Alterations of prodynorphin gene expression in the rat mesocorticolimbic system during heroin self-administration.

Opiate-induced alterations in the gene expression of the opioid propeptides prodynorphin (PDYN) and proenkephalin (PENK) in the brain have previously been described. However, there are no studies examining opioid propeptide system alterations due to long-lasting heroin self-administration. In our study, using in situ hybridization, we measured PDYN and PENK mRNA levels in the dorsal striatum, central nucleus of amygdala (CEA), and nucleus accumbens (NAcc) shell and core in rats after 6 weeks of heroin self-administration (fixed ratio 5, 0.

Increased analgesic tolerance to acute morphine in fosB knock-out mice: a gender study.

The proteins of Fos family are a potential candidate to link molecular mechanisms of morphine action with behavioural effects such as morphine-induced reward, dependence and tolerance. We used both male and female mice lacking fosB gene to study its contribution to morphine effects. Morphine analgesia (tail-flick test) and hypothermia were studied using morphine at cumulative doses in morphine-naive and morphine-tolerant (tolerance induced by 24 h prior 100 mg/kg morphine administration) mice.

alpha-Synuclein expression in the brain and blood during abstinence from chronic alcohol drinking in mice.

alpha-Synuclein is a presynaptic protein proposed to serve as a negative regulator of dopaminergic neurotransmission. Recent research has implicated alpha-synuclein in chronic neuroadaptations produced by psychostimulant and opiate use, as well as in genetically determined susceptibility to alcoholism in humans. The aim of our study was to characterize the changes in alpha-synuclein expression after short-term abstinence from chronic alcohol drinking in mice.

Role of fosB in behaviours related to morphine reward and spatial memory.

The immediate early genes (IEGs) have been suggested to be implicated in mechanisms of addiction, as well as in learning and memory processes. fosB, which belongs to IEG, has been reported to have pleiotropic impact on response to psychoactive drugs, as well as motivational and stress-related behaviours. In the present study, we used mice with constitutive knock-out of fosB in order to study fosB role in mouse phenotype.

Role of opioidergic mechanisms and GABA uptake inhibition in the heroin-induced discriminative stimulus effects in rats.

The present study was designed to investigate the involvement of opioidergic component as well as to study GABAergic mechanisms in the expression of heroin discrimination. Male Wistar rats were trained to discriminate heroin (0.5 mg/kg, i.