The partial opioid agonist thienorphine is currently in Phase II clinical trials in China as a candidate drug for the treatment of opioid dependence. However, its effect on synaptic plasticity in the NAc (nucleus accumbens) remains unclear. In the present study, we measured structural parameters of the synaptic interface to investigate the effect of thienorphine, morphine or a combination of bo...

Opiate withdrawal is followed by a protracted abstinence syndrome consisting of craving and physiological changes. However, few studies have been dedicated to both the characterization and understanding of these long-term alterations in post-dependent subjects. The aim of the present study was to develop an opiate dependence model, which induces long-lasting behavioral changes in abstinent rats...

BACKGROUND Methadone is widely accepted as the most effective treatment of opioid dependence. However, clinical observations indicate that the medication is less effective in individuals abusing cocaine. Diminished therapeutic efficacy of methadone in cocaine users is intriguing, but its mechanism has not been studied. METHODS Here, the conditioned place preference (CPP) procedure was used to...

Using a food-reinforced two-lever operant procedure, rats were trained to discriminate 0.04 mg/kg fentanyl from saline. At different time intervals after the establishment of discriminative responding, stimulus generalization experiments were performed with equivalent dose ranges of fentanyl (0.0025 to 0.02 mg/kg) and morphine (2.5 to 20 mg/kg). It was found that the ED50 values of both compoun...

background and objective: traditional iranian medicine (tim) has a long history in the field of diagnosis and treatment of various diseases, particularly addiction. different therapeutic methods have been recommended in this respect. one of these methods is the replacement of natural narcotics instead of opium. hab-o shefa is a natural product of tim which has been used as an alternative for op...

Opiates are potent analgesic and addictive compounds. They also act on immune responses, and morphine, the prototypic opiate, has been repeatedly described as an immunosuppressive drug. Pharmacological studies have suggested that the inhibitory action of opiates on immunity is mediated by multiple opioid receptor sites but molecular evidence has remained elusive. Recently, three genes encoding ...

Stress induces the release of the peptide corticotropin-releasing factor (CRF) into the ventral tegmental area (VTA), and also increases dopamine (DA) levels in brain regions receiving dense VTA input. Since the role of stress in drug addiction is well established, the present study examined the possible involvement of CRF1 receptor in the interaction between morphine withdrawal and catecholami...

The nucleus accumbens (NAc) plays a crucial role in addiction. We have recently shown that activation of presynaptic metabotropic glutamate 2/3 receptors (mGlu2/3) induces long-term depression (LTD) at glutamatergic synapses in the mouse nucleus accumbens (NAc) through the long lasting inhibition of P/Q-type Ca2+ channels and the cAMP/protein kinase A (PKA) pathway. Because presynaptic mGlu2/3 ...

Methadone is clinically effective as substitution therapy in patients with opioid dependence. The diversity of methadone and morphine in their intracellular activity is postulated. We compared the effects of repeated daily treatment of Sprague-Dawley rats with morphine (10 mg/kg) and methadone (1 mg/kg) on the expression of the Gα(i1-i3) mRNAs in several rat brain areas using RT-qPCR. We found ...

OBJECTIVE We aimed to assess the positive percentages of urine morphine tests and correlates among methadone maintenance treatment (MMT) clients with HIV/AIDS in Guangdong, China. SETTING Fourteen MMT clinics located in nine cities of Guangdong were chosen as study sites. PARTICIPANTS In this study, we reviewed 293 clients with opioid dependence, who were HIV seropositive, 18 years or older...