the catastrophic effects of opioids use on public health and the economy are documented clearly in numerous studies. repeated morphine administration can lead to either a decrease (tolerance) or an increase (sensitization) in its behavioral and rewarding effects. morphine-induced sensitization is a major problem and plays an important role in abuse of the opioid drugs. studies reported that mor...

Inhibition of primary afferent neurons contributes to the antihyperalgesic effects of opioid and CB1 receptor agonists. Two bioassays were used to compare the effects of the CB1 receptor agonist CP 55,940 and morphine on dissociated adult rat DRG neurons. Both agonists inhibited the increase in free intracellular Ca2+ concentration evoked by depolarization; however, effects of CP 55,940 occurre...

The aim of the study was to evaluate changes in the opioid receptor binding (mu, delta and kappa) in the hypothalamus, anterior pituitary and adrenal cortex (HPA) of lambs treated in vivo with corticotrophin releasing hormone (CRH), naltrexone, an opioid receptor antagonist (NAL), and dexamethasone, a potent cortisol analog (DEX). Experiment was carried out on 3 months old female lambs of polis...

In order to gain insight into a possible modulatory role for mu, delta, and kappa opioid receptors of the nigrostriatal dopaminergic pathway, we investigated the topographical organization of the receptors with respect to pre- and postsynaptic membranes. Dopaminergic terminals projecting from the substantia nigra to the corpus striatum were destroyed by unilateral injection of 6-hydroxydopamine...

OBJECTIVES Prescription opioid medications are the most commonly implicated substances in unintentional overdoses. Outpatient health care encounters represent a potential opportunity to intervene to reduce opioid overdose risk. This study assessed the timing and type of outpatient provider contacts prior to death from unintentional prescription opioid overdose. METHODS This study examined all...

Introduction: The neuroprotective role of opioid morphine against 6-hydroxydopamineinduced cell death has been demonstrated. However, the exact mechanism(s) underlying such neuroprotection, especially the role of subtype receptors, has not yet been fully clarified. Methods: Here, we investigated the effects of different opioid agonists on 6-OHDA-induced neurotoxicity in human neuroblastoma...

Two highly selective mu-opioid receptor agonists, endomorphin-1 and endomorphin-2, have been identified and postulated to be endogenous mu-opioid receptor ligands. We determined the antinociceptive effects of these two ligands at the supraspinal level in mice with the tail-flick and hot-plate responses. The i.c.v. injection of endomorphin-1 and -2 inhibited the tail-flick and hot-plate response...

background:naltrexone is a competitive opioid receptor antagonist blocking the euphoric effects of exogenous opioids. when used concomitantly with opioids, naltrexone causes severe withdrawal symptoms.the main aim of the study is to determine the symptomatology and outcome of patients who consumed naltrexone in conjunction with an opioid substance. methods:this cross-sectional study was perform...

The discovery of the opioid receptors began in the 1970s and three (μ, δ and κ) are now recognised. Most current opioid analgesics interact preferentially with μ receptors, although some have actions at δ and κ receptors. The revelation that opioid receptors are present on peripheral sensory neurones and immune system cells, has led to the realisation that the opioid system is involved in a hos...

opioids are widely used for the treatment of malignant and non-malignant pains. these medications are accompanied by adverse effects, in particular gastrointestinal symptoms known as opioid bowel dysfunction (obd). the most common symptom of obd is refractory constipation that is usually stable regardless of the use of laxatives. narcotic bowel syndrome (nbs) is a subset of obd described as amb...