The expression of mRNAs for the glial glutamate transporters, GLT-1 and GLAST, in the rat brain accompanied with morphine dependence and naloxone-precipitated withdrawal was investigated by Northern blot analysis. The expression of GLT-1 mRNA was significantly decreased in the striatum and thalamus of morphine-dependent rats, and significantly increased in the striatum 2 h after the naloxone-pr...

Introduction: It has been shown that orexin peptides have a role in opioid withdrawal behaviors. Orexin-expressing neurons that are present in the hypothalamic nuclei send dense projections to the Locus Coeruleus (LC). Withdrawal syndrome is temporally associated with hyperactivity of LC neurons. However, LC neurons do not show withdrawalinduced hyperactivity in the brain slices from morphin...

Although morphine induces both analgesia and dependence through mu-opioid receptors (MORs), the respective contributions of the intracellular effectors engaged by MORs remain unknown. To examine the contribution of G-protein-gated inwardly rectifying K(+) (GIRK, Kir3) channels to morphine dependence and analgesia, we quantified naloxone-precipitated withdrawal behavior and morphine analgesia us...

background: chronic administration of morphine cause physical dependence but the exact mechanism of this phenomenon remains unclear. the aim of this study is the assessment of systemic and intracerebroventricular (icv) administration of ramelteon (a melatonin receptor agonist) on morphine physical dependence. methods: 88 adult male rats were divided into 2 major groups, namely “systematic” and ...

AIMS The current study assessed the in vivo antagonist properties of nalmefene using procedures previously used to characterize the opioid antagonists naloxone, naltrexone, 6beta-naltrexol and nalbuphine. MAIN METHODS ICR mice were used to generate antagonist dose-response curves with intraperitoneal (i.p.) nalmefene against fixed A(90) doses of morphine in models of morphine-stimulated hyper...

Previous pharmacological studies have implicated serotonergic brain systems in opiate withdrawal syndrome. Increased brain 5-HT release is associated with the development of physical dependence to morphine. Specific serotonin reuptake inhibitors, such as fluvoxamine and sertraline reduce the severity of naloxone precipitated opioid withdrawal syndrome. Other studies have shown that 5-HT system ...

There are very few studies that examine the effects that morphine withdrawal has on immune functioning, and of these even fewer describe the mechanisms by which withdrawal brings about these changes. Our previous work demonstrated that morphine withdrawal contributed to Th cell differentiation by biasing cells toward the Th2 lineage. A major finding from these studies was that IL-12 was decreas...

Physical dependence on morphine is evidenced by the withdrawal syndromes, including body weight loss, which are induced by the discontinuation of morphine exposure or by the treatment with naloxone, an opioid receptor antagonist. The present study was designed to examine whether the elevation of serum corticosterone (SCS) level induced by naloxone-precipitated morphine withdrawal was a useful i...

The increasing prescription of opioids is fueling an epidemic of addiction and overdose deaths. Morphine is a highly addictive drug characterized by a high relapse rate - even after a long period of abstinence. Serotonin (5-HT) neurotransmission participates in the development of morphine dependence, as well as the expression of morphine withdrawal. In this study, we examined the effect of bloc...

The effects of Hypericum perforatum (St John's wort) on morphine withdrawal syndrome and comparison with clonidine have been investigated in morphine-dependent rats. Adult male Wistar rats were subjects. The frequencies of withdrawal behavioral signs (rearing, teeth chattering and jumping) induced by naloxone challenge were demonstrated in morphine dependent rats receiving Hypericum perforatum ...