Rats show gender differences in responses to morphine and the N-methyl-D-aspartate receptor antagonist dizocilpine (MK-801); the role of sex steroids in mediating these differences is unclear. We tested the overall hypothesis that circulating gonadal steroids determine the gender differences in morphine- and MK-801-induced behavior and c-Fos expression. Morphine caused a greater expression of c...

Since their discovery, miRNAs have emerged as a promising therapeutical approach in the treatment of several diseases, as demonstrated by miR-212 and its relation to addiction. Here we prove that the miR-212/132 cluster can be regulated by morphine, through the activation of mu opioid receptor (Oprm1). The molecular pathways triggered after morphine administration also induce changes in the lev...

Gut-brain hormones such as ghrelin have recently been suggested to have a role in reward regulation. Ghrelin was traditionally known to regulate food intake and body weight homoeostasis. In addition, recent work has pin-pointed that this peptide has a novel role in drug-induced reward, including morphine-induced increase in the extracellular levels of accumbal dopamine in rats. Herein the effec...

PURPOSE To examine oncologists' knowledge of cancer pain and morphine's clinical application in the People's Republic of China. In addition, this study analyzes and discusses the negative factors that currently affect the clinical application of morphine. PATIENTS AND METHODS A questionnaire survey was given to a random sample of 150 oncologists from Tianjin Medical University Cancer Institut...

Narcotics affect adenylate cyclase [ATP pyrophosphate-lyase (cyclizing), EC 4.6.1.1] in two opposing ways, both mediated by the opiate receptor. The first process is the readily reversible inhibition of the enzyme by narcotics; the second is a compensatory increase in enzyme activity which is delayed in onset and relatively stable. Late positive regulation of the enzyme counteracts the inhibito...

In this study, we analyzed the efficacy and feasibility of a community-based integrated heroin addiction treatment model in Chinese patients. The 210 heroin addicts belonging to six Chinese communities received an integrated biopsychosocial intervention that included pharmacological treatment, counseling and social assistance. High proportions of study participants were retained at the 12-month...

BACKGROUND A difficult problem in treating opioid addicts is the maintenance of a drug-free state because of the negative emotional symptoms associated with withdrawal, which may trigger relapse. Several lines of evidence suggest a role for the metabotropic glutamate receptor 5 in opioid addiction; however, its involvement during opioid withdrawal is not clear. METHODS Mice were treated with ...

Morphine induces adaptive changes in gene expression throughout the reward circuitry of brain. Recent research has proven the functional interactions between opioid and endogenous cannabinoid system in the central nervous system (CNS). The cannabinoid receptor 1 (CB1-R) is one of the receptors that mediate the actions of cannabinoids and endocannabinoids in the CNS. Here, we investigated the ex...

Mitogen-activated protein kinases (MAPK) can be activated by opioids such as morphine via opioid receptor, and their activations have been observed in synaptic plasticity, learning, memory and addiction. Long-term exposure to morphine may induce physical dependence, manifested as somatic withdrawal symptoms such as diarrhea, body weight loss, jumping and headshaking, when drug is deprived. Thou...