the mechanisms of drug dependence and rewarding properties of opiates are not exactly known and several neurotransmitters seem to be involved. it is possible that the rennin-angiotensin system could interact with the opioid system, since it has been shown that angiotensin ii(ang) and ace inhibitors have analgesic, anticonvulsant and antidepression effects and in some cases they could antagonize...

The role of stress in drug addiction is well established. The negative affective states of withdrawal most probably involve recruitment of brain stress neurocircuitry [e.g., induction of hypothalamo-pituitary-adrenocortical (HPA) axis, noradrenergic activity, and corticotropin-releasing factor (CRF) activity]. The present study investigated t$he role of CRF receptor-1 subtype (CRF1R) on the res...

Opioid-related constipation is one of the most frequent side effects of chronic pain treatment. Enteral administration of naloxone blocks opioid action at the intestinal receptor level but has low systemic bioavailability due to marked hepatic first-pass metabolism. The aim of this study was to examine the effects of oral naloxone on opioid-associated constipation in an intraindividually contro...

Noradrenergic neurons of the brain nucleus locus coeruleus (LC) become hyperactive during opiate withdrawal. It has been uncertain to what extent such hyperactivity reflects changes in intrinsic properties of these cells. The effects of withdrawal from chronic morphine on the activity of LC neurons were studied using intracellular recordings in rat brain slices. LC neurons in slices from chroni...

The present study assessed the ability of various site-selective N-methyl-D-aspartate (NMDA) receptor antagonists to affect the discriminative stimulus properties of naloxone in morphine-dependent rats. Adult male Wistar rats were trained to discriminate 0.1 mg/kg of s.c. naloxone from saline using a Y-maze shock-avoidance procedure. Naloxone-appropriate responding was exhibited as a function o...

OBJECTIVE  Assess whether patients with chronic pain receiving 80 to 220 mg oral morphine sulfate equivalent of a full Μ: -opioid agonist could be transitioned to buccal buprenorphine at approximately 50% of their full dose without inducing opioid withdrawal or sacrificing analgesic efficacy. METHODS  A randomized, double-blind, double-dummy, active-controlled, two-period crossover study in a...

Physician adoption of buprenorphine treatment of opioid dependence may be limited in part by concerns regarding the induction process. Although national guidelines recommend observed induction, some physicians utilize unobserved induction outside the office. The aim of this pilot randomized clinical trial was to assess preliminary safety and effectiveness of unobserved versus observed office bu...

Single-cell activity was recorded in the locus coeruleus (LC) of morphine-dependent, halothane-anesthetized rats. Systemic administration of the opiate antagonist naloxone (0.1 mg/kg, i.v.) robustly increased the activity of LC neurons. Local microinjection of naloxone or of its hydrophilic derivative, naloxone methiodide, into LC (10 mM, 20-40 nl) did not activate LC neurons in dependent rats....

objective: withdrawal symptoms are a main reason of continuous use of opioid. this study compares the efficacy of augmentation of amantadine with clonidine in decreasing opioid withdrawal symptoms. methods: this double-blind randomized clinical trial was carried out in the detoxification and rehabilitation inpatient ward at razi hospital, tabriz, iran during 2012. the patients were randomly ass...

AIMS The current study assessed the in vivo antagonist properties of nalmefene using procedures previously used to characterize the opioid antagonists naloxone, naltrexone, 6beta-naltrexol and nalbuphine. MAIN METHODS ICR mice were used to generate antagonist dose-response curves with intraperitoneal (i.p.) nalmefene against fixed A(90) doses of morphine in models of morphine-stimulated hyper...