings indicate that opioid receptor (OR) antagonists, such as naltrexone (NTX), reduce the alcohol deprivation effect (ADE). However, a detailed analysis of published data shows the existence of a delayed increase in ethanol consumption after continuous OR blockade, a phenomenon originally called as ‘delayed ADE’. We have recently reported that D-penicillamine (DP) is able to prevent ADE through a mechanism dependent on the inactivation of acetaldehyde, the main metabolite of ethanol. Hypothetically, OR activation would be trigge…
Induction of conditioned place preference and dopamine release by salsolinol in posterior VTA of rats: involvement of μ-opioid receptors.
2011
Salsolinol (Sal), locally administered into the posterior VTA (pVTA) of rats, produces psychomotor responses and reinforcing effects, probably, through the activation of μ-opioid receptors (MORs). The neurochemical correlates of these phenomena are, however, practically unknown. In this paper, we explore the neurochemical events and the mechanisms involved in these behaviors. To do that, we test the ability of Sal, directly microinjected into the pVTA, to induce conditioned place preference (CPP) and to increase dopamine levels in the nucleus accumbens shell. Bilateral injections of 30 pmol of Sal induced a strong CPP (rats spent around 70% of the total test time), a result that could be ex…
The gamma(2)-MSH peptide mediates a central analgesic effect via a GABA-ergic mechanism that is independent from activation of melanocortin receptors.
2001
Using the latency for tail-flick after thermal stimulation we have assessed the effects of alpha-, gamma(1)- and gamma(2)-MSH on nociceptive threshold in the mice. Intracisternal injections of gamma(2)-MSH induced a distinct analgesia, while gamma(1)-MSH in the same doses gave only a minor analgesia. Intracisternal alpha-MSH instead gave a short-term hyperalgesia. The effect of gamma(2)-MSH was not blocked by any of the MC(4)/MC(3)receptor antagonist HS014, naloxone or by the prior intracisternal administrations of gamma(1)-MSH. However, the gamma(2)-MSH analgesic response was completely attenuated by treating animals with the GABA(A)antagonist bicuculline. The gamma(2)-MSH analgesic effect…
Determinants of interest in extended-released buprenorphine: A survey among 366 French patients treated with buprenorphine or methadone
2021
International audience; Aim: To explore the factors determining the interest in extended-release buprenorphine (XR-BUP) injections among patients receiving opioid agonist treatment (OAT) in France.Methods: 366 patients receiving OAT for opioid use disorder, recruited in 66 French centers, were interviewed from 12/2018 to 05/2019. A structured questionnaire assessed their interest in XR-BUP using a [1-10] Likert scale. 'More' vs. 'less' interested groups were defined using the median score of interest, and their characteristics were explored using adjusted odds ratios (aORs) and 95 % confidence interval (95 %CI). Independent variables were as follows: sociodemographic characteristics, OAT-re…
Environment associated with morphine and experience of aggression modulate behaviors of postdependent mice
2002
Contexts associated with drug use can acquire secondary reinforcing properties. Furthermore, context-specific withdrawal has been observed to reflect a relatively long-lasting learned response. The aim of this study was to evaluate the effect of the environment paired with morphine after 15 days of abstinence. In the first experiment, isolated male mice received saline or morphine either in their home cage or in the distinctive environment, performing two agonistic encounters in the distinctive environment during spontaneous withdrawal. Similar groups were assigned but without aggression encounters during withdrawal. In the second experiment, animals received saline or morphine as previousl…
The dopamine release inhibitor CGS 10746B blocks conditioned physical signs of morphine withdrawal
2003
Environment previously paired with morphine withdrawal leads to conditioned physical signs of withdrawal, this effect being modulated by additional exposition to morphine administration. In this study, the putative role of dopamine in conditioned withdrawal signs is evaluated by administering the dopamine release inhibitor CGS 10746B prior to suffering two naloxone-induced withdrawals in a distinctive environment associated or not with morphine administration. The results show that dopamine seems to be necessary for the development of conditioned somatic signs of morphine withdrawal, as animals which received CGS 10746B do not present paw tremor or body shakes when they are placed in the en…
Memantine presents different effects from MK-801 in motivational and physical signs of morphine withdrawal
2003
Adaptive changes in neural systems due to chronic opiate exposure are related to the neural plasticity phenomenon, NMDA receptors being implicated in these processes, e.g. tolerance, dependence or withdrawal. In this work, we investigated the effect of two non-competitive NMDA antagonists, memantine and MK-801, in motivational (Conditioned Place Aversion paradigm, CPA) and physical aspects of morphine withdrawal. After the induction of morphine dependence, animals in which the CPA was studied, received memantine (5 and 10 mg/kg) or MK-801 (0.3-0.006 mg/kg) either during the acquisition (conditioning) or expression (test) phase of this procedure. Both drugs were capable of inhibiting conditi…
Effects of SCH 23390, Raclopride, and Haloperidol on Morphine Withdrawal-Induced Aggression in Male Mice
1999
Abstract RODRIGUEZ-ARIAS, M., J. PINAZO, J. MINARRO AND L. STINUS. Effects of SCH 23390, raclopride, and haloperidol on morphine withdrawal-induced aggression in male mice. PHARMACOL BIOCHEM BEHAV 64(1) 123–130, 1999.—Dopamine seems to play a very important role in aggressive behavior observed in morphine withdrawal. The effect of SCH 23390 (0.5 mg/kg), raclopride (0.3 mg/kg), and haloperidol (0.1 mg/kg) on morphine withdrawal-induced aggression has been studied in this work. Mice were rendered dependent by a daily injection of morphine (2.5 mg/kg) for 14 days. Three different experiments were carried out with the objective to evaluate the antiaggressive effect of the dopamine antagonists o…
Role of central oxytocin in the inhibition by endotoxin of distension-stimulated gastric acid secretion
2000
The gastric acid hyposecretory state associated with endotoxemia is mediated by a nervous reflex involving the central nervous system. The aim of the present study was to analyse the central effects of different peptides on distension-stimulated gastric acid secretion and the endogenous role of such peptides on the hyposecretory effects of endotoxin. The effect of an intracisternal (i.c.) administration of oxytocin, vasopressin, corticotropin releasing factor (CRF), bombesin, somatostatin and the opioid receptor agonist BW443C or an intravenous (i.v.) injection of a small dose of endotoxin on distension-stimulated gastric acid secretion was studied in the continuously perfused stomach of an…
Gene Transcription Alterations Associated with Decrease of Ethanol Intake Induced by Naltrexone in the Brain of Wistar Rats
2006
Preclinical and clinical studies suggest that the administration of the opioid antagonist naltrexone decreases the intake of ethanol. However, the neuroplastic adaptations in the brain associated to reduction of ethanol consumption remains to be elucidated. The aim of the study was to identify gene transcription alterations underlying the attenuation of voluntary ethanol intake by administration of naltrexone in rats. Increasing doses of naltrexone (0.7 mg/kg, 4 days and 1.4 mg/kg/day, 4 days) to rats with acquired high preferring ethanol consumption (>3.5 g of ethanol/kg/day) decreased voluntary ethanol intake (50%). Voluntary ethanol consumption altered mu-opioid receptor function in the …