Acute and repeated cocaine induces alterations in FosB/DeltaFosB expression in the paraventricular nucleus of the hypothalamus.

Apart from activation of the brain reward system, cocaine administration influences the activity of the hypothalamo-pituitary-adrenal (HPA) axis by affecting CRH neurons in the paraventricular nucleus of the hypothalamus (PVN). In order to find a molecular mechanism of cocaine-evoked effects in the PVN, in the present study, we investigated the impact of cocaine on the expression of FosB/DeltaFosB transcription factors in the PVN. Using an immunohistochemical method, we found that acute cocaine treatment (25 mg/kg) induced a relatively long-lasting (at least 72 h) expression of FosB/DeltaFosB in the PVN, whereas repeated cocaine administration (25 mg/kg, once daily for 5 consecutive days) caused accumulation of FosB/DeltaFosB in the PVN.

A competitive antagonist of NMDA receptors CGP 40116 attenuates experimental symptoms of schizophrenia evoked by MK-801.

In the present study, the interaction between a noncompetitive [(+)-MK-801] and a competitive (CGP 40116) NMDA receptor antagonists was tested in two different behavioral paradigms: locomotor activity test and prepulse inhibition of the acoustic startle reflex. Additionally, their effects on working memory and selective attention were evaluated in the delayed alternation task. All above paradigms served to model the symptoms of schizophrenia.

Role of glucocorticoids in the regulation of dopaminergic neurotransmission.

Several lines of evidence indicate that exposure to various types of stressors, or stress hormones may increase or induce sensitization to psychostimulants or enhance susceptibility of experimental animals to the effects of abusing substances. In order to find out what is a biological substrate of the above phenomenon, we investigate the impact of stress hormones on the dopaminergic neurotransmission. It is postulated, first, that corticosterone, an important stress hormone, regulates the dopaminergic neurotransmission at the level of dopamine D-1 receptors.

Different pattern of brain c-Fos expression following re-exposure to ethanol or sucrose self-administration environment.

Exposure of alcohol addicts to alcohol-related environmental cues may elicit alcohol-seeking behavior and lead to relapse to heavy drinking. The aim of the present study was to identify brain regions activated by alcohol (ethanol)-related stimuli in Wistar rats trained to lever press for 8% ethanol solution in operant self-administration cages. Ethanol self-administration was stabilized in a maintenance phase, which lasted for 30 days.

Serotonin 5-HT1A receptors might control the output of cortical glutamatergic neurons in rat cingulate cortex.

The present study was designed to investigate the distribution of serotonin 5-HT1A receptor protein (5-HT1A-immunoreactivity) and its localization within cortical pyramidal neurons of the rat cingulate cortex. This experimental direction was inspired by recent data showing the role of 5-HT1A receptors in the pathology of schizophrenia, and in the mechanism of action of novel antipsychotic drugs as well as by the importance of the cingulate cortex in regulation of cognitive functions. It was found that 5-HT1A-immunoreactivity was densely distributed in neuronal eyelash-like elements, and their size, shape and spatial orientation may suggest concentration of 5-HT1A-immunopositive material in the proximal fragments of axons of cortical neurons.

Prolonged corticosterone treatment alters the responsiveness of 5-HT1A receptors to 8-OH-DPAT in rat CA1 hippocampal neurons.

Hippocampal 5-HT(1A) receptors have been shown to be suppressed by glucocorticoids in a variety of animal studies, however the molecular mechanism and the functional meaning of this effect are still not well understood. The present study was designed to investigate the impact of repeated administration of corticosterone (10 mg/kg s.c.

Inhibition of arachidonic acid cascade attenuates the induction of c-Fos proteins by DOI, 5-HT2A/2C receptor agonist, in the rat cortex.

Previous immunohistochemical studies have shown that c-Fos proteins induced by DOI, a 5-HT2A/2C agonist, are present in the population of cortical neurons, which are devoid of 5-HT2A receptors. A mechanism of the induction of c-Fos proteins expression by DOI is still unclear. However, the involvement of the 5-HT2A and AMPA, but not 5-HT2C receptors in this process has been reported.