The conditioned place preference (CPP) induced by increasing doses (1.25–40 mg/kg) of cocaine or the specific dopamine uptake inhibitor GBR12783 was investigated in rats previously treated with cocaine (10 or 20 mg/kg), GBR12783 (10 mg/kg) or morphine (10 mg/kg) for 15 days. In solvent-pretreated rats, cocaineand GBR12783-induced CPPs were biphasic, with the highest scores observed at 20 mg/kg....

Morphine pretreatment attenuates aversive taste reactions elicited by quinine solution when assessed by the taste reactivity test. To determine whether this effect changes across trials, rats were administered morphine (2 mg/kg, subcutaneously) 30 min before a 5-min intraoral infusion of quinine solution (0.05%) on each of eight trials. Neither tolerance nor sensitization developed to morphine-...

The initial aim of this study was to identify protein changes associated with long-term morphine treatment in a recombinant human neuroblastoma SH-SY5Y clone (sc2) stably overexpressing the human mu-opioid (MOP) receptor. In MOP receptor-overexpressing sc2 cells, short-term morphine exposure was found to be much more potent and efficacious in inhibiting forskolin-elicited production of cAMP, an...

BACKGROUND Currently approved medications for opioid addiction have shown clinical efficacy, but undesired side effects, dependence induced by the medications themselves, and low treatment compliance necessitate the need for novel therapies. METHODS A novel morphine-keyhole limpet hemocyanin conjugate vaccine was synthesized with 6-glutarylmorphine as the hapten and a lengthened linker of 6 c...

BACKGROUND The chronic use of opioids prior to surgery leads to lowered pain thresholds and exaggerated pain levels after these procedures. Several mechanisms have been proposed to explain this heightened sensitivity commonly termed opioid-induced hyperalgesia (OIH). Most of these proposed mechanisms involve plastic events in the central or peripheral nervous systems. Alterations in the abundan...

Neuroplasticity in the mesolimbic dopaminergic system is critical for behavioral adaptations associated with opioid reward and addiction. These processes may be influenced by cholinergic transmission arising from the laterodorsal tegmental nucleus (LDTg), a main source of acetylcholine to mesolimbic dopaminergic neurons. To examine this possibility we asked if chronic systemic morphine administ...

The brain's noradrenergic system is involved in the development of behaviours induced by drugs of abuse, e.g. dependence and withdrawal, and also reward or psychomotor effects. To investigate how noradrenergic system activity is controlled in the context associated with drug-induced behaviours, we generated a Cre/loxP mouse model in which the essential glutamate NMDA receptor subunit NR1 is abl...

In mammals, rewarding properties of drugs depend on their capacity to activate appetitive motivational states. With the underlying mechanisms strongly conserved in evolution, invertebrates have recently emerged as a powerful new model in addiction research. In crayfish natural reward has proven surprisingly sensitive to human drugs of abuse, opening an unlikely avenue of research into the basic...

Nazari Z1, Sahraei H2, Sadoughi M3 1. MSc in Animal Biology (physiology trend), Lorestan Education Organization, Khorramabad, Iran 2. Assistant Professor, Department of Physiology, Faculty of Medicine, Baghyatallah University of Mesical Sciences, Tehran, Iran 3. Assistant Professor, Department of Biology, Faculty of Science, North Tehran Branch, Islamic Azad University, Tehran, Iran Abstract ...

introduction: regulators of g-protein signaling protein negatively control g protein -coupled receptor signaling duration by accelerating gα subunit guanosine triphosphate hydrolysis. since regulator of g-protein signaling4 has an important role in modulating morphine effects at the cellular level and the exact mechanism(s) of adrenalectomy-induced morphine sensitization have not been fully cla...