An unbiased conditioned place preference (CPP) paradigm was used to evaluate the reward effects of endogenous mu-opioid receptor ligands endomorphin-1 (EM-1) and endomorphin-2 (EM-2) from the mesolimbic posterior nucleus accumbens (Acb) shell and the ventral tegmental area (VTA) in CD rats. EM-1 (1.6-8.1 nmol) microinjected into posterior Acb shell produced CPP, whereas EM-2 (8.7-17.5 nmol) giv...

introduction: nitric oxide (no) is a neuronal messenger molecule in the central nervous system, which is generated from l-arginine by nitric oxide synthase (nos) and involves in many important opioid-induced effects. our previous studies revealed that cuminum cyminum interestingly reduces morphine sensitization, tolerance and dependency in male mice. therefore, in the present study, the effect ...

The monoamine transporters are the main targets of psychostimulant drugs, including methamphetamine (METH) and cocaine. Interestingly, the rewarding effects of cocaine are retained in dopamine transporter (DAT) knockout (KO) mice, while serotonin transporter (SERT) and DAT double KO mice do not exhibit conditioned place preference (CPP) to cocaine. These data suggest that SERT inhibition decrea...

Concurrent use of cocaine and heroin is a major public health issue with no effective relapse prevention treatment currently available. To this purpose, a combination of buprenorphine and naltrexone, a mixed very-low efficacy mu-opioid receptor agonist/kappa-opioid receptor antagonist/nociceptin receptor agonist, was investigated. The tail-withdrawal and the conditioned place preference (CPP) a...

Background In our previous experiments a trend to sensitisation to maternal behavioural disruptive and conditioned place preference (CPP)-inducing effects of morphine (MO) was observed when rat dams were treated chronically with a constant medium dose of MO during pregnancy and lactation. The aim of the present work was to perform more detailed studies how chronic MO treatment of dams influence...

nucleus accumbens (nac) has been considered as a center for the induction of drug dependence. since a high concentration of the enzyme, nitric oxide synthase (nos) has been found in the nac, and this fact that the role of nitric oxide (no) in acquisition and expression of drug dependence has become clear in recent years, therefore in this study the effects of intraaccumbal injections of l-argin...

d-Cycloserine, a partial NMDA agonist, significantly accelerated extinction of a cocaine-induced conditioned place preference (CPP) when rats were given systemic injections immediately, but not 4h, after each extinction trial. Infusions directly into the basolateral amygdala had a similar effect. The facilitative effect of d-cycloserine on the extinction of appetitive conditioning is consistent...

Association between the reward caused by consuming drugs and the context in which they are consumed is essential in the formation of morphine-induced conditioned place preference (CPP). Glucocorticoid receptor (GRs) activation in different regions of the brain affects reward-based reinforcement and memory processing. A wide array of studies have demonstrated that blockage of GRs in some brain a...

Repeated exposure to drugs of abuse produces forms of experience-dependent plasticity including behavioral sensitization. Although a single exposure to many addicting substances elicits locomotor sensitization, there is little information regarding the motivational effects of such single exposures. This study demonstrates that a single cocaine exposure enhances both rewarding and aversive forms...

Reactivation of memories may render them labile and subject to disruption by amnestic drugs thus reducing their impact on future behavior, but whether it is possible with well-established memories is not known. Here we examined the effect of two amnestic agents on reconsolidation of a conditioned place preference (CPP) for morphine when memory strength and memory age were varied. In a three-com...