Using quantitative receptor autoradiography, [3H]D-Ala-D-Leu-enkephalin (DADL) and [3H]naloxone binding were studied in rat striatum and striatal projection areas (globus pallidus (GP) and substantia nigra pars reticulata (SNr] after unilateral striatal kainic acid lesions. [3H]DADL and [3H]naloxone binding were each examined by two methods. Initially, [3H]DADL binding was performed in 50 mM Tr...

Experiment 1: It is well known that the social context powerfully influences behaviour. Here we examine whether it also influences drug-seeking. Further, acamprosate and naloxone have been discussed to affect different types of craving: acamprosate was reported to affect withdrawalcraving, while naloxone affects reward-craving. Conditioned drug-seeking was modelled using the conditioned place p...

BACKGROUND Opioid overdose is a leading cause of death among injection drug users. Over half of injection drug users report at least one nonfatal overdose during their lifetime. Death from opioid overdose rarely occurs instantaneously, but rather over the course of one to three hours, allowing ample time for providing life-saving measures. In response to the prevalence of overdoses in the U.S.,...

The effectiveness of naloxone and nalorphine in antagonizing the effects of fentanyl and droperidol on the hot plate reaction time and the respiratory rate of the mouse has been compared. Naloxone was superior to nalorphine, being a more effective antagonist, and was also free from significant agonist effects. However, neither antagonist was completely effective against the respiratory rate dep...

INTRODUCTION This randomized, cross-over, double-blind, controlled study of continuous intrathecal morphine administration in patients with severe, long-term pain addresses whether the supplementation of low doses of naloxone in this setting is associated with beneficial clinical effects. METHODS All of the study subjects (n=11) provided informed consent and were recruited from a subset of pa...

Nalbuphine, an agonist-antagonist kappa-opioid, produces brief analgesia followed by enhanced pain/hyperalgesia in male postsurgical patients. However, it produces profound analgesia without pain enhancement when co-administration with low dose naloxone. To examine the effect of nalbuphine or nalbuphine plus naloxone on activity in brain regions that may explain these differences, we employed p...

The role of opioid receptors in infant-mother attachment has been well established. Morphine, a preferential μ opioid receptor (MOR) agonist, attenuates separation distress vocalizations and decreases physical contact between infant and mother. However, there is little research on how opioid receptors are involved in adult attachment. The present study used the monogamous titi monkey (Callicebu...

Endogenous opioid regulation of neurohypophysial and hypothalamo-pituitary-adrenal (HPA) axis hormone secretion in response to forced swimming (90 s in deep water at 19 degrees C) was investigated in virgin and 21-day-pregnant rats. There was no difference in basal plasma oxytocin concentrations between pregnant and virgin rats, but the opioid antagonist, naloxone, increased basal oxytocin secr...

Electric footshock elicited an immediate burst of activity followed by a period of immobility termed freezing. Naloxone, an opiate antagonist, enhanced both of these postshock reactions (Experiment 1). Naloxone's effects on the active and inactive components of the postshock reaction paralleled those of increasing shock intensity (Experiment 2). This finding suggests that the drug caused these ...

Two experiments tested the effects of opioid receptor blockage on behavior. In Experiment 1, rats reinforced for lever pressing with either sucrose or food pellets received treatment with saline, 2, and 10 mg/kg naloxone, i.p. (within-subject design). Naloxone 10 mg/kg increased response latency, but 2 mg/kg had no effect. When shifted to extinction (between-group design), naloxone (2 and 10 mg...