Opioid peptides long have been hypothesized to play a role in ethanol reinforcement. Neuropharmacological studies have shown that opioid receptor antagonists decrease ethanol selfadministration in rodents and prevent relapse in humans. However, the exact mechanism for such powerful effects has remained elusive. The availability of m-opioid receptor knockout mice has made possible the direct exa...

Agonist-induced receptor phosphorylation is an initial step in opioid receptor desensitization, a molecular mechanism of opioid tolerance and dependence. Our previous research suggested that agonist-induced delta-opioid receptor (DOR) phosphorylation occurs at the receptor carboxyl terminal domain. The current study was carried out to identify the site of DOR phosphorylation during agonist stim...

Salvia divinorum is a natural occurring hallucinogen that is traditionally used by the Mazatec Indians of central Mexico. The diterpene salvinorin A was identified as an active component of S. divinorum over 20 years ago, but only recently has biochemical screening indicated that a molecular target of salvinorin A in vitro is the kappa-opioid receptor. We have examined whether salvinorin A, the...

Heroin administered i.c.v. acts on supraspinal mu opioid receptors in ICR mice but on delta receptors in Swiss Webster mice. The purpose of this study was to determine the degree to which genotype plays a role in the opioid receptor selectivity of heroin across a range of fully inbred strains of mice. Six inbred strains were given heroin i.c.v. 10 min before the tail-flick test. Differences in ...

Ozaki, Noriyuki, J. N. Sengupta, and G. F. Gebhart. Differential effects of m-, d-, and k-opioid receptor agonists on mechanosensitive gastric vagal afferent fibers in the rat. J. Neurophysiol. 83: 2209–2216, 2000. Single-fiber recordings were made from the decentralized right cervical vagus nerve (hyponodosal) of the rat. A total of 56 afferent fibers that responded to gastric distension (GD) ...

Anne Morinville,1,2 Catherine M. Cahill,2 M. James Esdaile,2 Haneen Aibak,2 Brian Collier,1 Brigitte L. Kieffer,3 and Alain Beaudet2 1Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec, Canada H3G 1Y6, 2Montréal Neurological Institute, McGill University, Montréal, Québec, Canada H3A 2B4, and 3Institute of Genetics and of Molecular and Cellular Biology, National Cen...

We have previously shown that cinnamoyl derivatives of 14β-amino-17-cyclopropylmethyl-7,8-dihydronormorphinone and 7α-aminomethyl-6,14-endoethanonororipavine have pronounced pseudoirreversible μ opioid receptor (MOR) antagonism. The present communication describes the synthesis and evaluation of fumaroylamino analogues of these cinnamoylamino derivatives together with some related fumaroyl deri...

BACKGROUND Mice lacking the mu-opioid receptor gene have been used to characterize the role of mu-opioid receptors in nociception and the analgesic actions of opioid agonists. In this study, the authors determined the role of mu-opioid receptors in neuropathic pain behaviors and the effectiveness of mu- and kappa-opioid receptor agonists on this behavior in mice. METHODS The authors studied t...

Constipation is frequently encountered in hospital settings and can have potentially serious consequences yet often underrecognized undertreated. Opioid-induced constipation a common cause of hospitalized patients. Opioids induce through agonistic effects on enteric µ-opioid receptors. This review aims to provide insight the identification management inpatient settings, with particular focus op...

Opioid drugs have powerful antidiarrheal effects and many patients taking these drugs for chronic pain relief experience chronic constipation that can progress to opioid-induced bowel dysfunction. Three classes of opioid receptors are expressed by enteric neurons: μ-, δ-, and κ-opioid receptors (MOR, DOR, and KOR). MOR and DOR couple to inhibition of adenylate cylase and nerve terminal Ca(2+) c...