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...

The Food and Drug Administration (FDA) first approved naloxone in 1971 as an injection (Narcan) for reversing opioid intoxication or overdose. Although the brand-name version has been discontinued, generic versions of naloxone have been available since 1985, and today injections are available in two doses (0.4 mg per milliliter and 1 mg per milliliter; see table below. Recent and Current Prices...

Human diabetes mellitus is characterized by impaired insulin response to intravenous glucose. In search of possible factors which impair insulin release, we have investigated the effect of naloxone, a specific opiate receptor blocker, on insulin responses to glucose in subjects with non-insulin-dependent diabetes, as well as in normal subjects. Naloxone was given as a priming dose of 0.4 mg fol...

The possibility of developing a hormone-based test to predict libido was evaluated using the response of LH and testosterone to naloxone. This test has been used to identify sexually active and inactive mature rams during the breeding season. The objective of this study was to determine whether the blood test could be used to detect differences in sexual activity of early postpubertal (29 +/- 0...